<?php

static $registry = null;

// Error Handler
function error_handler_for_export_import($errno, $errstr, $errfile, $errline) {
	global $registry;
	
	switch ($errno) {
		case E_NOTICE:
		case E_USER_NOTICE:
			$errors = "Notice";
			break;
		case E_WARNING:
		case E_USER_WARNING:
			$errors = "Warning";
			break;
		case E_ERROR:
		case E_USER_ERROR:
			$errors = "Fatal Error";
			break;
		default:
			$errors = "Unknown";
			break;
	}
	
	$config = $registry->get('config');
	$url = $registry->get('url');
	$request = $registry->get('request');
	$session = $registry->get('session');
	$log = $registry->get('log');
	
	if ($config->get('config_error_log')) {
		$log->write('PHP ' . $errors . ':  ' . $errstr . ' in ' . $errfile . ' on line ' . $errline);
	}

	if (($errors=='Warning') || ($errors=='Unknown')) {
		return true;
	}

	$dir = version_compare(VERSION,'3.0','>=') ? 'extension' : 'tool';
	if (($errors != "Fatal Error") && isset($request->get['route']) && ($request->get['route']!="$dir/export_import/download"))  {
		if ($config->get('config_error_display')) {
			echo '<b>' . $errors . '</b>: ' . $errstr . ' in <b>' . $errfile . '</b> on line <b>' . $errline . '</b>';
		}
	} else {
		$session->data['export_import_error'] = array( 'errstr'=>$errstr, 'errno'=>$errno, 'errfile'=>$errfile, 'errline'=>$errline );
		$token = version_compare(VERSION,'3.0','>=') ? $request->get['user_token'] : $request->get['token'];
		$link = $url->link( "$dir/export_import", version_compare(VERSION,'3.0','>=') ? 'user_token='.$token : 'token='.$token, true );
		header('Status: ' . 302);
		header('Location: ' . str_replace(array('&amp;', "\n", "\r"), array('&', '', ''), $link));
		exit();
	}

	return true;
}


function fatal_error_shutdown_handler_for_export_import()
{
	$last_error = error_get_last();
	if (($last_error) && ($last_error['type'] === E_ERROR)) {
		// fatal error
		error_handler_for_export_import(E_ERROR, $last_error['message'], $last_error['file'], $last_error['line']);
	}
}


class ModelToolExportImport extends Model {

	private $error = array();
	protected $null_array = array();
	protected $use_table_seo_url = false;
	protected $posted_categories = '';
	protected $posted_manufacturers = '';
	protected $version = '4.13';


	public function __construct( $registry ) {
		parent::__construct( $registry );
		$this->use_table_seo_url = version_compare(VERSION,'3.0','>=') ? true : false;
	}


	protected function clean( &$str, $allowBlanks=false ) {
		$result = "";
		$n = strlen( $str );
		for ($m=0; $m<$n; $m++) {
			$ch = substr( $str, $m, 1 );
			if (($ch==" ") && (!$allowBlanks) || ($ch=="\n") || ($ch=="\r") || ($ch=="\t") || ($ch=="\0") || ($ch=="\x0B")) {
				continue;
			}
			$result .= $ch;
		}
		return $result;
	}


	protected function multiquery( $sql ) {
		foreach (explode(";\n", $sql) as $sql) {
			$sql = trim($sql);
			if ($sql) {
				$this->db->query($sql);
			}
		}
	}


	protected function startsWith( $haystack, $needle ) {
		if (strlen( $haystack ) < strlen( $needle )) {
			return false;
		}
		return (substr( $haystack, 0, strlen($needle) ) == $needle);
	}

	protected function endsWith( $haystack, $needle ) {
		if (strlen( $haystack ) < strlen( $needle )) {
			return false;
		}
		return (substr( $haystack, strlen($haystack)-strlen($needle), strlen($needle) ) == $needle);
	}


	protected function getDefaultLanguageId() {
		$code = $this->config->get('config_language');
		$sql = "SELECT language_id FROM `".DB_PREFIX."language` WHERE code = '$code'";
		$result = $this->db->query( $sql );
		$language_id = 1;
		if ($result->rows) {
			foreach ($result->rows as $row) {
				$language_id = $row['language_id'];
				break;
			}
		}
		return $language_id;
	}


	protected function getLanguages() {
		$query = $this->db->query( "SELECT * FROM `".DB_PREFIX."language` WHERE `status`=1 ORDER BY `code`" );
		return $query->rows;
	}


	protected function getDefaultWeightUnit() {
		$weight_class_id = $this->config->get( 'config_weight_class_id' );
		$language_id = $this->getDefaultLanguageId();
		$sql = "SELECT unit FROM `".DB_PREFIX."weight_class_description` WHERE language_id='".(int)$language_id."'";
		$query = $this->db->query( $sql );
		if ($query->num_rows > 0) {
			return $query->row['unit'];
		}
		$sql = "SELECT language_id FROM `".DB_PREFIX."language` WHERE code = 'en'";
		$query = $this->db->query( $sql );
		if ($query->num_rows > 0) {
			$language_id = $query->row['language_id'];
			$sql = "SELECT unit FROM `".DB_PREFIX."weight_class_description` WHERE language_id='".(int)$language_id."'";
			$query = $this->db->query( $sql );
			if ($query->num_rows > 0) {
				return $query->row['unit'];
			}
		}
		return 'kg';
	}


	protected function getDefaultMeasurementUnit() {
		$length_class_id = $this->config->get( 'config_length_class_id' );
		$language_id = $this->getDefaultLanguageId();
		$sql = "SELECT unit FROM `".DB_PREFIX."length_class_description` WHERE language_id='".(int)$language_id."'";
		$query = $this->db->query( $sql );
		if ($query->num_rows > 0) {
			return $query->row['unit'];
		}
		$sql = "SELECT language_id FROM `".DB_PREFIX."language` WHERE code = 'en'";
		$query = $this->db->query( $sql );
		if ($query->num_rows > 0) {
			$language_id = $query->row['language_id'];
			$sql = "SELECT unit FROM `".DB_PREFIX."length_class_description` WHERE language_id='".(int)$language_id."'";
			$query = $this->db->query( $sql );
			if ($query->num_rows > 0) {
				return $query->row['unit'];
			}
		}
		return 'cm';
	}


	protected function getManufacturers() {
		// find all manufacturers already stored in the database
		$manufacturer_ids = array();
		$sql  = "SELECT ms.manufacturer_id, ms.store_id, m.`name` FROM `".DB_PREFIX."manufacturer_to_store` ms ";
		$sql .= "INNER JOIN `".DB_PREFIX."manufacturer` m ON m.manufacturer_id=ms.manufacturer_id";
		$result = $this->db->query( $sql );
		$manufacturers = array();
		foreach ($result->rows as $row) {
			$manufacturer_id = $row['manufacturer_id'];
			$store_id = $row['store_id'];
			$name = $row['name'];
			if (!isset($manufacturers[$name])) {
				$manufacturers[$name] = array();
			}
			if (!isset($manufacturers[$name]['manufacturer_id'])) {
				$manufacturers[$name]['manufacturer_id'] = $manufacturer_id;
			}
			if (!isset($manufacturers[$name]['store_ids'])) {
				$manufacturers[$name]['store_ids'] = array();
			}
			if (!in_array($store_id,$manufacturers[$name]['store_ids'])) {
				$manufacturers[$name]['store_ids'][] = $store_id;
			}
		}
		return $manufacturers;
	}


	protected function storeManufacturerIntoDatabase( &$manufacturers, $name, &$store_ids, &$available_store_ids ) {
		foreach ($store_ids as $store_id) {
			if (!in_array( $store_id, $available_store_ids )) {
				continue;
			}
			if (!isset($manufacturers[$name]['manufacturer_id'])) {
				$this->db->query("INSERT INTO ".DB_PREFIX."manufacturer SET name = '".$this->db->escape($name)."', image='', sort_order = '0'");
				$manufacturer_id = $this->db->getLastId();
				if (!isset($manufacturers[$name])) {
					$manufacturers[$name] = array();
				}
				$manufacturers[$name]['manufacturer_id'] = $manufacturer_id;
			}
			if (!isset($manufacturers[$name]['store_ids'])) {
				$manufacturers[$name]['store_ids'] = array();
			}
			if (!in_array($store_id,$manufacturers[$name]['store_ids'])) {
				$manufacturer_id = $manufacturers[$name]['manufacturer_id'];
				$sql = "INSERT INTO `".DB_PREFIX."manufacturer_to_store` SET manufacturer_id='".(int)$manufacturer_id."', store_id='".(int)$store_id."'";
				$this->db->query( $sql );
				$manufacturers[$name]['store_ids'][] = $store_id;
			}
		}
	}


	protected function getWeightClassIds() {
		// find the default language id
		$language_id = $this->getDefaultLanguageId();
		
		// find all weight classes already stored in the database
		$weight_class_ids = array();
		$sql = "SELECT `weight_class_id`, `unit` FROM `".DB_PREFIX."weight_class_description` WHERE `language_id`=$language_id;";
		$result = $this->db->query( $sql );
		if ($result->rows) {
			foreach ($result->rows as $row) {
				$weight_class_id = $row['weight_class_id'];
				$unit = $row['unit'];
				if (!isset($weight_class_ids[$unit])) {
					$weight_class_ids[$unit] = $weight_class_id;
				}
			}
		}

		return $weight_class_ids;
	}


	protected function getLengthClassIds() {
		// find the default language id
		$language_id = $this->getDefaultLanguageId();
		
		// find all length classes already stored in the database
		$length_class_ids = array();
		$sql = "SELECT `length_class_id`, `unit` FROM `".DB_PREFIX."length_class_description` WHERE `language_id`=$language_id;";
		$result = $this->db->query( $sql );
		if ($result->rows) {
			foreach ($result->rows as $row) {
				$length_class_id = $row['length_class_id'];
				$unit = $row['unit'];
				if (!isset($length_class_ids[$unit])) {
					$length_class_ids[$unit] = $length_class_id;
				}
			}
		}

		return $length_class_ids;
	}


	protected function getLayoutIds() {
		$result = $this->db->query( "SELECT * FROM `".DB_PREFIX."layout`" );
		$layout_ids = array();
		foreach ($result->rows as $row) {
			$layout_ids[$row['name']] = $row['layout_id'];
		}
		return $layout_ids;
	}


	protected function getAvailableStoreIds() {
		$sql = "SELECT store_id FROM `".DB_PREFIX."store`;";
		$result = $this->db->query( $sql );
		$store_ids = array(0);
		foreach ($result->rows as $row) {
			if (!in_array((int)$row['store_id'],$store_ids)) {
				$store_ids[] = (int)$row['store_id'];
			}
		}
		return $store_ids;
	}


	protected function getAvailableProductIds(&$data) {
		$available_product_ids = array();
		$k = $data->getHighestRow();
		for ($i=1; $i<$k; $i+=1) {
			$j = 1;
			$product_id = trim($this->getCell($data,$i,$j++));
			if ($product_id=="") {
				continue;
			}
			$available_product_ids[$product_id] = $product_id;
		}
		return $available_product_ids;
	}


	protected function getAvailableCategoryIds() {
		$sql = "SELECT `category_id` FROM `".DB_PREFIX."category`;";
		$result = $this->db->query( $sql );
		$category_ids = array();
		foreach ($result->rows as $row) {
			$category_ids[$row['category_id']] = $row['category_id'];
		}
		return $category_ids;
	}


	protected function getCustomerGroupIds() {
		$sql = "SHOW TABLES LIKE \"".DB_PREFIX."customer_group_description\"";
		$query = $this->db->query( $sql );
		if ($query->num_rows) {
			$language_id = $this->getDefaultLanguageId();
			$sql  = "SELECT `customer_group_id`, `name` FROM `".DB_PREFIX."customer_group_description` ";
			$sql .= "WHERE language_id=$language_id ";
			$sql .= "ORDER BY `customer_group_id` ASC";
			$query = $this->db->query( $sql );
		} else {
			$sql  = "SELECT `customer_group_id`, `name` FROM `".DB_PREFIX."customer_group` ";
			$sql .= "ORDER BY `customer_group_id` ASC";
			$query = $this->db->query( $sql );
		}
		$customer_group_ids = array();
		foreach ($query->rows as $row) {
			$customer_group_id = $row['customer_group_id'];
			$name = $row['name'];
			$customer_group_ids[$name] = $customer_group_id;
		}
		return $customer_group_ids;
	}


	protected function getPostedCategories() {
		$posted_categories = '';
		if (isset($this->request->post['categories'])) {
			if (count($this->request->post['categories']) > 0) {
				foreach ($this->request->post['categories'] as $category_id) {
					$posted_categories .= ($posted_categories=='') ? '(' : ',';
					$posted_categories .= $category_id;
				}
				$posted_categories .= ')';
			}
		}
		return $posted_categories;
	}


	protected function getPostedManufacturers() {
		$posted_manufacturers = '';
		if (isset($this->request->post['manufacturers'])) {
			if (count($this->request->post['manufacturers']) > 0) {
				foreach ($this->request->post['manufacturers'] as $manufacturer_id) {
					$posted_manufacturers .= ($posted_manufacturers=='') ? '(' : ',';
					$posted_manufacturers .= $manufacturer_id;
				}
				$posted_manufacturers .= ')';
			}
		}
		return $posted_manufacturers;
	}


	protected function getCategoryUrlAliasIds() {
		$sql  = "SELECT url_alias_id, SUBSTRING( query, CHAR_LENGTH('category_id=')+1 ) AS category_id ";
		$sql .= "FROM `".DB_PREFIX."url_alias` ";
		$sql .= "WHERE query LIKE 'category_id=%'";
		$query = $this->db->query( $sql );
		$url_alias_ids = array();
		foreach ($query->rows as $row) {
			$url_alias_id = $row['url_alias_id'];
			$category_id = $row['category_id'];
			$url_alias_ids[$category_id] = $url_alias_id;
		}
		return $url_alias_ids;
	}


	protected function storeCategoryIntoDatabase( &$category, &$languages, $exist_meta_title, &$layout_ids, &$available_store_ids, &$url_alias_ids ) {
		// extract the category details
		$category_id = $category['category_id'];
		$image_name = $this->db->escape($category['image']);
		$parent_id = $category['parent_id'];
		$top = $category['top'];
		$top = ((strtoupper($top)=="TRUE") || (strtoupper($top)=="YES") || (strtoupper($top)=="ENABLED")) ? 1 : 0;
		$columns = $category['columns'];
		$sort_order = $category['sort_order'];
		$date_added = $category['date_added'];
		$date_modified = $category['date_modified'];
		$names = $category['names'];
		$descriptions = $category['descriptions'];
		if ($exist_meta_title) {
			$meta_titles = $category['meta_titles'];
		}
		$meta_descriptions = $category['meta_descriptions'];
		$meta_keywords = $category['meta_keywords'];
		if (!$this->use_table_seo_url) {
			$seo_keyword = $category['seo_keyword'];
		}
		$store_ids = $category['store_ids'];
		$layout = $category['layout'];
		$status = $category['status'];
		$status = ((strtoupper($status)=="TRUE") || (strtoupper($status)=="YES") || (strtoupper($status)=="ENABLED")) ? 1 : 0;

		// generate and execute SQL for inserting the category
		$sql = "INSERT INTO `".DB_PREFIX."category` (`category_id`, `image`, `parent_id`, `top`, `column`, `sort_order`, `date_added`, `date_modified`, `status`) VALUES ";
		$sql .= "( $category_id, '$image_name', $parent_id, $top, $columns, $sort_order, ";
		$sql .= ($date_added=='NOW()') ? "$date_added," : "'$date_added',";
		$sql .= ($date_modified=='NOW()') ? "$date_modified," : "'$date_modified',";
		$sql .= " $status);";
		$this->db->query( $sql );
		foreach ($languages as $language) {
			$language_code = $language['code'];
			$language_id = $language['language_id'];
			$name = isset($names[$language_code]) ? $this->db->escape($names[$language_code]) : '';
			$description = isset($descriptions[$language_code]) ? $this->db->escape($descriptions[$language_code]) : '';
			if ($exist_meta_title) {
				$meta_title = isset($meta_titles[$language_code]) ? $this->db->escape($meta_titles[$language_code]) : '';
			}
			$meta_description = isset($meta_descriptions[$language_code]) ? $this->db->escape($meta_descriptions[$language_code]) : '';
			$meta_keyword = isset($meta_keywords[$language_code]) ? $this->db->escape($meta_keywords[$language_code]) : '';
			if ($exist_meta_title) {
				$sql  = "INSERT INTO `".DB_PREFIX."category_description` (`category_id`, `language_id`, `name`, `description`, `meta_title`, `meta_description`, `meta_keyword`) VALUES ";
				$sql .= "( $category_id, $language_id, '$name', '$description', '$meta_title', '$meta_description', '$meta_keyword' );";
			} else {
				$sql  = "INSERT INTO `".DB_PREFIX."category_description` (`category_id`, `language_id`, `name`, `description`, `meta_description`, `meta_keyword`) VALUES ";
				$sql .= "( $category_id, $language_id, '$name', '$description', '$meta_description', '$meta_keyword' );";
			}
			$this->db->query( $sql );
		}
		if (!$this->use_table_seo_url) {
			if ($seo_keyword) {
				if (isset($url_alias_ids[$category_id])) {
					$url_alias_id = $url_alias_ids[$category_id];
					$sql = "INSERT INTO `".DB_PREFIX."url_alias` (`url_alias_id`,`query`,`keyword`) VALUES ($url_alias_id,'category_id=$category_id','$seo_keyword');";
					unset($url_alias_ids[$category_id]);
				} else {
					$sql = "INSERT INTO `".DB_PREFIX."url_alias` (`query`,`keyword`) VALUES ('category_id=$category_id','$seo_keyword');";
				}
				$this->db->query($sql);
			}
		}
		foreach ($store_ids as $store_id) {
			if (in_array((int)$store_id,$available_store_ids)) {
				$sql = "INSERT INTO `".DB_PREFIX."category_to_store` (`category_id`,`store_id`) VALUES ($category_id,$store_id);";
				$this->db->query($sql);
			}
		}
		$layouts = array();
		foreach ($layout as $layout_part) {
			$next_layout = explode(':',$layout_part);
			if ($next_layout===false) {
				$next_layout = array( 0, $layout_part );
			} else if (count($next_layout)==1) {
				$next_layout = array( 0, $layout_part );
			}
			if ( (count($next_layout)==2) && (in_array((int)$next_layout[0],$available_store_ids)) && (is_string($next_layout[1])) ) {
				$store_id = (int)$next_layout[0];
				$layout_name = $next_layout[1];
				if (isset($layout_ids[$layout_name])) {
					$layout_id = (int)$layout_ids[$layout_name];
					if (!isset($layouts[$store_id])) {
						$layouts[$store_id] = $layout_id;
					}
				}
			}
		}
		foreach ($layouts as $store_id => $layout_id) {
			$sql = "INSERT INTO `".DB_PREFIX."category_to_layout` (`category_id`,`store_id`,`layout_id`) VALUES ($category_id,$store_id,$layout_id);";
			$this->db->query($sql);
		}
	}


	protected function deleteCategory( $category_id ) {
		$sql  = "DELETE FROM `".DB_PREFIX."category` WHERE `category_id` = '".(int)$category_id."' ;\n";
		$sql .= "DELETE FROM `".DB_PREFIX."category_description` WHERE `category_id` = '".(int)$category_id."' ;\n";
		$sql .= "DELETE FROM `".DB_PREFIX."category_to_store` WHERE `category_id` = '".(int)$category_id."' ;\n";
		if (!$this->use_table_seo_url) {
			$sql .= "DELETE FROM `".DB_PREFIX."url_alias` WHERE `query` LIKE 'category_id=".(int)$category_id."';\n";
		}
		$sql .= "DELETE FROM `".DB_PREFIX."category_to_layout` WHERE `category_id` = '".(int)$category_id."' ;\n";
		$this->multiquery( $sql );
		$sql = "SHOW TABLES LIKE \"".DB_PREFIX."category_path\"";
		$query = $this->db->query( $sql );
		if ($query->num_rows) {
			$sql = "DELETE FROM `".DB_PREFIX."category_path` WHERE `category_id` = '".(int)$category_id."'";
			$this->db->query( $sql );
		}
	}


	protected function deleteCategories( &$url_alias_ids ) {
		$sql  = "TRUNCATE TABLE `".DB_PREFIX."category`;\n";
		$sql .= "TRUNCATE TABLE `".DB_PREFIX."category_description`;\n";
		$sql .= "TRUNCATE TABLE `".DB_PREFIX."category_to_store`;\n";
		if (!$this->use_table_seo_url) {
			$sql .= "DELETE FROM `".DB_PREFIX."url_alias` WHERE `query` LIKE 'category_id=%';\n";
		}
		$sql .= "TRUNCATE TABLE `".DB_PREFIX."category_to_layout`;\n";
		$this->multiquery( $sql );
		$sql = "SHOW TABLES LIKE \"".DB_PREFIX."category_path\"";
		$query = $this->db->query( $sql );
		if ($query->num_rows) {
			$sql = "TRUNCATE TABLE `".DB_PREFIX."category_path`";
			$this->db->query( $sql );
		}
		if (!$this->use_table_seo_url) {
			$sql = "SELECT (MAX(url_alias_id)+1) AS next_url_alias_id FROM `".DB_PREFIX."url_alias` LIMIT 1";
			$query = $this->db->query( $sql );
			$next_url_alias_id = $query->row['next_url_alias_id'];
			$sql = "ALTER TABLE `".DB_PREFIX."url_alias` AUTO_INCREMENT = $next_url_alias_id";
			$this->db->query( $sql );
			$remove = array();
			foreach ($url_alias_ids as $category_id=>$url_alias_id) {
				if ($url_alias_id >= $next_url_alias_id) {
					$remove[$category_id] = $url_alias_id;
				}
			}
			foreach ($remove as $category_id=>$url_alias_id) {
				unset($url_alias_ids[$category_id]);
			}
		}
	}


	// function for reading additional cells in class extensions
	protected function moreCategoryCells( $i, &$j, &$worksheet, &$category ) {
		return;
	}


	protected function uploadCategories( &$reader, $incremental, &$available_category_ids=array() ) {
		// get worksheet if there
		$data = $reader->getSheetByName( 'Categories' );
		if ($data==null) {
			return;
		}

		// Opencart versions from 2.0 onwards also have category_description.meta_title
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."category_description` LIKE 'meta_title'";
		$query = $this->db->query( $sql );
		$exist_meta_title = ($query->num_rows > 0) ? true : false;

		// get old url_alias_ids
		if (!$this->use_table_seo_url) {
			$url_alias_ids = $this->getCategoryUrlAliasIds();
		}

		// if incremental then find current category IDs else delete all old categories
		$available_category_ids = array();
		if ($incremental) {
			$old_category_ids = $this->getAvailableCategoryIds();
		} else {
			$this->deleteCategories($url_alias_ids);
		}

		// get pre-defined layouts
		$layout_ids = $this->getLayoutIds();

		// get pre-defined store_ids
		$available_store_ids = $this->getAvailableStoreIds();

		// find the installed languages
		$languages = $this->getLanguages();

		$first_row = array();
		$i = 0;
		$k = $data->getHighestRow();

		for ($i=0; $i<$k; $i+=1) {
			if ($i==0) {
				$max_col = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
				for ($j=1; $j<=$max_col; $j+=1) {
					$first_row[] = $this->getCell($data,$i,$j);
				}
				continue;
			}
			$j = 1;
			$category_id = trim($this->getCell($data,$i,$j++));
			if ($category_id=="") {
				continue;
			}
			$parent_id = $this->getCell($data,$i,$j++,'0');
			$names = array();
			while ($this->startsWith($first_row[$j-1],"name(")) {
				$language_code = substr($first_row[$j-1],strlen("name("),strlen($first_row[$j-1])-strlen("name(")-1);
				$name = $this->getCell($data,$i,$j++);
				$name = htmlspecialchars( $name );
				$names[$language_code] = $name;
			}
			$top = $this->getCell($data,$i,$j++,($parent_id=='0')?'true':'false');
			$columns = $this->getCell($data,$i,$j++,($parent_id=='0')?'1':'0');
			$sort_order = $this->getCell($data,$i,$j++,'0');
			$image_name = trim($this->getCell($data,$i,$j++));
			$date_added = trim($this->getCell($data,$i,$j++));
			$date_added = ((is_string($date_added)) && (strlen($date_added)>0)) ? $date_added : "NOW()";
			$date_modified = trim($this->getCell($data,$i,$j++));
			$date_modified = ((is_string($date_modified)) && (strlen($date_modified)>0)) ? $date_modified : "NOW()";
			if (!$this->use_table_seo_url) {
				$seo_keyword = $this->getCell($data,$i,$j++);
			}
			$descriptions = array();
			while ($this->startsWith($first_row[$j-1],"description(")) {
				$language_code = substr($first_row[$j-1],strlen("description("),strlen($first_row[$j-1])-strlen("description(")-1);
				$description = $this->getCell($data,$i,$j++);
				$description = htmlspecialchars( $description );
				$descriptions[$language_code] = $description;
			}
			if ($exist_meta_title) {
				$meta_titles = array();
				while ($this->startsWith($first_row[$j-1],"meta_title(")) {
					$language_code = substr($first_row[$j-1],strlen("meta_title("),strlen($first_row[$j-1])-strlen("meta_title(")-1);
					$meta_title = $this->getCell($data,$i,$j++);
					$meta_title = htmlspecialchars( $meta_title );
					$meta_titles[$language_code] = $meta_title;
				}
			}
			$meta_descriptions = array();
			while ($this->startsWith($first_row[$j-1],"meta_description(")) {
				$language_code = substr($first_row[$j-1],strlen("meta_description("),strlen($first_row[$j-1])-strlen("meta_description(")-1);
				$meta_description = $this->getCell($data,$i,$j++);
				$meta_description = htmlspecialchars( $meta_description );
				$meta_descriptions[$language_code] = $meta_description;
			}
			$meta_keywords = array();
			while ($this->startsWith($first_row[$j-1],"meta_keywords(")) {
				$language_code = substr($first_row[$j-1],strlen("meta_keywords("),strlen($first_row[$j-1])-strlen("meta_keywords(")-1);
				$meta_keyword = $this->getCell($data,$i,$j++);
				$meta_keyword = htmlspecialchars( $meta_keyword );
				$meta_keywords[$language_code] = $meta_keyword;
			}
			$store_ids = $this->getCell($data,$i,$j++);
			$layout = $this->getCell($data,$i,$j++,'');
			$status = $this->getCell($data,$i,$j++,'true');
			$category = array();
			$category['category_id'] = $category_id;
			$category['image'] = $image_name;
			$category['parent_id'] = $parent_id;
			$category['sort_order'] = $sort_order;
			$category['date_added'] = $date_added;
			$category['date_modified'] = $date_modified;
			$category['names'] = $names;
			$category['top'] = $top;
			$category['columns'] = $columns;
			$category['descriptions'] = $descriptions;
			if ($exist_meta_title) {
				$category['meta_titles'] = $meta_titles;
			}
			$category['meta_descriptions'] = $meta_descriptions;
			$category['meta_keywords'] = $meta_keywords;
			if (!$this->use_table_seo_url) {
				$category['seo_keyword'] = $seo_keyword;
			}
			$store_ids = trim( $this->clean($store_ids, false) );
			$category['store_ids'] = ($store_ids=="") ? array() : explode( ",", $store_ids );
			if ($category['store_ids']===false) {
				$category['store_ids'] = array();
			}
			$category['layout'] = ($layout=="") ? array() : explode( ",", $layout );
			if ($category['layout']===false) {
				$category['layout'] = array();
			}
			$category['status'] = $status;
			if ($incremental) {
				if ($old_category_ids) {
					if (in_array((int)$category_id,$old_category_ids)) {
						$this->deleteCategory( $category_id );
					}
				}
			}
			$available_category_ids[$category_id] = $category_id;
			$this->moreCategoryCells( $i, $j, $data, $category );
			$this->storeCategoryIntoDatabase( $category, $languages, $exist_meta_title, $layout_ids, $available_store_ids, $url_alias_ids );
		}

		// restore category paths for faster lookups on the frontend (only for newer OpenCart versions)
		$this->load->model( 'catalog/category' );
		if (is_callable(array($this->model_catalog_category,'repairCategories'))) {
			$this->model_catalog_category->repairCategories(0);
		}
	}


	protected function storeCategoryFilterIntoDatabase( &$category_filter, &$languages ) {
		$category_id = $category_filter['category_id'];
		$filter_id = $category_filter['filter_id'];
		$sql  = "INSERT INTO `".DB_PREFIX."category_filter` (`category_id`, `filter_id`) VALUES ";
		$sql .= "( $category_id, $filter_id );";
		$this->db->query( $sql );
	}


	protected function deleteCategoryFilters() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."category_filter`";
		$this->db->query( $sql );
	}


	protected function deleteCategoryFilter( $category_id ) {
		$sql = "DELETE FROM `".DB_PREFIX."category_filter` WHERE category_id='".(int)$category_id."'";
		$this->db->query( $sql );
	}


	protected function deleteUnlistedCategoryFilters( &$unlisted_category_ids ) {
		foreach ($unlisted_category_ids as $category_id) {
			$sql = "DELETE FROM `".DB_PREFIX."category_filter` WHERE category_id='".(int)$category_id."'";
			$this->db->query( $sql );
		}
	}


	// function for reading additional cells in class extensions
	protected function moreCategoryFilterCells( $i, &$j, &$worksheet, &$category_filter ) {
		return;
	}


	protected function uploadCategoryFilters( &$reader, $incremental, &$available_category_ids ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'CategoryFilters' );
		if ($data==null) {
			return;
		}

		// if incremental then find current category IDs else delete all old category filters
		if ($incremental) {
			$unlisted_category_ids = $available_category_ids;
		} else {
			$this->deleteCategoryFilters();
		}

		if (!$this->config->get( 'export_import_settings_use_filter_group_id' )) {
			$filter_group_ids = $this->getFilterGroupIds();
		}
		if (!$this->config->get( 'export_import_settings_use_filter_id' )) {
			$filter_ids = $this->getFilterIds();
		}

		// load the worksheet cells and store them to the database
		$languages = $this->getLanguages();
		$previous_category_id = 0;
		$first_row = array();
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			if ($i==0) {
				$max_col = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
				for ($j=1; $j<=$max_col; $j+=1) {
					$first_row[] = $this->getCell($data,$i,$j);
				}
				continue;
			}
			$j = 1;
			$category_id = trim($this->getCell($data,$i,$j++));
			if ($category_id=='') {
				continue;
			}
			if ($this->config->get( 'export_import_settings_use_filter_group_id' )) {
				$filter_group_id = $this->getCell($data,$i,$j++,'');
			} else {
				$filter_group_name = $this->getCell($data,$i,$j++);
				$filter_group_id = isset($filter_group_ids[$filter_group_name]) ? $filter_group_ids[$filter_group_name] : '';
			}
			if ($filter_group_id=='') {
				continue;
			}
			if ($this->config->get( 'export_import_settings_use_filter_id' )) {
				$filter_id = $this->getCell($data,$i,$j++,'');
			} else {
				$filter_name = $this->getCell($data,$i,$j++);
				$filter_id = isset($filter_ids[$filter_group_id][$filter_name]) ? $filter_ids[$filter_group_id][$filter_name] : '';
			}
			if ($filter_id=='') {
				continue;
			}
			$category_filter = array();
			$category_filter['category_id'] = $category_id;
			$category_filter['filter_group_id'] = $filter_group_id;
			$category_filter['filter_id'] = $filter_id;
			if (($incremental) && ($category_id != $previous_category_id)) {
				$this->deleteCategoryFilter( $category_id );
				if (isset($unlisted_category_ids[$category_id])) {
					unset($unlisted_category_ids[$category_id]);
				}
			}
			$this->moreCategoryFilterCells( $i, $j, $data, $category_filter );
			$this->storeCategoryFilterIntoDatabase( $category_filter, $languages );
			$previous_category_id = $category_id;
		}
		if ($incremental) {
			$this->deleteUnlistedCategoryFilters( $unlisted_category_ids );
		}
	}


	protected function storeCategorySEOKeywordIntoDatabase( &$category_seo_keyword, &$languages, $old_seo_url_ids ) {
		$category_id = $category_seo_keyword['category_id'];
		$store_id = $category_seo_keyword['store_id'];
		$keywords = $category_seo_keyword['keywords'];
		foreach ($languages as $language) {
			$language_id = $language['language_id'];
			$language_code = $language['code'];
			if (isset($keywords[$language_code])) {
				$keyword = $keywords[$language_code];
				if ($keyword != '') {
					if (isset($old_seo_url_ids[$category_id][$store_id][$language_id])) {
						$seo_url_id = $old_seo_url_ids[$category_id][$store_id][$language_id];
						$sql  = "INSERT INTO `".DB_PREFIX."seo_url` (`seo_url_id`, `store_id`, `language_id`, `query`, `keyword`) VALUES ";
						$sql .= "($seo_url_id, $store_id, $language_id, 'category_id=$category_id', '".$this->db->escape($keyword)."');";
						$this->db->query( $sql );
						unset($old_seo_url_ids[$category_id][$store_id][$language_id]);
					} else {
						$sql  = "INSERT INTO `".DB_PREFIX."seo_url` (`store_id`, `language_id`, `query`, `keyword`) VALUES ";
						$sql .= "($store_id, $language_id, 'category_id=$category_id', '".$this->db->escape($keyword)."');";
						$this->db->query( $sql );
					}
				}
			}
		}
	}


	protected function deleteCategorySEOKeywords() {
		$sql = "DELETE FROM `".DB_PREFIX."seo_url` WHERE query LIKE 'category_id=%';";
		$this->db->query( $sql );
		$sql = "SELECT MAX(seo_url_id) AS max_seo_url_id FROM `".DB_PREFIX."seo_url`";
		$query = $this->db->query( $sql );
		$max_seo_url_id = isset( $query->row['max_seo_url_id'] ) ? $query->row['max_seo_url_id'] : 0;
		$auto_increment = $max_seo_url_id + 1;
		$sql = "ALTER TABLE `".DB_PREFIX."seo_url` AUTO_INCREMENT = $auto_increment;";
		$this->db->query( $sql );
	}


	protected function deleteCategorySEOKeyword( $category_id ) {
		$old_seo_url_ids = array();
		$sql = "SELECT * FROM `".DB_PREFIX."seo_url` WHERE query='category_id=".(int)$category_id."';";
		$query = $this->db->query( $sql );
		foreach ($query->rows as $row) {
			$seo_url_id = $row['seo_url_id'];
			$store_id = $row['store_id'];
			$category_id = (int)substr($row['query'],strlen('category_id='));
			$language_id = $row['language_id'];
			$old_seo_url_ids[$category_id][$store_id][$language_id] = $seo_url_id;
		}
		$sql = "DELETE FROM `".DB_PREFIX."seo_url` WHERE query='category_id=".(int)$category_id."';";
		$this->db->query( $sql );
		return $old_seo_url_ids;
	}


	protected function deleteUnlistedCategorySEOKeywords( &$unlisted_category_ids ) {
		foreach ($unlisted_category_ids as $category_id) {
			$sql = "DELETE FROM `".DB_PREFIX."seo_url` WHERE query='category_id=".(int)$category_id."';";
			$this->db->query( $sql );
		}
	}


	// function for reading additional cells in class extensions
	protected function moreCategorySEOKeywordCells( $i, &$j, &$worksheet, &$category_seo_keyword ) {
		return;
	}


	protected function uploadCategorySEOKeywords( &$reader, $incremental, &$available_category_ids ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'CategorySEOKeywords' );
		if ($data==null) {
			return;
		}

		// if DB table 'seo_url' doesn't exist (OpenCart 1.5.x, 2.x versions) then return immediately
		if (!$this->use_table_seo_url) {
			return;
		}

		// if incremental then find current category IDs else delete all old category SEO keywords
		if ($incremental) {
			$unlisted_category_ids = $available_category_ids;
		} else {
			$this->deleteCategorySEOKeywords();
		}

		// load the worksheet cells and store them to the database
		$old_seo_url_ids = array();
		$languages = $this->getLanguages();
		$previous_category_id = 0;
		$first_row = array();
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			if ($i==0) {
				$max_col = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
				for ($j=1; $j<=$max_col; $j+=1) {
					$first_row[] = $this->getCell($data,$i,$j);
				}
				continue;
			}
			$j = 1;
			$category_id = trim($this->getCell($data,$i,$j++));
			if ($category_id=='') {
				continue;
			}
			$store_id = trim($this->getCell($data,$i,$j++));
			if ($store_id=='') {
				continue;
			}
			$keywords = array();
			while (($j<=$max_col) && $this->startsWith($first_row[$j-1],"keyword(")) {
				$language_code = substr($first_row[$j-1],strlen("keyword("),strlen($first_row[$j-1])-strlen("keyword(")-1);
				$keyword = trim($this->getCell($data,$i,$j++,''));
				$keyword = htmlspecialchars( $keyword );
				$keywords[$language_code] = $keyword;
			}
			$category_seo_keyword = array();
			$category_seo_keyword['category_id'] = $category_id;
			$category_seo_keyword['store_id'] = $store_id;
			$category_seo_keyword['keywords'] = $keywords;
			if (($incremental) && ($category_id != $previous_category_id)) {
				$old_seo_url_ids = $this->deleteCategorySEOKeyword( $category_id );
				if (isset($unlisted_category_ids[$category_id])) {
					unset($unlisted_category_ids[$category_id]);
				}
			}
			$this->moreCategorySEOKeywordCells( $i, $j, $data, $category_seo_keyword );
			$this->storeCategorySEOKeywordIntoDatabase( $category_seo_keyword, $languages, $old_seo_url_ids );
			$previous_category_id = $category_id;
		}
		if ($incremental) {
			$this->deleteUnlistedCategorySEOKeywords( $unlisted_category_ids );
		}
	}


	protected function getProductViewCounts() {
		$query = $this->db->query( "SELECT product_id, viewed FROM `".DB_PREFIX."product`" );
		$view_counts = array();
		foreach ($query->rows as $row) {
			$product_id = $row['product_id'];
			$viewed = $row['viewed'];
			$view_counts[$product_id] = $viewed;
		}
		return $view_counts;
	}


	protected function getProductUrlAliasIds() {
		$sql  = "SELECT url_alias_id, SUBSTRING( query, CHAR_LENGTH('product_id=')+1 ) AS product_id ";
		$sql .= "FROM `".DB_PREFIX."url_alias` ";
		$sql .= "WHERE query LIKE 'product_id=%'";
		$query = $this->db->query( $sql );
		$url_alias_ids = array();
		foreach ($query->rows as $row) {
			$url_alias_id = $row['url_alias_id'];
			$product_id = $row['product_id'];
			$url_alias_ids[$product_id] = $url_alias_id;
		}
		return $url_alias_ids;
	}


	protected function storeProductIntoDatabase( &$product, &$languages, &$product_fields, $exist_table_product_tag, $exist_meta_title, &$layout_ids, &$available_store_ids, &$manufacturers, &$weight_class_ids, &$length_class_ids, &$url_alias_ids ) {
		// extract the product details
		$product_id = $product['product_id'];
		$names = $product['names'];
		$categories = $product['categories'];
		$quantity = $product['quantity'];
		$model = $this->db->escape($product['model']);
		$manufacturer_name = $product['manufacturer_name'];
		$image = $this->db->escape($product['image']);
		$shipping = $product['shipping'];
		$shipping = ((strtoupper($shipping)=="YES") || (strtoupper($shipping)=="Y") || (strtoupper($shipping)=="TRUE")) ? 1 : 0;
		$price = trim($product['price']);
		$price_2 = trim($product['price_2']);
		$price_3 = trim($product['price_3']);
		$points = $product['points'];
		$date_added = $product['date_added'];
		$date_modified = $product['date_modified'];
		$date_available = $product['date_available'];
		$weight = ($product['weight']=="") ? 0 : $product['weight'];
		$weight_unit = $product['weight_unit'];
		$weight_class_id = (isset($weight_class_ids[$weight_unit])) ? $weight_class_ids[$weight_unit] : 0;
		$status = $product['status'];
		$status = ((strtoupper($status)=="TRUE") || (strtoupper($status)=="YES") || (strtoupper($status)=="ENABLED")) ? 1 : 0;
		$tax_class_id = $product['tax_class_id'];
		$viewed = $product['viewed'];
		$descriptions = $product['descriptions'];
		$stock_status_id = $product['stock_status_id'];
		if ($exist_meta_title) {
			$meta_titles = $product['meta_titles'];
		}
		$meta_descriptions = $product['meta_descriptions'];
		$length = $product['length'];
		$width = $product['width'];
		$height = $product['height'];
		if (!$this->use_table_seo_url) {
			$keyword = $this->db->escape($product['seo_keyword']);
		}
		$length_unit = $product['measurement_unit'];
		$length_class_id = (isset($length_class_ids[$length_unit])) ? $length_class_ids[$length_unit] : 0;
		$sku = $this->db->escape($product['sku']);
		$upc = $this->db->escape($product['upc']);
		if (in_array('ean',$product_fields)) {
			$ean = $this->db->escape($product['ean']);
		}
		if (in_array('jan',$product_fields)) {
			$jan = $this->db->escape($product['jan']);
		}
		if (in_array('isbn',$product_fields)) {
			$isbn = $this->db->escape($product['isbn']);
		}
		if (in_array('mpn',$product_fields)) {
			$mpn = $this->db->escape($product['mpn']);
		}
		$location = $this->db->escape($product['location']);
		$store_ids = $product['store_ids'];
		$layout = $product['layout'];
		$related_ids = $product['related_ids'];
		$subtract = $product['subtract'];
		$subtract = ((strtoupper($subtract)=="TRUE") || (strtoupper($subtract)=="YES") || (strtoupper($subtract)=="ENABLED")) ? 1 : 0;
		$minimum = $product['minimum'];
		$meta_keywords = $product['meta_keywords'];
		$tags = $product['tags'];
		$sort_order = $product['sort_order'];
		if ($manufacturer_name) {
			$this->storeManufacturerIntoDatabase( $manufacturers, $manufacturer_name, $store_ids, $available_store_ids );
			$manufacturer_id = $manufacturers[$manufacturer_name]['manufacturer_id'];
		} else {
			$manufacturer_id = 0;
		}

		// generate and execute SQL for inserting the product
		$sql  = "INSERT INTO `".DB_PREFIX."product` (`product_id`,`quantity`,`sku`,`upc`,";
		$sql .= in_array('ean',$product_fields) ? "`ean`," : "";
		$sql .= in_array('jan',$product_fields) ? "`jan`," : "";
		$sql .= in_array('isbn',$product_fields) ? "`isbn`," : "";
		$sql .= in_array('mpn',$product_fields) ? "`mpn`," : "";
		$sql .= "`location`,`stock_status_id`,`model`,`manufacturer_id`,`image`,`shipping`,`price`,`price_2`,`price_3`,`points`,`date_added`,`date_modified`,`date_available`,`weight`,`weight_class_id`,`status`,";
		$sql .= "`tax_class_id`,`viewed`,`length`,`width`,`height`,`length_class_id`,`sort_order`,`subtract`,`minimum`) VALUES ";
		$sql .= "($product_id,$quantity,'$sku','$upc',";
		$sql .= in_array('ean',$product_fields) ? "'$ean'," : "";
		$sql .= in_array('jan',$product_fields) ? "'$jan'," : "";
		$sql .= in_array('isbn',$product_fields) ? "'$isbn'," : "";
		$sql .= in_array('mpn',$product_fields) ? "'$mpn'," : "";
		$sql .= "'$location',$stock_status_id,'$model',$manufacturer_id,'$image',$shipping,$price,$price_2,$price_3,$points,";
		$sql .= ($date_added=='NOW()') ? "$date_added," : "'$date_added',";
		$sql .= ($date_modified=='NOW()') ? "$date_modified," : "'$date_modified',";
		$sql .= ($date_available=='NOW()') ? "$date_available," : "'$date_available',";
		$sql .= "$weight,$weight_class_id,$status,";
		$sql .= "$tax_class_id,$viewed,$length,$width,$height,'$length_class_id','$sort_order','$subtract','$minimum');";
		$this->db->query($sql);
		foreach ($languages as $language) {
			$language_code = $language['code'];
			$language_id = $language['language_id'];
			$name = isset($names[$language_code]) ? $this->db->escape($names[$language_code]) : '';
			$description = isset($descriptions[$language_code]) ? $this->db->escape($descriptions[$language_code]) : '';
			if ($exist_meta_title) {
				$meta_title = isset($meta_titles[$language_code]) ? $this->db->escape($meta_titles[$language_code]) : '';
			}
			$meta_description = isset($meta_descriptions[$language_code]) ? $this->db->escape($meta_descriptions[$language_code]) : '';
			$meta_keyword = isset($meta_keywords[$language_code]) ? $this->db->escape($meta_keywords[$language_code]) : '';
			$tag = isset($tags[$language_code]) ? $this->db->escape($tags[$language_code]) : '';
			if ($exist_table_product_tag) {
				if ($exist_meta_title) {
					$sql  = "INSERT INTO `".DB_PREFIX."product_description` (`product_id`, `language_id`, `name`, `description`, `meta_title`, `meta_description`, `meta_keyword`) VALUES ";
					$sql .= "( $product_id, $language_id, '$name', '$description', '$meta_title', '$meta_description', '$meta_keyword' );";
				} else {
					$sql  = "INSERT INTO `".DB_PREFIX."product_description` (`product_id`, `language_id`, `name`, `description`, `meta_description`, `meta_keyword`) VALUES ";
					$sql .= "( $product_id, $language_id, '$name', '$description', '$meta_description', '$meta_keyword' );";
				}
				$this->db->query( $sql );
				$tag = trim($tag);
				if ($tag) {
					$tag_elements = explode(',',$tag);
					foreach ($tag_elements as $tag_element) {
						$sql  = "INSERT INTO `".DB_PREFIX."product_tag` (`product_id`,`language_id`,`tag`) VALUES ";
						$sql .= "($product_id, $language_id, '$tag_element')";
						$this->db->query($sql);
					}
				}
			} else {
				if ($exist_meta_title) {
					$sql  = "INSERT INTO `".DB_PREFIX."product_description` (`product_id`, `language_id`, `name`, `description`, `meta_title`, `meta_description`, `meta_keyword`, `tag`) VALUES ";
					$sql .= "( $product_id, $language_id, '$name', '$description', '$meta_title', '$meta_description', '$meta_keyword', '$tag' );";
				} else {
					$sql  = "INSERT INTO `".DB_PREFIX."product_description` (`product_id`, `language_id`, `name`, `description`, `meta_description`, `meta_keyword`, `tag`) VALUES ";
					$sql .= "( $product_id, $language_id, '$name', '$description', '$meta_description', '$meta_keyword', '$tag' );";
				}
				$this->db->query( $sql );
			}
		}
		if (count($categories) > 0) {
			$sql = "INSERT INTO `".DB_PREFIX."product_to_category` (`product_id`,`category_id`) VALUES ";
			$first = true;
			foreach ($categories as $category_id) {
				$sql .= ($first) ? "\n" : ",\n";
				$first = false;
				$sql .= "($product_id,$category_id)";
			}
			$sql .= ";";
			$this->db->query($sql);
		}
		if (!$this->use_table_seo_url) {
			if ($keyword) {
				if (isset($url_alias_ids[$product_id])) {
					$url_alias_id = $url_alias_ids[$product_id];
					$sql = "INSERT INTO `".DB_PREFIX."url_alias` (`url_alias_id`,`query`,`keyword`) VALUES ($url_alias_id,'product_id=$product_id','$keyword');";
					unset($url_alias_ids[$product_id]);
				} else {
					$sql = "INSERT INTO `".DB_PREFIX."url_alias` (`query`,`keyword`) VALUES ('product_id=$product_id','$keyword');";
				}
				$this->db->query($sql);
			}
		}
		foreach ($store_ids as $store_id) {
			if (in_array((int)$store_id,$available_store_ids)) {
				$sql = "INSERT INTO `".DB_PREFIX."product_to_store` (`product_id`,`store_id`) VALUES ($product_id,$store_id);";
				$this->db->query($sql);
			}
		}
		$layouts = array();
		foreach ($layout as $layout_part) {
			$next_layout = explode(':',$layout_part);
			if ($next_layout===false) {
				$next_layout = array( 0, $layout_part );
			} else if (count($next_layout)==1) {
				$next_layout = array( 0, $layout_part );
			}
			if ( (count($next_layout)==2) && (in_array((int)$next_layout[0],$available_store_ids)) && (is_string($next_layout[1])) ) {
				$store_id = (int)$next_layout[0];
				$layout_name = $next_layout[1];
				if (isset($layout_ids[$layout_name])) {
					$layout_id = (int)$layout_ids[$layout_name];
					if (!isset($layouts[$store_id])) {
						$layouts[$store_id] = $layout_id;
					}
				}
			}
		}
		foreach ($layouts as $store_id => $layout_id) {
			$sql = "INSERT INTO `".DB_PREFIX."product_to_layout` (`product_id`,`store_id`,`layout_id`) VALUES ($product_id,$store_id,$layout_id);";
			$this->db->query($sql);
		}
		if (count($related_ids) > 0) {
			$sql = "INSERT INTO `".DB_PREFIX."product_related` (`product_id`,`related_id`) VALUES ";
			$first = true;
			foreach ($related_ids as $related_id) {
				$sql .= ($first) ? "\n" : ",\n";
				$first = false;
				$sql .= "($product_id,$related_id)";
			}
			$sql .= ";";
			$this->db->query($sql);
		}
	}


	protected function deleteProducts( $exist_table_product_tag, &$url_alias_ids ) {
		$sql  = "TRUNCATE TABLE `".DB_PREFIX."product`;\n";
		$sql .= "TRUNCATE TABLE `".DB_PREFIX."product_description`;\n";
		$sql .= "TRUNCATE TABLE `".DB_PREFIX."product_to_category`;\n";
		$sql .= "TRUNCATE TABLE `".DB_PREFIX."product_to_store`;\n";
		if (!$this->use_table_seo_url) {
			$sql .= "DELETE FROM `".DB_PREFIX."url_alias` WHERE `query` LIKE 'product_id=%';\n";
		}
		$sql .= "TRUNCATE TABLE `".DB_PREFIX."product_related`;\n";
		$sql .= "TRUNCATE TABLE `".DB_PREFIX."product_to_layout`;\n";
		if ($exist_table_product_tag) {
			$sql .= "TRUNCATE TABLE `".DB_PREFIX."product_tag`;\n";
		}
		$this->multiquery( $sql );
		if (!$this->use_table_seo_url) {
			$sql = "SELECT (MAX(url_alias_id)+1) AS next_url_alias_id FROM `".DB_PREFIX."url_alias` LIMIT 1";
			$query = $this->db->query( $sql );
			$next_url_alias_id = $query->row['next_url_alias_id'];
			$sql = "ALTER TABLE `".DB_PREFIX."url_alias` AUTO_INCREMENT = $next_url_alias_id";
			$this->db->query( $sql );
			$remove = array();
			foreach ($url_alias_ids as $product_id=>$url_alias_id) {
				if ($url_alias_id >= $next_url_alias_id) {
					$remove[$product_id] = $url_alias_id;
				}
			}
			foreach ($remove as $product_id=>$url_alias_id) {
				unset($url_alias_ids[$product_id]);
			}
		}
	}


	protected function deleteProduct( $product_id, $exist_table_product_tag ) {
		$sql  = "DELETE FROM `".DB_PREFIX."product` WHERE `product_id` = '$product_id';\n";
		$sql .= "DELETE FROM `".DB_PREFIX."product_description` WHERE `product_id` = '$product_id';\n";
		$sql .= "DELETE FROM `".DB_PREFIX."product_to_category` WHERE `product_id` = '$product_id';\n";
		$sql .= "DELETE FROM `".DB_PREFIX."product_to_store` WHERE `product_id` = '$product_id';\n";
		if (!$this->use_table_seo_url) {
			$sql .= "DELETE FROM `".DB_PREFIX."url_alias` WHERE `query` LIKE 'product_id=$product_id';\n";
		}
		$sql .= "DELETE FROM `".DB_PREFIX."product_related` WHERE `product_id` = '$product_id';\n";
		$sql .= "DELETE FROM `".DB_PREFIX."product_to_layout` WHERE `product_id` = '$product_id';\n";
		if ($exist_table_product_tag) {
			$sql .= "DELETE FROM `".DB_PREFIX."product_tag` WHERE `product_id` = '$product_id';\n";
		}
		$this->multiquery( $sql );
	}


	// function for reading additional cells in class extensions
	protected function moreProductCells( $i, &$j, &$worksheet, &$product ) {
		return;
	}


	protected function uploadProducts( &$reader, $incremental, &$available_product_ids=array() ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'Products' );
		if ($data==null) {
			return;
		}

		// save product view counts
		$view_counts = $this->getProductViewCounts();

		// save old url_alias_ids
		$url_alias_ids = array();
		if (!$this->use_table_seo_url) {
			$url_alias_ids = $this->getProductUrlAliasIds();
		}

		// some older versions of OpenCart use the 'product_tag' table
		$exist_table_product_tag = false;
		$query = $this->db->query( "SHOW TABLES LIKE '".DB_PREFIX."product_tag'" );
		$exist_table_product_tag = ($query->num_rows > 0);

		// Opencart versions from 2.0 onwards also have product_description.meta_title
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."product_description` LIKE 'meta_title'";
		$query = $this->db->query( $sql );
		$exist_meta_title = ($query->num_rows > 0) ? true : false;

		// if incremental then find current product IDs else delete all old products
		$available_product_ids = array();
		if ($incremental) {
			$old_product_ids = $this->getAvailableProductIds($data);
		} else {
			$this->deleteProducts($exist_table_product_tag,$url_alias_ids);
		}

		// get pre-defined layouts
		$layout_ids = $this->getLayoutIds();

		// get pre-defined store_ids
		$available_store_ids = $this->getAvailableStoreIds();

		// find the installed languages
		$languages = $this->getLanguages();

		// find the default units
		$default_weight_unit = $this->getDefaultWeightUnit();
		$default_measurement_unit = $this->getDefaultMeasurementUnit();
		$default_stock_status_id = $this->config->get('config_stock_status_id');

		// find existing manufacturers, only newly specified manufacturers will be added
		$manufacturers = $this->getManufacturers();

		// get weight classes
		$weight_class_ids = $this->getWeightClassIds();

		// get length classes
		$length_class_ids = $this->getLengthClassIds();

		// get list of the field names, some are only available for certain OpenCart versions
		$query = $this->db->query( "DESCRIBE `".DB_PREFIX."product`" );
		$product_fields = array();
		foreach ($query->rows as $row) {
			$product_fields[] = $row['Field'];
		}

		// load the worksheet cells and store them to the database
		$first_row = array();
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			if ($i==0) {
				$max_col = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
				for ($j=1; $j<=$max_col; $j+=1) {
					$first_row[] = $this->getCell($data,$i,$j);
				}
				continue;
			}
			$j = 1;
			$product_id = trim($this->getCell($data,$i,$j++));
			if ($product_id=="") {
				continue;
			}
			$names = array();
			while ($this->startsWith($first_row[$j-1],"name(")) {
				$language_code = substr($first_row[$j-1],strlen("name("),strlen($first_row[$j-1])-strlen("name(")-1);
				$name = $this->getCell($data,$i,$j++);
				$name = htmlspecialchars( $name );
				$names[$language_code] = $name;
			}
			$categories = $this->getCell($data,$i,$j++);
			$sku = $this->getCell($data,$i,$j++,'');
			$upc = $this->getCell($data,$i,$j++,'');
			if (in_array('ean',$product_fields)) {
				$ean = $this->getCell($data,$i,$j++,'');
			}
			if (in_array('jan',$product_fields)) {
				$jan = $this->getCell($data,$i,$j++,'');
			}
			if (in_array('isbn',$product_fields)) {
				$isbn = $this->getCell($data,$i,$j++,'');
			}
			if (in_array('mpn',$product_fields)) {
				$mpn = $this->getCell($data,$i,$j++,'');
			}
			$location = $this->getCell($data,$i,$j++,'');
			$quantity = $this->getCell($data,$i,$j++,'0');
			$model = $this->getCell($data,$i,$j++,'   ');
			$manufacturer_name = $this->getCell($data,$i,$j++);
			$image_name = $this->getCell($data,$i,$j++);
			$shipping = $this->getCell($data,$i,$j++,'yes');
			$price = $this->getCell($data,$i,$j++,'0.00');
			$price_2 = $this->getCell($data,$i,$j++,'0.00');
			$price_3 = $this->getCell($data,$i,$j++,'0.00');
			$points = $this->getCell($data,$i,$j++,'0');
			$date_added = $this->getCell($data,$i,$j++);
			$date_added = ((is_string($date_added)) && (strlen($date_added)>0)) ? $date_added : "NOW()";
			$date_modified = $this->getCell($data,$i,$j++);
			$date_modified = ((is_string($date_modified)) && (strlen($date_modified)>0)) ? $date_modified : "NOW()";
			$date_available = $this->getCell($data,$i,$j++);
			$date_available = ((is_string($date_available)) && (strlen($date_available)>0)) ? $date_available : "NOW()";
			$weight = $this->getCell($data,$i,$j++,'0');
			$weight_unit = $this->getCell($data,$i,$j++,$default_weight_unit);
			$length = $this->getCell($data,$i,$j++,'0');
			$width = $this->getCell($data,$i,$j++,'0');
			$height = $this->getCell($data,$i,$j++,'0');
			$measurement_unit = $this->getCell($data,$i,$j++,$default_measurement_unit);
			$status = $this->getCell($data,$i,$j++,'true');
			$tax_class_id = $this->getCell($data,$i,$j++,'0');
			if (!$this->use_table_seo_url) {
				$keyword = $this->getCell($data,$i,$j++);
			}
			$descriptions = array();
			while ($this->startsWith($first_row[$j-1],"description(")) {
				$language_code = substr($first_row[$j-1],strlen("description("),strlen($first_row[$j-1])-strlen("description(")-1);
				$description = $this->getCell($data,$i,$j++);
				$description = htmlspecialchars( $description );
				$descriptions[$language_code] = $description;
			}
			if ($exist_meta_title) {
				$meta_titles = array();
				while ($this->startsWith($first_row[$j-1],"meta_title(")) {
					$language_code = substr($first_row[$j-1],strlen("meta_title("),strlen($first_row[$j-1])-strlen("meta_title(")-1);
					$meta_title = $this->getCell($data,$i,$j++);
					$meta_title = htmlspecialchars( $meta_title );
					$meta_titles[$language_code] = $meta_title;
				}
			}
			$meta_descriptions = array();
			while ($this->startsWith($first_row[$j-1],"meta_description(")) {
				$language_code = substr($first_row[$j-1],strlen("meta_description("),strlen($first_row[$j-1])-strlen("meta_description(")-1);
				$meta_description = $this->getCell($data,$i,$j++);
				$meta_description = htmlspecialchars( $meta_description );
				$meta_descriptions[$language_code] = $meta_description;
			}
			$meta_keywords = array();
			while ($this->startsWith($first_row[$j-1],"meta_keywords(")) {
				$language_code = substr($first_row[$j-1],strlen("meta_keywords("),strlen($first_row[$j-1])-strlen("meta_keywords(")-1);
				$meta_keyword = $this->getCell($data,$i,$j++);
				$meta_keyword = htmlspecialchars( $meta_keyword );
				$meta_keywords[$language_code] = $meta_keyword;
			}
			$stock_status_id = $this->getCell($data,$i,$j++,$default_stock_status_id);
			$store_ids = $this->getCell($data,$i,$j++);
			$layout = $this->getCell($data,$i,$j++);
			$related = $this->getCell($data,$i,$j++);
			$tags = array();
			while ($this->startsWith($first_row[$j-1],"tags(")) {
				$language_code = substr($first_row[$j-1],strlen("tags("),strlen($first_row[$j-1])-strlen("tags(")-1);
				$tag = $this->getCell($data,$i,$j++);
				$tag = htmlspecialchars( $tag );
				$tags[$language_code] = $tag;
			}
			$sort_order = $this->getCell($data,$i,$j++,'0');
			$subtract = $this->getCell($data,$i,$j++,'true');
			$minimum = $this->getCell($data,$i,$j++,'1');
			$product = array();
			$product['product_id'] = $product_id;
			$product['names'] = $names;
			$categories = trim( $this->clean($categories, false) );
			$product['categories'] = ($categories=="") ? array() : explode( ",", $categories );
			if ($product['categories']===false) {
				$product['categories'] = array();
			}
			$product['quantity'] = $quantity;
			$product['model'] = $model;
			$product['manufacturer_name'] = $manufacturer_name;
			$product['image'] = $image_name;
			$product['shipping'] = $shipping;
			$product['price'] = $price;
			$product['price_2'] = $price_2;
			$product['price_3'] = $price_3;
			$product['points'] = $points;
			$product['date_added'] = $date_added;
			$product['date_modified'] = $date_modified;
			$product['date_available'] = $date_available;
			$product['weight'] = $weight;
			$product['weight_unit'] = $weight_unit;
			$product['status'] = $status;
			$product['tax_class_id'] = $tax_class_id;
			$product['viewed'] = isset($view_counts[$product_id]) ? $view_counts[$product_id] : 0;
			$product['descriptions'] = $descriptions;
			$product['stock_status_id'] = $stock_status_id;
			if ($exist_meta_title) {
				$product['meta_titles'] = $meta_titles;
			}
			$product['meta_descriptions'] = $meta_descriptions;
			$product['length'] = $length;
			$product['width'] = $width;
			$product['height'] = $height;
			if (!$this->use_table_seo_url) {
				$product['seo_keyword'] = $keyword;
			}
			$product['measurement_unit'] = $measurement_unit;
			$product['sku'] = $sku;
			$product['upc'] = $upc;
			if (in_array('ean',$product_fields)) {
				$product['ean'] = $ean;
			}
			if (in_array('jan',$product_fields)) {
				$product['jan'] = $jan;
			}
			if (in_array('isbn',$product_fields)) {
				$product['isbn'] = $isbn;
			}
			if (in_array('mpn',$product_fields)) {
				$product['mpn'] = $mpn;
			}
			$product['location'] = $location;
			$store_ids = trim( $this->clean($store_ids, false) );
			$product['store_ids'] = ($store_ids=="") ? array() : explode( ",", $store_ids );
			if ($product['store_ids']===false) {
				$product['store_ids'] = array();
			}
			$product['related_ids'] = ($related=="") ? array() : explode( ",", $related );
			if ($product['related_ids']===false) {
				$product['related_ids'] = array();
			}
			$product['layout'] = ($layout=="") ? array() : explode( ",", $layout );
			if ($product['layout']===false) {
				$product['layout'] = array();
			}
			$product['subtract'] = $subtract;
			$product['minimum'] = $minimum;
			$product['meta_keywords'] = $meta_keywords;
			$product['tags'] = $tags;
			$product['sort_order'] = $sort_order;
			if ($incremental) {
				$this->deleteProduct( $product_id, $exist_table_product_tag );
			}
			$available_product_ids[$product_id] = $product_id;
			$this->moreProductCells( $i, $j, $data, $product );
			$this->storeProductIntoDatabase( $product, $languages, $product_fields, $exist_table_product_tag, $exist_meta_title, $layout_ids, $available_store_ids, $manufacturers, $weight_class_ids, $length_class_ids, $url_alias_ids );
		}
	}


	protected function storeAdditionalImageIntoDatabase( &$image, &$old_product_image_ids, $exist_sort_order=true ) {
		$product_id = $image['product_id'];
		$image_name = $image['image_name'];
		if ($exist_sort_order) {
			$sort_order = $image['sort_order'];
		}
		if (isset($old_product_image_ids[$product_id][$image_name])) {
			$product_image_id = $old_product_image_ids[$product_id][$image_name];
			if ($exist_sort_order) {
				$sql  = "INSERT INTO `".DB_PREFIX."product_image` (`product_image_id`,`product_id`,`image`,`sort_order` ) VALUES "; 
				$sql .= "($product_image_id,$product_id,'".$this->db->escape($image_name)."',$sort_order)";
			} else {
				$sql  = "INSERT INTO `".DB_PREFIX."product_image` (`product_image_id`,`product_id`,`image` ) VALUES "; 
				$sql .= "($product_image_id,$product_id,'".$this->db->escape($image_name)."')";
			}
			$this->db->query($sql);
			unset($old_product_image_ids[$product_id][$image_name]);
		} else {
			if ($exist_sort_order) {
				$sql  = "INSERT INTO `".DB_PREFIX."product_image` (`product_id`,`image`,`sort_order` ) VALUES "; 
				$sql .= "($product_id,'".$this->db->escape($image_name)."',$sort_order)";
			} else {
				$sql  = "INSERT INTO `".DB_PREFIX."product_image` (`product_id`,`image` ) VALUES "; 
				$sql .= "($product_id,'".$this->db->escape($image_name)."')";
			}
			$this->db->query($sql);
		}
	}


	protected function deleteAdditionalImages() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."product_image`";
		$this->db->query( $sql );
	}


	protected function deleteAdditionalImage( $product_id ) {
		$sql = "SELECT product_image_id, product_id, image FROM `".DB_PREFIX."product_image` WHERE product_id='".(int)$product_id."'";
		$query = $this->db->query( $sql );
		$old_product_image_ids = array();
		foreach ($query->rows as $row) {
			$product_image_id = $row['product_image_id'];
			$product_id = $row['product_id'];
			$image_name = $row['image'];
			$old_product_image_ids[$product_id][$image_name] = $product_image_id;
		}
		if ($old_product_image_ids) {
			$sql = "DELETE FROM `".DB_PREFIX."product_image` WHERE product_id='".(int)$product_id."'";
			$this->db->query( $sql );
		}
		return $old_product_image_ids;
	}


	protected function deleteUnlistedAdditionalImages( &$unlisted_product_ids ) {
		foreach ($unlisted_product_ids as $product_id) {
			$sql = "DELETE FROM `".DB_PREFIX."product_image` WHERE product_id='".(int)$product_id."'";
			$this->db->query( $sql );
		}
	}


	// function for reading additional cells in class extensions
	protected function moreAdditionalImageCells( $i, &$j, &$worksheet, &$image ) {
		return;
	}


	protected function uploadAdditionalImages( &$reader, $incremental, &$available_product_ids ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'AdditionalImages' );
		if ($data==null) {
			return;
		}

		// if incremental then find current product IDs else delete all old additional images
		if ($incremental) {
			$unlisted_product_ids = $available_product_ids;
		} else {
			$this->deleteAdditionalImages();
		}

		// check for the existence of product_image.sort_order field
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."product_image` LIKE 'sort_order'";
		$query = $this->db->query( $sql );
		$exist_sort_order = ($query->num_rows > 0) ? true : false;

		// load the worksheet cells and store them to the database
		$old_product_image_ids = array();
		$previous_product_id = 0;
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			$j= 1;
			if ($i==0) {
				continue;
			}
			$product_id = trim($this->getCell($data,$i,$j++));
			if ($product_id=="") {
				continue;
			}
			$image_name = $this->getCell($data,$i,$j++,'');
			if ($exist_sort_order) {
				$sort_order = $this->getCell($data,$i,$j++,'0');
			}
			$image = array();
			$image['product_id'] = $product_id;
			$image['image_name'] = $image_name;
			if ($exist_sort_order) {
				$image['sort_order'] = $sort_order;
			}
			if (($incremental) && ($product_id != $previous_product_id)) {
				$old_product_image_ids = $this->deleteAdditionalImage( $product_id );
				if (isset($unlisted_product_ids[$product_id])) {
					unset($unlisted_product_ids[$product_id]);
				}
			}
			$this->moreAdditionalImageCells( $i, $j, $data, $image );
			$this->storeAdditionalImageIntoDatabase( $image, $old_product_image_ids, $exist_sort_order );
			$previous_product_id = $product_id;
		}
		if ($incremental) {
			$this->deleteUnlistedAdditionalImages( $unlisted_product_ids );
		}
	}


	protected function storeSpecialIntoDatabase( &$special, &$old_product_special_ids, &$customer_group_ids ) {
		$product_id = $special['product_id'];
		$name = $special['customer_group'];
		$customer_group_id = isset($customer_group_ids[$name]) ? $customer_group_ids[$name] : $this->config->get('config_customer_group_id');
		$priority = $special['priority'];
		$price = $special['price'];
		$date_start = $special['date_start'];
		$date_end = $special['date_end'];
		if (isset($old_product_special_ids[$product_id][$customer_group_id])) {
			$product_special_id = $old_product_special_ids[$product_id][$customer_group_id];
			$sql  = "INSERT INTO `".DB_PREFIX."product_special` (`product_special_id`,`product_id`,`customer_group_id`,`priority`,`price`,`date_start`,`date_end` ) VALUES "; 
			$sql .= "($product_special_id,$product_id,$customer_group_id,$priority,$price,'$date_start','$date_end')";
			$this->db->query($sql);
			unset($old_product_special_ids[$product_id][$customer_group_id]);
		} else {
			$sql  = "INSERT INTO `".DB_PREFIX."product_special` (`product_id`,`customer_group_id`,`priority`,`price`,`date_start`,`date_end` ) VALUES "; 
			$sql .= "($product_id,$customer_group_id,$priority,$price,'$date_start','$date_end')";
			$this->db->query($sql);
		}
	}


	protected function deleteSpecials() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."product_special`";
		$this->db->query( $sql );
	}


	protected function deleteSpecial( $product_id ) {
		$sql = "SELECT product_special_id, product_id, customer_group_id FROM `".DB_PREFIX."product_special` WHERE product_id='".(int)$product_id."'";
		$query = $this->db->query( $sql );
		$old_product_special_ids = array();
		foreach ($query->rows as $row) {
			$product_special_id = $row['product_special_id'];
			$product_id = $row['product_id'];
			$customer_group_id = $row['customer_group_id'];
			$old_product_special_ids[$product_id][$customer_group_id] = $product_special_id;
		}
		if ($old_product_special_ids) {
			$sql = "DELETE FROM `".DB_PREFIX."product_special` WHERE product_id='".(int)$product_id."'";
			$this->db->query( $sql );
		}
		return $old_product_special_ids;
	}


	protected function deleteUnlistedSpecials( &$unlisted_product_ids ) {
		foreach ($unlisted_product_ids as $product_id) {
			$sql = "DELETE FROM `".DB_PREFIX."product_special` WHERE product_id='".(int)$product_id."'";
			$this->db->query( $sql );
		}
	}


	// function for reading additional cells in class extensions
	protected function moreSpecialCells( $i, &$j, &$worksheet, &$special ) {
		return;
	}


	protected function uploadSpecials( &$reader, $incremental, &$available_product_ids ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'Specials' );
		if ($data==null) {
			return;
		}

		// if incremental then find current product IDs else delete all old specials
		if ($incremental) {
			$unlisted_product_ids = $available_product_ids;
		} else {
			$this->deleteSpecials();
		}

		// get existing customer groups
		$customer_group_ids = $this->getCustomerGroupIds();

		// load the worksheet cells and store them to the database
		$old_product_special_ids = array();
		$previous_product_id = 0;
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			$j = 1;
			if ($i==0) {
				continue;
			}
			$product_id = trim($this->getCell($data,$i,$j++));
			if ($product_id=="") {
				continue;
			}
			$customer_group = trim($this->getCell($data,$i,$j++));
			if ($customer_group=="") {
				continue;
			}
			$priority = $this->getCell($data,$i,$j++,'0');
			$price = $this->getCell($data,$i,$j++,'0');
			$date_start = $this->getCell($data,$i,$j++,'0000-00-00');
			$date_end = $this->getCell($data,$i,$j++,'0000-00-00');
			$special = array();
			$special['product_id'] = $product_id;
			$special['customer_group'] = $customer_group;
			$special['priority'] = $priority;
			$special['price'] = $price;
			$special['date_start'] = $date_start;
			$special['date_end'] = $date_end;
			if (($incremental) && ($product_id != $previous_product_id)) {
				$old_product_special_ids = $this->deleteSpecial( $product_id );
				if (isset($unlisted_product_ids[$product_id])) {
					unset($unlisted_product_ids[$product_id]);
				}
			}
			$this->moreSpecialCells( $i, $j, $data, $special );
			$this->storeSpecialIntoDatabase( $special, $old_product_special_ids, $customer_group_ids );
			$previous_product_id = $product_id;
		}
		if ($incremental) {
			$this->deleteUnlistedSpecials( $unlisted_product_ids );
		}
	}


	protected function storeDiscountIntoDatabase( &$discount, &$old_product_discount_ids, &$customer_group_ids ) {
		$product_id = $discount['product_id'];
		$name = $discount['customer_group'];
		$customer_group_id = isset($customer_group_ids[$name]) ? $customer_group_ids[$name] : $this->config->get('config_customer_group_id');
		$quantity = $discount['quantity'];
		$priority = $discount['priority'];
		$price = $discount['price'];
		$date_start = $discount['date_start'];
		$date_end = $discount['date_end'];
		if (isset($old_product_discount_ids[$product_id][$customer_group_id][$quantity])) {
			$product_discount_id = $old_product_discount_ids[$product_id][$customer_group_id][$quantity];
			$sql  = "INSERT INTO `".DB_PREFIX."product_discount` (`product_discount_id`,`product_id`,`customer_group_id`,`quantity`,`priority`,`price`,`date_start`,`date_end` ) VALUES "; 
			$sql .= "($product_discount_id,$product_id,$customer_group_id,$quantity,$priority,$price,'$date_start','$date_end')";
			$this->db->query($sql);
			unset($old_product_discount_ids[$product_id][$customer_group_id][$quantity]);
		} else {
			$sql  = "INSERT INTO `".DB_PREFIX."product_discount` (`product_id`,`customer_group_id`,`quantity`,`priority`,`price`,`date_start`,`date_end` ) VALUES "; 
			$sql .= "($product_id,$customer_group_id,$quantity,$priority,$price,'$date_start','$date_end')";
			$this->db->query($sql);
		}
	}


	protected function deleteDiscounts() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."product_discount`";
		$this->db->query( $sql );
	}


	protected function deleteDiscount( $product_id ) {
		$sql = "SELECT product_discount_id, product_id, customer_group_id, quantity FROM `".DB_PREFIX."product_discount` WHERE product_id='".(int)$product_id."' ORDER BY product_id ASC, customer_group_id ASC, quantity ASC;";
		$query = $this->db->query( $sql );
		$old_product_discount_ids = array();
		foreach ($query->rows as $row) {
			$product_discount_id = $row['product_discount_id'];
			$product_id = $row['product_id'];
			$customer_group_id = $row['customer_group_id'];
			$quantity = $row['quantity'];
			$old_product_discount_ids[$product_id][$customer_group_id][$quantity] = $product_discount_id;
		}
		if ($old_product_discount_ids) {
			$sql = "DELETE FROM `".DB_PREFIX."product_discount` WHERE product_id='".(int)$product_id."'";
			$this->db->query( $sql );
		}
		return $old_product_discount_ids;
	}


	protected function deleteUnlistedDiscounts( &$unlisted_product_ids ) {
		foreach ($unlisted_product_ids as $product_id) {
			$sql = "DELETE FROM `".DB_PREFIX."product_discount` WHERE product_id='".(int)$product_id."'";
			$this->db->query( $sql );
		}
	}


	// function for reading additional cells in class extensions
	protected function moreDiscountCells( $i, &$j, &$worksheet, &$discount ) {
		return;
	}


	protected function uploadDiscounts( &$reader, $incremental, &$available_product_ids ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'Discounts' );
		if ($data==null) {
			return;
		}

		// if incremental then find current product IDs else delete all old discounts
		if ($incremental) {
			$unlisted_product_ids = $available_product_ids;
		} else {
			$this->deleteDiscounts();
		}

		// get existing customer groups
		$customer_group_ids = $this->getCustomerGroupIds();

		// load the worksheet cells and store them to the database
		$old_product_discount_ids = array();
		$previous_product_id = 0;
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			$j = 1;
			if ($i==0) {
				continue;
			}
			$product_id = trim($this->getCell($data,$i,$j++));
			if ($product_id=="") {
				continue;
			}
			$customer_group = trim($this->getCell($data,$i,$j++));
			if ($customer_group=="") {
				continue;
			}
			$quantity = $this->getCell($data,$i,$j++,'0');
			$priority = $this->getCell($data,$i,$j++,'0');
			$price = $this->getCell($data,$i,$j++,'0');
			$date_start = $this->getCell($data,$i,$j++,'0000-00-00');
			$date_end = $this->getCell($data,$i,$j++,'0000-00-00');
			$discount = array();
			$discount['product_id'] = $product_id;
			$discount['customer_group'] = $customer_group;
			$discount['quantity'] = $quantity;
			$discount['priority'] = $priority;
			$discount['price'] = $price;
			$discount['date_start'] = $date_start;
			$discount['date_end'] = $date_end;
			if (($incremental) && ($product_id != $previous_product_id)) {
				$old_product_discount_ids = $this->deleteDiscount( $product_id );
				if (isset($unlisted_product_ids[$product_id])) {
					unset($unlisted_product_ids[$product_id]);
				}
			}
			$this->moreDiscountCells( $i, $j, $data, $discount );
			$this->storeDiscountIntoDatabase( $discount, $old_product_discount_ids, $customer_group_ids );
			$previous_product_id = $product_id;
		}
		if ($incremental) {
			$this->deleteUnlistedDiscounts( $unlisted_product_ids );
		}
	}


	protected function storeRewardIntoDatabase( &$reward, &$old_product_reward_ids, &$customer_group_ids ) {
		$product_id = $reward['product_id'];
		$name = $reward['customer_group'];
		$customer_group_id = isset($customer_group_ids[$name]) ? $customer_group_ids[$name] : $this->config->get('config_customer_group_id');
		$points = $reward['points'];
		if (isset($old_product_reward_ids[$product_id][$customer_group_id])) {
			$product_reward_id = $old_product_reward_ids[$product_id][$customer_group_id];
			$sql  = "INSERT INTO `".DB_PREFIX."product_reward` (`product_reward_id`,`product_id`,`customer_group_id`,`points` ) VALUES "; 
			$sql .= "($product_reward_id,$product_id,$customer_group_id,$points)";
			$this->db->query($sql);
			unset($old_product_reward_ids[$product_id][$customer_group_id]);
		} else {
			$sql  = "INSERT INTO `".DB_PREFIX."product_reward` (`product_id`,`customer_group_id`,`points` ) VALUES "; 
			$sql .= "($product_id,$customer_group_id,$points)";
			$this->db->query($sql);
		}
	}


	protected function deleteRewards() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."product_reward`";
		$this->db->query( $sql );
	}


	protected function deleteReward( $product_id ) {
		$sql = "SELECT product_reward_id, product_id, customer_group_id FROM `".DB_PREFIX."product_reward` WHERE product_id='".(int)$product_id."'";
		$query = $this->db->query( $sql );
		$old_product_reward_ids = array();
		foreach ($query->rows as $row) {
			$product_reward_id = $row['product_reward_id'];
			$product_id = $row['product_id'];
			$customer_group_id = $row['customer_group_id'];
			$old_product_reward_ids[$product_id][$customer_group_id] = $product_reward_id;
		}
		if ($old_product_reward_ids) {
			$sql = "DELETE FROM `".DB_PREFIX."product_reward` WHERE product_id='".(int)$product_id."'";
			$this->db->query( $sql );
		}
		return $old_product_reward_ids;
	}


	protected function deleteUnlistedRewards( &$unlisted_product_ids ) {
		foreach ($unlisted_product_ids as $product_id) {
			$sql = "DELETE FROM `".DB_PREFIX."product_reward` WHERE product_id='".(int)$product_id."'";
			$this->db->query( $sql );
		}
	}


	// function for reading additional cells in class extensions
	protected function moreRewardCells( $i, &$j, &$worksheet, &$reward ) {
		return;
	}


	protected function uploadRewards( &$reader, $incremental, &$available_product_ids ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'Rewards' );
		if ($data==null) {
			return;
		}

		// if incremental then find current product IDs else delete all old rewards
		if ($incremental) {
			$unlisted_product_ids = $available_product_ids;
		} else {
			$this->deleteRewards();
		}

		// get existing customer groups
		$customer_group_ids = $this->getCustomerGroupIds();

		// load the worksheet cells and store them to the database
		$old_product_reward_ids = array();
		$previous_product_id = 0;
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			$j = 1;
			if ($i==0) {
				continue;
			}
			$product_id = trim($this->getCell($data,$i,$j++));
			if ($product_id=="") {
				continue;
			}
			$customer_group = trim($this->getCell($data,$i,$j++));
			if ($customer_group=="") {
				continue;
			}
			$points = $this->getCell($data,$i,$j++,'0');
			$reward = array();
			$reward['product_id'] = $product_id;
			$reward['customer_group'] = $customer_group;
			$reward['points'] = $points;
			if (($incremental) && ($product_id != $previous_product_id)) {
				$old_product_reward_ids = $this->deleteReward( $product_id );
				if (isset($unlisted_product_ids[$product_id])) {
					unset($unlisted_product_ids[$product_id]);
				}
			}
			$this->moreRewardCells( $i, $j, $data, $reward );
			$this->storeRewardIntoDatabase( $reward, $old_product_reward_ids, $customer_group_ids );
			$previous_product_id = $product_id;
		}
		if ($incremental) {
			$this->deleteUnlistedRewards( $unlisted_product_ids );
		}
	}


	protected function getOptionIds() {
		$language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT option_id, name FROM `".DB_PREFIX."option_description` WHERE language_id='".(int)$language_id."'";
		$query = $this->db->query( $sql );
		$option_ids = array();
		foreach ($query->rows as $row) {
			$option_id = $row['option_id'];
			$name = htmlspecialchars_decode($row['name']);
			$option_ids[$name] = $option_id;
		}
		return $option_ids;
	}


	protected function storeProductOptionIntoDatabase( &$product_option, &$old_product_option_ids ) {
		// Opencart versions from 2.0 onwards use product_option.value instead of the older product_option.option_value
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."product_option` LIKE 'value'";
		$query = $this->db->query( $sql );
		$exist_po_value = ($query->num_rows > 0) ? true : false;

		// DB query for storing the product option
		$product_id = $product_option['product_id'];
		$option_id = $product_option['option_id'];
		$option_value = $product_option['option_value'];
		$required = $product_option['required'];
		$required = ((strtoupper($required)=="TRUE") || (strtoupper($required)=="YES") || (strtoupper($required)=="ENABLED")) ? 1 : 0;
		if (isset($old_product_option_ids[$product_id][$option_id])) {
			$product_option_id = $old_product_option_ids[$product_id][$option_id];
			if ($exist_po_value) {
				$sql  = "INSERT INTO `".DB_PREFIX."product_option` (`product_option_id`,`product_id`,`option_id`,`value`,`required` ) VALUES "; 
			} else {
				$sql  = "INSERT INTO `".DB_PREFIX."product_option` (`product_option_id`,`product_id`,`option_id`,`option_value`,`required` ) VALUES "; 
			}
			$sql .= "($product_option_id,$product_id,$option_id,'".$this->db->escape($option_value)."',$required)";
			$this->db->query($sql);
			unset($old_product_option_ids[$product_id][$option_id]);
		} else {
			if ($exist_po_value) {
				$sql  = "INSERT INTO `".DB_PREFIX."product_option` (`product_id`,`option_id`,`value`,`required` ) VALUES "; 
			} else {
				$sql  = "INSERT INTO `".DB_PREFIX."product_option` (`product_id`,`option_id`,`option_value`,`required` ) VALUES "; 
			}
			$sql .= "($product_id,$option_id,'".$this->db->escape($option_value)."',$required)";
			$this->db->query($sql);
		}
	}


	protected function deleteProductOptions() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."product_option`";
		$this->db->query( $sql );
	}


	protected function deleteProductOption( $product_id ) {
		$sql = "SELECT product_option_id, product_id, option_id FROM `".DB_PREFIX."product_option` WHERE product_id='".(int)$product_id."'";
		$query = $this->db->query( $sql );
		$old_product_option_ids = array();
		foreach ($query->rows as $row) {
			$product_option_id = $row['product_option_id'];
			$product_id = $row['product_id'];
			$option_id = $row['option_id'];
			$old_product_option_ids[$product_id][$option_id] = $product_option_id;
		}
		if ($old_product_option_ids) {
			$sql = "DELETE FROM `".DB_PREFIX."product_option` WHERE product_id='".(int)$product_id."'";
			$this->db->query( $sql );
		}
		return $old_product_option_ids;
	}


	protected function deleteUnlistedProductOptions( &$unlisted_product_ids ) {
		foreach ($unlisted_product_ids as $product_id) {
			$sql = "DELETE FROM `".DB_PREFIX."product_option` WHERE product_id='".(int)$product_id."'";
			$this->db->query( $sql );
		}
	}


	// function for reading additional cells in class extensions
	protected function moreProductOptionCells( $i, &$j, &$worksheet, &$product_option ) {
		return;
	}


	protected function uploadProductOptions( &$reader, $incremental, &$available_product_ids ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'ProductOptions' );
		if ($data==null) {
			return;
		}

		// if incremental then find current product IDs else delete all old product options
		if ($incremental) {
			$unlisted_product_ids = $available_product_ids;
		} else {
			$this->deleteProductOptions();
		}

		if (!$this->config->get( 'export_import_settings_use_option_id' )) {
			$option_ids = $this->getOptionIds();
		}

		// load the worksheet cells and store them to the database
		$old_product_option_ids = array();
		$previous_product_id = 0;
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			$j = 1;
			if ($i==0) {
				continue;
			}
			$product_id = trim($this->getCell($data,$i,$j++));
			if ($product_id=='') {
				continue;
			}
			if ($this->config->get( 'export_import_settings_use_option_id' )) {
				$option_id = $this->getCell($data,$i,$j++,'');
			} else {
				$option_name = $this->getCell($data,$i,$j++);
				$option_id = isset($option_ids[$option_name]) ? $option_ids[$option_name] : '';
			}
			if ($option_id=='') {
				continue;
			}
			$option_value = $this->getCell($data,$i,$j++,'');
			$required = $this->getCell($data,$i,$j++,'0');
			$product_option = array();
			$product_option['product_id'] = $product_id;
			$product_option['option_id'] = $option_id;
			$product_option['option_value'] = $option_value;
			$product_option['required'] = $required;
			if (($incremental) && ($product_id != $previous_product_id)) {
				$old_product_option_ids = $this->deleteProductOption( $product_id );
				if (isset($unlisted_product_ids[$product_id])) {
					unset($unlisted_product_ids[$product_id]);
				}
			}
			$this->moreProductOptionCells( $i, $j, $data, $product_option );
			$this->storeProductOptionIntoDatabase( $product_option, $old_product_option_ids );
			$previous_product_id = $product_id;
		}
		if ($incremental) {
			$this->deleteUnlistedProductOptions( $unlisted_product_ids );
		}
	}


	protected function getOptionValueIds() {
		$language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT option_id, option_value_id, name FROM `".DB_PREFIX."option_value_description` ";
		$sql .= "WHERE language_id='".(int)$language_id."'";
		$query = $this->db->query( $sql );
		$option_value_ids = array();
		foreach ($query->rows as $row) {
			$option_id = $row['option_id'];
			$option_value_id = $row['option_value_id'];
			$name = htmlspecialchars_decode($row['name']);
			$option_value_ids[$option_id][$name] = $option_value_id;
		}
		return $option_value_ids;
	}


	protected function getProductOptionIds( $product_id ) {
		$sql  = "SELECT product_option_id, option_id FROM `".DB_PREFIX."product_option` ";
		$sql .= "WHERE product_id='".(int)$product_id."'";
		$query = $this->db->query( $sql );
		$product_option_ids = array();
		foreach ($query->rows as $row) {
			$product_option_id = $row['product_option_id'];
			$option_id = $row['option_id'];
			$product_option_ids[$option_id] = $product_option_id;
		}
		return $product_option_ids;
	}


	protected function storeProductOptionValueIntoDatabase( &$product_option_value, &$old_product_option_value_ids ) {
		$product_id = $product_option_value['product_id'];
		$option_id = $product_option_value['option_id'];
		$option_value_id = $product_option_value['option_value_id'];
		$quantity = $product_option_value['quantity'];
		$subtract = $product_option_value['subtract'];
		$subtract = ((strtoupper($subtract)=="TRUE") || (strtoupper($subtract)=="YES") || (strtoupper($subtract)=="ENABLED")) ? 1 : 0;
		$price = $product_option_value['price'];
		$price_prefix = $product_option_value['price_prefix'];
		$points = $product_option_value['points'];
		$points_prefix = $product_option_value['points_prefix'];
		$weight = $product_option_value['weight'];
		$weight_prefix = $product_option_value['weight_prefix'];
		$product_option_id = $product_option_value['product_option_id'];
		if (isset($old_product_option_value_ids[$product_id][$option_id][$option_value_id])) {
			$product_option_value_id = $old_product_option_value_ids[$product_id][$option_id][$option_value_id];
			$sql  = "INSERT INTO `".DB_PREFIX."product_option_value` ";
			$sql .= "(`product_option_value_id`,`product_option_id`,`product_id`,`option_id`,`option_value_id`,`quantity`,`subtract`,`price`,`price_prefix`,`points`,`points_prefix`,`weight`,`weight_prefix` ) VALUES "; 
			$sql .= "($product_option_value_id,$product_option_id,$product_id,$option_id,$option_value_id,$quantity,$subtract,$price,'$price_prefix',$points,'$points_prefix',$weight,'$weight_prefix')";
			$this->db->query($sql);
			unset($old_product_option_value_ids[$product_id][$option_id][$option_value_id]);
		} else {
			$sql  = "INSERT INTO `".DB_PREFIX."product_option_value` ";
			$sql .= "(`product_option_id`,`product_id`,`option_id`,`option_value_id`,`quantity`,`subtract`,`price`,`price_prefix`,`points`,`points_prefix`,`weight`,`weight_prefix` ) VALUES "; 
			$sql .= "($product_option_id,$product_id,$option_id,$option_value_id,$quantity,$subtract,$price,'$price_prefix',$points,'$points_prefix',$weight,'$weight_prefix')";
			$this->db->query($sql);
		}
	}


	protected function deleteProductOptionValues() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."product_option_value`";
		$this->db->query( $sql );
	}


	protected function deleteProductOptionValue( $product_id ) {
		$sql = "SELECT product_option_value_id, product_id, option_id, option_value_id FROM `".DB_PREFIX."product_option_value` WHERE product_id='".(int)$product_id."'";
		$query = $this->db->query( $sql );
		$old_product_option_value_ids = array();
		foreach ($query->rows as $row) {
			$product_option_value_id = $row['product_option_value_id'];
			$product_id = $row['product_id'];
			$option_id = $row['option_id'];
			$option_value_id = $row['option_value_id'];
			$old_product_option_value_ids[$product_id][$option_id][$option_value_id] = $product_option_value_id;
		}
		if ($old_product_option_value_ids) {
			$sql = "DELETE FROM `".DB_PREFIX."product_option_value` WHERE product_id='".(int)$product_id."'";
			$this->db->query( $sql );
		}
		return $old_product_option_value_ids;
	}


	protected function deleteUnlistedProductOptionValues( &$unlisted_product_ids ) {
		foreach ($unlisted_product_ids as $product_id) {
			$sql = "DELETE FROM `".DB_PREFIX."product_option_value` WHERE product_id='".(int)$product_id."'";
			$this->db->query( $sql );
		}
	}


	// function for reading additional cells in class extensions
	protected function moreProductOptionValueCells( $i, &$j, &$worksheet, &$product_option_value ) {
		return;
	}


	protected function uploadProductOptionValues( &$reader, $incremental, &$available_product_ids ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'ProductOptionValues' );
		if ($data==null) {
			return;
		}

		// if incremental then find current product IDs else delete all old product option values
		if ($incremental) {
			$unlisted_product_ids = $available_product_ids;
		} else {
			$this->deleteProductOptionValues();
		}

		if (!$this->config->get( 'export_import_settings_use_option_id' )) {
			$option_ids = $this->getOptionIds();
		}
		if (!$this->config->get( 'export_import_settings_use_option_value_id' )) {
			$option_value_ids = $this->getOptionValueIds();
		}

		// load the worksheet cells and store them to the database
		$old_product_option_value_ids = array();
		$previous_product_id = 0;
		$product_option_id = 0;
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			$j = 1;
			if ($i==0) {
				continue;
			}
			$product_id = trim($this->getCell($data,$i,$j++));
			if ($product_id=='') {
				continue;
			}
			if ($this->config->get( 'export_import_settings_use_option_id' )) {
				$option_id = $this->getCell($data,$i,$j++,'');
			} else {
				$option_name = $this->getCell($data,$i,$j++);
				$option_id = isset($option_ids[$option_name]) ? $option_ids[$option_name] : '';
			}
			if ($option_id=='') {
				continue;
			}
			if ($this->config->get( 'export_import_settings_use_option_value_id' )) {
				$option_value_id = $this->getCell($data,$i,$j++,'');
			} else {
				$option_value_name = $this->getCell($data,$i,$j++);
				$option_value_id = isset($option_value_ids[$option_id][$option_value_name]) ? $option_value_ids[$option_id][$option_value_name] : '';
			}
			if ($option_value_id=='') {
				continue;
			}
			$quantity = $this->getCell($data,$i,$j++,'0');
			$subtract = $this->getCell($data,$i,$j++,'false');
			$price = $this->getCell($data,$i,$j++,'0');
			$price_prefix = $this->getCell($data,$i,$j++,'+');
			$points = $this->getCell($data,$i,$j++,'0');
			$points_prefix = $this->getCell($data,$i,$j++,'+');
			$weight = $this->getCell($data,$i,$j++,'0.00');
			$weight_prefix = $this->getCell($data,$i,$j++,'+');
			if ($product_id != $previous_product_id) {
				$product_option_ids = $this->getProductOptionIds( $product_id );
			}
			$product_option_value = array();
			$product_option_value['product_id'] = $product_id;
			$product_option_value['option_id'] = $option_id;
			$product_option_value['option_value_id'] = $option_value_id;
			$product_option_value['quantity'] = $quantity;
			$product_option_value['subtract'] = $subtract;
			$product_option_value['price'] = $price;
			$product_option_value['price_prefix'] = $price_prefix;
			$product_option_value['points'] = $points;
			$product_option_value['points_prefix'] = $points_prefix;
			$product_option_value['weight'] = $weight;
			$product_option_value['weight_prefix'] = $weight_prefix;
			$product_option_value['product_option_id'] = isset($product_option_ids[$option_id]) ? $product_option_ids[$option_id] : 0;
			if (($incremental) && ($product_id != $previous_product_id)) {
				$old_product_option_value_ids = $this->deleteProductOptionValue( $product_id );
				if (isset($unlisted_product_ids[$product_id])) {
					unset($unlisted_product_ids[$product_id]);
				}
			}
			$this->moreProductOptionValueCells( $i, $j, $data, $product_option_value );
			$this->storeProductOptionValueIntoDatabase( $product_option_value, $old_product_option_value_ids );
			$previous_product_id = $product_id;
		}
		if ($incremental) {
			$this->deleteUnlistedProductOptionValues( $unlisted_product_ids );
		}
	}


	protected function getAttributeGroupIds() {
		$language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT attribute_group_id, name FROM `".DB_PREFIX."attribute_group_description` ";
		$sql .= "WHERE language_id='".(int)$language_id."'";
		$query = $this->db->query( $sql );
		$attribute_group_ids = array();
		foreach ($query->rows as $row) {
			$attribute_group_id = $row['attribute_group_id'];
			$name = html_entity_decode($row['name'],ENT_QUOTES,'UTF-8');
			$attribute_group_ids[$name] = $attribute_group_id;
		}
		return $attribute_group_ids;
	}


	protected function getAttributeIds() {
		$language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT a.attribute_group_id, ad.attribute_id, ad.name FROM `".DB_PREFIX."attribute_description` ad ";
		$sql .= "INNER JOIN `".DB_PREFIX."attribute` a ON a.attribute_id=ad.attribute_id ";
		$sql .= "WHERE ad.language_id='".(int)$language_id."'";
		$query = $this->db->query( $sql );
		$attribute_ids = array();
		foreach ($query->rows as $row) {
			$attribute_group_id = $row['attribute_group_id'];
			$attribute_id = $row['attribute_id'];
			$name = html_entity_decode($row['name'],ENT_QUOTES,'UTF-8');
			$attribute_ids[$attribute_group_id][$name] = $attribute_id;
		}
		return $attribute_ids;
	}


	protected function storeProductAttributeIntoDatabase( &$product_attribute, &$languages ) {
		$product_id = $product_attribute['product_id'];
		$attribute_id = $product_attribute['attribute_id'];
		$texts = $product_attribute['texts'];
		foreach ($languages as $language) {
			$language_code = $language['code'];
			$language_id = $language['language_id'];
			$text = isset($texts[$language_code]) ? $this->db->escape($texts[$language_code]) : '';
			$sql  = "INSERT INTO `".DB_PREFIX."product_attribute` (`product_id`, `attribute_id`, `language_id`, `text`) VALUES ";
			$sql .= "( $product_id, $attribute_id, $language_id, '$text' );";
			$this->db->query( $sql );
		}
	}


	protected function deleteProductAttributes() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."product_attribute`";
		$this->db->query( $sql );
	}


	protected function deleteProductAttribute( $product_id ) {
		$sql = "DELETE FROM `".DB_PREFIX."product_attribute` WHERE product_id='".(int)$product_id."'";
		$this->db->query( $sql );
	}


	protected function deleteUnlistedProductAttributes( &$unlisted_product_ids ) {
		foreach ($unlisted_product_ids as $product_id) {
			$sql = "DELETE FROM `".DB_PREFIX."product_attribute` WHERE product_id='".(int)$product_id."'";
			$this->db->query( $sql );
		}
	}


	// function for reading additional cells in class extensions
	protected function moreProductAttributeCells( $i, &$j, &$worksheet, &$product_attribute ) {
		return;
	}


	protected function uploadProductAttributes( &$reader, $incremental, &$available_product_ids ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'ProductAttributes' );
		if ($data==null) {
			return;
		}

		// if incremental then find current product IDs else delete all old product attributes
		if ($incremental) {
			$unlisted_product_ids = $available_product_ids;
		} else {
			$this->deleteProductAttributes();
		}

		if (!$this->config->get( 'export_import_settings_use_attribute_group_id' )) {
			$attribute_group_ids = $this->getAttributeGroupIds();
		}
		if (!$this->config->get( 'export_import_settings_use_attribute_id' )) {
			$attribute_ids = $this->getAttributeIds();
		}

		// load the worksheet cells and store them to the database
		$languages = $this->getLanguages();
		$previous_product_id = 0;
		$first_row = array();
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			if ($i==0) {
				$max_col = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
				for ($j=1; $j<=$max_col; $j+=1) {
					$first_row[] = $this->getCell($data,$i,$j);
				}
				continue;
			}
			$j = 1;
			$product_id = trim($this->getCell($data,$i,$j++));
			if ($product_id=='') {
				continue;
			}
			if ($this->config->get( 'export_import_settings_use_attribute_group_id' )) {
				$attribute_group_id = $this->getCell($data,$i,$j++,'');
			} else {
				$attribute_group_name = $this->getCell($data,$i,$j++);
				$attribute_group_id = isset($attribute_group_ids[$attribute_group_name]) ? $attribute_group_ids[$attribute_group_name] : '';
			}
			if ($attribute_group_id=='') {
				continue;
			}
			if ($this->config->get( 'export_import_settings_use_attribute_id' )) {
				$attribute_id = $this->getCell($data,$i,$j++,'');
			} else {
				$attribute_name = $this->getCell($data,$i,$j++);
				$attribute_id = isset($attribute_ids[$attribute_group_id][$attribute_name]) ? $attribute_ids[$attribute_group_id][$attribute_name] : '';
			}
			if ($attribute_id=='') {
				continue;
			}
			$texts = array();
			while (($j<=$max_col) && $this->startsWith($first_row[$j-1],"text(")) {
				$language_code = substr($first_row[$j-1],strlen("text("),strlen($first_row[$j-1])-strlen("text(")-1);
				$text = $this->getCell($data,$i,$j++);
				$text = htmlspecialchars( $text );
				$texts[$language_code] = $text;
			}
			$product_attribute = array();
			$product_attribute['product_id'] = $product_id;
			$product_attribute['attribute_group_id'] = $attribute_group_id;
			$product_attribute['attribute_id'] = $attribute_id;
			$product_attribute['texts'] = $texts;
			if (($incremental) && ($product_id != $previous_product_id)) {
				$this->deleteProductAttribute( $product_id );
				if (isset($unlisted_product_ids[$product_id])) {
					unset($unlisted_product_ids[$product_id]);
				}
			}
			$this->moreProductAttributeCells( $i, $j, $data, $product_attribute );
			$this->storeProductAttributeIntoDatabase( $product_attribute, $languages );
			$previous_product_id = $product_id;
		}
		if ($incremental) {
			$this->deleteUnlistedProductAttributes( $unlisted_product_ids );
		}
	}


	protected function getFilterGroupIds() {
		$language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT filter_group_id, name FROM `".DB_PREFIX."filter_group_description` ";
		$sql .= "WHERE language_id='".(int)$language_id."'";
		$query = $this->db->query( $sql );
		$filter_group_ids = array();
		foreach ($query->rows as $row) {
			$filter_group_id = $row['filter_group_id'];
			$name = html_entity_decode($row['name'],ENT_QUOTES,'UTF-8');
			$filter_group_ids[$name] = $filter_group_id;
		}
		return $filter_group_ids;
	}


	protected function getFilterIds() {
		$language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT f.filter_group_id, fd.filter_id, fd.name FROM `".DB_PREFIX."filter_description` fd ";
		$sql .= "INNER JOIN `".DB_PREFIX."filter` f ON f.filter_id=fd.filter_id ";
		$sql .= "WHERE fd.language_id='".(int)$language_id."'";
		$query = $this->db->query( $sql );
		$filter_ids = array();
		foreach ($query->rows as $row) {
			$filter_group_id = $row['filter_group_id'];
			$filter_id = $row['filter_id'];
			$name = html_entity_decode($row['name'],ENT_QUOTES,'UTF-8');
			$filter_ids[$filter_group_id][$name] = $filter_id;
		}
		return $filter_ids;
	}


	protected function storeProductFilterIntoDatabase( &$product_filter, &$languages ) {
		$product_id = $product_filter['product_id'];
		$filter_id = $product_filter['filter_id'];
		$sql  = "INSERT INTO `".DB_PREFIX."product_filter` (`product_id`, `filter_id`) VALUES ";
		$sql .= "( $product_id, $filter_id );";
		$this->db->query( $sql );
	}


	protected function deleteProductFilters() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."product_filter`";
		$this->db->query( $sql );
	}


	protected function deleteProductFilter( $product_id ) {
		$sql = "DELETE FROM `".DB_PREFIX."product_filter` WHERE product_id='".(int)$product_id."'";
		$this->db->query( $sql );
	}


	protected function deleteUnlistedProductFilters( &$unlisted_product_ids ) {
		foreach ($unlisted_product_ids as $product_id) {
			$sql = "DELETE FROM `".DB_PREFIX."product_filter` WHERE product_id='".(int)$product_id."'";
			$this->db->query( $sql );
		}
	}


	// function for reading additional cells in class extensions
	protected function moreProductFilterCells( $i, &$j, &$worksheet, &$product_filter ) {
		return;
	}


	protected function uploadProductFilters( &$reader, $incremental, &$available_product_ids ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'ProductFilters' );
		if ($data==null) {
			return;
		}

		// if incremental then find current product IDs else delete all old product filters
		if ($incremental) {
			$unlisted_product_ids = $available_product_ids;
		} else {
			$this->deleteProductFilters();
		}

		if (!$this->config->get( 'export_import_settings_use_filter_group_id' )) {
			$filter_group_ids = $this->getFilterGroupIds();
		}
		if (!$this->config->get( 'export_import_settings_use_filter_id' )) {
			$filter_ids = $this->getFilterIds();
		}

		// load the worksheet cells and store them to the database
		$languages = $this->getLanguages();
		$previous_product_id = 0;
		$first_row = array();
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			if ($i==0) {
				$max_col = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
				for ($j=1; $j<=$max_col; $j+=1) {
					$first_row[] = $this->getCell($data,$i,$j);
				}
				continue;
			}
			$j = 1;
			$product_id = trim($this->getCell($data,$i,$j++));
			if ($product_id=='') {
				continue;
			}
			if ($this->config->get( 'export_import_settings_use_filter_group_id' )) {
				$filter_group_id = $this->getCell($data,$i,$j++,'');
			} else {
				$filter_group_name = $this->getCell($data,$i,$j++);
				$filter_group_id = isset($filter_group_ids[$filter_group_name]) ? $filter_group_ids[$filter_group_name] : '';
			}
			if ($filter_group_id=='') {
				continue;
			}
			if ($this->config->get( 'export_import_settings_use_filter_id' )) {
				$filter_id = $this->getCell($data,$i,$j++,'');
			} else {
				$filter_name = $this->getCell($data,$i,$j++);
				$filter_id = isset($filter_ids[$filter_group_id][$filter_name]) ? $filter_ids[$filter_group_id][$filter_name] : '';
			}
			if ($filter_id=='') {
				continue;
			}
			$product_filter = array();
			$product_filter['product_id'] = $product_id;
			$product_filter['filter_group_id'] = $filter_group_id;
			$product_filter['filter_id'] = $filter_id;
			if (($incremental) && ($product_id != $previous_product_id)) {
				$this->deleteProductFilter( $product_id );
				if (isset($unlisted_product_ids[$product_id])) {
					unset($unlisted_product_ids[$product_id]);
				}
			}
			$this->moreProductFilterCells( $i, $j, $data, $product_filter );
			$this->storeProductFilterIntoDatabase( $product_filter, $languages );
			$previous_product_id = $product_id;
		}
		if ($incremental) {
			$this->deleteUnlistedProductFilters( $unlisted_product_ids );
		}
	}


	protected function storeProductSEOKeywordIntoDatabase( &$product_seo_keyword, &$languages, $old_seo_url_ids ) {
		$product_id = $product_seo_keyword['product_id'];
		$store_id = $product_seo_keyword['store_id'];
		$keywords = $product_seo_keyword['keywords'];
		foreach ($languages as $language) {
			$language_id = $language['language_id'];
			$language_code = $language['code'];
			if (isset($keywords[$language_code])) {
				$keyword = $keywords[$language_code];
				if ($keyword != '') {
					if (isset($old_seo_url_ids[$product_id][$store_id][$language_id])) {
						$seo_url_id = $old_seo_url_ids[$product_id][$store_id][$language_id];
						$sql  = "INSERT INTO `".DB_PREFIX."seo_url` (`seo_url_id`, `store_id`, `language_id`, `query`, `keyword`) VALUES ";
						$sql .= "($seo_url_id, $store_id, $language_id, 'product_id=$product_id', '".$this->db->escape($keyword)."');";
						$this->db->query( $sql );
						unset($old_seo_url_ids[$product_id][$store_id][$language_id]);
					} else {
						$sql  = "INSERT INTO `".DB_PREFIX."seo_url` (`store_id`, `language_id`, `query`, `keyword`) VALUES ";
						$sql .= "($store_id, $language_id, 'product_id=$product_id', '".$this->db->escape($keyword)."');";
						$this->db->query( $sql );
					}
				}
			}
		}
	}


	protected function deleteProductSEOKeywords() {
		$sql = "DELETE FROM `".DB_PREFIX."seo_url` WHERE query LIKE 'product_id=%';";
		$this->db->query( $sql );
		$sql = "SELECT MAX(seo_url_id) AS max_seo_url_id FROM `".DB_PREFIX."seo_url`";
		$query = $this->db->query( $sql );
		$max_seo_url_id = isset( $query->row['max_seo_url_id'] ) ? $query->row['max_seo_url_id'] : 0;
		$auto_increment = $max_seo_url_id + 1;
		$sql = "ALTER TABLE `".DB_PREFIX."seo_url` AUTO_INCREMENT = $auto_increment;";
		$this->db->query( $sql );
	}


	protected function deleteProductSEOKeyword( $product_id ) {
		$old_seo_url_ids = array();
		$sql = "SELECT * FROM `".DB_PREFIX."seo_url` WHERE query='product_id=".(int)$product_id."';";
		$query = $this->db->query( $sql );
		foreach ($query->rows as $row) {
			$seo_url_id = $row['seo_url_id'];
			$store_id = $row['store_id'];
			$product_id = (int)substr($row['query'],strlen('product_id='));
			$language_id = $row['language_id'];
			$old_seo_url_ids[$product_id][$store_id][$language_id] = $seo_url_id;
		}
		$sql = "DELETE FROM `".DB_PREFIX."seo_url` WHERE query='product_id=".(int)$product_id."';";
		$this->db->query( $sql );
		return $old_seo_url_ids;
	}


	protected function deleteUnlistedProductSEOKeywords( &$unlisted_product_ids ) {
		foreach ($unlisted_product_ids as $product_id) {
			$sql = "DELETE FROM `".DB_PREFIX."seo_url` WHERE query='product_id=".(int)$product_id."';";
			$this->db->query( $sql );
		}
	}


	// function for reading additional cells in class extensions
	protected function moreProductSEOKeywordCells( $i, &$j, &$worksheet, &$product_seo_keyword ) {
		return;
	}


	protected function uploadProductSEOKeywords( &$reader, $incremental, &$available_product_ids ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'ProductSEOKeywords' );
		if ($data==null) {
			return;
		}

		// if DB table 'seo_url' doesn't exist (OpenCart 1.5.x, 2.x versions) then return immediately
		if (!$this->use_table_seo_url) {
			return;
		}

		// if incremental then find current product IDs else delete all old product SEO keywords
		if ($incremental) {
			$unlisted_product_ids = $available_product_ids;
		} else {
			$this->deleteProductSEOKeywords();
		}

		// load the worksheet cells and store them to the database
		$old_seo_url_ids = array();
		$languages = $this->getLanguages();
		$previous_product_id = 0;
		$first_row = array();
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			if ($i==0) {
				$max_col = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
				for ($j=1; $j<=$max_col; $j+=1) {
					$first_row[] = $this->getCell($data,$i,$j);
				}
				continue;
			}
			$j = 1;
			$product_id = trim($this->getCell($data,$i,$j++));
			if ($product_id=='') {
				continue;
			}
			$store_id = trim($this->getCell($data,$i,$j++));
			if ($store_id=='') {
				continue;
			}
			$keywords = array();
			while (($j<=$max_col) && $this->startsWith($first_row[$j-1],"keyword(")) {
				$language_code = substr($first_row[$j-1],strlen("keyword("),strlen($first_row[$j-1])-strlen("keyword(")-1);
				$keyword = trim($this->getCell($data,$i,$j++,''));
				$keyword = htmlspecialchars( $keyword );
				$keywords[$language_code] = $keyword;
			}
			$product_seo_keyword = array();
			$product_seo_keyword['product_id'] = $product_id;
			$product_seo_keyword['store_id'] = $store_id;
			$product_seo_keyword['keywords'] = $keywords;
			if (($incremental) && ($product_id != $previous_product_id)) {
				$old_seo_url_ids = $this->deleteProductSEOKeyword( $product_id );
				if (isset($unlisted_product_ids[$product_id])) {
					unset($unlisted_product_ids[$product_id]);
				}
			}
			$this->moreProductSEOKeywordCells( $i, $j, $data, $product_seo_keyword );
			$this->storeProductSEOKeywordIntoDatabase( $product_seo_keyword, $languages, $old_seo_url_ids );
			$previous_product_id = $product_id;
		}
		if ($incremental) {
			$this->deleteUnlistedProductSEOKeywords( $unlisted_product_ids );
		}
	}


	protected function storeOptionIntoDatabase( &$option, &$languages ) {
		$option_id = $option['option_id'];
		$type = $option['type'];
		$sort_order = $option['sort_order'];
		$names = $option['names'];
		$sql  = "INSERT INTO `".DB_PREFIX."option` (`option_id`,`type`,`sort_order`) VALUES ";
		$sql .= "( $option_id, '".$this->db->escape($type)."', $sort_order );";
		$this->db->query( $sql );
		foreach ($languages as $language) {
			$language_code = $language['code'];
			$language_id = $language['language_id'];
			$name = isset($names[$language_code]) ? $this->db->escape($names[$language_code]) : '';
			$sql  = "INSERT INTO `".DB_PREFIX."option_description` (`option_id`, `language_id`, `name`) VALUES ";
			$sql .= "( $option_id, $language_id, '$name' );";
			$this->db->query( $sql );
		}
	}


	protected function deleteOptions() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."option`";
		$this->db->query( $sql );
		$sql = "TRUNCATE TABLE `".DB_PREFIX."option_description`";
		$this->db->query( $sql );
	}


	protected function deleteOption( $option_id ) {
		$sql = "DELETE FROM `".DB_PREFIX."option` WHERE option_id='".(int)$option_id."'";
		$this->db->query( $sql );
		$sql = "DELETE FROM `".DB_PREFIX."option_description` WHERE option_id='".(int)$option_id."'";
		$this->db->query( $sql );
	}


	// function for reading additional cells in class extensions
	protected function moreOptionCells( $i, &$j, &$worksheet, &$option ) {
		return;
	}


	protected function uploadOptions( &$reader, $incremental ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'Options' );
		if ($data==null) {
			return;
		}

		// find the installed languages
		$languages = $this->getLanguages();

		// if not incremental then delete all old options
		if (!$incremental) {
			$this->deleteOptions();
		}

		// load the worksheet cells and store them to the database
		$first_row = array();
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			if ($i==0) {
				$max_col = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
				for ($j=1; $j<=$max_col; $j+=1) {
					$first_row[] = $this->getCell($data,$i,$j);
				}
				continue;
			}
			$j = 1;
			$option_id = trim($this->getCell($data,$i,$j++));
			if ($option_id=='') {
				continue;
			}
			$type = $this->getCell($data,$i,$j++,'');
			$sort_order = $this->getCell($data,$i,$j++,'0');
			$names = array();
			while (($j<=$max_col) && $this->startsWith($first_row[$j-1],"name(")) {
				$language_code = substr($first_row[$j-1],strlen("name("),strlen($first_row[$j-1])-strlen("name(")-1);
				$name = $this->getCell($data,$i,$j++);
				$name = htmlspecialchars( $name );
				$names[$language_code] = $name;
			}
			$option = array();
			$option['option_id'] = $option_id;
			$option['type'] = $type;
			$option['sort_order'] = $sort_order;
			$option['names'] = $names;
			if ($incremental) {
				$this->deleteOption( $option_id );
			}
			$this->moreOptionCells( $i, $j, $data, $option );
			$this->storeOptionIntoDatabase( $option, $languages );
		}
	}


	protected function storeOptionValueIntoDatabase( &$option_value, &$languages, $exist_image=true ) {
		$option_value_id = $option_value['option_value_id'];
		$option_id = $option_value['option_id'];
		if ($exist_image) {
			$image = $option_value['image'];
		}
		$sort_order = $option_value['sort_order'];
		$names = $option_value['names'];
		if ($exist_image) {
			$sql  = "INSERT INTO `".DB_PREFIX."option_value` (`option_value_id`,`option_id`,`image`,`sort_order`) VALUES ";
			$sql .= "( $option_value_id, $option_id, '".$this->db->escape($image)."', $sort_order );"; 
		} else {
			$sql  = "INSERT INTO `".DB_PREFIX."option_value` (`option_value_id`,`option_id`,`sort_order`) VALUES ";
			$sql .= "( $option_value_id, $option_id, $sort_order );"; 
		}
		$this->db->query( $sql );
		foreach ($languages as $language) {
			$language_code = $language['code'];
			$language_id = $language['language_id'];
			$name = isset($names[$language_code]) ? $this->db->escape($names[$language_code]) : '';
			$sql  = "INSERT INTO `".DB_PREFIX."option_value_description` (`option_value_id`, `language_id`, `option_id`, `name`) ";
			$sql .= "VALUES ( $option_value_id, $language_id, $option_id, '$name' );";
			$this->db->query( $sql );
		}
	}


	protected function deleteOptionValues() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."option_value`";
		$this->db->query( $sql );
		$sql = "TRUNCATE TABLE `".DB_PREFIX."option_value_description`";
		$this->db->query( $sql );
	}


	protected function deleteOptionValue( $option_value_id ) {
		$sql = "DELETE FROM `".DB_PREFIX."option_value` WHERE option_value_id='".(int)$option_value_id."'";
		$this->db->query( $sql );
		$sql = "DELETE FROM `".DB_PREFIX."option_value_description` WHERE option_value_id='".(int)$option_value_id."'";
		$this->db->query( $sql );
	}


	// function for reading additional cells in class extensions
	protected function moreOptionValueCells( $i, &$j, &$worksheet, &$option ) {
		return;
	}


	protected function uploadOptionValues( &$reader, $incremental ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'OptionValues' );
		if ($data==null) {
			return;
		}

		// check for the existence of option_value.image field
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."option_value` LIKE 'image'";
		$query = $this->db->query( $sql );
		$exist_image = ($query->num_rows > 0) ? true : false;

		// find the installed languages
		$languages = $this->getLanguages();

		// if not incremental then delete all old option values
		if (!$incremental) {
			$this->deleteOptionValues();
		}

		// load the worksheet cells and store them to the database
		$first_row = array();
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			if ($i==0) {
				$max_col = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
				for ($j=1; $j<=$max_col; $j+=1) {
					$first_row[] = $this->getCell($data,$i,$j);
				}
				continue;
			}
			$j = 1;
			$option_value_id = trim($this->getCell($data,$i,$j++));
			if ($option_value_id=='') {
				continue;
			}
			$option_id = trim($this->getCell($data,$i,$j++));
			if ($option_id=='') {
				continue;
			}
			if ($exist_image) {
				$image = $this->getCell($data,$i,$j++,'');
			}
			$sort_order = $this->getCell($data,$i,$j++,'0');
			$names = array();
			while (($j<=$max_col) && $this->startsWith($first_row[$j-1],"name(")) {
				$language_code = substr($first_row[$j-1],strlen("name("),strlen($first_row[$j-1])-strlen("name(")-1);
				$name = $this->getCell($data,$i,$j++);
				$name = htmlspecialchars( $name );
				$names[$language_code] = $name;
			}
			$option_value = array();
			$option_value['option_value_id'] = $option_value_id;
			$option_value['option_id'] = $option_id;
			if ($exist_image) {
				$option_value['image'] = $image;
			}
			$option_value['sort_order'] = $sort_order;
			$option_value['names'] = $names;
			if ($incremental) {
				$this->deleteOptionValue( $option_value_id );
			}
			$this->moreOptionValueCells( $i, $j, $data, $option_value );
			$this->storeOptionValueIntoDatabase( $option_value, $languages, $exist_image );
		}
	}


	protected function storeAttributeGroupIntoDatabase( &$attribute_group, &$languages ) {
		$attribute_group_id = $attribute_group['attribute_group_id'];
		$sort_order = $attribute_group['sort_order'];
		$names = $attribute_group['names'];
		$sql  = "INSERT INTO `".DB_PREFIX."attribute_group` (`attribute_group_id`,`sort_order`) VALUES ";
		$sql .= "( $attribute_group_id, $sort_order );"; 
		$this->db->query( $sql );
		foreach ($languages as $language) {
			$language_code = $language['code'];
			$language_id = $language['language_id'];
			$name = isset($names[$language_code]) ? $this->db->escape($names[$language_code]) : '';
			$sql  = "INSERT INTO `".DB_PREFIX."attribute_group_description` (`attribute_group_id`, `language_id`, `name`) VALUES ";
			$sql .= "( $attribute_group_id, $language_id, '$name' );";
			$this->db->query( $sql );
		}
	}


	protected function deleteAttributeGroups() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."attribute_group`";
		$this->db->query( $sql );
		$sql = "TRUNCATE TABLE `".DB_PREFIX."attribute_group_description`";
		$this->db->query( $sql );
	}


	protected function deleteAttributeGroup( $attribute_group_id ) {
		$sql = "DELETE FROM `".DB_PREFIX."attribute_group` WHERE attribute_group_id='".(int)$attribute_group_id."'";
		$this->db->query( $sql );
		$sql = "DELETE FROM `".DB_PREFIX."attribute_group_description` WHERE attribute_group_id='".(int)$attribute_group_id."'";
		$this->db->query( $sql );
	}


	// function for reading additional cells in class extensions
	protected function moreAttributeGroupCells( $i, &$j, &$worksheet, &$attribute_group ) {
		return;
	}


	protected function uploadAttributeGroups( &$reader, $incremental ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'AttributeGroups' );
		if ($data==null) {
			return;
		}

		// find the installed languages
		$languages = $this->getLanguages();

		// if not incremental then delete all old attribute groups
		if (!$incremental) {
			$this->deleteAttributeGroups();
		}

		// load the worksheet cells and store them to the database
		$first_row = array();
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			if ($i==0) {
				$max_col = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
				for ($j=1; $j<=$max_col; $j+=1) {
					$first_row[] = $this->getCell($data,$i,$j);
				}
				continue;
			}
			$j = 1;
			$attribute_group_id = trim($this->getCell($data,$i,$j++));
			if ($attribute_group_id=='') {
				continue;
			}
			$sort_order = $this->getCell($data,$i,$j++,'0');
			$names = array();
			while (($j<=$max_col) && $this->startsWith($first_row[$j-1],"name(")) {
				$language_code = substr($first_row[$j-1],strlen("name("),strlen($first_row[$j-1])-strlen("name(")-1);
				$name = $this->getCell($data,$i,$j++);
				$name = htmlspecialchars( $name );
				$names[$language_code] = $name;
			}
			$attribute_group = array();
			$attribute_group['attribute_group_id'] = $attribute_group_id;
			$attribute_group['sort_order'] = $sort_order;
			$attribute_group['names'] = $names;
			if ($incremental) {
				$this->deleteAttributeGroup( $attribute_group_id );
			}
			$this->moreAttributeGroupCells( $i, $j, $data, $attribute_group );
			$this->storeAttributeGroupIntoDatabase( $attribute_group, $languages );
		}
	}


	protected function storeAttributeIntoDatabase( &$attribute, &$languages ) {
		$attribute_id = $attribute['attribute_id'];
		$attribute_group_id = $attribute['attribute_group_id'];
		$sort_order = $attribute['sort_order'];
		$names = $attribute['names'];
		$sql  = "INSERT INTO `".DB_PREFIX."attribute` (`attribute_id`,`attribute_group_id`,`sort_order`) VALUES ";
		$sql .= "( $attribute_id, $attribute_group_id, $sort_order );"; 
		$this->db->query( $sql );
		foreach ($languages as $language) {
			$language_code = $language['code'];
			$language_id = $language['language_id'];
			$name = isset($names[$language_code]) ? $this->db->escape($names[$language_code]) : '';
			$sql  = "INSERT INTO `".DB_PREFIX."attribute_description` (`attribute_id`, `language_id`, `name`) ";
			$sql .= "VALUES ( $attribute_id, $language_id, '$name' );";
			$this->db->query( $sql );
		}
	}


	protected function deleteAttributes() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."attribute`";
		$this->db->query( $sql );
		$sql = "TRUNCATE TABLE `".DB_PREFIX."attribute_description`";
		$this->db->query( $sql );
	}


	protected function deleteAttribute( $attribute_id ) {
		$sql = "DELETE FROM `".DB_PREFIX."attribute` WHERE attribute_id='".(int)$attribute_id."'";
		$this->db->query( $sql );
		$sql = "DELETE FROM `".DB_PREFIX."attribute_description` WHERE attribute_id='".(int)$attribute_id."'";
		$this->db->query( $sql );
	}


	// function for reading additional cells in class extensions
	protected function moreAttributeCells( $i, &$j, &$worksheet, &$attribute ) {
		return;
	}


	protected function uploadAttributes( &$reader, $incremental ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'Attributes' );
		if ($data==null) {
			return;
		}

		// find the installed languages
		$languages = $this->getLanguages();

		// if not incremental then delete all old attributes
		if (!$incremental) {
			$this->deleteAttributes();
		}

		// load the worksheet cells and store them to the database
		$first_row = array();
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			if ($i==0) {
				$max_col = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
				for ($j=1; $j<=$max_col; $j+=1) {
					$first_row[] = $this->getCell($data,$i,$j);
				}
				continue;
			}
			$j = 1;
			$attribute_id = trim($this->getCell($data,$i,$j++));
			if ($attribute_id=='') {
				continue;
			}
			$attribute_group_id = trim($this->getCell($data,$i,$j++));
			if ($attribute_group_id=='') {
				continue;
			}
			$sort_order = $this->getCell($data,$i,$j++,'0');
			$names = array();
			while (($j<=$max_col) && $this->startsWith($first_row[$j-1],"name(")) {
				$language_code = substr($first_row[$j-1],strlen("name("),strlen($first_row[$j-1])-strlen("name(")-1);
				$name = $this->getCell($data,$i,$j++);
				$name = htmlspecialchars( $name );
				$names[$language_code] = $name;
			}
			$attribute = array();
			$attribute['attribute_id'] = $attribute_id;
			$attribute['attribute_group_id'] = $attribute_group_id;
			$attribute['sort_order'] = $sort_order;
			$attribute['names'] = $names;
			if ($incremental) {
				$this->deleteAttribute( $attribute_id );
			}
			$this->moreAttributeCells( $i, $j, $data, $attribute );
			$this->storeAttributeIntoDatabase( $attribute, $languages );
		}
	}


	protected function storeFilterGroupIntoDatabase( &$filter_group, &$languages ) {
		$filter_group_id = $filter_group['filter_group_id'];
		$sort_order = $filter_group['sort_order'];
		$names = $filter_group['names'];
		$sql  = "INSERT INTO `".DB_PREFIX."filter_group` (`filter_group_id`,`sort_order`) VALUES ";
		$sql .= "( $filter_group_id, $sort_order );"; 
		$this->db->query( $sql );
		foreach ($languages as $language) {
			$language_code = $language['code'];
			$language_id = $language['language_id'];
			$name = isset($names[$language_code]) ? $this->db->escape($names[$language_code]) : '';
			$sql  = "INSERT INTO `".DB_PREFIX."filter_group_description` (`filter_group_id`, `language_id`, `name`) VALUES ";
			$sql .= "( $filter_group_id, $language_id, '$name' );";
			$this->db->query( $sql );
		}
	}


	protected function deleteFilterGroups() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."filter_group`";
		$this->db->query( $sql );
		$sql = "TRUNCATE TABLE `".DB_PREFIX."filter_group_description`";
		$this->db->query( $sql );
	}


	protected function deleteFilterGroup( $filter_group_id ) {
		$sql = "DELETE FROM `".DB_PREFIX."filter_group` WHERE filter_group_id='".(int)$filter_group_id."'";
		$this->db->query( $sql );
		$sql = "DELETE FROM `".DB_PREFIX."filter_group_description` WHERE filter_group_id='".(int)$filter_group_id."'";
		$this->db->query( $sql );
	}


	// function for reading additional cells in class extensions
	protected function moreFilterGroupCells( $i, &$j, &$worksheet, &$filter_group ) {
		return;
	}


	protected function uploadFilterGroups( &$reader, $incremental ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'FilterGroups' );
		if ($data==null) {
			return;
		}

		// find the installed languages
		$languages = $this->getLanguages();

		// if not incremental then delete all old filter groups
		if (!$incremental) {
			$this->deleteFilterGroups();
		}

		// load the worksheet cells and store them to the database
		$first_row = array();
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			if ($i==0) {
				$max_col = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
				for ($j=1; $j<=$max_col; $j+=1) {
					$first_row[] = $this->getCell($data,$i,$j);
				}
				continue;
			}
			$j = 1;
			$filter_group_id = trim($this->getCell($data,$i,$j++));
			if ($filter_group_id=='') {
				continue;
			}
			$sort_order = $this->getCell($data,$i,$j++,'0');
			$names = array();
			while (($j<=$max_col) && $this->startsWith($first_row[$j-1],"name(")) {
				$language_code = substr($first_row[$j-1],strlen("name("),strlen($first_row[$j-1])-strlen("name(")-1);
				$name = $this->getCell($data,$i,$j++);
				$name = htmlspecialchars( $name );
				$names[$language_code] = $name;
			}
			$filter_group = array();
			$filter_group['filter_group_id'] = $filter_group_id;
			$filter_group['sort_order'] = $sort_order;
			$filter_group['names'] = $names;
			if ($incremental) {
				$this->deleteFilterGroup( $filter_group_id );
			}
			$this->moreFilterGroupCells( $i, $j, $data, $filter_group );
			$this->storeFilterGroupIntoDatabase( $filter_group, $languages );
		}
	}


	protected function storeFilterIntoDatabase( &$filter, &$languages ) {
		$filter_id = $filter['filter_id'];
		$filter_group_id = $filter['filter_group_id'];
		$sort_order = $filter['sort_order'];
		$names = $filter['names'];
		$sql  = "INSERT INTO `".DB_PREFIX."filter` (`filter_id`,`filter_group_id`,`sort_order`) VALUES ";
		$sql .= "( $filter_id, $filter_group_id, $sort_order );"; 
		$this->db->query( $sql );
		foreach ($languages as $language) {
			$language_code = $language['code'];
			$language_id = $language['language_id'];
			$name = isset($names[$language_code]) ? $this->db->escape($names[$language_code]) : '';
			$sql  = "INSERT INTO `".DB_PREFIX."filter_description` (`filter_id`, `language_id`, `filter_group_id`, `name`) ";
			$sql .= "VALUES ( $filter_id, $language_id, $filter_group_id, '$name' );";
			$this->db->query( $sql );
		}
	}


	protected function deleteFilters() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."filter`";
		$this->db->query( $sql );
		$sql = "TRUNCATE TABLE `".DB_PREFIX."filter_description`";
		$this->db->query( $sql );
	}


	protected function deleteFilter( $filter_id ) {
		$sql = "DELETE FROM `".DB_PREFIX."filter` WHERE filter_id='".(int)$filter_id."'";
		$this->db->query( $sql );
		$sql = "DELETE FROM `".DB_PREFIX."filter_description` WHERE filter_id='".(int)$filter_id."'";
		$this->db->query( $sql );
	}

	
	// function for reading additional cells in class extensions
	protected function moreFilterCells( $i, &$j, &$worksheet, &$filter ) {
		return;
	}


	protected function uploadFilters( &$reader, $incremental ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'Filters' );
		if ($data==null) {
			return;
		}

		// find the installed languages
		$languages = $this->getLanguages();

		// if not incremental then delete all old filters
		if (!$incremental) {
			$this->deleteFilters();
		}

		// load the worksheet cells and store them to the database
		$first_row = array();
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			if ($i==0) {
				$max_col = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
				for ($j=1; $j<=$max_col; $j+=1) {
					$first_row[] = $this->getCell($data,$i,$j);
				}
				continue;
			}
			$j = 1;
			$filter_id = trim($this->getCell($data,$i,$j++));
			if ($filter_id=='') {
				continue;
			}
			$filter_group_id = trim($this->getCell($data,$i,$j++));
			if ($filter_group_id=='') {
				continue;
			}
			$sort_order = $this->getCell($data,$i,$j++,'0');
			$names = array();
			while (($j<=$max_col) && $this->startsWith($first_row[$j-1],"name(")) {
				$language_code = substr($first_row[$j-1],strlen("name("),strlen($first_row[$j-1])-strlen("name(")-1);
				$name = $this->getCell($data,$i,$j++);
				$name = htmlspecialchars( $name );
				$names[$language_code] = $name;
			}
			$filter = array();
			$filter['filter_id'] = $filter_id;
			$filter['filter_group_id'] = $filter_group_id;
			$filter['sort_order'] = $sort_order;
			$filter['names'] = $names;
			if ($incremental) {
				$this->deleteFilter( $filter_id );
			}
			$this->moreFilterCells( $i, $j, $data, $filter );
			$this->storeFilterIntoDatabase( $filter, $languages );
		}
	}


	protected function getAvailableCustomerIds() {
		$sql = "SELECT `customer_id` FROM `".DB_PREFIX."customer`;";
		$result = $this->db->query( $sql );
		$customer_ids = array();
		foreach ($result->rows as $row) {
			$customer_ids[$row['customer_id']] = $row['customer_id'];
		}
		return $customer_ids;
	}


	protected function storeCustomerIntoDatabase( &$customer, $exist_custom_field, $exist_salt, $exist_safe, $exist_token, $exist_code, $exist_approved ) {
		$customer_id = $customer['customer_id'];
		$customer_group_id = $customer['customer_group_id'];
		$store_id = $customer['store_id'];
		$firstname = $customer['firstname'];
		$lastname = $customer['lastname'];
		$email = $customer['email'];
		$telephone = $customer['telephone'];
		$fax = $customer['fax'];
		$password = $customer['password'];
		if ($exist_salt) {
			$salt = $customer['salt'];
		}
		$cart = $customer['cart'];
		$wishlist = $customer['wishlist'];
		$wishlist = ((strtoupper($wishlist)=="TRUE") || (strtoupper($wishlist)=="YES") || (strtoupper($wishlist)=="ENABLED")) ? 1 : 0;
		$newsletter = $customer['newsletter'];
		$newsletter = ((strtoupper($newsletter)=="TRUE") || (strtoupper($newsletter)=="YES") || (strtoupper($newsletter)=="ENABLED")) ? 1 : 0;
		$address_id = '0';
		if ($exist_custom_field) {
			$custom_field = $customer['custom_field'];
		}
		$ip = $customer['ip'];
		$status = $customer['status'];
		$status = ((strtoupper($status)=="TRUE") || (strtoupper($status)=="YES") || (strtoupper($status)=="ENABLED")) ? 1 : 0;
		if ($exist_approved) {
			$approved = $customer['approved'];
			$approved = ((strtoupper($approved)=="TRUE") || (strtoupper($approved)=="YES") || (strtoupper($approved)=="ENABLED")) ? 1 : 0;
		}
		if ($exist_safe) {
			$safe = $customer['safe'];
			$safe = ((strtoupper($safe)=="TRUE") || (strtoupper($safe)=="YES") || (strtoupper($safe)=="ENABLED")) ? 1 : 0;
		}
		if ($exist_token) {
			$token = $customer['token'];
		}
		if ($exist_code) {
			$code = $customer['code'];
		}
		$date_added = $customer['date_added'];

		$sql  = "INSERT INTO `".DB_PREFIX."customer` ";
		$sql .= "(`customer_id`,`customer_group_id`,`store_id`,`firstname`,`lastname`,";
		$sql .= "`email`,`telephone`,`fax`,`password`,";
		if ($exist_salt) {
			$sql .= "`salt`,";
		}
		$sql .= "`cart`,`wishlist`,`newsletter`,`address_id`,";
		if ($exist_custom_field) {
			$sql .= "`custom_field`,";
		}
		$sql .= "`ip`,`status`,";
		if ($exist_approved) {
			$sql .= "`approved`,";
		}
		if ($exist_safe) {
			$sql .= "`safe`,";
		}
		if ($exist_token) {
			$sql .= "`token`,";
		}
		if ($exist_code) {
			$sql .= "`code`,";
		}
		$sql .= "`date_added`) VALUES ";
		$sql .= "( $customer_id, $customer_group_id, $store_id, ";
		$sql .= "'".$this->db->escape($firstname)."', ";
		$sql .= "'".$this->db->escape($lastname)."', ";
		$sql .= "'".$this->db->escape($email)."', ";
		$sql .= "'".$this->db->escape($telephone)."', ";
		$sql .= "'".$this->db->escape($fax)."', ";
		$sql .= "'".$this->db->escape($password)."', ";
		if ($exist_salt) {
			$sql .= "'".$this->db->escape($salt)."', ";
		}
		$sql .= "'".$this->db->escape($cart)."', ";
		$sql .= "$wishlist, $newsletter, $address_id, ";
		if ($exist_custom_field) {
			$sql .= "'".$this->db->escape($custom_field)."', ";
		}
		$sql .= "'".$this->db->escape($ip)."', ";
		$sql .= "$status, ";
		if ($exist_approved) {
			$sql .= "$approved, ";
		}
		if ($exist_safe) {
			$sql .= "$safe, ";
		}
		if ($exist_token) {
			$sql .= "'".$this->db->escape($token)."', ";
		}
		if ($exist_code) {
			$sql .= "'".$this->db->escape($code)."', ";
		}
		$sql .= "'".$this->db->escape($date_added)."');";
		$this->db->query( $sql );
	}


	protected function deleteCustomers() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."customer`";
		$this->db->query( $sql );
	}


	protected function deleteCustomer( $customer_id ) {
		$sql = "DELETE FROM `".DB_PREFIX."customer` WHERE customer_id='".(int)$customer_id."'";
		$this->db->query( $sql );
	}


	// function for reading additional cells in class extensions
	protected function moreCustomerCells( $i, &$j, &$worksheet, &$customer ) {
		return;
	}


	protected function uploadCustomers( &$reader, $incremental, &$available_customer_ids=array() ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'Customers' );
		if ($data==null) {
			return;
		}

		// Some fields are only available in certain Opencart versions
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'custom_field'";
		$query = $this->db->query( $sql );
		$exist_custom_field = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'salt'";
		$query = $this->db->query( $sql );
		$exist_salt = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'safe'";
		$query = $this->db->query( $sql );
		$exist_safe = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'token'";
		$query = $this->db->query( $sql );
		$exist_token = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'code'";
		$query = $this->db->query( $sql );
		$exist_code = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'approved'";
		$query = $this->db->query( $sql );
		$exist_approved = ($query->num_rows > 0) ? true : false;

		// get customer_group ids indexed by customer group names
		$customer_group_ids = $this->getCustomerGroupIds();

		// if incremental then find current customer IDs else delete all old customers
		$available_customer_ids = array();
		if ($incremental) {
			$old_customer_ids = $this->getAvailableCustomerIds();
		} else {
			$this->deleteCustomers();
		}

		// load the worksheet cells and store them to the database
		$first_row = array();
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			if ($i==0) {
				$max_col = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
				for ($j=1; $j<=$max_col; $j+=1) {
					$first_row[] = $this->getCell($data,$i,$j);
				}
				continue;
			}
			$j = 1;
			$customer_id = trim($this->getCell($data,$i,$j++));
			if ($customer_id=="") {
				continue;
			}
			$customer_group = trim($this->getCell($data,$i,$j++));
			$customer_group_id = isset($customer_group_ids[$customer_group]) ? $customer_group_ids[$customer_group] : '0';
			$store_id = $this->getCell($data,$i,$j++,'0');
			$firstname = trim($this->getCell($data,$i,$j++));
			$lastname = trim($this->getCell($data,$i,$j++));
			$email = trim($this->getCell($data,$i,$j++));
			$telephone = trim($this->getCell($data,$i,$j++));
			$fax = trim($this->getCell($data,$i,$j++));
			$password = trim($this->getCell($data,$i,$j++));
			if ($exist_salt) {
				$salt = trim($this->getCell($data,$i,$j++));
			}
			if ($password == '') {
				// generate a default password 'opencart'
				if ($exist_salt) {
					if ($salt == '') {
						$salt = version_compare(VERSION,'2.1.0.0','<') ? substr(md5(uniqid(rand(), true)), 0, 9) : token(9); 
					}
					$password = sha1($salt . sha1($salt . sha1('opencart')));
				} else {
					$password = md5('opencart');
				}
			}
			$cart = trim($this->getCell($data,$i,$j++));
			$wishlist = trim($this->getCell($data,$i,$j++));
			$newsletter = $this->getCell($data,$i,$j++,'no');
			if ($exist_custom_field) {
				$custom_field = trim($this->getCell($data,$i,$j++));
			}
			$ip = trim($this->getCell($data,$i,$j++));
			$status = $this->getCell($data,$i,$j++,'true');
			if ($exist_approved) {
				$approved = $this->getCell($data,$i,$j++,'true');
			}
			if ($exist_safe) {
				$safe = $this->getCell($data,$i,$j++,'true');
			}
			if ($exist_token) {
				$token = trim($this->getCell($data,$i,$j++));
			}
			if ($exist_code) {
				$code = trim($this->getCell($data,$i,$j++));
			}
			$date_added = trim($this->getCell($data,$i,$j++));
			$date_added = ((is_string($date_added)) && (strlen($date_added)>0)) ? $date_added : "NOW()";

			$customer = array();
			$customer['customer_id'] = $customer_id;
			$customer['customer_group_id'] = $customer_group_id;
			$customer['store_id'] = $store_id;
			$customer['firstname'] = $firstname;
			$customer['lastname'] = $lastname;
			$customer['email'] = $email;
			$customer['telephone'] = $telephone;
			$customer['fax'] = $fax;
			$customer['password'] = $password;
			if ($exist_salt) {
				$customer['salt'] = $salt;
			}
			$customer['cart'] = $cart;
			$customer['wishlist'] = $wishlist;
			$customer['newsletter'] = $newsletter;
			if ($exist_custom_field) {
				$customer['custom_field'] = $custom_field;
			}
			$customer['ip'] = $ip;
			$customer['status'] = $status;
			if ($exist_approved) {
				$customer['approved'] = $approved;
			}
			if ($exist_safe) {
				$customer['safe'] = $safe;
			}
			if ($exist_token) {
				$customer['token'] = $token;
			}
			if ($exist_code) {
				$customer['code'] = $code;
			}
			$customer['date_added'] = $date_added;
			if ($incremental) {
				if ($old_customer_ids) {
					if (in_array((int)$customer_id,$old_customer_ids)) {
						$this->deleteCustomer( $customer_id );
					}
				}
			}
			$available_customer_ids[$customer_id] = $customer_id;
			$this->moreCustomerCells( $i, $j, $data, $customer );
			$this->storeCustomerIntoDatabase( $customer, $exist_custom_field, $exist_salt, $exist_safe, $exist_token, $exist_code, $exist_approved );
		}
	}


	protected function getAvailableCountryIds() {
		$sql = "SELECT country_id, `name` AS country_name FROM `".DB_PREFIX."country`";
		$query = $this->db->query( $sql );
		$country_ids = array();
		foreach ($query->rows as $row) {
			$country_id = $row['country_id'];
			$country = $row['country_name'];
			$country_ids[$country] = $country_id;
		}
		return $country_ids;
	}


	protected function getAvailableZoneIds() {
		$sql  = "SELECT c.country_id, z.zone_id, c.`name` AS country_name, z.`name` AS zone_name ";
		$sql .= "FROM `".DB_PREFIX."country` c ";
		$sql .= "LEFT JOIN `".DB_PREFIX."zone` z ON z.country_id=c.country_id";
		$query = $this->db->query( $sql );
		$zone_ids = array();
		foreach ($query->rows as $row) {
			$country_id = $row['country_id'];
			$country = $row['country_name'];
			$zone_id = ($row['zone_id']) ? $row['zone_id'] : 0;
			$zone = ($row['zone_name']) ? $row['zone_name'] : '';
			$zone_ids[$country][$zone] = $zone_id;
		}
		return $zone_ids;
	}


	protected function storeAddressIntoDatabase( &$address, $exist_company_id, $exist_tax_id, $exist_custom_field ) {
		$customer_id = $address['customer_id'];
		$firstname = $address['firstname'];
		$lastname = $address['lastname'];
		$company = $address['company'];
		if ($exist_company_id) {
			$company_id = $address['company_id'];
		}
		if ($exist_tax_id) {
			$tax_id = $address['tax_id'];
		}
		$address_1 = $address['address_1'];
		$address_2 = $address['address_2'];
		$city = $address['city'];
		$postcode = $address['postcode'];
		$country_id = $address['country_id'];
		$zone_id = $address['zone_id'];
		if ($exist_custom_field) {
			$custom_field = $address['custom_field'];
		}
		$default = $address['default'];
		$default = ((strtoupper($default)=="TRUE") || (strtoupper($default)=="YES") || (strtoupper($default)=="ENABLED")) ? 1 : 0;
		$sql  = "INSERT INTO `".DB_PREFIX."address` ";
		$sql .= "(`customer_id`,`firstname`,`lastname`,`company`,";
		if ($exist_company_id) {
			$sql .= "`company_id`,";
		}
		if ($exist_tax_id) {
			$sql .= "`tax_id`,";
		}
		if ($exist_custom_field) {
			$sql .= "`address_1`,`address_2`,`city`,`postcode`,`country_id`,`zone_id`,`custom_field`) ";
		} else {
			$sql .= "`address_1`,`address_2`,`city`,`postcode`,`country_id`,`zone_id`) ";
		}
		$sql .= "VALUES ($customer_id, ";
		$sql .= "'".$this->db->escape($firstname)."', ";
		$sql .= "'".$this->db->escape($lastname)."', ";
		$sql .= "'".$this->db->escape($company)."', ";
		if ($exist_company_id) {
			$sql .= "'".$this->db->escape($company_id)."', ";
		}
		if ($exist_tax_id) {
			$sql .= "'".$this->db->escape($tax_id)."', ";
		}
		$sql .= "'".$this->db->escape($address_1)."', ";
		$sql .= "'".$this->db->escape($address_2)."', ";
		$sql .= "'".$this->db->escape($city)."', ";
		$sql .= "'".$this->db->escape($postcode)."', ";
		if ($exist_custom_field) {
			$sql .= "$country_id, $zone_id, '".$this->db->escape($custom_field)."'";
		} else {
			$sql .= "$country_id, $zone_id";
		}
		$sql .= ");";
		$this->db->query( $sql );
		if ($default) {
			$address_id = $this->db->getLastId();
			$sql = "UPDATE `".DB_PREFIX."customer` SET address_id='".(int)$address_id."' WHERE customer_id='".(int)$customer_id."'";
			$this->db->query($sql);
		}
	}


	protected function deleteAddresses() {
		$sql = "TRUNCATE TABLE `".DB_PREFIX."address`";
		$this->db->query( $sql );
	}


	protected function deleteAddress( $customer_id ) {
		$sql = "DELETE FROM `".DB_PREFIX."address` WHERE customer_id='".(int)$customer_id."'";
		$this->db->query( $sql );
	}


	protected function deleteUnlistedAddresses( &$unlisted_customer_ids ) {
		foreach ($unlisted_customer_ids as $customer_id) {
			$sql = "DELETE FROM `".DB_PREFIX."address` WHERE customer_id='".(int)$customer_id."'";
			$this->db->query( $sql );
		}
	}


	// function for reading additional cells in class extensions
	protected function moreAddressCells( $i, &$j, &$worksheet, &$option ) {
		return;
	}


	protected function uploadAddresses( &$reader, $incremental, &$available_customer_ids ) {
		// get worksheet, if not there return immediately
		$data = $reader->getSheetByName( 'Addresses' );
		if ($data==null) {
			return;
		}

		// some fields only exist in certain OpenCart versions
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."address` LIKE 'company_id'";
		$query = $this->db->query( $sql );
		$exist_company_id = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."address` LIKE 'tax_id'";
		$query = $this->db->query( $sql );
		$exist_tax_id = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."address` LIKE 'custom_field'";
		$query = $this->db->query( $sql );
		$exist_custom_field = ($query->num_rows > 0) ? true : false;

		// find the available country_ids indexed by country names
		$available_country_ids = $this->getAvailableCountryIds();

		// find the available zone_ids indexed by country names and zone names
		$available_zone_ids = $this->getAvailableZoneIds();

		// if incremental then find current customer IDs else delete all old addresses
		if ($incremental) {
			$unlisted_customer_ids = $available_customer_ids;
		} else {
			$this->deleteAddresses();
		}

		// load the worksheet cells and store them to the database
		$previous_customer_id = 0;
		$first_row = array();
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=0; $i<$k; $i+=1) {
			if ($i==0) {
				$max_col = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
				for ($j=1; $j<=$max_col; $j+=1) {
					$first_row[] = $this->getCell($data,$i,$j);
				}
				continue;
			}
			$j = 1;
			$customer_id = trim($this->getCell($data,$i,$j++));
			if ($customer_id=='') {
				continue;
			}
			$firstname = $this->getCell($data,$i,$j++,'');
			$lastname = $this->getCell($data,$i,$j++,'');
			$company = $this->getCell($data,$i,$j++,'');
			if ($exist_company_id) {
				$company_id = $this->getCell($data,$i,$j++,'');
			}
			if ($exist_tax_id) {
				$tax_id = $this->getCell($data,$i,$j++,'');
			}
			$address_1 = $this->getCell($data,$i,$j++,'');
			$address_2 = $this->getCell($data,$i,$j++,'');
			$city = $this->getCell($data,$i,$j++,'');
			$postcode = $this->getCell($data,$i,$j++,'');
			$zone = $this->getCell($data,$i,$j++,'');
			$country = $this->getCell($data,$i,$j++,'');
			if (!isset($available_country_ids[$country])) {
				$country = html_entity_decode($country,ENT_QUOTES,'UTF-8');
			}
			$country_id = isset($available_country_ids[$country]) ? $available_country_ids[$country] : 0;
			if (!isset($available_zone_ids[$country][$zone])) {
				$zone = html_entity_decode($zone,ENT_QUOTES,'UTF-8');
			}
			if (!isset($available_zone_ids[$country][$zone])) {
				$zone = htmlentities($zone,ENT_NOQUOTES,'UTF-8');
			}
			if (!isset($available_zone_ids[$country][$zone])) {
				$zone = html_entity_decode($zone,ENT_QUOTES,'UTF-8');
				$zone = htmlentities($zone,ENT_QUOTES,'UTF-8');
			}
			if (!isset($available_zone_ids[$country][$zone])) {
				$zone = html_entity_decode($zone,ENT_QUOTES,'UTF-8');
				$zone = htmlentities($zone,ENT_NOQUOTES,'UTF-8');
				$zone = str_replace( "'", "&#39;", $zone );
			}
			$zone_id = isset($available_zone_ids[$country][$zone]) ? $available_zone_ids[$country][$zone] : 0;
			if ($exist_custom_field) {
				$custom_field = $this->getCell($data,$i,$j++,'');
			}
			$default = $this->getCell($data,$i,$j++,'no');
			$address = array();
			$address['customer_id'] = $customer_id;
			$address['firstname'] = $firstname;
			$address['lastname'] = $lastname;
			$address['company'] = $company;
			if ($exist_company_id) {
				$address['company_id'] = $company_id;
			}
			if ($exist_tax_id) {
				$address['tax_id'] = $tax_id;
			}
			$address['address_1'] = $address_1;
			$address['address_2'] = $address_2;
			$address['city'] = $city;
			$address['postcode'] = $postcode;
			$address['country_id'] = $country_id;
			$address['zone_id'] = $zone_id;
			if ($exist_custom_field) {
				$address['custom_field'] = $custom_field;
			}
			$address['default'] = $default;
			if (($incremental) && ($customer_id != $previous_customer_id)) {
				$this->deleteAddress( $customer_id );
				if (isset($unlisted_customer_ids[$customer_id])) {
					unset($unlisted_customer_ids[$customer_id]);
				}
			}
			$this->moreAddressCells( $i, $j, $data, $address );
			$this->storeAddressIntoDatabase( $address, $exist_company_id, $exist_tax_id, $exist_custom_field );
			$previous_customer_id = $customer_id;
		}
		if ($incremental) {
			$this->deleteUnlistedAddresses( $unlisted_customer_ids );
		}
	}


	protected function getCell(&$worksheet,$row,$col,$default_val='') {
//		$col -= 1; // we use 1-based, PHPExcel uses 0-based column index, PhpSpreadsheet now uses 1-based column index
		$row += 1; // we use 0-based, PhpSpreadsheet uses 1-based row index
		$val = ($worksheet->cellExistsByColumnAndRow($col,$row)) ? $worksheet->getCellByColumnAndRow($col,$row)->getValue() : $default_val;
		if ($val===null) {
			$val = $default_val;
		}
		return $val;
	}


	protected function validateHeading( &$data, &$expected, &$multilingual ) {
		$default_language_code = $this->config->get('config_language');
		$heading = array();
		$k = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
		$i = 0;
		for ($j=1; $j <= $k; $j+=1) {
			$entry = $this->getCell($data,$i,$j);
			$bracket_start = strripos( $entry, '(', 0 );
			if ($bracket_start === false) {
				if (in_array( $entry, $multilingual )) {
					return false;
				}
				$heading[] = strtolower($entry);
			} else {
				$name = strtolower(substr( $entry, 0, $bracket_start ));
				if (!in_array( $name, $multilingual )) {
					return false;
				}
				$bracket_end = strripos( $entry, ')', $bracket_start );
				if ($bracket_end <= $bracket_start) {
					return false;
				}
				if ($bracket_end+1 != strlen($entry)) {
					return false;
				}
				$language_code = strtolower(substr( $entry, $bracket_start+1, $bracket_end-$bracket_start-1 ));
				if (count($heading) <= 0) {
					return false;
				}
				if ($heading[count($heading)-1] != $name) {
					$heading[] = $name;
				}
			}
		}
		for ($i=0; $i < count($expected); $i+=1) {
			if (!isset($heading[$i])) {
				return false;
			}
			if ($heading[$i] != $expected[$i]) {
				return false;
			}
		}
		return true;
	}


	protected function validateCategories( &$reader ) {
		$data = $reader->getSheetByName( 'Categories' );
		if ($data==null) {
			return true;
		}

		// Opencart versions from 2.0 onwards also have category_description.meta_title
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."category_description` LIKE 'meta_title'";
		$query = $this->db->query( $sql );
		$exist_meta_title = ($query->num_rows > 0) ? true : false;

		if ($this->use_table_seo_url) {
			if ($exist_meta_title) {
				$expected_heading = array
				( "category_id", "parent_id", "name", "top", "columns", "sort_order", "image_name", "date_added", "date_modified", "description", "meta_title", "meta_description", "meta_keywords", "store_ids", "layout", "status" );
			} else {
				$expected_heading = array
				( "category_id", "parent_id", "name", "top", "columns", "sort_order", "image_name", "date_added", "date_modified", "description", "meta_description", "meta_keywords", "store_ids", "layout", "status" );
			}
		} else {
			if ($exist_meta_title) {
				$expected_heading = array
				( "category_id", "parent_id", "name", "top", "columns", "sort_order", "image_name", "date_added", "date_modified", "seo_keyword", "description", "meta_title", "meta_description", "meta_keywords", "store_ids", "layout", "status" );
			} else {
				$expected_heading = array
				( "category_id", "parent_id", "name", "top", "columns", "sort_order", "image_name", "date_added", "date_modified", "seo_keyword", "description", "meta_description", "meta_keywords", "store_ids", "layout", "status" );
			}
		}
		if ($exist_meta_title) {
			$expected_multilingual = array( "name", "description", "meta_title", "meta_description", "meta_keywords" );
		} else {
			$expected_multilingual = array( "name", "description", "meta_description", "meta_keywords" );
		}
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateCategoryFilters( &$reader ) {
		$data = $reader->getSheetByName( 'CategoryFilters' );
		if ($data==null) {
			return true;
		}
		if (!$this->existFilter()) {
			throw new Exception( $this->language->get( 'error_filter_not_supported' ) );
		}
		if ($this->config->get('export_import_settings_use_filter_group_id')) {
			if ($this->config->get('export_import_settings_use_filter_id')) {
				$expected_heading = array( "category_id", "filter_group_id", "filter_id" );
			} else {
				$expected_heading = array( "category_id", "filter_group_id", "filter" );
			}
		} else {
			if ($this->config->get('export_import_settings_use_filter_id')) {
				$expected_heading = array( "category_id", "filter_group", "filter_id" );
			} else {
				$expected_heading = array( "category_id", "filter_group", "filter" );
			}
		}
		$expected_multilingual = array();
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateCategorySEOKeywords( &$reader ) {
		$data = $reader->getSheetByName( 'CategorySEOKeywords' );
		if ($data==null) {
			return true;
		}
		if (!$this->use_table_seo_url) {
			throw new Exception( str_replace( '%1', 'CategorySEOKeywords', $this->language->get( 'error_seo_keywords_not_supported' ) ) );
		}
		$expected_heading = array( "category_id", "store_id", "keyword" );
		$expected_multilingual = array( "keyword" );
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateProducts( &$reader ) {
		$data = $reader->getSheetByName( 'Products' );
		if ($data==null) {
			return true;
		}

		// get list of the field names, some are only available for certain OpenCart versions
		$query = $this->db->query( "DESCRIBE `".DB_PREFIX."product`" );
		$product_fields = array();
		foreach ($query->rows as $row) {
			$product_fields[] = $row['Field'];
		}

		// Opencart versions from 2.0 onwards also have product_description.meta_title
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."product_description` LIKE 'meta_title'";
		$query = $this->db->query( $sql );
		$exist_meta_title = ($query->num_rows > 0) ? true : false;

		$expected_heading = array
		( "product_id", "name", "categories", "sku", "upc" );
		if (in_array("ean",$product_fields)) {
			$expected_heading[] = "ean";
		}
		if (in_array("jan",$product_fields)) {
			$expected_heading[] = "jan";
		}
		if (in_array("isbn",$product_fields)) {
			$expected_heading[] = "isbn";
		}
		if (in_array("mpn",$product_fields)) {
			$expected_heading[] = "mpn";
		}
		if ($this->use_table_seo_url) {
			$expected_heading = array_merge( $expected_heading, array( "location", "quantity", "model", "manufacturer", "image_name", "shipping", "price", "price_2", "price_3", "points", "date_added", "date_modified", "date_available", "weight", "weight_unit", "length", "width", "height", "length_unit", "status", "tax_class_id", "description") );
		} else {
			$expected_heading = array_merge( $expected_heading, array( "location", "quantity", "model", "manufacturer", "image_name", "shipping", "price","price_2","price_3", "points", "date_added", "date_modified", "date_available", "weight", "weight_unit", "length", "width", "height", "length_unit", "status", "tax_class_id", "seo_keyword", "description") );
		}
		if ($exist_meta_title) {
			$expected_heading[] = "meta_title";
		}
		$expected_heading = array_merge( $expected_heading, array( "meta_description", "meta_keywords", "stock_status_id", "store_ids", "layout", "related_ids", "tags", "sort_order", "subtract", "minimum" ) );
		if ($exist_meta_title) {
			$expected_multilingual = array( "name", "description", "meta_title", "meta_description", "meta_keywords", "tags" );
		} else {
			$expected_multilingual = array( "name", "description", "meta_description", "meta_keywords", "tags" );
		}
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateAdditionalImages( &$reader ) {
		$data = $reader->getSheetByName( 'AdditionalImages' );
		if ($data==null) {
			return true;
		}
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."product_image` LIKE 'sort_order'";
		$query = $this->db->query( $sql );
		$exist_sort_order = ($query->num_rows > 0) ? true : false;
		if ($exist_sort_order) {
			$expected_heading = array( "product_id", "image", "sort_order" );
		} else {
			$expected_heading = array( "product_id", "image" );
		}
		$expected_multilingual = array();
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateSpecials( &$reader ) {
		$data = $reader->getSheetByName( 'Specials' );
		if ($data==null) {
			return true;
		}
		$expected_heading = array( "product_id", "customer_group", "priority", "price", "date_start", "date_end" );
		$expected_multilingual = array();
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateDiscounts( &$reader ) {
		$data = $reader->getSheetByName( 'Discounts' );
		if ($data==null) {
			return true;
		}
		$expected_heading = array( "product_id", "customer_group", "quantity", "priority", "price", "date_start", "date_end" );
		$expected_multilingual = array();
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateRewards( &$reader ) {
		$data = $reader->getSheetByName( 'Rewards' );
		if ($data==null) {
			return true;
		}
		$expected_heading = array( "product_id", "customer_group", "points" );
		$expected_multilingual = array();
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateProductOptions( &$reader ) {
		$data = $reader->getSheetByName( 'ProductOptions' );
		if ($data==null) {
			return true;
		}
		if ($this->config->get('export_import_settings_use_option_id')) {
			$expected_heading = array( "product_id", "option_id", "default_option_value", "required" );
		} else {
			$expected_heading = array( "product_id", "option", "default_option_value", "required" );
		}
		$expected_multilingual = array();
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateProductOptionValues( &$reader ) {
		$data = $reader->getSheetByName( 'ProductOptionValues' );
		if ($data==null) {
			return true;
		}
		if ($this->config->get('export_import_settings_use_option_id')) {
			if ($this->config->get('export_import_settings_use_option_value_id')) {
				$expected_heading = array( "product_id", "option_id", "option_value_id", "quantity", "subtract", "price", "price_prefix", "points", "points_prefix", "weight", "weight_prefix" );
			} else {
				$expected_heading = array( "product_id", "option_id", "option_value", "quantity", "subtract", "price", "price_prefix", "points", "points_prefix", "weight", "weight_prefix" );
			}
		} else {
			if ($this->config->get('export_import_settings_use_option_value_id')) {
				$expected_heading = array( "product_id", "option", "option_value_id", "quantity", "subtract", "price", "price_prefix", "points", "points_prefix", "weight", "weight_prefix" );
			} else {
				$expected_heading = array( "product_id", "option", "option_value", "quantity", "subtract", "price", "price_prefix", "points", "points_prefix", "weight", "weight_prefix" );
			}
		}
		$expected_multilingual = array();
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateProductAttributes( &$reader ) {
		$data = $reader->getSheetByName( 'ProductAttributes' );
		if ($data==null) {
			return true;
		}
		if ($this->config->get('export_import_settings_use_attribute_group_id')) {
			if ($this->config->get('export_import_settings_use_attribute_id')) {
				$expected_heading = array( "product_id", "attribute_group_id", "attribute_id", "text" );
			} else {
				$expected_heading = array( "product_id", "attribute_group_id", "attribute", "text" );
			}
		} else {
			if ($this->config->get('export_import_settings_use_attribute_id')) {
				$expected_heading = array( "product_id", "attribute_group", "attribute_id", "text" );
			} else {
				$expected_heading = array( "product_id", "attribute_group", "attribute", "text" );
			}
		}
		$expected_multilingual = array( "text" );
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateProductFilters( &$reader ) {
		$data = $reader->getSheetByName( 'ProductFilters' );
		if ($data==null) {
			return true;
		}
		if (!$this->existFilter()) {
			throw new Exception( $this->language->get( 'error_filter_not_supported' ) );
		}
		if ($this->config->get('export_import_settings_use_filter_group_id')) {
			if ($this->config->get('export_import_settings_use_filter_id')) {
				$expected_heading = array( "product_id", "filter_group_id", "filter_id" );
			} else {
				$expected_heading = array( "product_id", "filter_group_id", "filter" );
			}
		} else {
			if ($this->config->get('export_import_settings_use_filter_id')) {
				$expected_heading = array( "product_id", "filter_group", "filter_id" );
			} else {
				$expected_heading = array( "product_id", "filter_group", "filter" );
			}
		}
		$expected_multilingual = array();
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateProductSEOKeywords( &$reader ) {
		$data = $reader->getSheetByName( 'ProductSEOKeywords' );
		if ($data==null) {
			return true;
		}
		if (!$this->use_table_seo_url) {
			throw new Exception( str_replace( '%1', 'ProductSEOKeywords', $this->language->get( 'error_seo_keywords_not_supported' ) ) );
		}
		$expected_heading = array( "product_id", "store_id", "keyword" );
		$expected_multilingual = array( "keyword" );
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateOptions( &$reader ) {
		$data = $reader->getSheetByName( 'Options' );
		if ($data==null) {
			return true;
		}
		$expected_heading = array( "option_id", "type", "sort_order", "name" );
		$expected_multilingual = array( "name" );
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateOptionValues( &$reader ) {
		$data = $reader->getSheetByName( 'OptionValues' );
		if ($data==null) {
			return true;
		}
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."option_value` LIKE 'image'";
		$query = $this->db->query( $sql );
		$exist_image = ($query->num_rows > 0) ? true : false;
		if ($exist_image) {
			$expected_heading = array( "option_value_id", "option_id", "image", "sort_order", "name" );
		} else {
			$expected_heading = array( "option_value_id", "option_id", "sort_order", "name" );
		}
		$expected_multilingual = array( "name" );
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateAttributeGroups( &$reader ) {
		$data = $reader->getSheetByName( 'AttributeGroups' );
		if ($data==null) {
			return true;
		}
		$expected_heading = array( "attribute_group_id", "sort_order", "name" );
		$expected_multilingual = array( "name" );
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateAttributes( &$reader ) {
		$data = $reader->getSheetByName( 'Attributes' );
		if ($data==null) {
			return true;
		}
		$expected_heading = array( "attribute_id", "attribute_group_id", "sort_order", "name" );
		$expected_multilingual = array( "name" );
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateFilterGroups( &$reader ) {
		$data = $reader->getSheetByName( 'FilterGroups' );
		if ($data==null) {
			return true;
		}
		if (!$this->existFilter()) {
			throw new Exception( $this->language->get( 'error_filter_not_supported' ) );
		}
		$expected_heading = array( "filter_group_id", "sort_order", "name" );
		$expected_multilingual = array( "name" );
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateFilters( &$reader ) {
		$data = $reader->getSheetByName( 'Filters' );
		if ($data==null) {
			return true;
		}
		if (!$this->existFilter()) {
			throw new Exception( $this->language->get( 'error_filter_not_supported' ) );
		}
		$expected_heading = array( "filter_id", "filter_group_id", "sort_order", "name" );
		$expected_multilingual = array( "name" );
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateCustomers( &$reader ) {
		$data = $reader->getSheetByName( 'Customers' );
		if ($data==null) {
			return true;
		}

		// Some fields are only available in newer Opencart versions
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'custom_field'";
		$query = $this->db->query( $sql );
		$exist_custom_field = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'salt'";
		$query = $this->db->query( $sql );
		$exist_salt = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'safe'";
		$query = $this->db->query( $sql );
		$exist_safe = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'token'";
		$query = $this->db->query( $sql );
		$exist_token = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'code'";
		$query = $this->db->query( $sql );
		$exist_code = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'approved'";
		$query = $this->db->query( $sql );
		$exist_approved = ($query->num_rows > 0) ? true : false;

		$expected_heading = array( "customer_id", "customer_group", "store_id", "firstname", "lastname", "email", "telephone", "fax", "password" );
		if ($exist_salt) {
			$expected_heading[] = "salt";
		}
		$expected_heading = array_merge( $expected_heading, array( "cart", "wishlist", "newsletter" ) );
		if ($exist_custom_field) {
			$expected_heading[] = "custom_field";
		}
		$expected_heading = array_merge( $expected_heading, array( "ip", "status" ) );
		if ($exist_approved) {
			$expected_heading[] = "approved";
		}
		if ($exist_safe) {
			$expected_heading[] = "safe";
		}
		if ($exist_token) {
			$expected_heading[] = "token";
		}
		if ($exist_code) {
			$expected_heading[] = "code";
		}
		$expected_heading[] = "date_added";
		$expected_multilingual = array();
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateAddresses( &$reader ) {
		$data = $reader->getSheetByName( 'Addresses' );
		if ($data==null) {
			return true;
		}

		// Some Opencart 1.5.x versions also have company_id
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."address` LIKE 'company_id'";
		$query = $this->db->query( $sql );
		$exist_company_id = ($query->num_rows > 0) ? true : false;

		// Some Opencart 1.5.x versions also have tax_id
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."address` LIKE 'tax_id'";
		$query = $this->db->query( $sql );
		$exist_tax_id = ($query->num_rows > 0) ? true : false;

		// Opencart 2.x versions have custom_field
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."address` LIKE 'custom_field'";
		$query = $this->db->query( $sql );
		$exist_custom_field = ($query->num_rows > 0) ? true : false;

		$expected_heading = array( "customer_id", "firstname", "lastname", "company" );
		if ($exist_company_id) {
			$expected_heading[] = "company_id";
		}
		if ($exist_tax_id) {
			$expected_heading[] = "tax_id";
		}
		$expected_heading = array_merge( $expected_heading, array( "address_1", "address_2", "city", "postcode", "zone", "country" ) );
		if ($exist_custom_field) {
			$expected_heading[] = "custom_field";
		}
		$expected_heading[] = "default";
		$expected_multilingual = array();
		return $this->validateHeading( $data, $expected_heading, $expected_multilingual );
	}


	protected function validateProductIdColumns( &$reader ) {
		$data = $reader->getSheetByName( 'Products' );
		if ($data==null) {
			return true;
		}
		$ok = true;
		
		// only unique numeric product_ids can be used, in ascending order, in worksheet 'Products'
		$previous_product_id = 0;
		$has_missing_product_ids = false;
		$product_ids = array();
		$k = $data->getHighestRow();
		for ($i=1; $i<$k; $i+=1) {
			$product_id = $this->getCell($data,$i,1);
			if ($product_id=="") {
				if (!$has_missing_product_ids) {
					$msg = str_replace( '%1', 'Products', $this->language->get( 'error_missing_product_id' ) );
					$this->log->write( $msg );
					$has_missing_product_ids = true;
				}
				$ok = false;
				continue;
			}
			if (!$this->isInteger($product_id)) {
				$msg = str_replace( '%2', $product_id, str_replace( '%1', 'Products', $this->language->get( 'error_invalid_product_id' ) ) );
				$this->log->write( $msg );
				$ok = false;
				continue;
			}
			if (in_array( $product_id, $product_ids )) {
				$msg = str_replace( '%2', $product_id, str_replace( '%1', 'Products', $this->language->get( 'error_duplicate_product_id' ) ) );
				$this->log->write( $msg );
				$ok = false;
			}
			$product_ids[] = $product_id;
			if ($product_id < $previous_product_id) {
				$msg = str_replace( '%2', $product_id, str_replace( '%1', 'Products', $this->language->get( 'error_wrong_order_product_id' ) ) );
				$this->log->write( $msg );
				$ok = false;
			}
			$previous_product_id = $product_id;
		}
		
		// make sure product_ids are numeric entries and are also mentioned in worksheet 'Products'
		$worksheets = array( 'AdditionalImages', 'Specials', 'Discounts', 'Rewards', 'ProductOptions', 'ProductOptionValues', 'ProductAttributes', 'ProductFilters', 'ProductSEOKeywords' );
		foreach ($worksheets as $worksheet) {
			$data = $reader->getSheetByName( $worksheet );
			if ($data==null) {
				continue;
			}
			$previous_product_id = 0;
			$has_missing_product_ids = false;
			$unlisted_product_ids = array();
			$k = $data->getHighestRow();
			for ($i=1; $i<$k; $i+=1) {
				$product_id = $this->getCell($data,$i,1);
				if ($product_id=="") {
					if (!$has_missing_product_ids) {
						$msg = str_replace( '%1', $worksheet, $this->language->get( 'error_missing_product_id' ) );
						$this->log->write( $msg );
						$has_missing_product_ids = true;
					}
					$ok = false;
					continue;
				}
				if (!$this->isInteger($product_id)) {
					$msg = str_replace( '%2', $product_id, str_replace( '%1', $worksheet, $this->language->get( 'error_invalid_product_id' ) ) );
					$this->log->write( $msg );
					$ok = false;
					continue;
				}
				if (!in_array( $product_id, $product_ids )) {
					if (!in_array( $product_id, $unlisted_product_ids )) {
						$unlisted_product_ids[] = $product_id;
						$msg = str_replace( '%2', $product_id, str_replace( '%1', $worksheet, $this->language->get( 'error_unlisted_product_id' ) ) );
						$this->log->write( $msg );
						$ok = false;
					}
				}
				if ($product_id < $previous_product_id) {
					$msg = str_replace( '%2', $product_id, str_replace( '%1', $worksheet, $this->language->get( 'error_wrong_order_product_id' ) ) );
					$this->log->write( $msg );
					$ok = false;
				}
				$previous_product_id = $product_id;
			}
		}
		
		return $ok;
	}


	protected function validateCategoryIdColumns( &$reader ) {
		$data = $reader->getSheetByName( 'Categories' );
		if ($data==null) {
			return true;
		}
		$ok = true;
		
		// only unique numeric category_ids can be used, in ascending order, in worksheet 'Categories'
		$previous_category_id = 0;
		$has_missing_category_ids = false;
		$category_ids = array();
		$k = $data->getHighestRow();
		for ($i=1; $i<$k; $i+=1) {
			$category_id = $this->getCell($data,$i,1);
			if ($category_id=="") {
				if (!$has_missing_category_ids) {
					$msg = str_replace( '%1', 'Categories', $this->language->get( 'error_missing_category_id' ) );
					$this->log->write( $msg );
					$has_missing_category_ids = true;
				}
				$ok = false;
				continue;
			}
			if (!$this->isInteger($category_id)) {
				$msg = str_replace( '%2', $category_id, str_replace( '%1', 'Categories', $this->language->get( 'error_invalid_category_id' ) ) );
				$this->log->write( $msg );
				$ok = false;
				continue;
			}
			if (in_array( $category_id, $category_ids )) {
				$msg = str_replace( '%2', $category_id, str_replace( '%1', 'Categories', $this->language->get( 'error_duplicate_category_id' ) ) );
				$this->log->write( $msg );
				$ok = false;
			}
			$category_ids[] = $category_id;
			if ($category_id < $previous_category_id) {
				$msg = str_replace( '%2', $category_id, str_replace( '%1', 'Categories', $this->language->get( 'error_wrong_order_category_id' ) ) );
				$this->log->write( $msg );
				$ok = false;
			}
			$previous_category_id = $category_id;
		}
		
		// make sure category_ids are numeric entries and are also mentioned in worksheet 'Categories'
		$worksheets = array( 'CategoryFilters', 'CategorySEOKeywords' );
		foreach ($worksheets as $worksheet) {
			$data = $reader->getSheetByName( $worksheet );
			if ($data==null) {
				continue;
			}
			$previous_category_id = 0;
			$has_missing_category_ids = false;
			$unlisted_category_ids = array();
			$k = $data->getHighestRow();
			for ($i=1; $i<$k; $i+=1) {
				$category_id = $this->getCell($data,$i,1);
				if ($category_id=="") {
					if (!$has_missing_category_ids) {
						$msg = str_replace( '%1', $worksheet, $this->language->get( 'error_missing_category_id' ) );
						$this->log->write( $msg );
						$has_missing_category_ids = true;
					}
					$ok = false;
					continue;
				}
				if (!$this->isInteger($category_id)) {
					$msg = str_replace( '%2', $category_id, str_replace( '%1', $worksheet, $this->language->get( 'error_invalid_category_id' ) ) );
					$this->log->write( $msg );
					$ok = false;
					continue;
				}
				if (!in_array( $category_id, $category_ids )) {
					if (!in_array( $category_id, $unlisted_category_ids )) {
						$unlisted_category_ids[] = $category_id;
						$msg = str_replace( '%2', $category_id, str_replace( '%1', $worksheet, $this->language->get( 'error_unlisted_category_id' ) ) );
						$this->log->write( $msg );
						$ok = false;
					}
				}
				if ($category_id < $previous_category_id) {
					$msg = str_replace( '%2', $category_id, str_replace( '%1', $worksheet, $this->language->get( 'error_wrong_order_category_id' ) ) );
					$this->log->write( $msg );
					$ok = false;
				}
				$previous_category_id = $category_id;
			}
		}
		
		return $ok;
	}


	protected function validateCustomerIdColumns( &$reader ) {
		$data = $reader->getSheetByName( 'Customers' );
		if ($data==null) {
			return true;
		}
		$ok = true;
		
		// only unique numeric customer_ids can be used, in ascending order, in worksheet 'Customers'
		$previous_customer_id = 0;
		$has_missing_customer_ids = false;
		$customer_ids = array();
		$k = $data->getHighestRow();
		for ($i=1; $i<$k; $i+=1) {
			$customer_id = $this->getCell($data,$i,1);
			if ($customer_id=="") {
				if (!$has_missing_customer_ids) {
					$msg = str_replace( '%1', 'Customers', $this->language->get( 'error_missing_customer_id' ) );
					$this->log->write( $msg );
					$has_missing_customer_ids = true;
				}
				$ok = false;
				continue;
			}
			if (!$this->isInteger($customer_id)) {
				$msg = str_replace( '%2', $customer_id, str_replace( '%1', 'Customers', $this->language->get( 'error_invalid_customer_id' ) ) );
				$this->log->write( $msg );
				$ok = false;
				continue;
			}
			if (in_array( $customer_id, $customer_ids )) {
				$msg = str_replace( '%2', $customer_id, str_replace( '%1', 'Customers', $this->language->get( 'error_duplicate_customer_id' ) ) );
				$this->log->write( $msg );
				$ok = false;
			}
			$customer_ids[] = $customer_id;
			if ($customer_id < $previous_customer_id) {
				$msg = str_replace( '%2', $customer_id, str_replace( '%1', 'Customers', $this->language->get( 'error_wrong_order_customer_id' ) ) );
				$this->log->write( $msg );
				$ok = false;
			}
			$previous_customer_id = $customer_id;
		}
		
		// make sure customer_ids are numeric entries and are also mentioned in worksheet 'Customers'
		$worksheets = array( 'Addresses' );
		foreach ($worksheets as $worksheet) {
			$data = $reader->getSheetByName( $worksheet );
			if ($data==null) {
				continue;
			}
			$previous_customer_id = 0;
			$has_missing_customer_ids = false;
			$unlisted_customer_ids = array();
			$k = $data->getHighestRow();
			for ($i=1; $i<$k; $i+=1) {
				$customer_id = $this->getCell($data,$i,1);
				if ($customer_id=="") {
					if (!$has_missing_customer_ids) {
						$msg = str_replace( '%1', $worksheet, $this->language->get( 'error_missing_customer_id' ) );
						$this->log->write( $msg );
						$has_missing_customer_ids = true;
					}
					$ok = false;
					continue;
				}
				if (!$this->isInteger($customer_id)) {
					$msg = str_replace( '%2', $customer_id, str_replace( '%1', $worksheet, $this->language->get( 'error_invalid_customer_id' ) ) );
					$this->log->write( $msg );
					$ok = false;
					continue;
				}
				if (!in_array( $customer_id, $customer_ids )) {
					if (!in_array( $customer_id, $unlisted_customer_ids )) {
						$unlisted_customer_ids[] = $customer_id;
						$msg = str_replace( '%2', $customer_id, str_replace( '%1', $worksheet, $this->language->get( 'error_unlisted_customer_id' ) ) );
						$this->log->write( $msg );
					}
					$ok = false;
				}
				if ($customer_id < $previous_customer_id) {
					$msg = str_replace( '%2', $customer_id, str_replace( '%1', $worksheet, $this->language->get( 'error_wrong_order_customer_id' ) ) );
					$this->log->write( $msg );
					$ok = false;
				}
				$previous_customer_id = $customer_id;
			}
		}
		
		return $ok;
	}


	protected function validateAddressCountriesAndZones( &$reader ) {
		$data = $reader->getSheetByName( 'Addresses' );
		if ($data==null) {
			return true;
		}
		$ok = true;

		$country_col = 0;
		$zone_col = 0;
		$k = PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString( $data->getHighestColumn() );
		$i = 0;
		for ($j=1; $j <= $k; $j+=1) {
			$entry = $this->getCell($data,$i,$j);
			if ($entry=='country') {
				$country_col = $j;
			} else if ($entry=='zone') {
				$zone_col = $j;
			}
		}
		if ($country_col==0) {
			$msg = $this->language->get('error_missing_country_col');
			$msg = str_replace( '%1', 'Addresses', $msg );
			$this->log->write( $msg );
			$ok = false;
		}
		if ($zone_col==0) {
			$msg = $this->language->get('error_missing_zone_col');
			$msg = str_replace( '%1', 'Addresses', $msg );
			$this->log->write( $msg );
			$ok = false;
		}
		if (!$ok) {
			return false;
		}

		$available_country_ids = $this->getAvailableCountryIds();
		$available_zone_ids = $this->getAvailableZoneIds();
		$undefined_countries = array();
		$undefined_zones = array();
		$k = $data->getHighestRow();
		for ($i=1; $i<$k; $i+=1) {
			$country = $this->getCell($data,$i,$country_col);
			$zone = $this->getCell($data,$i,$zone_col);
			if (!isset($available_country_ids[$country])) {
				$country = html_entity_decode($country,ENT_QUOTES,'UTF-8');
				if (!isset($available_country_ids[$country])) {
					if (!in_array( $country, $undefined_countries )) {
						$undefined_countries[] = $country;
						$msg = $this->language->get( 'error_undefined_country' );
						$msg = str_replace( '%1', $country, $msg );
						$msg = str_replace( '%2', 'Addresses', $msg );
						$this->log->write( $msg );
						$ok = false;
					}
					continue;
				}
			}
			if ($zone != '') {
				if (!isset($available_zone_ids[$country][$zone])) {
					$zone = html_entity_decode($zone,ENT_QUOTES,'UTF-8');
					if (!isset($available_zone_ids[$country][$zone])) {
						$zone = htmlentities($zone,ENT_NOQUOTES,'UTF-8');
						if (!isset($available_zone_ids[$country][$zone])) {
							$zone = html_entity_decode($zone,ENT_QUOTES,'UTF-8');
							$zone = htmlentities($zone,ENT_QUOTES,'UTF-8');
							if (!isset($available_zone_ids[$country][$zone])) {
								$zone = html_entity_decode($zone,ENT_QUOTES,'UTF-8');
								$zone = htmlentities($zone,ENT_NOQUOTES,'UTF-8');
								$zone = str_replace( "'", "&#39;", $zone );
								if (!isset($available_zone_ids[$country][$zone])) {
									if (!isset($undefined_zones[$country])) {
										$undefined_zones[$country] = array();
									}
									if (!in_array( $zone, $undefined_zones[$country] )) {
										$undefined_zones[$country][] = $zone;
										$msg = $this->language->get( 'error_undefined_zone' );
										$msg = str_replace( '%1', $country, $msg );
										$msg = str_replace( '%2', $zone, $msg );
										$msg = str_replace( '%3', 'Addresses', $msg );
										$this->log->write( $msg );
										$ok = false;
									}
									continue;
								}
							}
						}
					}
				}
			}
		}

		return $ok;
	}


	protected function validateCustomerGroupColumns( &$reader ) {
		// all customer_groups mentioned in the worksheets must be defined
		$worksheets = array( 'Specials', 'Discounts', 'Rewards', 'Customers' );
		$ok = true;
		$customer_groups = array();
		$customer_group_ids = $this->getCustomerGroupIds();
		foreach ($worksheets as $worksheet) {
			$data = $reader->getSheetByName( $worksheet );
			if ($data==null) {
				continue;
			}
			$has_missing_customer_groups = false;
			$k = $data->getHighestRow();
			for ($i=1; $i<$k; $i+=1) {
				$customer_group = trim($this->getCell($data,$i,2));
				if ($customer_group=="") {
					if (!$has_missing_customer_groups) {
						$msg = $this->language->get( 'error_missing_customer_group' );
						$msg = str_replace( '%1', $worksheet, $msg );
						$this->log->write( $msg );
						$has_missing_customer_groups = true;
					}
					$ok = false;
					continue;
				}
				if (!in_array( $customer_group, $customer_groups )) {
					if (!isset($customer_group_ids[$customer_group])) {
						$msg = $this->language->get( 'error_invalid_customer_group' );
						$msg = str_replace( '%1', $worksheet, str_replace( '%2', $customer_group, $msg ) );
						$this->log->write( $msg );
						$ok = false;
					}
					$customer_groups[] = $customer_group;
				}
			}
		}
		return $ok;
	}


	protected function validateOptionColumns( &$reader ) {
		// get all existing options and option values
		$ok = true;
		$export_import_settings_use_option_id = $this->config->get('export_import_settings_use_option_id');
		$export_import_settings_use_option_value_id = $this->config->get('export_import_settings_use_option_value_id');
		$language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT od.option_id, od.name AS option_name, ovd.option_value_id, ovd.name AS option_value_name ";
		$sql .= "FROM `".DB_PREFIX."option_description` od ";
		$sql .= "LEFT JOIN `".DB_PREFIX."option_value_description` ovd ON ovd.option_id=od.option_id AND ovd.language_id='".(int)$language_id."' ";
		$sql .= "WHERE od.language_id='".(int)$language_id."'";
		$query = $this->db->query( $sql );
		$options = array();
		foreach ($query->rows as $row) {
			if ($export_import_settings_use_option_id) {
				$option_id = $row['option_id'];
				if (!isset($options[$option_id])) {
					$options[$option_id] = array();
				}
				if ($export_import_settings_use_option_value_id) {
					$option_value_id = $row['option_value_id'];
					if (!is_null($option_value_id)) {
						$options[$option_id][$option_value_id] = true;
					}
				} else {
					$option_value_name = htmlspecialchars_decode($row['option_value_name']);
					if (!is_null($option_value_name)) {
						$options[$option_id][$option_value_name] = true;
					}
				}
			} else {
				$option_name = htmlspecialchars_decode($row['option_name']);
				if (!isset($options[$option_name])) {
					$options[$option_name] = array();
				}
				if ($export_import_settings_use_option_value_id) {
					$option_value_id = $row['option_value_id'];
					if (!is_null($option_value_id)) {
						$options[$option_name][$option_value_id] = true;
					}
				} else {
					$option_value_name = htmlspecialchars_decode($row['option_value_name']);
					if (!is_null($option_value_name)) {
						$options[$option_name][$option_value_name] = true;
					}
				}
			}
		}
		
		// only existing options can be used in 'ProductOptions' worksheet
		$product_options = array();
		$data = $reader->getSheetByName( 'ProductOptions' );
		if ($data==null) {
			return $ok;
		}
		$has_missing_options = false;
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=1; $i<$k; $i+=1) {
			$product_id = trim($this->getCell($data,$i,1));
			if ($product_id=="") {
				continue;
			}
			if ($export_import_settings_use_option_id) {
				$option_id = trim($this->getCell($data,$i,2));
				if ($option_id=="") {
					if (!$has_missing_options) {
						$msg = str_replace( '%1', 'ProductOptions', $this->language->get( 'error_missing_option_id' ) );
						$this->log->write( $msg );
						$has_missing_options = true;
					}
					$ok = false;
					continue;
				}
				if (!isset($options[$option_id])) {
					$msg = $this->language->get( 'error_invalid_option_id' );
					$msg = str_replace( '%1', 'ProductOptions', $msg );
					$msg = str_replace( '%2', $option_id, $msg );
					$this->log->write( $msg );
					$ok = false;
					continue;
				}
				$product_options[$product_id][$option_id] = true;
			} else {
				$option_name = trim($this->getCell($data,$i,2));
				if ($option_name=="") {
					if (!$has_missing_options) {
						$msg = str_replace( '%1', 'ProductOptions', $this->language->get( 'error_missing_option_name' ) );
						$this->log->write( $msg );
						$has_missing_options = true;
					}
					$ok = false;
					continue;
				}
				if (!isset($options[$option_name])) {
					$msg = $this->language->get( 'error_invalid_option_name' );
					$msg = str_replace( '%1', 'ProductOptions', $msg );
					$msg = str_replace( '%2', $option_name, $msg );
					$this->log->write( $msg );
					$ok= false;
					continue;
				}
				$product_options[$product_id][$option_name] = true;
			}
		}
		
		// only existing options and option values can be used in 'ProductOptionValues' worksheet
		$data = $reader->getSheetByName( 'ProductOptionValues' );
		if ($data==null) {
			return $ok;
		}
		$has_missing_options = false;
		$has_missing_option_values = false;
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=1; $i<$k; $i+=1) {
			$product_id = trim($this->getCell($data,$i,1));
			if ($product_id=="") {
				continue;
			}
			if ($export_import_settings_use_option_id) {
				$option_id = trim($this->getCell($data,$i,2));
				if ($option_id=="") {
					if (!$has_missing_options) {
						$msg = str_replace( '%1', 'ProductOptionValues', $this->language->get( 'error_missing_option_id' ) );
						$this->log->write( $msg );
						$has_missing_options = true;
					}
					$ok = false;
					continue;
				}
				if (!isset($options[$option_id])) {
					$msg = $this->language->get( 'error_invalid_option_id' );
					$msg = str_replace( '%1', 'ProductOptionValues', $msg );
					$msg = str_replace( '%2', $option_id, $msg );
					$this->log->write( $msg );
					$ok = false;
					continue;
				}
				if (!isset($product_options[$product_id][$option_id])) {
					$msg = $this->language->get( 'error_invalid_product_id_option_id' );
					$msg = str_replace( '%1', 'ProductOptionValues', $msg );
					$msg = str_replace( '%2', $product_id, $msg );
					$msg = str_replace( '%3', $option_id, $msg );
					$msg = str_replace( '%4', 'ProductOptions', $msg );
					$this->log->write( $msg );
					$ok = false;
					continue;
				}
				if ($export_import_settings_use_option_value_id) {
					$option_value_id = trim($this->getCell($data,$i,3));
					if ($option_value_id=="") {
						if (!$has_missing_option_values) {
							$msg = str_replace( '%1', 'ProductOptionValues', $this->language->get( 'error_missing_option_value_id' ) );
							$this->log->write( $msg );
							$has_missing_option_values = true;
						}
						$ok = false;
						continue;
					}
					if (!isset($options[$option_id][$option_value_id])) {
						$msg = $this->language->get( 'error_invalid_option_id_option_value_id' );
						$msg = str_replace( '%1', 'ProductOptionValues', $msg );
						$msg = str_replace( '%2', $option_id, $msg );
						$msg = str_replace( '%3', $option_value_id, $msg );
						$this->log->write( $msg );
						$ok = false;
						continue;
					}
				} else {
					$option_value_name = trim($this->getCell($data,$i,3));
					if ($option_value_name=="") {
						if (!$has_missing_option_values) {
							$msg = str_replace( '%1', 'ProductOptionValues', $this->language->get( 'error_missing_option_value_name' ) );
							$this->log->write( $msg );
							$has_missing_option_values = true;
						}
						$ok = false;
						continue;
					}
					if (!isset($options[$option_id][$option_value_name])) {
						$msg = $this->language->get( 'error_invalid_option_id_option_value_name' );
						$msg = str_replace( '%1', 'ProductOptionValues', $msg );
						$msg = str_replace( '%2', $option_id, $msg );
						$msg = str_replace( '%3', $option_value_name, $msg );
						$this->log->write( $msg );
						$ok = false;
						continue;
					}
				}
			} else {
				$option_name = trim($this->getCell($data,$i,2));
				if ($option_name=="") {
					if (!$has_missing_options) {
						$msg = str_replace( '%1', 'ProductOptionValues', $this->language->get( 'error_missing_option_name' ) );
						$this->log->write( $msg );
						$has_missing_options = true;
					}
					$ok = false;
					continue;
				}
				if (!isset($options[$option_name])) {
					$msg = $this->language->get( 'error_invalid_option_name' );
					$msg = str_replace( '%1', 'ProductOptionValues', $msg );
					$msg = str_replace( '%2', $option_name, $msg );
					$this->log->write( $msg );
					$ok= false;
					continue;
				}
				if (!isset($product_options[$product_id][$option_name])) {
					$msg = $this->language->get( 'error_invalid_product_id_option_name' );
					$msg = str_replace( '%1', 'ProductOptionValues', $msg );
					$msg = str_replace( '%2', $product_id, $msg );
					$msg = str_replace( '%3', $option_name, $msg );
					$msg = str_replace( '%4', 'ProductOptions', $msg );
					$this->log->write( $msg );
					$ok = false;
					continue;
				}
				if ($export_import_settings_use_option_value_id) {
					$option_value_id = trim($this->getCell($data,$i,3));
					if ($option_value_id=="") {
						if (!$has_missing_option_values) {
							$msg = str_replace( '%1', 'ProductOptionValues', $this->language->get( 'error_missing_option_value_id' ) );
							$this->log->write( $msg );
							$has_missing_option_values = true;
						}
						$ok = false;
						continue;
					}
					if (!isset($options[$option_name][$option_value_id])) {
						$msg = $this->language->get( 'error_invalid_option_name_option_value_id' );
						$msg = str_replace( '%1', 'ProductOptionValues', $msg );
						$msg = str_replace( '%2', $option_name, $msg );
						$msg = str_replace( '%3', $option_value_id, $msg );
						$this->log->write( $msg );
						$ok = false;
						continue;
					}
				} else {
					$option_value_name = trim($this->getCell($data,$i,3));
					if ($option_value_name=="") {
						if (!$has_missing_option_values) {
							$msg = str_replace( '%1', 'ProductOptionValues', $this->language->get( 'error_missing_option_value_name' ) );
							$this->log->write( $msg );
							$has_missing_option_values = true;
						}
						$ok = false;
						continue;
					}
					if (!isset($options[$option_name][$option_value_name])) {
						$msg = $this->language->get( 'error_invalid_option_name_option_value_name' );
						$msg = str_replace( '%1', 'ProductOptionValues', $msg );
						$msg = str_replace( '%2', $option_name, $msg );
						$msg = str_replace( '%3', $option_value_name, $msg );
						$this->log->write( $msg );
						$ok = false;
						continue;
					}
				}
			}
		}
		
		return $ok;
	}


	protected function validateAttributeColumns( &$reader ) {
		// get all existing attribute_groups and attributes
		$ok = true;
		$export_import_settings_use_attribute_group_id = $this->config->get('export_import_settings_use_attribute_group_id');
		$export_import_settings_use_attribute_id = $this->config->get('export_import_settings_use_attribute_id');
		$language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT agd.attribute_group_id, agd.name AS attribute_group_name, ad.attribute_id, ad.name AS attribute_name ";
		$sql .= "FROM `".DB_PREFIX."attribute_group_description` agd ";
		$sql .= "LEFT JOIN `".DB_PREFIX."attribute` a ON a.attribute_group_id=agd.attribute_group_id ";
		$sql .= "LEFT JOIN `".DB_PREFIX."attribute_description` ad ON ad.attribute_id=a.attribute_id AND ad.language_id='".(int)$language_id."' ";
		$sql .= "WHERE agd.language_id='".(int)$language_id."'";
		$query = $this->db->query( $sql );
		$attribute_groups = array();
		foreach ($query->rows as $row) {
			if ($export_import_settings_use_attribute_group_id) {
				$attribute_group_id = $row['attribute_group_id'];
				if (!isset($attribute_groups[$attribute_group_id])) {
					$attribute_groups[$attribute_group_id] = array();
				}
				if ($export_import_settings_use_attribute_id) {
					$attribute_id = $row['attribute_id'];
					if (!is_null($attribute_id)) {
						$attribute_groups[$attribute_group_id][$attribute_id] = true;
					}
				} else {
					$attribute_name = htmlspecialchars_decode($row['attribute_name']);
					if (!is_null($attribute_name)) {
						$attribute_groups[$attribute_group_id][$attribute_name] = true;
					}
				}
			} else {
				$attribute_group_name = htmlspecialchars_decode($row['attribute_group_name']);
				if (!isset($attribute_groups[$attribute_group_name])) {
					$attribute_groups[$attribute_group_name] = array();
				}
				if ($export_import_settings_use_attribute_id) {
					$attribute_id = $row['attribute_id'];
					if (!is_null($attribute_id)) {
						$attribute_groups[$attribute_group_name][$attribute_id] = true;
					}
				} else {
					$attribute_name = htmlspecialchars_decode($row['attribute_name']);
					if (!is_null($attribute_name)) {
						$attribute_groups[$attribute_group_name][$attribute_name] = true;
					}
				}
			}
		}
		
		// only existing attribute_groups and attributes can be used in 'ProductAttributes' worksheet
		$data = $reader->getSheetByName( 'ProductAttributes' );
		if ($data==null) {
			return $ok;
		}
		$has_missing_attribute_groups = false;
		$has_missing_attributes = false;
		$i = 0;
		$k = $data->getHighestRow();
		for ($i=1; $i<$k; $i+=1) {
			$product_id = trim($this->getCell($data,$i,1));
			if ($product_id=="") {
				continue;
			}
			if ($export_import_settings_use_attribute_group_id) {
				$attribute_group_id = trim($this->getCell($data,$i,2));
				if ($attribute_group_id=="") {
					if (!$has_missing_attribute_groups) {
						$msg = str_replace( '%1', 'ProductAttributes', $this->language->get( 'error_missing_attribute_group_id' ) );
						$this->log->write( $msg );
						$has_missing_attribute_groups = true;
					}
					$ok = false;
					continue;
				}
				if (!isset($attribute_groups[$attribute_group_id])) {
					$msg = $this->language->get( 'error_invalid_attribute_group_id' );
					$msg = str_replace( '%1', 'ProductAttributes', $msg );
					$msg = str_replace( '%2', $attribute_group_id, $msg );
					$this->log->write( $msg );
					$ok = false;
					continue;
				}
				if ($export_import_settings_use_attribute_id) {
					$attribute_id = trim($this->getCell($data,$i,3));
					if ($attribute_id=="") {
						if (!$has_missing_attributes) {
							$msg = str_replace( '%1', 'ProductAttributes', $this->language->get( 'error_missing_attribute_id' ) );
							$this->log->write( $msg );
							$has_missing_attributes = true;
						}
						$ok = false;
						continue;
					}
					if (!isset($attribute_groups[$attribute_group_id][$attribute_id])) {
						$msg = $this->language->get( 'error_invalid_attribute_group_id_attribute_id' );
						$msg = str_replace( '%1', 'ProductAttributes', $msg );
						$msg = str_replace( '%2', $attribute_group_id, $msg );
						$msg = str_replace( '%3', $attribute_id, $msg );
						$this->log->write( $msg );
						$ok = false;
						continue;
					}
				} else {
					$attribute_name = trim($this->getCell($data,$i,3));
					if ($attribute_name=="") {
						if (!$has_missing_attributes) {
							$msg = str_replace( '%1', 'ProductAttributes', $this->language->get( 'error_missing_attribute_name' ) );
							$this->log->write( $msg );
							$has_missing_attributes = true;
						}
						$ok = false;
						continue;
					}
					if (!isset($attribute_groups[$attribute_group_id][$attribute_name])) {
						$msg = $this->language->get( 'error_invalid_attribute_group_id_attribute_name' );
						$msg = str_replace( '%1', 'ProductAttributes', $msg );
						$msg = str_replace( '%2', $attribute_group_id, $msg );
						$msg = str_replace( '%3', $attribute_name, $msg );
						$this->log->write( $msg );
						$ok = false;
						continue;
					}
				}
			} else {
				$attribute_group_name = trim($this->getCell($data,$i,2));
				if ($attribute_group_name=="") {
					if (!$has_missing_attribute_groups) {
						$msg = str_replace( '%1', 'ProductAttributes', $this->language->get( 'error_missing_attribute_group_name' ) );
						$this->log->write( $msg );
						$has_missing_attribute_groups = true;
					}
					$ok = false;
					continue;
				}
				if (!isset($attribute_groups[$attribute_group_name])) {
					$msg = $this->language->get( 'error_invalid_attribute_group_name' );
					$msg = str_replace( '%1', 'ProductAttributes', $msg );
					$msg = str_replace( '%2', $attribute_group_name, $msg );
					$this->log->write( $msg );
					$ok= false;
					continue;
				}
				if ($export_import_settings_use_attribute_id) {
					$attribute_id = trim($this->getCell($data,$i,3));
					if ($attribute_id=="") {
						if (!$has_missing_attributes) {
							$msg = str_replace( '%1', 'ProductAttributes', $this->language->get( 'error_missing_attribute_id' ) );
							$this->log->write( $msg );
							$has_missing_attributes = true;
						}
						$ok = false;
						continue;
					}
					if (!isset($attribute_groups[$attribute_group_name][$attribute_id])) {
						$msg = $this->language->get( 'error_invalid_attribute_group_name_attribute_id' );
						$msg = str_replace( '%1', 'ProductAttributes', $msg );
						$msg = str_replace( '%2', $attribute_group_name, $msg );
						$msg = str_replace( '%3', $attribute_id, $msg );
						$this->log->write( $msg );
						$ok = false;
						continue;
					}
				} else {
					$attribute_name = trim($this->getCell($data,$i,3));
					if ($attribute_name=="") {
						if (!$has_missing_attributes) {
							$msg = str_replace( '%1', 'ProductAttributes', $this->language->get( 'error_missing_attribute_name' ) );
							$this->log->write( $msg );
							$has_missing_attributes = true;
						}
						$ok = false;
						continue;
					}
					if (!isset($attribute_groups[$attribute_group_name][$attribute_name])) {
						$msg = $this->language->get( 'error_invalid_attribute_group_name_attribute_name' );
						$msg = str_replace( '%1', 'ProductAttributes', $msg );
						$msg = str_replace( '%2', $attribute_group_name, $msg );
						$msg = str_replace( '%3', $attribute_name, $msg );
						$this->log->write( $msg );
						$ok = false;
						continue;
					}
				}
			}
		}
		
		return $ok;
	}


	protected function validateFilterColumns( &$reader ) {
		// get all existing filter_groups and filters
		$ok = true;
		$export_import_settings_use_filter_group_id = $this->config->get('export_import_settings_use_filter_group_id');
		$export_import_settings_use_filter_id = $this->config->get('export_import_settings_use_filter_id');
		$language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT fgd.filter_group_id, fgd.name AS filter_group_name, fd.filter_id, fd.name AS filter_name ";
		$sql .= "FROM `".DB_PREFIX."filter_group_description` fgd ";
		$sql .= "LEFT JOIN `".DB_PREFIX."filter` f ON f.filter_group_id=fgd.filter_group_id ";
		$sql .= "LEFT JOIN `".DB_PREFIX."filter_description` fd ON fd.filter_id=f.filter_id AND fd.language_id='".(int)$language_id."' ";
		$sql .= "WHERE fgd.language_id='".(int)$language_id."'";
		$query = $this->db->query( $sql );
		$filter_groups = array();
		foreach ($query->rows as $row) {
			if ($export_import_settings_use_filter_group_id) {
				$filter_group_id = $row['filter_group_id'];
				if (!isset($filter_groups[$filter_group_id])) {
					$filter_groups[$filter_group_id] = array();
				}
				if ($export_import_settings_use_filter_id) {
					$filter_id = $row['filter_id'];
					if (!is_null($filter_id)) {
						$filter_groups[$filter_group_id][$filter_id] = true;
					}
				} else {
					$filter_name = htmlspecialchars_decode($row['filter_name']);
					if (!is_null($filter_name)) {
						$filter_groups[$filter_group_id][$filter_name] = true;
					}
				}
			} else {
				$filter_group_name = htmlspecialchars_decode($row['filter_group_name']);
				if (!isset($filter_groups[$filter_group_name])) {
					$filter_groups[$filter_group_name] = array();
				}
				if ($export_import_settings_use_filter_id) {
					$filter_id = $row['filter_id'];
					if (!is_null($filter_id)) {
						$filter_groups[$filter_group_name][$filter_id] = true;
					}
				} else {
					$filter_name = htmlspecialchars_decode($row['filter_name']);
					if (!is_null($filter_name)) {
						$filter_groups[$filter_group_name][$filter_name] = true;
					}
				}
			}
		}

		// only existing filter_groups and filters can be used in the 'ProductFilters' and 'CategoryFilters' worksheets
		$worksheet_names = array('ProductFilters','CategoryFilters');
		foreach ($worksheet_names as $worksheet_name) {
			$data = $reader->getSheetByName( 'ProductFilters' );
			if ($data==null) {
				return $ok;
			}
			$has_missing_filter_groups = false;
			$has_missing_filters = false;
			$i = 0;
			$k = $data->getHighestRow();
			for ($i=1; $i<$k; $i+=1) {
				$id = trim($this->getCell($data,$i,1));
				if ($id=="") {
					continue;
				}
				if ($export_import_settings_use_filter_group_id) {
					$filter_group_id = trim($this->getCell($data,$i,2));
					if ($filter_group_id=="") {
						if (!$has_missing_filter_groups) {
							$msg = str_replace( '%1', $worksheet_name, $this->language->get( 'error_missing_filter_group_id' ) );
							$this->log->write( $msg );
							$has_missing_filter_groups = true;
						}
						$ok = false;
						continue;
					}
					if (!isset($filter_groups[$filter_group_id])) {
						$msg = $this->language->get( 'error_invalid_filter_group_id' );
						$msg = str_replace( '%1', $worksheet_name, $msg );
						$msg = str_replace( '%2', $filter_group_id, $msg );
						$this->log->write( $msg );
						$ok = false;
						continue;
					}
					if ($export_import_settings_use_filter_id) {
						$filter_id = trim($this->getCell($data,$i,3));
						if ($filter_id=="") {
							if (!$has_missing_filters) {
								$msg = str_replace( '%1', $worksheet_name, $this->language->get( 'error_missing_filter_id' ) );
								$this->log->write( $msg );
								$has_missing_filters = true;
							}
							$ok = false;
							continue;
						}
						if (!isset($filter_groups[$filter_group_id][$filter_id])) {
							$msg = $this->language->get( 'error_invalid_filter_group_id_filter_id' );
							$msg = str_replace( '%1', $worksheet_name, $msg );
							$msg = str_replace( '%2', $filter_group_id, $msg );
							$msg = str_replace( '%3', $filter_id, $msg );
							$this->log->write( $msg );
							$ok = false;
							continue;
						}
					} else {
						$filter_name = trim($this->getCell($data,$i,3));
						if ($filter_name=="") {
							if (!$has_missing_filters) {
								$msg = str_replace( '%1', $worksheet_name, $this->language->get( 'error_missing_filter_name' ) );
								$this->log->write( $msg );
								$has_missing_filters = true;
							}
							$ok = false;
							continue;
						}
						if (!isset($filter_groups[$filter_group_id][$filter_name])) {
							$msg = $this->language->get( 'error_invalid_filter_group_id_filter_name' );
							$msg = str_replace( '%1', $worksheet_name, $msg );
							$msg = str_replace( '%2', $filter_group_id, $msg );
							$msg = str_replace( '%3', $filter_name, $msg );
							$this->log->write( $msg );
							$ok = false;
							continue;
						}
					}
				} else {
					$filter_group_name = trim($this->getCell($data,$i,2));
					if ($filter_group_name=="") {
						if (!$has_missing_filter_groups) {
							$msg = str_replace( '%1', $worksheet_name, $this->language->get( 'error_missing_filter_group_name' ) );
							$this->log->write( $msg );
							$has_missing_filter_groups = true;
						}
						$ok = false;
						continue;
					}
					if (!isset($filter_groups[$filter_group_name])) {
						$msg = $this->language->get( 'error_invalid_filter_group_name' );
						$msg = str_replace( '%1', $worksheet_name, $msg );
						$msg = str_replace( '%2', $filter_group_name, $msg );
						$this->log->write( $msg );
						$ok= false;
						continue;
					}
					if ($export_import_settings_use_filter_id) {
						$filter_id = trim($this->getCell($data,$i,3));
						if ($filter_id=="") {
							if (!$has_missing_filters) {
								$msg = str_replace( '%1', $worksheet_name, $this->language->get( 'error_missing_filter_id' ) );
								$this->log->write( $msg );
								$has_missing_filters = true;
							}
							$ok = false;
							continue;
						}
						if (!isset($filter_groups[$filter_group_name][$filter_id])) {
							$msg = $this->language->get( 'error_invalid_filter_group_name_filter_id' );
							$msg = str_replace( '%1', $worksheet_name, $msg );
							$msg = str_replace( '%2', $filter_group_name, $msg );
							$msg = str_replace( '%3', $filter_id, $msg );
							$this->log->write( $msg );
							$ok = false;
							continue;
						}
					} else {
						$filter_name = trim($this->getCell($data,$i,3));
						if ($filter_name=="") {
							if (!$has_missing_filters) {
								$msg = str_replace( '%1', $worksheet_name, $this->language->get( 'error_missing_filter_name' ) );
								$this->log->write( $msg );
								$has_missing_filters = true;
							}
							$ok = false;
							continue;
						}
						if (!isset($filter_groups[$filter_group_name][$filter_name])) {
							$msg = $this->language->get( 'error_invalid_filter_group_name_filter_name' );
							$msg = str_replace( '%1', $worksheet_name, $msg );
							$msg = str_replace( '%2', $filter_group_name, $msg );
							$msg = str_replace( '%3', $filter_name, $msg );
							$this->log->write( $msg );
							$ok = false;
							continue;
						}
					}
				}
			}
		}

		return $ok;
	}


	protected function isInteger($input){
		return(ctype_digit(strval($input)));
	}


	protected function validateStoreIds( &$reader ) {
		$worksheets = array( 'Customers', 'CategorySEOKeywords', 'ProductSEOKeywords' );
		$ok = true;
		$store_ids = $this->getAvailableStoreIds();
		foreach ($worksheets as $worksheet) {
			$data = $reader->getSheetByName( $worksheet );
			if ($data==null) {
				continue;
			}
			$k = $data->getHighestRow();
			for ($i=1; $i<$k; $i+=1) {
				$j = ($worksheet=='Customers') ? 3 : 2;
				$store_id = $this->getCell($data,$i,$j);
				if (!$this->isInteger($store_id)) {
					// Invalid store_id='...' used in worksheet '...'
					$msg = $this->language->get( 'error_invalid_store_id' );
					$msg = str_replace( '%1', $store_id, $msg );
					$msg = str_replace( '%2', $worksheet, $msg );
					$this->log->write( $msg );
					$ok = false;
				} else if (!in_array( (int)$store_id, $store_ids )) {
					// Invalid store_id='...' used in worksheet '...'
					$msg = $this->language->get( 'error_invalid_store_id' );
					$msg = str_replace( '%1', $store_id, $msg );
					$msg = str_replace( '%2', $worksheet, $msg );
					$this->log->write( $msg );
					$ok = false;
				}
			}
		}
		return $ok;
	}


	protected function validateIncrementalOnly( &$reader, $incremental ) {
		// certain worksheets can only be imported in incremental mode for the time being
		$ok = true;
		$worksheets = array( 'Customers', 'Addresses' );
		foreach ($worksheets as $worksheet) {
			$data = $reader->getSheetByName( $worksheet );
			if ($data) {
				if (!$incremental) {
					$msg = $this->language->get( 'error_incremental_only' );
					$msg = str_replace( '%1', $worksheet, $msg );
					$this->log->write( $msg );
					$ok = false;
				}
			}
		}
		return $ok;
	}


	protected function validateCategorySEOUrls( &$reader, &$languages ) {
		$ok = true;

		// all category_id/store_id combinations must be unique
		$data = $reader->getSheetByName( 'CategorySEOKeywords' );
		if ($data==null) {
			return true;
		}
		$category_id_store_id = array();
		$k = $data->getHighestRow();
		for ($i=1; $i<$k; $i+=1) {
			$j = 1;
			$category_id = $this->getCell($data,$i,$j);
			if (!$this->isInteger($category_id)) {
				continue;
			}
			$j += 1;
			$store_id = $this->getCell($data,$i,$j);
			if (!$this->isInteger($store_id)) {
				continue;
			}
			if (!isset($category_id_store_id[$category_id])) {
				$category_id_store_id[$category_id] = array();
			}
			if (!isset($category_id_store_id[$category_id][$store_id])) {
				$category_id_store_id[$category_id][$store_id] = 0;
			}
			$category_id_store_id[$category_id][$store_id] += 1;
		}
		foreach ($category_id_store_id as $category_id=>$val1) {
			foreach ($val1 as $store_id=>$val2) {
				if ($val2 > 1) {
					$msg = $this->language->get( 'error_multiple_category_id_store_id' );
					$msg = str_replace( '%1', $category_id, $msg );
					$msg = str_replace( '%2', $store_id, $msg );
					$this->log->write( $msg );
					$ok = false;
				}
			}
		}
		if (!$ok) {
			return false;
		}

		// all keywords for each store_id must unique
		$store_ids = $this->getAvailableStoreIds();
		foreach ($store_ids as $next_store_id) {
			$keyword_counts = array();
			$k = $data->getHighestRow();
			for ($i=1; $i<$k; $i+=1) {
				$j = 1;
				$category_id = $this->getCell($data,$i,$j);
				if (!$this->isInteger($category_id)) {
					continue;
				}
				$j += 1;
				$store_id = $this->getCell($data,$i,$j);
				if (!$this->isInteger($store_id)) {
					continue;
				}
				if ($store_id != $next_store_id) {
					continue;
				}
				foreach ($languages as $language) {
					$j += 1;
					$keyword = trim( $this->getCell($data,$i,$j,'') );
					if ($keyword != '') {
						if (!isset($keyword_counts[$keyword])) {
							$keyword_counts[$keyword] = 0;
						}
						$keyword_counts[$keyword] += 1;
					}
				}
			}
			foreach ($keyword_counts as $keyword=>$count) {
				if ($count > 1) {
					$msg = $this->language->get( 'error_unique_keyword' );
					$msg = str_replace( '%1', $keyword, $msg );
					$msg = str_replace( '%2', $next_store_id, $msg );
					$msg = str_replace( '%3', 'CategorySEOKeywords', $msg );
					$this->log->write( $msg );
					$ok = false;
				}
			}
		}
		
		return $ok;
	}


	protected function validateProductSEOUrls( &$reader, &$languages ) {
		$ok = true;

		// all product_id/store_id combinations must be unique
		$data = $reader->getSheetByName( 'ProductSEOKeywords' );
		if ($data==null) {
			return true;
		}
		$product_id_store_id = array();
		$k = $data->getHighestRow();
		for ($i=1; $i<$k; $i+=1) {
			$j = 1;
			$product_id = $this->getCell($data,$i,$j);
			if (!$this->isInteger($product_id)) {
				continue;
			}
			$j += 1;
			$store_id = $this->getCell($data,$i,$j);
			if (!$this->isInteger($store_id)) {
				continue;
			}
			if (!isset($product_id_store_id[$product_id])) {
				$product_id_store_id[$product_id] = array();
			}
			if (!isset($product_id_store_id[$product_id][$store_id])) {
				$product_id_store_id[$product_id][$store_id] = 0;
			}
			$product_id_store_id[$product_id][$store_id] += 1;
		}
		foreach ($product_id_store_id as $product_id=>$val1) {
			foreach ($val1 as $store_id=>$val2) {
				if ($val2 > 1) {
					$msg = $this->language->get( 'error_multiple_product_id_store_id' );
					$msg = str_replace( '%1', $product_id, $msg );
					$msg = str_replace( '%2', $store_id, $msg );
					$this->log->write( $msg );
					$ok = false;
				}
			}
		}
		if (!$ok) {
			return false;
		}

		// all keywords for each store_id must unique
		$store_ids = $this->getAvailableStoreIds();
		foreach ($store_ids as $next_store_id) {
			$keyword_counts = array();
			$k = $data->getHighestRow();
			for ($i=1; $i<$k; $i+=1) {
				$j = 1;
				$product_id = $this->getCell($data,$i,$j);
				if (!$this->isInteger($product_id)) {
					continue;
				}
				$j += 1;
				$store_id = $this->getCell($data,$i,$j);
				if (!$this->isInteger($store_id)) {
					continue;
				}
				if ($store_id != $next_store_id) {
					continue;
				}
				foreach ($languages as $language) {
					$j += 1;
					$keyword = trim( $this->getCell($data,$i,$j,'') );
					if ($keyword != '') {
						if (!isset($keyword_counts[$keyword])) {
							$keyword_counts[$keyword] = 0;
						}
						$keyword_counts[$keyword] += 1;
					}
				}
			}
			foreach ($keyword_counts as $keyword=>$count) {
				if ($count > 1) {
					$msg = $this->language->get( 'error_unique_keyword' );
					$msg = str_replace( '%1', $keyword, $msg );
					$msg = str_replace( '%2', $next_store_id, $msg );
					$msg = str_replace( '%3', 'ProductSEOKeywords', $msg );
					$this->log->write( $msg );
					$ok = false;
				}
			}
		}
		
		return $ok;
	}


	protected function validateWorksheetNames( &$reader ) {
		$allowed_worksheets = array(
			'Categories',
			'CategoryFilters',
			'CategorySEOKeywords',
			'Products',
			'AdditionalImages',
			'Specials',
			'Discounts',
			'Rewards',
			'ProductOptions',
			'ProductOptionValues',
			'ProductAttributes',
			'ProductFilters',
			'ProductSEOKeywords',
			'Options',
			'OptionValues',
			'AttributeGroups',
			'Attributes',
			'FilterGroups',
			'Filters',
			'Customers',
			'Addresses'
		);
		$all_worksheets_ignored = true;
		$worksheets = $reader->getSheetNames();
		foreach ($worksheets as $worksheet) {
			if (in_array($worksheet,$allowed_worksheets)) {
				$all_worksheets_ignored = false;
				break;
			}
		}
		if ($all_worksheets_ignored) {
			return false;
		}
		return true;
	}


	protected function validateUpload( &$reader )
	{
		$ok = true;
		$languages = $this->getLanguages();

		// make sure at least one of worksheet names is valid
		if (!$this->validateWorksheetNames( $reader )) {
			$this->log->write( $this->language->get( 'error_worksheets' ) );
			$ok = false;
		}

		// worksheets must have correct heading rows
		if (!$this->validateCategories( $reader )) {
			$this->log->write( $this->language->get('error_categories_header') );
			$ok = false;
		}
		if (!$this->validateCategoryFilters( $reader )) {
			$this->log->write( $this->language->get('error_category_filters_header') );
			$ok = false;
		}
		if (!$this->validateCategorySEOKeywords( $reader )) {
			$this->log->write( $this->language->get('error_category_seo_keywords_header') );
			$ok = false;
		}
		if (!$this->validateProducts( $reader )) {
			$this->log->write( $this->language->get('error_products_header') );
			$ok = false;
		}
		if (!$this->validateAdditionalImages( $reader )) {
			$this->log->write( $this->language->get('error_additional_images_header') );
			$ok = false;
		}
		if (!$this->validateSpecials( $reader )) {
			$this->log->write( $this->language->get('error_specials_header') );
			$ok = false;
		}
		if (!$this->validateDiscounts( $reader )) {
			$this->log->write( $this->language->get('error_discounts_header') );
			$ok = false;
		}
		if (!$this->validateRewards( $reader )) {
			$this->log->write( $this->language->get('error_rewards_header') );
			$ok = false;
		}
		if (!$this->validateProductOptions( $reader )) {
			$this->log->write( $this->language->get('error_product_options_header') );
			$ok = false;
		}
		if (!$this->validateProductOptionValues( $reader )) {
			$this->log->write( $this->language->get('error_product_option_values_header') );
			$ok = false;
		}
		if (!$this->validateProductAttributes( $reader )) {
			$this->log->write( $this->language->get('error_product_attributes_header') );
			$ok = false;
		}
		if (!$this->validateProductFilters( $reader )) {
			$this->log->write( $this->language->get('error_product_filters_header') );
			$ok = false;
		}
		if (!$this->validateProductSEOKeywords( $reader )) {
			$this->log->write( $this->language->get('error_product_seo_keywords_header') );
			$ok = false;
		}
		if (!$this->validateOptions( $reader )) {
			$this->log->write( $this->language->get('error_options_header') );
			$ok = false;
		}
		if (!$this->validateOptionValues( $reader )) {
			$this->log->write( $this->language->get('error_option_values_header') );
			$ok = false;
		}
		if (!$this->validateAttributeGroups( $reader )) {
			$this->log->write( $this->language->get('error_attribute_groups_header') );
			$ok = false;
		}
		if (!$this->validateAttributes( $reader )) {
			$this->log->write( $this->language->get('error_attributes_header') );
			$ok = false;
		}
		if (!$this->validateFilterGroups( $reader )) {
			$this->log->write( $this->language->get('error_filter_groups_header') );
			$ok = false;
		}
		if (!$this->validateFilters( $reader )) {
			$this->log->write( $this->language->get('error_filters_header') );
			$ok = false;
		}
		if (!$this->validateCustomers( $reader )) {
			$this->log->write( $this->language->get('error_customers_header') );
			$ok = false;
		}
		if (!$this->validateAddresses( $reader )) {
			$this->log->write( $this->language->get('error_addresses_header') );
			$ok = false;
		}

		// certain worksheets rely on the existence of other worksheets
		$names = $reader->getSheetNames();
		$exist_categories = false;
		$exist_category_filters = false;
		$exist_category_seo_keywords = false;
		$exist_product_options = false;
		$exist_product_option_values = false;
		$exist_products = false;
		$exist_additional_images = false;
		$exist_specials = false;
		$exist_discounts = false;
		$exist_rewards = false;
		$exist_product_attributes = false;
		$exist_product_filters = false;
		$exist_product_seo_keywords = false;
		$exist_attribute_groups = false;
		$exist_filters = false;
		$exist_filter_groups = false;
		$exist_attributes = false;
		$exist_options = false;
		$exist_option_values = false;
		$exist_customers = false;
		$exist_addresses = false;
		foreach ($names as $name) {
			if ($name=='Categories') {
				$exist_categories = true;
				continue;
			}
			if ($name=='CategoryFilters') {
				if (!$exist_categories) {
					// Missing Categories worksheet, or Categories worksheet not listed before CategoryFilters
					$this->log->write( $this->language->get('error_category_filters') );
					$ok = false;
				}
				$exist_category_filters = true;
				continue;
			}
			if ($name=='CategorySEOKeywords') {
				if (!$exist_categories) {
					// Missing Categories worksheet, or Categories worksheet not listed before CategorySEOKeywords
					$this->log->write( $this->language->get('error_category_seo_keywords') );
					$ok = false;
				}
				$exist_category_seo_keywords = true;
				continue;
			}
			if ($name=='Products') {
				$exist_products = true;
				continue;
			}
			if ($name=='ProductOptions') {
				if (!$exist_products) {
					// Missing Products worksheet, or Products worksheet not listed before ProductOptions
					$this->log->write( $this->language->get('error_product_options') );
					$ok = false;
				}
				$exist_product_options = true;
				continue;
			}
			if ($name=='ProductOptionValues') {
				if (!$exist_products) {
					// Missing Products worksheet, or Products worksheet not listed before ProductOptionValues
					$this->log->write( $this->language->get('error_product_option_values') );
					$ok = false;
				}
				if (!$exist_product_options) {
					// Missing ProductOptions worksheet, or ProductOptions worksheet not listed before ProductOptionValues
					$this->log->write( $this->language->get('error_product_option_values_2') );
					$ok = false;
				}
				$exist_product_option_values = true;
				continue;
			}
			if ($name=='AdditionalImages') {
				if (!$exist_products) {
					// Missing Products worksheet, or Products worksheet not listed before AdditionalImages
					$this->log->write( $this->language->get('error_additional_images') );
					$ok = false;
				}
				$exist_additional_images = true;
				continue;
			}
			if ($name=='Specials') {
				if (!$exist_products) {
					// Missing Products worksheet, or Products worksheet not listed before Specials
					$this->log->write( $this->language->get('error_specials') );
					$ok = false;
				}
				$exist_specials = true;
				continue;
			}
			if ($name=='Discounts') {
				if (!$exist_products) {
					// Missing Products worksheet, or Products worksheet not listed before Discounts
					$this->log->write( $this->language->get('error_discounts') );
					$ok = false;
				}
				$exist_discounts = true;
				continue;
			}
			if ($name=='Rewards') {
				if (!$exist_products) {
					// Missing Products worksheet, or Products worksheet not listed before Rewards
					$this->log->write( $this->language->get('error_rewards') );
					$ok = false;
				}
				$exist_rewards = true;
				continue;
			}
			if ($name=='ProductAttributes') {
				if (!$exist_products) {
					// Missing Products worksheet, or Products worksheet not listed before ProductAttributes
					$this->log->write( $this->language->get('error_product_attributes') );
					$ok = false;
				}
				$exist_product_attributes = true;
				continue;
			}
			if ($name=='AttributeGroups') {
				$exist_attribute_groups = true;
				continue;
			}
			if ($name=='Attributes') {
				if (!$exist_attribute_groups) {
					// Missing AttributeGroups worksheet, or AttributeGroups worksheet not listed before Attributes
					$this->log->write( $this->language->get('error_attributes') );
					$ok = false;
				}
				$exist_attributes = true;
				continue;
			}
			if ($name=='ProductFilters') {
				if (!$exist_products) {
					// Missing Products worksheet, or Products worksheet not listed before ProductFilters
					$this->log->write( $this->language->get('error_product_filters') );
					$ok = false;
				}
				$exist_product_filters = true;
				continue;
			}
			if ($name=='ProductSEOKeywords') {
				if (!$exist_products) {
					// Missing Products worksheet, or Products worksheet not listed before ProductSEOKeywords
					$this->log->write( $this->language->get('error_product_seo_keywords') );
					$ok = false;
				}
				$exist_product_seo_keywords = true;
				continue;
			}
			if ($name=='FilterGroups') {
				$exist_filter_groups = true;
				continue;
			}
			if ($name=='Filters') {
				if (!$exist_filter_groups) {
					// Missing FilterGroups worksheet, or FilterGroups worksheet not listed before Filters
					$this->log->write( $this->language->get('error_filters') );
					$ok = false;
				}
				$exist_filters = true;
				continue;
			}
			if ($name=='Options') {
				$exist_options = true;
				continue;
			}
			if ($name=='OptionValues') {
				if (!$exist_options) {
					// Missing Options worksheet, or Options worksheet not listed before OptionValues
					$this->log->write( $this->language->get('error_option_values') );
					$ok = false;
				}
				$exist_option_values = true;
				continue;
			}
			if ($name=='Customers') {
				$exist_customers = true;
				continue;
			}
			if ($name=='Addresses') {
				if (!$exist_customers) {
					// Missing Cutomers worksheet, or Customers worksheet not listed before Addresses
					$this->log->write( $this->language->get('error_addresses') );
					$ok = false;
				}
				$exist_addresses = true;
				continue;
			}
		}
		if ($exist_product_options) {
			if (!$exist_product_option_values) {
				// ProductOptionValues worksheet also expected after a ProductOptions worksheet
				$this->log->write( $this->language->get('error_product_option_values_3') );
				$ok = false;
			}
		}
		if ($exist_attribute_groups) {
			if (!$exist_attributes) {
				// Attributes worksheet also expected after an AttributeGroups worksheet
				$this->log->write( $this->language->get('error_attributes_2') );
				$ok = false;
			}
		}
		if ($exist_filter_groups) {
			if (!$exist_filters) {
				// Filters worksheet also expected after an FilterGroups worksheet
				$this->log->write( $this->language->get('error_filters_2') );
				$ok = false;
			}
		}
		if ($exist_options) {
			if (!$exist_option_values) {
				// OptionValues worksheet also expected after an Options worksheet
				$this->log->write( $this->language->get('error_option_values_2') );
				$ok = false;
			}
		}
		if ($exist_customers) {
			if (!$exist_addresses) {
				// Addresses worksheet also expected after Customers worksheet
				$this->log->write( $this->language->get('error_addresses_2') );
				$ok = false;
			}
		}

		if (!$ok) {
			return false;
		}

		if (!$this->validateProductIdColumns( $reader )) {
			$ok = false;
		}

		if (!$this->validateCategoryIdColumns( $reader )) {
			$ok = false;
		}

		if (!$this->validateCustomerIdColumns( $reader )) {
			$ok = false;
		}

		if (!$this->validateCustomerGroupColumns( $reader )) {
			$ok = false;
		}

		if (!$this->validateOptionColumns( $reader )) {
			$ok = false;
		}

		if (!$this->validateAttributeColumns( $reader )) {
			$ok = false;
		}

		if ($this->existFilter()) {
			if (!$this->validateFilterColumns( $reader )) {
				$ok = false;
			}
		}

		if (!$this->validateStoreIds( $reader )) {
			$ok = false;
		}

		if (!$this->validateAddressCountriesAndZones( $reader )) {
			$ok = false;
		}

		if ($this->use_table_seo_url) {
			if (!$this->validateCategorySEOUrls( $reader, $languages )) {
				$ok = false;
			}

			if (!$this->validateProductSEOUrls( $reader, $languages )) {
				$ok = false;
			}
		}

		return $ok;
	}


	protected function clearCache() {
		$this->cache->delete('*');
	}


	public function upload( $filename, $incremental=false ) {
		// we use our own error handler
		global $registry;
		$registry = $this->registry;
		set_error_handler('error_handler_for_export_import',E_ALL);
		register_shutdown_function('fatal_error_shutdown_handler_for_export_import');

		try {
			if (version_compare(phpversion(), '7.2.', '<')) {
				// php version isn't high enough
				throw new Exception( $this->language->get( 'error_php_version' ) );
			}

			$this->session->data['export_import_nochange'] = 1;

			// enable auto_load from system/library/export_import
			require( DIR_SYSTEM.'library/export_import/vendor/autoload.php' );

			// Use the PhoOffice/PhpSpreadsheet package from https://github.com/PHPOffice/PhpSpreadsheet
			$workbook = new PhpOffice\PhpSpreadsheet\Spreadsheet();

			// parse uploaded spreadsheet file
			$inputFileType = PhpOffice\PhpSpreadsheet\IOFactory::identify($filename);
			$objReader = PhpOffice\PhpSpreadsheet\IOFactory::createReader($inputFileType);
			$objReader->setReadDataOnly(true);
			$reader = $objReader->load($filename);

			// read the various worksheets and load them to the database
			if (!$this->validateIncrementalOnly( $reader, $incremental )) {
				return false;
			}
			if (!$this->validateUpload( $reader )) {
				return false;
			}
			$this->clearCache();
			$this->session->data['export_import_nochange'] = 0;
			$available_product_ids = array();
			$available_category_ids = array();
			$available_customer_ids = array();
			$this->uploadCategories( $reader, $incremental, $available_category_ids );
			$this->uploadCategoryFilters( $reader, $incremental, $available_category_ids );
			$this->uploadCategorySEOKeywords( $reader, $incremental, $available_category_ids );
			$this->uploadProducts( $reader, $incremental, $available_product_ids );
			$this->uploadAdditionalImages( $reader, $incremental, $available_product_ids );
			$this->uploadSpecials( $reader, $incremental, $available_product_ids );
			$this->uploadDiscounts( $reader, $incremental, $available_product_ids );
			$this->uploadRewards( $reader, $incremental, $available_product_ids );
			$this->uploadProductOptions( $reader, $incremental, $available_product_ids );
			$this->uploadProductOptionValues( $reader, $incremental, $available_product_ids );
			$this->uploadProductAttributes( $reader, $incremental, $available_product_ids );
			$this->uploadProductFilters( $reader, $incremental, $available_product_ids );
			$this->uploadProductSEOKeywords( $reader, $incremental, $available_product_ids );
			$this->uploadOptions( $reader, $incremental );
			$this->uploadOptionValues( $reader, $incremental );
			$this->uploadAttributeGroups( $reader, $incremental );
			$this->uploadAttributes( $reader, $incremental );
			$this->uploadFilterGroups( $reader, $incremental );
			$this->uploadFilters( $reader, $incremental );
			$this->uploadCustomers( $reader, $incremental, $available_customer_ids );
			$this->uploadAddresses( $reader, $incremental, $available_customer_ids );
			return true;
		} catch (Exception $e) {
			$errstr = $e->getMessage();
			$errline = $e->getLine();
			$errfile = $e->getFile();
			$errno = $e->getCode();
			$this->session->data['export_import_error'] = array( 'errstr'=>$errstr, 'errno'=>$errno, 'errfile'=>$errfile, 'errline'=>$errline );
			if ($this->config->get('config_error_log')) {
				$this->log->write('PHP ' . get_class($e) . ':  ' . $errstr . ' in ' . $errfile . ' on line ' . $errline);
			}
			return false;
		}
	}


	protected function getStoreIdsForCategories() {
		$sql =  "SELECT category_id, store_id FROM `".DB_PREFIX."category_to_store` cs;";
		$store_ids = array();
		$result = $this->db->query( $sql );
		foreach ($result->rows as $row) {
			$categoryId = $row['category_id'];
			$store_id = $row['store_id'];
			if (!isset($store_ids[$categoryId])) {
				$store_ids[$categoryId] = array();
			}
			if (!in_array($store_id,$store_ids[$categoryId])) {
				$store_ids[$categoryId][] = $store_id;
			}
		}
		return $store_ids;
	}


	protected function getLayoutsForCategories() {
		$sql  = "SELECT cl.*, l.name FROM `".DB_PREFIX."category_to_layout` cl ";
		$sql .= "LEFT JOIN `".DB_PREFIX."layout` l ON cl.layout_id = l.layout_id ";
		$sql .= "ORDER BY cl.category_id, cl.store_id;";
		$result = $this->db->query( $sql );
		$layouts = array();
		foreach ($result->rows as $row) {
			$categoryId = $row['category_id'];
			$store_id = $row['store_id'];
			$name = $row['name'];
			if (!isset($layouts[$categoryId])) {
				$layouts[$categoryId] = array();
			}
			$layouts[$categoryId][$store_id] = $name;
		}
		return $layouts;
	}


	protected function setColumnStyles( &$worksheet, &$styles, $min_row, $max_row ) {
		if ($max_row < $min_row) {
			return;
		}
		foreach ($styles as $col=>$style) {
			$from = PhpOffice\PhpSpreadsheet\Cell\Coordinate::stringFromColumnIndex($col).$min_row;
			$to = PhpOffice\PhpSpreadsheet\Cell\Coordinate::stringFromColumnIndex($col).$max_row;
			$range = $from.':'.$to;
			$worksheet->getStyle( $range )->applyFromArray( $style, false );
		}
	}


	protected function setCellRow( $worksheet, $row/*1-based*/, $data, &$default_style=null, &$styles=null ) {
		if (!empty($default_style)) {
			$worksheet->getStyle( "$row:$row" )->applyFromArray( $default_style, false );
		}
		if (!empty($styles)) {
			foreach ($styles as $col=>$style) {
				$worksheet->getStyleByColumnAndRow($col,$row)->applyFromArray($style,false);
			}
		}
		$worksheet->fromArray( $data, null, 'A'.$row, true );
	}


	protected function setCell( &$worksheet, $row/*1-based*/, $col/*1-based*/, $val, &$style=null ) {
		$worksheet->setCellValueByColumnAndRow( $col, $row, $val );
		if (!empty($style)) {
			$worksheet->getStyleByColumnAndRow($col,$row)->applyFromArray( $style, false );
		}
	}


	protected function getCategoryDescriptions( &$languages, $offset=null, $rows=null, $min_id=null, $max_id=null ) {
		// query the category_description table for each language
		$category_descriptions = array();
		foreach ($languages as $language) {
			$language_id = $language['language_id'];
			$language_code = $language['code'];
			$sql  = "SELECT c.category_id, cd.* ";
			$sql .= "FROM `".DB_PREFIX."category` c ";
			$sql .= "LEFT JOIN `".DB_PREFIX."category_description` cd ON cd.category_id=c.category_id AND cd.language_id='".(int)$language_id."' ";
			if (isset($min_id) && isset($max_id)) {
				$sql .= "WHERE c.category_id BETWEEN $min_id AND $max_id ";
			}
			$sql .= "GROUP BY c.`category_id` ";
			$sql .= "ORDER BY c.`category_id` ASC ";
			if (isset($offset) && isset($rows)) {
				$sql .= "LIMIT $offset,$rows; ";
			} else {
				$sql .= "; ";
			}
			$query = $this->db->query( $sql );
			$category_descriptions[$language_code] = $query->rows;
		}
		return $category_descriptions;
	}


	protected function getCategories( &$languages, $exist_meta_title, $exist_seo_url_table, $offset=null, $rows=null, $min_id=null, $max_id=null ) {
		if ($exist_seo_url_table) {
			$sql  = "SELECT c.* FROM `".DB_PREFIX."category` c ";
		} else {
			$sql  = "SELECT c.*, ua.keyword FROM `".DB_PREFIX."category` c ";
			$sql .= "LEFT JOIN `".DB_PREFIX."url_alias` ua ON ua.query=CONCAT('category_id=',c.category_id) ";
		}
		if (isset($min_id) && isset($max_id)) {
			$sql .= "WHERE c.category_id BETWEEN $min_id AND $max_id ";
		}
		$sql .= "GROUP BY c.`category_id` ";
		$sql .= "ORDER BY c.`category_id` ASC ";
		if (isset($offset) && isset($rows)) {
			$sql .= "LIMIT $offset,$rows; ";
		} else {
			$sql .= "; ";
		}
		$results = $this->db->query( $sql );
		$category_descriptions = $this->getCategoryDescriptions( $languages, $offset, $rows, $min_id, $max_id );
		foreach ($languages as $language) {
			$language_code = $language['code'];
			foreach ($results->rows as $key=>$row) {
				if (isset($category_descriptions[$language_code][$key])) {
					$results->rows[$key]['name'][$language_code] = $category_descriptions[$language_code][$key]['name'];
					$results->rows[$key]['description'][$language_code] = $category_descriptions[$language_code][$key]['description'];
					if ($exist_meta_title) {
						$results->rows[$key]['meta_title'][$language_code] = $category_descriptions[$language_code][$key]['meta_title'];
					}
					$results->rows[$key]['meta_description'][$language_code] = $category_descriptions[$language_code][$key]['meta_description'];
					$results->rows[$key]['meta_keyword'][$language_code] = $category_descriptions[$language_code][$key]['meta_keyword'];
				} else {
					$results->rows[$key]['name'][$language_code] = '';
					$results->rows[$key]['description'][$language_code] = '';
					if ($exist_meta_title) {
						$results->rows[$key]['meta_title'][$language_code] = '';
					}
					$results->rows[$key]['meta_description'][$language_code] = '';
					$results->rows[$key]['meta_keyword'][$language_code] = '';
				}
			}
		}
		return $results->rows;
	}


	protected function populateCategoriesWorksheet( &$worksheet, &$languages, &$box_format, &$text_format, $offset=null, $rows=null, &$min_id=null, &$max_id=null ) {
		// Opencart versions from 2.0 onwards also have category_description.meta_title
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."category_description` LIKE 'meta_title'";
		$query = $this->db->query( $sql );
		$exist_meta_title = ($query->num_rows > 0) ? true : false;

		// Opencart versions from 3.0 onwards use the seo_url DB table
		$exist_seo_url_table = $this->use_table_seo_url;

		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('category_id')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('parent_id')+1);
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('name')+4,30)+1);
		}
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('top'),5)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('columns')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('sort_order')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('image_name'),12)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('date_added'),19)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('date_modified'),19)+1);
		if (!$exist_seo_url_table) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('seo_keyword'),16)+1);
		}
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('description'),32)+1);
		}
		if ($exist_meta_title) {
			foreach ($languages as $language) {
				$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('meta_title'),20)+1);
			}
		}
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('meta_description'),32)+1);
		}
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('meta_keywords'),32)+1);
		}
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('store_ids'),16)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('layout'),16)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('status'),5)+1);
		
		// The heading row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'category_id';
		$data[$j++] = 'parent_id';
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'name('.$language['code'].')';
		}
		$data[$j++] = 'top';
		$data[$j++] = 'columns';
		$data[$j++] = 'sort_order';
		$styles[$j] = &$text_format;
		$data[$j++] = 'image_name';
		$styles[$j] = &$text_format;
		$data[$j++] = 'date_added';
		$styles[$j] = &$text_format;
		$data[$j++] = 'date_modified';
		if (!$exist_seo_url_table) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'seo_keyword';
		}
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'description('.$language['code'].')';
		}
		if ($exist_meta_title) {
			foreach ($languages as $language) {
				$styles[$j] = &$text_format;
				$data[$j++] = 'meta_title('.$language['code'].')';
			}
		}
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'meta_description('.$language['code'].')';
		}
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'meta_keywords('.$language['code'].')';
		}
		$styles[$j] = &$text_format;
		$data[$j++] = 'store_ids';
		$styles[$j] = &$text_format;
		$data[$j++] = 'layout';
		$data[$j++] = 'status';
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual categories data
		$i += 1;
		$j = 1;
		$store_ids = $this->getStoreIdsForCategories();
		$layouts = $this->getLayoutsForCategories();
		$categories = $this->getCategories( $languages, $exist_meta_title, $exist_seo_url_table, $offset, $rows, $min_id, $max_id );
		$len = count($categories);
		$min_id = ($len>0) ? $categories[0]['category_id'] : 0;
		$max_id = ($len>0) ? $categories[$len-1]['category_id'] : 0;
		foreach ($categories as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(26);
			$data = array();
			$data[$j++] = $row['category_id'];
			$data[$j++] = $row['parent_id'];
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['name'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			$data[$j++] = ($row['top']==0) ? "false" : "true";
			$data[$j++] = $row['column'];
			$data[$j++] = $row['sort_order'];
			$data[$j++] = $row['image'];
			$data[$j++] = $row['date_added'];
			$data[$j++] = $row['date_modified'];
			if (!$exist_seo_url_table) {
				$data[$j++] = $row['keyword'];
			}
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['description'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			if ($exist_meta_title) {
				foreach ($languages as $language) {
					$data[$j++] = html_entity_decode($row['meta_title'][$language['code']],ENT_QUOTES,'UTF-8');
				}
			}
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['meta_description'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['meta_keyword'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			$store_id_list = '';
			$category_id = $row['category_id'];
			if (isset($store_ids[$category_id])) {
				foreach ($store_ids[$category_id] as $store_id) {
					$store_id_list .= ($store_id_list=='') ? $store_id : ','.$store_id;
				}
			}
			$data[$j++] = $store_id_list;
			$layout_list = '';
			if (isset($layouts[$category_id])) {
				foreach ($layouts[$category_id] as $store_id => $name) {
					$layout_list .= ($layout_list=='') ? $store_id.':'.$name : ','.$store_id.':'.$name;
				}
			}
			$data[$j++] = $layout_list;
			$data[$j++] = ($row['status']==0) ? 'false' : 'true';
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getFilterGroupNames( $language_id ) {
		$sql  = "SELECT filter_group_id, name ";
		$sql .= "FROM `".DB_PREFIX."filter_group_description` ";
		$sql .= "WHERE language_id='".(int)$language_id."' ";
		$sql .= "ORDER BY filter_group_id ASC";
		$query = $this->db->query( $sql );
		$filter_group_names = array();
		foreach ($query->rows as $row) {
			$filter_group_id = $row['filter_group_id'];
			$name = $row['name'];
			$filter_group_names[$filter_group_id] = $name;
		}
		return $filter_group_names;
	}


	protected function getFilterNames( $language_id ) {
		$sql  = "SELECT filter_id, name ";
		$sql .= "FROM `".DB_PREFIX."filter_description` ";
		$sql .= "WHERE language_id='".(int)$language_id."' ";
		$sql .= "ORDER BY filter_id ASC";
		$query = $this->db->query( $sql );
		$filter_names = array();
		foreach ($query->rows as $row) {
			$filter_id = $row['filter_id'];
			$filter_name = $row['name'];
			$filter_names[$filter_id] = $filter_name;
		}
		return $filter_names;
	}


	protected function getCategoryFilters( $min_id, $max_id ) {
		$sql  = "SELECT cf.category_id, fg.filter_group_id, cf.filter_id ";
		$sql .= "FROM `".DB_PREFIX."category_filter` cf ";
		$sql .= "INNER JOIN `".DB_PREFIX."filter` f ON f.filter_id=cf.filter_id ";
		$sql .= "INNER JOIN `".DB_PREFIX."filter_group` fg ON fg.filter_group_id=f.filter_group_id ";
		if (isset($min_id) && isset($max_id)) {
			$sql .= "WHERE category_id BETWEEN $min_id AND $max_id ";
		}
		$sql .= "ORDER BY cf.category_id ASC, fg.filter_group_id ASC, cf.filter_id ASC";
		$query = $this->db->query( $sql );
		$category_filters = array();
		foreach ($query->rows as $row) {
			$category_filter = array();
			$category_filter['category_id'] = $row['category_id'];
			$category_filter['filter_group_id'] = $row['filter_group_id'];
			$category_filter['filter_id'] = $row['filter_id'];
			$category_filters[] = $category_filter;
		}
		return $category_filters;
	}


	protected function populateCategoryFiltersWorksheet( &$worksheet, &$languages, $default_language_id, &$box_format, &$text_format, $min_id=null, $max_id=null ) {
		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('category_id')+1);
		if ($this->config->get( 'export_import_settings_use_filter_group_id' )) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('filter_group_id')+1);
		} else {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('filter_group'),30)+1);
		}
		if ($this->config->get( 'export_import_settings_use_filter_id' )) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('filter_id')+1);
		} else {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('filter'),30)+1);
		}
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('text')+4,30)+1);
		}

		// The heading row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'category_id';
		if ($this->config->get( 'export_import_settings_use_filter_group_id' )) {
			$data[$j++] = 'filter_group_id';
		} else {
			$styles[$j] = &$text_format;
			$data[$j++] = 'filter_group';
		}
		if ($this->config->get( 'export_import_settings_use_filter_id' )) {
			$data[$j++] = 'filter_id';
		} else {
			$styles[$j] = &$text_format;
			$data[$j++] = 'filter';
		}
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual category filters data
		if (!$this->config->get( 'export_import_settings_use_filter_group_id' )) {
			$filter_group_names = $this->getFilterGroupNames( $default_language_id );
		}
		if (!$this->config->get( 'export_import_settings_use_filter_id' )) {
			$filter_names = $this->getFilterNames( $default_language_id );
		}
		$i += 1;
		$j = 1;
		$category_filters = $this->getCategoryFilters( $min_id, $max_id );
		foreach ($category_filters as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data = array();
			$data[$j++] = $row['category_id'];
			if ($this->config->get( 'export_import_settings_use_filter_group_id' )) {
				$data[$j++] = $row['filter_group_id'];
			} else {
				$data[$j++] = html_entity_decode($filter_group_names[$row['filter_group_id']],ENT_QUOTES,'UTF-8');
			}
			if ($this->config->get( 'export_import_settings_use_filter_id' )) {
				$data[$j++] = $row['filter_id'];
			} else {
				$data[$j++] = html_entity_decode($filter_names[$row['filter_id']],ENT_QUOTES,'UTF-8');
			}
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getCategorySEOKeywords( &$languages, $min_id, $max_id ) {
		$sql  = "SELECT * FROM `".DB_PREFIX."seo_url` ";
		$sql .= "WHERE query LIKE 'category_id=%' AND ";
		$sql .= "CAST(SUBSTRING(query FROM 13) AS UNSIGNED INTEGER) >= '".(int)$min_id."' AND ";
		$sql .= "CAST(SUBSTRING(query FROM 13) AS UNSIGNED INTEGER) <= '".(int)$max_id."' ";
		$sql .= "ORDER BY CAST(SUBSTRING(query FROM 13) AS UNSIGNED INTEGER), store_id, language_id";
		$query = $this->db->query( $sql );
		$seo_keywords = array();
		foreach ($query->rows as $row) {
			$category_id = (int)substr($row['query'],12);
			$store_id = (int)$row['store_id'];
			$language_id = (int)$row['language_id'];
			if (!isset($seo_keywords[$category_id])) {
				$seo_keywords[$category_id] = array();
			}
			if (!isset($seo_keywords[$category_id][$store_id])) {
				$seo_keywords[$category_id][$store_id] = array();
			}
			$seo_keywords[$category_id][$store_id][$language_id] = $row['keyword'];
		}
		$results = array();
		foreach ($seo_keywords as $category_id=>$val1) {
			foreach ($val1 as $store_id=>$val2) {
				$keyword = array();
				foreach ($languages as $language) {
					$language_id = $language['language_id'];
					$language_code = $language['code'];
					$keyword[$language_code] = isset($val2[$language_id]) ? $val2[$language_id] : '';
				}
				$results[] = array(
					'category_id'   => $category_id,
					'store_id'      => $store_id,
					'keyword'       => $keyword
				);
			}
		}
		return $results;
	}


	protected function populateCategorySEOKeywordsWorksheet( &$worksheet, &$languages, &$box_format, &$text_format, $min_id=null, $max_id=null ) {
		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('category_id')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('store_id')+1);
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('keyword')+4,30)+1);
		}

		// The heading row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'category_id';
		$data[$j++] = 'store_id';
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'keyword('.$language['code'].')';
		}
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );
		
		// The actual category SEO keywords data
		$i += 1;
		$j = 1;
		$category_seo_keywords = $this->getCategorySEOKeywords( $languages, $min_id, $max_id );
		foreach ($category_seo_keywords as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(26);
			$data = array();
			$data[$j++] = $row['category_id'];
			$data[$j++] = $row['store_id'];
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['keyword'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getStoreIdsForProducts() {
		$sql =  "SELECT product_id, store_id FROM `".DB_PREFIX."product_to_store` ps;";
		$store_ids = array();
		$result = $this->db->query( $sql );
		foreach ($result->rows as $row) {
			$productId = $row['product_id'];
			$store_id = $row['store_id'];
			if (!isset($store_ids[$productId])) {
				$store_ids[$productId] = array();
			}
			if (!in_array($store_id,$store_ids[$productId])) {
				$store_ids[$productId][] = $store_id;
			}
		}
		return $store_ids;
	}


	protected function getLayoutsForProducts() {
		$sql  = "SELECT pl.*, l.name FROM `".DB_PREFIX."product_to_layout` pl ";
		$sql .= "LEFT JOIN `".DB_PREFIX."layout` l ON pl.layout_id = l.layout_id ";
		$sql .= "ORDER BY pl.product_id, pl.store_id;";
		$result = $this->db->query( $sql );
		$layouts = array();
		foreach ($result->rows as $row) {
			$productId = $row['product_id'];
			$store_id = $row['store_id'];
			$name = $row['name'];
			if (!isset($layouts[$productId])) {
				$layouts[$productId] = array();
			}
			$layouts[$productId][$store_id] = $name;
		}
		return $layouts;
	}


	protected function getProductDescriptions( &$languages, $offset=null, $rows=null, $min_id=null, $max_id=null ) {
		// some older versions of OpenCart use the 'product_tag' table
		$exist_table_product_tag = false;
		$query = $this->db->query( "SHOW TABLES LIKE '".DB_PREFIX."product_tag'" );
		$exist_table_product_tag = ($query->num_rows > 0);

		// query the product_description table for each language
		$product_descriptions = array();
		foreach ($languages as $language) {
			$language_id = $language['language_id'];
			$language_code = $language['code'];
			$sql  = "SELECT p.product_id, ".(($exist_table_product_tag) ? "GROUP_CONCAT(pt.tag SEPARATOR \",\") AS tag, " : "")."pd.* ";
			$sql .= "FROM `".DB_PREFIX."product` p ";
			$sql .= "LEFT JOIN `".DB_PREFIX."product_description` pd ON pd.product_id=p.product_id AND pd.language_id='".(int)$language_id."' ";
			if ($exist_table_product_tag) {
				$sql .= "LEFT JOIN `".DB_PREFIX."product_tag` pt ON pt.product_id=p.product_id AND pt.language_id='".(int)$language_id."' ";
			}
			if ($this->posted_categories) {
				$sql .= "LEFT JOIN `".DB_PREFIX."product_to_category` pc ON pc.product_id=p.product_id ";
			}
			if (isset($min_id) && isset($max_id)) {
				$sql .= "WHERE p.product_id BETWEEN $min_id AND $max_id ";
				if ($this->posted_categories) {
					$sql .= "AND pc.category_id IN ".$this->posted_categories." ";
				}
			} else if ($this->posted_categories) {
				$sql .= "WHERE pc.category_id IN ".$this->posted_categories." ";
			}
			if ($this->posted_manufacturers) {
				$sql .= (strpos($sql," WHERE ",0)===false) ? "WHERE " : "AND ";
				$sql .= "p.manufacturer_id IN ".$this->posted_manufacturers." ";
			}
			$sql .= "GROUP BY p.product_id ";
			$sql .= "ORDER BY p.product_id ";
			if (isset($offset) && isset($rows)) {
				$sql .= "LIMIT $offset,$rows; ";
			} else {
				$sql .= "; ";
			}
			$query = $this->db->query( $sql );
			$product_descriptions[$language_code] = $query->rows;
		}
		return $product_descriptions;
	}


	protected function getProducts( &$languages, $default_language_id, $product_fields, $exist_meta_title, $exist_seo_url_table, $offset=null, $rows=null, $min_id=null, $max_id=null ) {
		$sql  = "SELECT ";
		$sql .= "  p.product_id,";
		$sql .= "  GROUP_CONCAT( DISTINCT CAST(pc.category_id AS CHAR(11)) SEPARATOR \",\" ) AS categories,";
		$sql .= "  p.sku,";
		$sql .= "  p.upc,";
		if (in_array( 'ean', $product_fields )) {
			$sql .= "  p.ean,";
		}
		if (in_array('jan',$product_fields)) {
			$sql .= "  p.jan,";
		}
		if (in_array('isbn',$product_fields)) {
			$sql .= "  p.isbn,";
		}
		if (in_array('mpn',$product_fields)) {
			$sql .= "  p.mpn,";
		}
		$sql .= "  p.location,";
		$sql .= "  p.quantity,";
		$sql .= "  p.model,";
		$sql .= "  m.name AS manufacturer,";
		$sql .= "  p.image AS image_name,";
		$sql .= "  p.shipping,";
		$sql .= "  p.price,";
		$sql .= "  p.price_2,";
		$sql .= "  p.price_3,";
		$sql .= "  p.points,";
		$sql .= "  p.date_added,";
		$sql .= "  p.date_modified,";
		$sql .= "  p.date_available,";
		$sql .= "  p.weight,";
		$sql .= "  wc.unit AS weight_unit,";
		$sql .= "  p.length,";
		$sql .= "  p.width,";
		$sql .= "  p.height,";
		$sql .= "  p.status,";
		$sql .= "  p.tax_class_id,";
		$sql .= "  p.sort_order,";
		if (!$exist_seo_url_table) {
			$sql .= "  ua.keyword,";
		}
		$sql .= "  p.stock_status_id, ";
		$sql .= "  mc.unit AS length_unit, ";
		$sql .= "  p.subtract, ";
		$sql .= "  p.minimum, ";
		$sql .= "  GROUP_CONCAT( DISTINCT CAST(pr.related_id AS CHAR(11)) SEPARATOR \",\" ) AS related ";
		$sql .= "FROM `".DB_PREFIX."product` p ";
		$sql .= "LEFT JOIN `".DB_PREFIX."product_to_category` pc ON p.product_id=pc.product_id ";
		if ($this->posted_categories) {
			$sql .= " LEFT JOIN `".DB_PREFIX."product_to_category` pc2 ON p.product_id=pc2.product_id ";
		}
		if (!$exist_seo_url_table) {
			$sql .= "LEFT JOIN `".DB_PREFIX."url_alias` ua ON ua.query=CONCAT('product_id=',p.product_id) ";
		}
		$sql .= "LEFT JOIN `".DB_PREFIX."manufacturer` m ON m.manufacturer_id = p.manufacturer_id ";
		$sql .= "LEFT JOIN `".DB_PREFIX."weight_class_description` wc ON wc.weight_class_id = p.weight_class_id ";
		$sql .= "  AND wc.language_id=$default_language_id ";
		$sql .= "LEFT JOIN `".DB_PREFIX."length_class_description` mc ON mc.length_class_id=p.length_class_id ";
		$sql .= "  AND mc.language_id=$default_language_id ";
		$sql .= "LEFT JOIN `".DB_PREFIX."product_related` pr ON pr.product_id=p.product_id ";
		if (isset($min_id) && isset($max_id)) {
			$sql .= "WHERE p.product_id BETWEEN $min_id AND $max_id ";
			if ($this->posted_categories) {
				$sql .= "AND pc2.category_id IN ".$this->posted_categories." ";
			}
		} else if ($this->posted_categories) {
			$sql .= "WHERE pc2.category_id IN ".$this->posted_categories." ";
		}
		if ($this->posted_manufacturers) {
			$sql .= (strpos($sql," WHERE ",0)===false) ? "WHERE " : "AND ";
			$sql .= "p.manufacturer_id IN ".$this->posted_manufacturers." ";
		}
		$sql .= "GROUP BY p.product_id ";
		$sql .= "ORDER BY p.product_id ";
		if (isset($offset) && isset($rows)) {
			$sql .= "LIMIT $offset,$rows; ";
		} else {
			$sql .= "; ";
		}
		$results = $this->db->query( $sql );
		$product_descriptions = $this->getProductDescriptions( $languages, $offset, $rows, $min_id, $max_id );
		foreach ($languages as $language) {
			$language_code = $language['code'];
			foreach ($results->rows as $key=>$row) {
				if (isset($product_descriptions[$language_code][$key])) {
					$results->rows[$key]['name'][$language_code] = $product_descriptions[$language_code][$key]['name'];
					$results->rows[$key]['description'][$language_code] = $product_descriptions[$language_code][$key]['description'];
					if ($exist_meta_title) {
						$results->rows[$key]['meta_title'][$language_code] = $product_descriptions[$language_code][$key]['meta_title'];
					}
					$results->rows[$key]['meta_description'][$language_code] = $product_descriptions[$language_code][$key]['meta_description'];
					$results->rows[$key]['meta_keyword'][$language_code] = $product_descriptions[$language_code][$key]['meta_keyword'];
					$results->rows[$key]['tag'][$language_code] = $product_descriptions[$language_code][$key]['tag'];
				} else {
					$results->rows[$key]['name'][$language_code] = '';
					$results->rows[$key]['description'][$language_code] = '';
					if ($exist_meta_title) {
						$results->rows[$key]['meta_title'][$language_code] = '';
					}
					$results->rows[$key]['meta_description'][$language_code] = '';
					$results->rows[$key]['meta_keyword'][$language_code] = '';
					$results->rows[$key]['tag'][$language_code] = '';
				}
			}
		}
		return $results->rows;
	}


	protected function populateProductsWorksheet( &$worksheet, &$languages, $default_language_id, &$price_format, &$box_format, &$weight_format, &$text_format, $offset=null, $rows=null, &$min_id=null, &$max_id=null) {
		// get list of the field names, some are only available for certain OpenCart versions
		$query = $this->db->query( "DESCRIBE `".DB_PREFIX."product`" );
		$product_fields = array();
		foreach ($query->rows as $row) {
			$product_fields[] = $row['Field'];
		}

		// Opencart versions from 2.0 onwards also have product_description.meta_title
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."product_description` LIKE 'meta_title'";
		$query = $this->db->query( $sql );
		$exist_meta_title = ($query->num_rows > 0) ? true : false;

		// Opencart versions from 3.0 onwards use the seo_url DB table
		$exist_seo_url_table = $this->use_table_seo_url;

		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('product_id'),4)+1);
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('name')+4,30)+1);
		}
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('categories'),12)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('sku'),10)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('upc'),12)+1);
		if (in_array('ean',$product_fields)) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('ean'),14)+1);
		}
		if (in_array('jan',$product_fields)) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('jan'),13)+1);
		}
		if (in_array('isbn',$product_fields)) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('isbn'),13)+1);
		}
		if (in_array('mpn',$product_fields)) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('mpn'),15)+1);
		}
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('location'),10)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('quantity'),4)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('model'),8)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('manufacturer'),10)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('image_name'),12)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('shipping'),5)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('price'),10)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('price_2'),10)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('price_3'),10)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('points'),5)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('date_added'),19)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('date_modified'),19)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('date_available'),10)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('weight'),6)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('weight_unit'),3)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('length'),8)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('width'),8)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('height'),8)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('length_unit'),3)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('status'),5)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('tax_class_id'),2)+1);
		if (!$exist_seo_url_table) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('seo_keyword'),16)+1);
		}
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('description')+4,32)+1);
		}
		if ($exist_meta_title) {
			foreach ($languages as $language) {
				$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('meta_title')+4,20)+1);
			}
		}
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('meta_description')+4,32)+1);
		}
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('meta_keywords')+4,32)+1);
		}
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('stock_status_id'),3)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('store_ids'),16)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('layout'),16)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('related_ids'),16)+1);
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('tags')+4,32)+1);
		}
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('sort_order'),8)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('subtract'),5)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('minimum'),8)+1);

		// The product headings row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'product_id';
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'name('.$language['code'].')';
		}
		$styles[$j] = &$text_format;
		$data[$j++] = 'categories';
		$styles[$j] = &$text_format;
		$data[$j++] = 'sku';
		$styles[$j] = &$text_format;
		$data[$j++] = 'upc';
		if (in_array('ean',$product_fields)) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'ean';
		}
		if (in_array('jan',$product_fields)) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'jan';
		}
		if (in_array('isbn',$product_fields)) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'isbn';
		}
		if (in_array('mpn',$product_fields)) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'mpn';
		}
		$styles[$j] = &$text_format;
		$data[$j++] = 'location';
		$data[$j++] = 'quantity';
		$styles[$j] = &$text_format;
		$data[$j++] = 'model';
		$styles[$j] = &$text_format;
		$data[$j++] = 'manufacturer';
		$styles[$j] = &$text_format;
		$data[$j++] = 'image_name';
		$data[$j++] = 'shipping';
		$styles[$j] = &$price_format;
		$data[$j++] = 'price';
		$data[$j++] = 'price_2';
		$data[$j++] = 'price_3';
		$data[$j++] = 'points';
		$data[$j++] = 'date_added';
		$data[$j++] = 'date_modified';
		$data[$j++] = 'date_available';
		$styles[$j] = &$weight_format;
		$data[$j++] = 'weight';
		$data[$j++] = 'weight_unit';
		$data[$j++] = 'length';
		$data[$j++] = 'width';
		$data[$j++] = 'height';
		$data[$j++] = 'length_unit';
		$data[$j++] = 'status';
		$data[$j++] = 'tax_class_id';
		if (!$exist_seo_url_table) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'seo_keyword';
		}
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'description('.$language['code'].')';
		}
		if ($exist_meta_title) {
			foreach ($languages as $language) {
				$styles[$j] = &$text_format;
				$data[$j++] = 'meta_title('.$language['code'].')';
			}
		}
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'meta_description('.$language['code'].')';
		}
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'meta_keywords('.$language['code'].')';
		}
		$data[$j++] = 'stock_status_id';
		$data[$j++] = 'store_ids';
		$styles[$j] = &$text_format;
		$data[$j++] = 'layout';
		$data[$j++] = 'related_ids';
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'tags('.$language['code'].')';
		}
		$data[$j++] = 'sort_order';
		$data[$j++] = 'subtract';
		$data[$j++] = 'minimum';
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual products data
		$i += 1;
		$j = 1;
		$store_ids = $this->getStoreIdsForProducts();
		$layouts = $this->getLayoutsForProducts();
		$products = $this->getProducts( $languages, $default_language_id, $product_fields, $exist_meta_title, $exist_seo_url_table, $offset, $rows, $min_id, $max_id );
		$len = count($products);
		$min_id = ($len>0) ? $products[0]['product_id'] : 0;
		$max_id = ($len>0) ? $products[$len-1]['product_id'] : 0;
		foreach ($products as $row) {
			$data = array();
			$worksheet->getRowDimension($i)->setRowHeight(26);
			$product_id = $row['product_id'];
			$data[$j++] = $product_id;
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['name'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			$data[$j++] = $row['categories'];
			$data[$j++] = $row['sku'];
			$data[$j++] = $row['upc'];
			if (in_array('ean',$product_fields)) {
				$data[$j++] = $row['ean'];
			}
			if (in_array('jan',$product_fields)) {
				$data[$j++] = $row['jan'];
			}
			if (in_array('isbn',$product_fields)) {
				$data[$j++] = $row['isbn'];
			}
			if (in_array('mpn',$product_fields)) {
				$data[$j++] = $row['mpn'];
			}
			$data[$j++] = $row['location'];
			$data[$j++] = $row['quantity'];
			$data[$j++] = $row['model'];
			$data[$j++] = $row['manufacturer'];
			$data[$j++] = $row['image_name'];
			$data[$j++] = ($row['shipping']==0) ? 'no' : 'yes';
			$data[$j++] = $row['price'];
			$data[$j++] = $row['price_2'];
			$data[$j++] = $row['price_3'];
			$data[$j++] = $row['points'];
			$data[$j++] = $row['date_added'];
			$data[$j++] = $row['date_modified'];
			$data[$j++] = $row['date_available'];
			$data[$j++] = $row['weight'];
			$data[$j++] = $row['weight_unit'];
			$data[$j++] = $row['length'];
			$data[$j++] = $row['width'];
			$data[$j++] = $row['height'];
			$data[$j++] = $row['length_unit'];
			$data[$j++] = ($row['status']==0) ? 'false' : 'true';
			$data[$j++] = $row['tax_class_id'];
			if (!$exist_seo_url_table) {
				$data[$j++] = ($row['keyword']) ? $row['keyword'] : '';
			}
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['description'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			if ($exist_meta_title) {
				foreach ($languages as $language) {
					$data[$j++] = html_entity_decode($row['meta_title'][$language['code']],ENT_QUOTES,'UTF-8');
				}
			}
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['meta_description'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['meta_keyword'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			$data[$j++] = $row['stock_status_id'];
			$store_id_list = '';
			if (isset($store_ids[$product_id])) {
				foreach ($store_ids[$product_id] as $store_id) {
					$store_id_list .= ($store_id_list=='') ? $store_id : ','.$store_id;
				}
			}
			$data[$j++] = $store_id_list;
			$layout_list = '';
			if (isset($layouts[$product_id])) {
				foreach ($layouts[$product_id] as $store_id => $name) {
					$layout_list .= ($layout_list=='') ? $store_id.':'.$name : ','.$store_id.':'.$name;
				}
			}
			$data[$j++] = $layout_list;
			$data[$j++] = $row['related'];
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['tag'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			$data[$j++] = $row['sort_order'];
			$data[$j++] = ($row['subtract']==0) ? 'false' : 'true';
			$data[$j++] = $row['minimum'];
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getAdditionalImages( $min_id=null, $max_id=null, $exist_sort_order=true  ) {
		if ($exist_sort_order) {
			$sql  = "SELECT DISTINCT pi.product_id, pi.image, pi.sort_order ";
		} else {
			$sql  = "SELECT DISTINCT pi.product_id, pi.image ";
		}
		$sql .= "FROM `".DB_PREFIX."product_image` pi ";
		if ($this->posted_categories) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product_to_category` pc ON pc.product_id=pi.product_id ";
		}
		if ($this->posted_manufacturers) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product` p ON p.product_id=pi.product_id ";
		}
		if (isset($min_id) && isset($max_id)) {
			$sql .= "WHERE pi.product_id BETWEEN $min_id AND $max_id ";
			if ($this->posted_categories) {
				$sql .= "AND pc.category_id IN ".$this->posted_categories." ";
			}
		} else if ($this->posted_categories) {
			$sql .= "WHERE pc.category_id IN ".$this->posted_categories." ";
		}
		if ($this->posted_manufacturers) {
			$sql .= (strpos($sql," WHERE ",0)===false) ? "WHERE " : "AND ";
			$sql .= "p.manufacturer_id IN ".$this->posted_manufacturers." ";
		}
		if ($exist_sort_order) {
			$sql .= "ORDER BY product_id, sort_order, image;";
		} else {
			$sql .= "ORDER BY product_id, image;";
		}
		$result = $this->db->query( $sql );
		return $result->rows;
	}


	protected function populateAdditionalImagesWorksheet( &$worksheet, &$box_format, &$text_format, $min_id=null, $max_id=null) {
		// check for the existence of product_image.sort_order field
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."product_image` LIKE 'sort_order'";
		$query = $this->db->query( $sql );
		$exist_sort_order = ($query->num_rows > 0) ? true : false;

		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('product_id'),4)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('image'),30)+1);
		if ($exist_sort_order) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('sort_order'),5)+1);
		}

		// The additional images headings row and colum styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'product_id';
		$styles[$j] = &$text_format;
		$data[$j++] = 'image';
		if ($exist_sort_order) {
			$data[$j++] = 'sort_order';
		}
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual additional images data
		$styles = array();
		$i += 1;
		$j = 1;
		$additional_images = $this->getAdditionalImages( $min_id, $max_id, $exist_sort_order );
		foreach ($additional_images as $row) {
			$data = array();
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data[$j++] = $row['product_id'];
			$data[$j++] = $row['image'];
			if ($exist_sort_order) {
				$data[$j++] = $row['sort_order'];
			}
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getSpecials( $language_id, $min_id=null, $max_id=null ) {
		// Newer OC versions use the 'customer_group_description' instead of 'customer_group' table for the 'name' field
		$exist_table_customer_group_description = false;
		$query = $this->db->query( "SHOW TABLES LIKE '".DB_PREFIX."customer_group_description'" );
		$exist_table_customer_group_description = ($query->num_rows > 0);

		// get the product specials
		$sql  = "SELECT DISTINCT ps.*, ";
		$sql .= ($exist_table_customer_group_description) ? "cgd.name " : "cg.name ";
		$sql .= "FROM `".DB_PREFIX."product_special` ps ";
		if ($exist_table_customer_group_description) {
			$sql .= "LEFT JOIN `".DB_PREFIX."customer_group_description` cgd ON cgd.customer_group_id=ps.customer_group_id ";
			$sql .= "  AND cgd.language_id=$language_id ";
		} else {
			$sql .= "LEFT JOIN `".DB_PREFIX."customer_group` cg ON cg.customer_group_id=ps.customer_group_id ";
		}
		if ($this->posted_categories) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product_to_category` pc ON pc.product_id=ps.product_id ";
		}
		if ($this->posted_manufacturers) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product` p ON p.product_id=ps.product_id ";
		}
		if (isset($min_id) && isset($max_id)) {
			$sql .= "WHERE ps.product_id BETWEEN $min_id AND $max_id ";
			if ($this->posted_categories) {
				$sql .= "AND pc.category_id IN ".$this->posted_categories." ";
			}
		} else if ($this->posted_categories) {
			$sql .= "WHERE pc.category_id IN ".$this->posted_categories." ";
		}
		if ($this->posted_manufacturers) {
			$sql .= (strpos($sql," WHERE ",0)===false) ? "WHERE " : "AND ";
			$sql .= "p.manufacturer_id IN ".$this->posted_manufacturers." ";
		}
		$sql .= "ORDER BY ps.product_id, name, ps.priority";
		$result = $this->db->query( $sql );
		return $result->rows;
	}


	protected function populateSpecialsWorksheet( &$worksheet, $language_id, &$price_format, &$box_format, &$text_format, $min_id=null, $max_id=null ) {
		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('product_id')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('customer_group')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('priority')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('price'),10)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('date_start'),19)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('date_end'),19)+1);

		// The heading row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'product_id';
		$styles[$j] = &$text_format;
		$data[$j++] = 'customer_group';
		$data[$j++] = 'priority';
		$styles[$j] = &$price_format;
		$data[$j++] = 'price';
		$data[$j++] = 'date_start';
		$data[$j++] = 'date_end';
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual product specials data
		$i += 1;
		$j = 1;
		$specials = $this->getSpecials( $language_id, $min_id, $max_id );
		foreach ($specials as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data = array();
			$data[$j++] = $row['product_id'];
			$data[$j++] = $row['name'];
			$data[$j++] = $row['priority'];
			$data[$j++] = $row['price'];
			$data[$j++] = $row['date_start'];
			$data[$j++] = $row['date_end'];
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getDiscounts( $language_id, $min_id=null, $max_id=null ) {
		// Newer OC versions use the 'customer_group_description' instead of 'customer_group' table for the 'name' field
		$exist_table_customer_group_description = false;
		$query = $this->db->query( "SHOW TABLES LIKE '".DB_PREFIX."customer_group_description'" );
		$exist_table_customer_group_description = ($query->num_rows > 0);

		// get the product discounts
		$sql  = "SELECT pd.*, ";
		$sql .= ($exist_table_customer_group_description) ? "cgd.name " : "cg.name ";
		$sql .= "FROM `".DB_PREFIX."product_discount` pd ";
		if ($exist_table_customer_group_description) {
			$sql .= "LEFT JOIN `".DB_PREFIX."customer_group_description` cgd ON cgd.customer_group_id=pd.customer_group_id ";
			$sql .= "  AND cgd.language_id=$language_id ";
		} else {
			$sql .= "LEFT JOIN `".DB_PREFIX."customer_group` cg ON cg.customer_group_id=pd.customer_group_id ";
		}
		if ($this->posted_categories) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product_to_category` pc ON pc.product_id=pd.product_id ";
		}
		if ($this->posted_manufacturers) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product` p ON p.product_id=pd.product_id ";
		}
		if (isset($min_id) && isset($max_id)) {
			$sql .= "WHERE pd.product_id BETWEEN $min_id AND $max_id ";
			if ($this->posted_categories) {
				$sql .= "AND pc.category_id IN ".$this->posted_categories." ";
			}
		} else if ($this->posted_categories) {
			$sql .= "WHERE pc.category_id IN ".$this->posted_categories." ";
		}
		if ($this->posted_manufacturers) {
			$sql .= (strpos($sql," WHERE ",0)===false) ? "WHERE " : "AND ";
			$sql .= "p.manufacturer_id IN ".$this->posted_manufacturers." ";
		}
		$sql .= "ORDER BY pd.product_id ASC, name ASC, pd.quantity ASC";
		$result = $this->db->query( $sql );
		return $result->rows;
	}


	protected function populateDiscountsWorksheet( &$worksheet, $language_id, &$price_format, &$box_format, &$text_format, $min_id=null, $max_id=null ) {
		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('product_id')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('customer_group')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('quantity')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('priority')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('price'),10)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('date_start'),19)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('date_end'),19)+1);

		// The heading row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'product_id';
		$styles[$j] = &$text_format;
		$data[$j++] = 'customer_group';
		$data[$j++] = 'quantity';
		$data[$j++] = 'priority';
		$styles[$j] = &$price_format;
		$data[$j++] = 'price';
		$data[$j++] = 'date_start';
		$data[$j++] = 'date_end';
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual product discounts data
		$i += 1;
		$j = 1;
		$discounts = $this->getDiscounts( $language_id, $min_id, $max_id );
		foreach ($discounts as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data = array();
			$data[$j++] = $row['product_id'];
			$data[$j++] = $row['name'];
			$data[$j++] = $row['quantity'];
			$data[$j++] = $row['priority'];
			$data[$j++] = $row['price'];
			$data[$j++] = $row['date_start'];
			$data[$j++] = $row['date_end'];
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getRewards( $language_id, $min_id=null, $max_id=null ) {
		// Newer OC versions use the 'customer_group_description' instead of 'customer_group' table for the 'name' field
		$exist_table_customer_group_description = false;
		$query = $this->db->query( "SHOW TABLES LIKE '".DB_PREFIX."customer_group_description'" );
		$exist_table_customer_group_description = ($query->num_rows > 0);

		// get the product rewards
		$sql  = "SELECT DISTINCT pr.*, ";
		$sql .= ($exist_table_customer_group_description) ? "cgd.name " : "cg.name ";
		$sql .= "FROM `".DB_PREFIX."product_reward` pr ";
		if ($exist_table_customer_group_description) {
			$sql .= "LEFT JOIN `".DB_PREFIX."customer_group_description` cgd ON cgd.customer_group_id=pr.customer_group_id ";
			$sql .= "  AND cgd.language_id=$language_id ";
		} else {
			$sql .= "LEFT JOIN `".DB_PREFIX."customer_group` cg ON cg.customer_group_id=pr.customer_group_id ";
		}
		if ($this->posted_categories) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product_to_category` pc ON pc.product_id=pr.product_id ";
		}
		if ($this->posted_manufacturers) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product` p ON p.product_id=pr.product_id ";
		}
		if (isset($min_id) && isset($max_id)) {
			$sql .= "WHERE pr.product_id BETWEEN $min_id AND $max_id ";
			if ($this->posted_categories) {
				$sql .= "AND pc.category_id IN ".$this->posted_categories." ";
			}
		} else if ($this->posted_categories) {
			$sql .= "WHERE pc.category_id IN ".$this->posted_categories." ";
		}
		if ($this->posted_manufacturers) {
			$sql .= (strpos($sql," WHERE ",0)===false) ? "WHERE " : "AND ";
			$sql .= "p.manufacturer_id IN ".$this->posted_manufacturers." ";
		}
		$sql .= "ORDER BY pr.product_id, name";
		$result = $this->db->query( $sql );
		return $result->rows;
	}


	protected function populateRewardsWorksheet( &$worksheet, $language_id, &$box_format, &$text_format, $min_id=null, $max_id=null ) {
		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('product_id')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('customer_group')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('points')+1);

		// The heading row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'product_id';
		$styles[$j] = &$text_format;
		$data[$j++] = 'customer_group';
		$data[$j++] = 'points';
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual product rewards data
		$i += 1;
		$j = 1;
		$rewards = $this->getRewards( $language_id, $min_id, $max_id );
		foreach ($rewards as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data = array();
			$data[$j++] = $row['product_id'];
			$data[$j++] = $row['name'];
			$data[$j++] = $row['points'];
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getProductOptions( $min_id, $max_id ) {
		// get default language id
		$language_id = $this->getDefaultLanguageId();
		
		// Opencart versions from 2.0 onwards use product_option.value instead of the older product_option.option_value
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."product_option` LIKE 'value'";
		$query = $this->db->query( $sql );
		$exist_po_value = ($query->num_rows > 0) ? true : false;

		// DB query for getting the product options
		if ($exist_po_value) {
			$sql  = "SELECT p.product_id, po.option_id, po.value AS option_value, po.required, od.name AS `option` FROM ";
		} else {
			$sql  = "SELECT p.product_id, po.option_id, po.option_value, po.required, od.name AS `option` FROM ";
		}
		$sql .= "( SELECT p1.product_id ";
		$sql .= "  FROM `".DB_PREFIX."product` p1 ";
		if ($this->posted_categories) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product_to_category` pc ON pc.product_id=p1.product_id ";
		}
		if (isset($min_id) && isset($max_id)) {
			$sql .= "  WHERE p1.product_id BETWEEN $min_id AND $max_id ";
			if ($this->posted_categories) {
				$sql .= "AND pc.category_id IN ".$this->posted_categories." ";
			}
		} else if ($this->posted_categories) {
			$sql .= "WHERE pc.category_id IN ".$this->posted_categories." ";
		}
		if ($this->posted_manufacturers) {
			$sql .= (strpos($sql," WHERE ",0)===false) ? "WHERE " : "AND ";
			$sql .= "p1.manufacturer_id IN ".$this->posted_manufacturers." ";
		}
		$sql .= "  ORDER BY p1.product_id ASC ";
		$sql .= ") AS p ";
		$sql .= "INNER JOIN `".DB_PREFIX."product_option` po ON po.product_id=p.product_id ";
		$sql .= "INNER JOIN `".DB_PREFIX."option_description` od ON od.option_id=po.option_id AND od.language_id='".(int)$language_id."' ";
		$sql .= "ORDER BY p.product_id ASC, po.option_id ASC";
		$query = $this->db->query( $sql );
		return $query->rows;
	}


	protected function populateProductOptionsWorksheet( &$worksheet, &$box_format, &$text_format, $min_id=null, $max_id=null ) {
		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('product_id')+1);
		if ($this->config->get( 'export_import_settings_use_option_id' )) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('option_id')+1);
		} else {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('option'),30)+1);
		}
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('default_option_value')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('required'),5)+1);

		// The heading row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'product_id';
		if ($this->config->get( 'export_import_settings_use_option_id' )) {
			$data[$j++] = 'option_id';
		} else {
			$styles[$j] = &$text_format;
			$data[$j++] = 'option';
		}
		$styles[$j] = &$text_format;
		$data[$j++] = 'default_option_value';
		$data[$j++] = 'required';
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual product options data
		$i += 1;
		$j = 1;
		$product_options = $this->getProductOptions( $min_id, $max_id );
		foreach ($product_options as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data = array();
			$data[$j++] = $row['product_id'];
			if ($this->config->get( 'export_import_settings_use_option_id' )) {
				$data[$j++] = $row['option_id'];
			} else {
				$data[$j++] = html_entity_decode($row['option'],ENT_QUOTES,'UTF-8');
			}
			$data[$j++] = html_entity_decode($row['option_value'],ENT_QUOTES,'UTF-8');
			$data[$j++] = ($row['required']==0) ? 'false' : 'true';
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getProductOptionValues( $min_id, $max_id ) {
		$language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT ";
		$sql .= "  p.product_id, pov.option_id, pov.option_value_id, pov.quantity, pov.subtract, od.name AS `option`, ovd.name AS option_value, ";
		$sql .= "  pov.price, pov.price_prefix, pov.points, pov.points_prefix, pov.weight, pov.weight_prefix ";
		$sql .= "FROM ";
		$sql .= "( SELECT p1.product_id ";
		$sql .= "  FROM `".DB_PREFIX."product` p1 ";
		if ($this->posted_categories) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product_to_category` pc ON pc.product_id=p1.product_id ";
		}
		if (isset($min_id) && isset($max_id)) {
			$sql .= "  WHERE p1.product_id BETWEEN $min_id AND $max_id ";
			if ($this->posted_categories) {
				$sql .= "AND pc.category_id IN ".$this->posted_categories." ";
			}
		} else if ($this->posted_categories) {
			$sql .= "WHERE pc.category_id IN ".$this->posted_categories." ";
		}
		if ($this->posted_manufacturers) {
			$sql .= (strpos($sql," WHERE ",0)===false) ? "WHERE " : "AND ";
			$sql .= "p1.manufacturer_id IN ".$this->posted_manufacturers." ";
		}
		$sql .= "  ORDER BY product_id ASC ";
		$sql .= ") AS p ";
		$sql .= "INNER JOIN `".DB_PREFIX."product_option_value` pov ON pov.product_id=p.product_id ";
		$sql .= "INNER JOIN `".DB_PREFIX."option_value_description` ovd ON ovd.option_value_id=pov.option_value_id AND ovd.language_id='".(int)$language_id."' ";
		$sql .= "INNER JOIN `".DB_PREFIX."option_description` od ON od.option_id=ovd.option_id AND od.language_id='".(int)$language_id."' ";
		$sql .= "ORDER BY p.product_id ASC, pov.option_id ASC, pov.option_value_id";
		$query = $this->db->query( $sql );
		return $query->rows;
	}


	protected function populateProductOptionValuesWorksheet( &$worksheet, &$price_format, &$box_format, &$weight_format, &$text_format, $min_id=null, $max_id=null ) {
		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('product_id')+1);
		if ($this->config->get( 'export_import_settings_use_option_id' )) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('option_id')+1);
		} else {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('option'),30)+1);
		}
		if ($this->config->get( 'export_import_settings_use_option_value_id' )) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('option_value_id')+1);
		} else {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('option_value'),30)+1);
		}
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('quantity'),4)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('subtract'),5)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('price'),10)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('price_prefix'),5)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('points'),10)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('points_prefix'),5)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('weight'),10)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('weight_prefix'),5)+1);

		// The heading row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'product_id';
		if ($this->config->get( 'export_import_settings_use_option_id' )) {
			$data[$j++] = 'option_id';
		} else {
			$styles[$j] = &$text_format;
			$data[$j++] = 'option';
		}
		if ($this->config->get( 'export_import_settings_use_option_value_id' )) {
			$data[$j++] = 'option_value_id';
		} else {
			$styles[$j] = &$text_format;
			$data[$j++] = 'option_value';
		}
		$data[$j++] = 'quantity';
		$data[$j++] = 'subtract';
		$styles[$j] = &$price_format;
		$data[$j++] = 'price';
		$data[$j++] = "price_prefix";
		$data[$j++] = 'points';
		$data[$j++] = "points_prefix";
		$styles[$j] = &$weight_format;
		$data[$j++] = 'weight';
		$data[$j++] = 'weight_prefix';
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual product option values data
		$i += 1;
		$j = 1;
		$product_option_values = $this->getProductOptionValues( $min_id, $max_id );
		foreach ($product_option_values as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data = array();
			$data[$j++] = $row['product_id'];
			if ($this->config->get( 'export_import_settings_use_option_id' )) {
				$data[$j++] = $row['option_id'];
			} else {
				$data[$j++] = html_entity_decode($row['option'],ENT_QUOTES,'UTF-8');
			}
			if ($this->config->get( 'export_import_settings_use_option_value_id' )) {
				$data[$j++] = $row['option_value_id'];
			} else {
				$data[$j++] = html_entity_decode($row['option_value'],ENT_QUOTES,'UTF-8');
			}
			$data[$j++] = $row['quantity'];
			$data[$j++] = ($row['subtract']==0) ? 'false' : 'true';
			$data[$j++] = $row['price'];
			$data[$j++] = $row['price_prefix'];
			$data[$j++] = $row['points'];
			$data[$j++] = $row['points_prefix'];
			$data[$j++] = $row['weight'];
			$data[$j++] = $row['weight_prefix'];
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getProductSEOKeywords( &$languages, $min_id, $max_id ) {
		$sql  = "SELECT s.* FROM `".DB_PREFIX."seo_url` s ";
		if ($this->posted_categories) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product_to_category` pc ON pc.product_id=CAST(SUBSTRING(s.query FROM 12) AS UNSIGNED INTEGER) ";
		}
		if ($this->posted_manufacturers) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product` p ON p.product_id=CAST(SUBSTRING(s.query FROM 12) AS UNSIGNED INTEGER) ";
		}
		$sql .= "WHERE s.query LIKE 'product_id=%' AND ";
		if ($this->posted_categories) {
			$sql .= "pc.category_id IN ".$this->posted_categories." AND ";
		}
		if ($this->posted_manufacturers) {
			$sql .= "p.manufacturer_id IN ".$this->posted_manufacturers." AND ";
		}
		$sql .= "CAST(SUBSTRING(s.query FROM 12) AS UNSIGNED INTEGER) >= '".(int)$min_id."' AND ";
		$sql .= "CAST(SUBSTRING(s.query FROM 12) AS UNSIGNED INTEGER) <= '".(int)$max_id."' ";
		$sql .= "ORDER BY CAST(SUBSTRING(s.query FROM 12) AS UNSIGNED INTEGER), s.store_id, s.language_id";
		$query = $this->db->query( $sql );
		$seo_keywords = array();
		foreach ($query->rows as $row) {
			$product_id = (int)substr($row['query'],11);
			$store_id = (int)$row['store_id'];
			$language_id = (int)$row['language_id'];
			if (!isset($seo_keywords[$product_id])) {
				$seo_keywords[$product_id] = array();
			}
			if (!isset($seo_keywords[$product_id][$store_id])) {
				$seo_keywords[$product_id][$store_id] = array();
			}
			$seo_keywords[$product_id][$store_id][$language_id] = $row['keyword'];
		}
		$results = array();
		foreach ($seo_keywords as $product_id=>$val1) {
			foreach ($val1 as $store_id=>$val2) {
				$keyword = array();
				foreach ($languages as $language) {
					$language_id = $language['language_id'];
					$language_code = $language['code'];
					$keyword[$language_code] = isset($val2[$language_id]) ? $val2[$language_id] : '';
				}
				$results[] = array(
					'product_id'    => $product_id,
					'store_id'      => $store_id,
					'keyword'       => $keyword
				);
			}
		}
		return $results;
	}


	protected function populateProductSEOKeywordsWorksheet( &$worksheet, &$languages, &$box_format, &$text_format, $min_id=null, $max_id=null ) {
		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('product_id')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('store_id')+1);
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('keyword')+4,30)+1);
		}

		// The heading row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'product_id';
		$data[$j++] = 'store_id';
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'keyword('.$language['code'].')';
		}
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );
		
		// The actual product SEO keywords data
		$i += 1;
		$j = 1;
		$product_seo_keywords = $this->getProductSEOKeywords( $languages, $min_id, $max_id );
		foreach ($product_seo_keywords as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(26);
			$data = array();
			$data[$j++] = $row['product_id'];
			$data[$j++] = $row['store_id'];
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['keyword'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}

	}


	protected function getAttributeGroupNames( $language_id ) {
		$sql  = "SELECT attribute_group_id, name ";
		$sql .= "FROM `".DB_PREFIX."attribute_group_description` ";
		$sql .= "WHERE language_id='".(int)$language_id."' ";
		$sql .= "ORDER BY attribute_group_id ASC";
		$query = $this->db->query( $sql );
		$attribute_group_names = array();
		foreach ($query->rows as $row) {
			$attribute_group_id = $row['attribute_group_id'];
			$name = $row['name'];
			$attribute_group_names[$attribute_group_id] = $name;
		}
		return $attribute_group_names;
	}


	protected function getAttributeNames( $language_id ) {
		$sql  = "SELECT attribute_id, name ";
		$sql .= "FROM `".DB_PREFIX."attribute_description` ";
		$sql .= "WHERE language_id='".(int)$language_id."' ";
		$sql .= "ORDER BY attribute_id ASC";
		$query = $this->db->query( $sql );
		$attribute_names = array();
		foreach ($query->rows as $row) {
			$attribute_id = $row['attribute_id'];
			$attribute_name = $row['name'];
			$attribute_names[$attribute_id] = $attribute_name;
		}
		return $attribute_names;
	}


	protected function getProductAttributes( &$languages, $min_id, $max_id ) {
		$sql  = "SELECT pa.product_id, ag.attribute_group_id, pa.attribute_id, pa.language_id, pa.text ";
		$sql .= "FROM `".DB_PREFIX."product_attribute` pa ";
		$sql .= "INNER JOIN `".DB_PREFIX."attribute` a ON a.attribute_id=pa.attribute_id ";
		$sql .= "INNER JOIN `".DB_PREFIX."attribute_group` ag ON ag.attribute_group_id=a.attribute_group_id ";
		if ($this->posted_categories) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product_to_category` pc ON pc.product_id=pa.product_id ";
		}
		if ($this->posted_manufacturers) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product` p ON p.product_id=pa.product_id ";
		}
		if (isset($min_id) && isset($max_id)) {
			$sql .= "WHERE pa.product_id BETWEEN $min_id AND $max_id ";
			if ($this->posted_categories) {
				$sql .= "AND pc.category_id IN ".$this->posted_categories." ";
			}
		} else if ($this->posted_categories) {
			$sql .= "WHERE pc.category_id IN ".$this->posted_categories." ";
		}
		if ($this->posted_manufacturers) {
			$sql .= (strpos($sql," WHERE ",0)===false) ? " WHERE " : " AND ";
			$sql .= "p.manufacturer_id IN ".$this->posted_manufacturers." ";
		}
		$sql .= "ORDER BY pa.product_id ASC, ag.attribute_group_id ASC, pa.attribute_id ASC";
		$query = $this->db->query( $sql );
		$texts = array();
		foreach ($query->rows as $row) {
			$product_id = $row['product_id'];
			$attribute_group_id = $row['attribute_group_id'];
			$attribute_id = $row['attribute_id'];
			$language_id = $row['language_id'];
			$text = $row['text'];
			$texts[$product_id][$attribute_group_id][$attribute_id][$language_id] = $text;
		}
		$product_attributes = array();
		foreach ($texts as $product_id=>$level1) {
			foreach ($level1 as $attribute_group_id=>$level2) {
				foreach ($level2 as $attribute_id=>$text) {
					$product_attribute = array();
					$product_attribute['product_id'] = $product_id;
					$product_attribute['attribute_group_id'] = $attribute_group_id;
					$product_attribute['attribute_id'] = $attribute_id;
					$product_attribute['text'] = array();
					foreach ($languages as $language) {
						$language_id = $language['language_id'];
						$code = $language['code'];
						if (isset($text[$language_id])) {
							$product_attribute['text'][$code] = $text[$language_id];
						} else {
							$product_attribute['text'][$code] = '';
						}
					}
					$product_attributes[] = $product_attribute;
				}
			}
		}
		return $product_attributes;
	}


	protected function populateProductAttributesWorksheet( &$worksheet, &$languages, $default_language_id, &$box_format, &$text_format, $min_id=null, $max_id=null ) {
		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('product_id')+1);
		if ($this->config->get( 'export_import_settings_use_attribute_group_id' )) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('attribute_group_id')+1);
		} else {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('attribute_group'),30)+1);
		}
		if ($this->config->get( 'export_import_settings_use_attribute_id' )) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('attribute_id')+1);
		} else {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('attribute'),30)+1);
		}
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('text')+4,30)+1);
		}

		// The heading row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'product_id';
		if ($this->config->get( 'export_import_settings_use_attribute_group_id' )) {
			$data[$j++] = 'attribute_group_id';
		} else {
			$styles[$j] = &$text_format;
			$data[$j++] = 'attribute_group';
		}
		if ($this->config->get( 'export_import_settings_use_attribute_id' )) {
			$data[$j++] = 'attribute_id';
		} else {
			$styles[$j] = &$text_format;
			$data[$j++] = 'attribute';
		}
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'text('.$language['code'].')';
		}
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual product attributes data
		if (!$this->config->get( 'export_import_settings_use_attribute_group_id' )) {
			$attribute_group_names = $this->getAttributeGroupNames( $default_language_id );
		}
		if (!$this->config->get( 'export_import_settings_use_attribute_id' )) {
			$attribute_names = $this->getAttributeNames( $default_language_id );
		}
		$i += 1;
		$j = 1;
		$product_attributes = $this->getProductAttributes( $languages, $min_id, $max_id );
		foreach ($product_attributes as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data = array();
			$data[$j++] = $row['product_id'];
			if ($this->config->get( 'export_import_settings_use_attribute_group_id' )) {
				$data[$j++] = $row['attribute_group_id'];
			} else {
				$data[$j++] = html_entity_decode($attribute_group_names[$row['attribute_group_id']],ENT_QUOTES,'UTF-8');
			}
			if ($this->config->get( 'export_import_settings_use_attribute_id' )) {
				$data[$j++] = $row['attribute_id'];
			} else {
				$data[$j++] = html_entity_decode($attribute_names[$row['attribute_id']],ENT_QUOTES,'UTF-8');
			}
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['text'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getProductFilters( $min_id, $max_id ) {
		$sql  = "SELECT pf.product_id, fg.filter_group_id, pf.filter_id ";
		$sql .= "FROM `".DB_PREFIX."product_filter` pf ";
		$sql .= "INNER JOIN `".DB_PREFIX."filter` f ON f.filter_id=pf.filter_id ";
		$sql .= "INNER JOIN `".DB_PREFIX."filter_group` fg ON fg.filter_group_id=f.filter_group_id ";
		if ($this->posted_categories) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product_to_category` pc ON pc.product_id=pf.product_id ";
		}
		if ($this->posted_manufacturers) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product` p ON p.product_id=pf.product_id ";
		}
		if (isset($min_id) && isset($max_id)) {
			$sql .= "WHERE pf.product_id BETWEEN $min_id AND $max_id ";
			if ($this->posted_categories) {
				$sql .= "AND pc.category_id IN ".$this->posted_categories." ";
			}
		} else if ($this->posted_categories) {
			$sql .= "WHERE pc.category_id IN ".$this->posted_categories." ";
		}
		if ($this->posted_manufacturers) {
			$sql .= (strpos($sql," WHERE ",0)===false) ? " WHERE " : " AND ";
			$sql .= "p.manufacturer_id IN ".$this->posted_manufacturers." ";
		}
		$sql .= "ORDER BY pf.product_id ASC, fg.filter_group_id ASC, pf.filter_id ASC";
		$query = $this->db->query( $sql );
		$product_filters = array();
		foreach ($query->rows as $row) {
			$product_filter = array();
			$product_filter['product_id'] = $row['product_id'];
			$product_filter['filter_group_id'] = $row['filter_group_id'];
			$product_filter['filter_id'] = $row['filter_id'];
			$product_filters[] = $product_filter;
		}
		return $product_filters;
	}


	protected function populateProductFiltersWorksheet( &$worksheet, &$languages, $default_language_id, &$box_format, &$text_format, $min_id=null, $max_id=null ) {
		// Set the column widths
		$j = 0;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('product_id')+1);
		if ($this->config->get( 'export_import_settings_use_filter_group_id' )) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('filter_group_id')+1);
		} else {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('filter_group'),30)+1);
		}
		if ($this->config->get( 'export_import_settings_use_filter_id' )) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('filter_id')+1);
		} else {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('filter'),30)+1);
		}
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('text')+4,30)+1);
		}

		// The heading row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'product_id';
		if ($this->config->get( 'export_import_settings_use_filter_group_id' )) {
			$data[$j++] = 'filter_group_id';
		} else {
			$styles[$j] = &$text_format;
			$data[$j++] = 'filter_group';
		}
		if ($this->config->get( 'export_import_settings_use_filter_id' )) {
			$data[$j++] = 'filter_id';
		} else {
			$styles[$j] = &$text_format;
			$data[$j++] = 'filter';
		}
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual product filters data
		if (!$this->config->get( 'export_import_settings_use_filter_group_id' )) {
			$filter_group_names = $this->getFilterGroupNames( $default_language_id );
		}
		if (!$this->config->get( 'export_import_settings_use_filter_id' )) {
			$filter_names = $this->getFilterNames( $default_language_id );
		}
		$i += 1;
		$j = 1;
		$product_filters = $this->getProductFilters( $min_id, $max_id );
		foreach ($product_filters as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data = array();
			$data[$j++] = $row['product_id'];
			if ($this->config->get( 'export_import_settings_use_filter_group_id' )) {
				$data[$j++] = $row['filter_group_id'];
			} else {
				$data[$j++] = html_entity_decode($filter_group_names[$row['filter_group_id']],ENT_QUOTES,'UTF-8');
			}
			if ($this->config->get( 'export_import_settings_use_filter_id' )) {
				$data[$j++] = $row['filter_id'];
			} else {
				$data[$j++] = html_entity_decode($filter_names[$row['filter_id']],ENT_QUOTES,'UTF-8');
			}
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getOptionDescriptions( &$languages ) {
		// query the option_description table for each language
		$option_descriptions = array();
		foreach ($languages as $language) {
			$language_id = $language['language_id'];
			$language_code = $language['code'];
			$sql  = "SELECT o.option_id, od.* ";
			$sql .= "FROM `".DB_PREFIX."option` o ";
			$sql .= "LEFT JOIN `".DB_PREFIX."option_description` od ON od.option_id=o.option_id AND od.language_id='".(int)$language_id."' ";
			$sql .= "GROUP BY o.option_id ";
			$sql .= "ORDER BY o.option_id ASC ";
			$query = $this->db->query( $sql );
			$option_descriptions[$language_code] = $query->rows;
		}
		return $option_descriptions;
	}


	protected function getOptions( &$languages ) {
		$results = $this->db->query( "SELECT * FROM `".DB_PREFIX."option` ORDER BY option_id ASC" );
		$option_descriptions = $this->getOptionDescriptions( $languages );
		foreach ($languages as $language) {
			$language_code = $language['code'];
			foreach ($results->rows as $key=>$row) {
				if (isset($option_descriptions[$language_code][$key])) {
					$results->rows[$key]['name'][$language_code] = $option_descriptions[$language_code][$key]['name'];
				} else {
					$results->rows[$key]['name'][$language_code] = '';
				}
			}
		}
		return $results->rows;
	}


	protected function populateOptionsWorksheet( &$worksheet, &$languages, &$box_format, &$text_format ) {
		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('option_id'),4)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('type'),10)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('sort_order'),5)+1);
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('name')+4,30)+1);
		}

		// The options headings row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'option_id';
		$data[$j++] = 'type';
		$data[$j++] = 'sort_order';
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'name('.$language['code'].')';
		}
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual options data
		$i += 1;
		$j = 1;
		$options = $this->getOptions( $languages );
		foreach ($options as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data = array();
			$data[$j++] = $row['option_id'];
			$data[$j++] = $row['type'];
			$data[$j++] = $row['sort_order'];
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['name'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getOptionValueDescriptions( &$languages ) {
		// query the option_description table for each language
		$option_value_descriptions = array();
		foreach ($languages as $language) {
			$language_id = $language['language_id'];
			$language_code = $language['code'];
			$sql  = "SELECT ov.option_id, ov.option_value_id, ovd.* ";
			$sql .= "FROM `".DB_PREFIX."option_value` ov ";
			$sql .= "LEFT JOIN `".DB_PREFIX."option_value_description` ovd ON ovd.option_value_id=ov.option_value_id AND ovd.language_id='".(int)$language_id."' ";
			$sql .= "GROUP BY ov.option_id, ov.option_value_id ";
			$sql .= "ORDER BY ov.option_id ASC, ov.option_value_id ASC ";
			$query = $this->db->query( $sql );
			$option_value_descriptions[$language_code] = $query->rows;
		}
		return $option_value_descriptions;
	}


	protected function getOptionValues( &$languages ) {
		$results = $this->db->query( "SELECT * FROM `".DB_PREFIX."option_value` ORDER BY option_id ASC, option_value_id ASC" );
		$option_value_descriptions = $this->getOptionValueDescriptions( $languages );
		foreach ($languages as $language) {
			$language_code = $language['code'];
			foreach ($results->rows as $key=>$row) {
				if (isset($option_value_descriptions[$language_code][$key])) {
					$results->rows[$key]['name'][$language_code] = $option_value_descriptions[$language_code][$key]['name'];
				} else {
					$results->rows[$key]['name'][$language_code] = '';
				}
			}
		}
		return $results->rows;
	}


	protected function populateOptionValuesWorksheet( &$worksheet, $languages, &$box_format, &$text_format ) {
		// check for the existence of option_value.image field
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."option_value` LIKE 'image'";
		$query = $this->db->query( $sql );
		$exist_image = ($query->num_rows > 0) ? true : false;

		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('option_value_id'),2)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('option_id'),4)+1);
		if ($exist_image) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('image'),12)+1);
		}
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('sort_order'),5)+1);
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('name')+4,30)+1);
		}

		// The option values headings row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'option_value_id';
		$data[$j++] = 'option_id';
		if ($exist_image) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'image';
		}
		$data[$j++] = 'sort_order';
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'name('.$language['code'].')';
		}
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual option values data
		$i += 1;
		$j = 1;
		$options = $this->getOptionValues( $languages );
		foreach ($options as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data = array();
			$data[$j++] = $row['option_value_id'];
			$data[$j++] = $row['option_id'];
			if ($exist_image) {
				$data[$j++] = $row['image'];
			}
			$data[$j++] = $row['sort_order'];
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['name'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getAttributeGroupDescriptions( &$languages ) {
		// query the attribute_group_description table for each language
		$attribute_group_descriptions = array();
		foreach ($languages as $language) {
			$language_id = $language['language_id'];
			$language_code = $language['code'];
			$sql  = "SELECT ag.attribute_group_id, agd.* ";
			$sql .= "FROM `".DB_PREFIX."attribute_group` ag ";
			$sql .= "LEFT JOIN `".DB_PREFIX."attribute_group_description` agd ON agd.attribute_group_id=ag.attribute_group_id AND agd.language_id='".(int)$language_id."' ";
			$sql .= "GROUP BY ag.attribute_group_id ";
			$sql .= "ORDER BY ag.attribute_group_id ASC ";
			$query = $this->db->query( $sql );
			$attribute_group_descriptions[$language_code] = $query->rows;
		}
		return $attribute_group_descriptions;
	}


	protected function getAttributeGroups( &$languages ) {
		$results = $this->db->query( "SELECT * FROM `".DB_PREFIX."attribute_group` ORDER BY attribute_group_id ASC" );
		$attribute_group_descriptions = $this->getAttributeGroupDescriptions( $languages );
		foreach ($languages as $language) {
			$language_code = $language['code'];
			foreach ($results->rows as $key=>$row) {
				if (isset($attribute_group_descriptions[$language_code][$key])) {
					$results->rows[$key]['name'][$language_code] = $attribute_group_descriptions[$language_code][$key]['name'];
				} else {
					$results->rows[$key]['name'][$language_code] = '';
				}
			}
		}
		return $results->rows;
	}


	protected function populateAttributeGroupsWorksheet( &$worksheet, $languages, &$box_format, &$text_format ) {
		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('attribute_group_id'),4)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('sort_order'),5)+1);
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('name')+4,30)+1);
		}
		
		// The attribute groups headings row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'attribute_group_id';
		$data[$j++] = 'sort_order';
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] ='name('.$language['code'].')';
		}
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual attribute groups data
		$i += 1;
		$j = 1;
		$attributes = $this->getAttributeGroups( $languages );
		foreach ($attributes as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data = array();
			$data[$j++] = $row['attribute_group_id'];
			$data[$j++] = $row['sort_order'];
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['name'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getAttributeDescriptions( &$languages ) {
		// query the attribute_description table for each language
		$attribute_descriptions = array();
		foreach ($languages as $language) {
			$language_id = $language['language_id'];
			$language_code = $language['code'];
			$sql  = "SELECT a.attribute_group_id, a.attribute_id, ad.* ";
			$sql .= "FROM `".DB_PREFIX."attribute` a ";
			$sql .= "LEFT JOIN `".DB_PREFIX."attribute_description` ad ON ad.attribute_id=a.attribute_id AND ad.language_id='".(int)$language_id."' ";
			$sql .= "GROUP BY a.attribute_group_id, a.attribute_id ";
			$sql .= "ORDER BY a.attribute_group_id ASC, a.attribute_id ASC ";
			$query = $this->db->query( $sql );
			$attribute_descriptions[$language_code] = $query->rows;
		}
		return $attribute_descriptions;
	}


	protected function getAttributes( &$languages ) {
		$results = $this->db->query( "SELECT * FROM `".DB_PREFIX."attribute` ORDER BY attribute_group_id ASC, attribute_id ASC" );
		$attribute_descriptions = $this->getAttributeDescriptions( $languages );
		foreach ($languages as $language) {
			$language_code = $language['code'];
			foreach ($results->rows as $key=>$row) {
				if (isset($attribute_descriptions[$language_code][$key])) {
					$results->rows[$key]['name'][$language_code] = $attribute_descriptions[$language_code][$key]['name'];
				} else {
					$results->rows[$key]['name'][$language_code] = '';
				}
			}
		}
		return $results->rows;
	}


	protected function populateAttributesWorksheet( &$worksheet, $languages, &$box_format, &$text_format ) {
		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('attribute_id'),2)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('attribute_group_id'),4)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('sort_order'),5)+1);
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('name')+4,30)+1);
		}

		// The attributes headings row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'attribute_id';
		$data[$j++] = 'attribute_group_id';
		$data[$j++] = 'sort_order';
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'name('.$language['code'].')';
		}
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );
		
		// The actual attributes values data
		$i += 1;
		$j = 1;
		$options = $this->getAttributes( $languages );
		foreach ($options as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data = array();
			$data[$j++] = $row['attribute_id'];
			$data[$j++] = $row['attribute_group_id'];
			$data[$j++] = $row['sort_order'];
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['name'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getFilterGroupDescriptions( &$languages ) {
		// query the filter_group_description table for each language
		$filter_group_descriptions = array();
		foreach ($languages as $language) {
			$language_id = $language['language_id'];
			$language_code = $language['code'];
			$sql  = "SELECT ag.filter_group_id, agd.* ";
			$sql .= "FROM `".DB_PREFIX."filter_group` ag ";
			$sql .= "LEFT JOIN `".DB_PREFIX."filter_group_description` agd ON agd.filter_group_id=ag.filter_group_id AND agd.language_id='".(int)$language_id."' ";
			$sql .= "GROUP BY ag.filter_group_id ";
			$sql .= "ORDER BY ag.filter_group_id ASC ";
			$query = $this->db->query( $sql );
			$filter_group_descriptions[$language_code] = $query->rows;
		}
		return $filter_group_descriptions;
	}


	protected function getFilterGroups( &$languages ) {
		$results = $this->db->query( "SELECT * FROM `".DB_PREFIX."filter_group` ORDER BY filter_group_id ASC" );
		$filter_group_descriptions = $this->getFilterGroupDescriptions( $languages );
		foreach ($languages as $language) {
			$language_code = $language['code'];
			foreach ($results->rows as $key=>$row) {
				if (isset($filter_group_descriptions[$language_code][$key])) {
					$results->rows[$key]['name'][$language_code] = $filter_group_descriptions[$language_code][$key]['name'];
				} else {
					$results->rows[$key]['name'][$language_code] = '';
				}
			}
		}
		return $results->rows;
	}


	protected function populateFilterGroupsWorksheet( &$worksheet, $languages, &$box_format, &$text_format ) {
		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('filter_group_id'),4)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('sort_order'),5)+1);
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('name')+4,30)+1);
		}
		
		// The filter groups headings row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'filter_group_id';
		$data[$j++] = 'sort_order';
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] ='name('.$language['code'].')';
		}
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual filter groups data
		$i += 1;
		$j = 1;
		$filters = $this->getFilterGroups( $languages );
		foreach ($filters as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data = array();
			$data[$j++] = $row['filter_group_id'];
			$data[$j++] = $row['sort_order'];
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['name'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getFilterDescriptions( &$languages ) {
		// query the filter_description table for each language
		$filter_descriptions = array();
		foreach ($languages as $language) {
			$language_id = $language['language_id'];
			$language_code = $language['code'];
			$sql  = "SELECT a.filter_group_id, a.filter_id, ad.* ";
			$sql .= "FROM `".DB_PREFIX."filter` a ";
			$sql .= "LEFT JOIN `".DB_PREFIX."filter_description` ad ON ad.filter_id=a.filter_id AND ad.language_id='".(int)$language_id."' ";
			$sql .= "GROUP BY a.filter_group_id, a.filter_id ";
			$sql .= "ORDER BY a.filter_group_id ASC, a.filter_id ASC ";
			$query = $this->db->query( $sql );
			$filter_descriptions[$language_code] = $query->rows;
		}
		return $filter_descriptions;
	}


	protected function getFilters( &$languages ) {
		$results = $this->db->query( "SELECT * FROM `".DB_PREFIX."filter` ORDER BY filter_group_id ASC, filter_id ASC" );
		$filter_descriptions = $this->getFilterDescriptions( $languages );
		foreach ($languages as $language) {
			$language_code = $language['code'];
			foreach ($results->rows as $key=>$row) {
				if (isset($filter_descriptions[$language_code][$key])) {
					$results->rows[$key]['name'][$language_code] = $filter_descriptions[$language_code][$key]['name'];
				} else {
					$results->rows[$key]['name'][$language_code] = '';
				}
			}
		}
		return $results->rows;
	}


	protected function populateFiltersWorksheet( &$worksheet, $languages, &$box_format, &$text_format ) {
		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('filter_id'),2)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('filter_group_id'),4)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('sort_order'),5)+1);
		foreach ($languages as $language) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('name')+4,30)+1);
		}

		// The filters headings row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'filter_id';
		$data[$j++] = 'filter_group_id';
		$data[$j++] = 'sort_order';
		foreach ($languages as $language) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'name('.$language['code'].')';
		}
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );
		
		// The actual filters values data
		$i += 1;
		$j = 1;
		$options = $this->getFilters( $languages );
		foreach ($options as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data = array();
			$data[$j++] = $row['filter_id'];
			$data[$j++] = $row['filter_group_id'];
			$data[$j++] = $row['sort_order'];
			foreach ($languages as $language) {
				$data[$j++] = html_entity_decode($row['name'][$language['code']],ENT_QUOTES,'UTF-8');
			}
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getCustomers( $exist_custom_field, $exist_salt, $exist_safe, $exist_token, $exist_code, $offset=null, $rows=null, $min_id=null, $max_id=null ) {
		// Newer OC versions use the 'customer_group_description' instead of 'customer_group' table for the 'name' field
		$exist_table_customer_group_description = false;
		$query = $this->db->query( "SHOW TABLES LIKE '".DB_PREFIX."customer_group_description'" );
		$exist_table_customer_group_description = ($query->num_rows > 0);

		$language_id = $this->getDefaultLanguageId();

		if ($exist_table_customer_group_description) {
			$sql  = "SELECT c.*, cgd.name AS customer_group FROM `".DB_PREFIX."customer` c ";
			$sql .= "INNER JOIN `".DB_PREFIX."customer_group_description` cgd ON cgd.customer_group_id=c.customer_group_id AND cgd.language_id='".(int)$language_id."' ";
		} else {
			$sql  = "SELECT c.*, cg.name AS customer_group FROM `".DB_PREFIX."customer` c ";
			$sql .= "INNER JOIN `".DB_PREFIX."customer_group` cg ON cg.customer_group_id=c.customer_group_id ";
		}
		if (isset($min_id) && isset($max_id)) {
			$sql .= "WHERE c.customer_id BETWEEN $min_id AND $max_id ";
		}
		$sql .= "GROUP BY c.`customer_id` ";
		$sql .= "ORDER BY c.`customer_id` ASC ";
		if (isset($offset) && isset($rows)) {
			$sql .= "LIMIT $offset,$rows; ";
		} else {
			$sql .= "; ";
		}
		$results = $this->db->query( $sql );
		return $results->rows;
	}


	protected function populateCustomersWorksheet( &$worksheet, &$box_format, &$text_format, $offset=null, $rows=null, &$min_id=null, &$max_id=null ) {
		// Some fields are only available in certain Opencart versions
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'custom_field'";
		$query = $this->db->query( $sql );
		$exist_custom_field = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'salt'";
		$query = $this->db->query( $sql );
		$exist_salt = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'safe'";
		$query = $this->db->query( $sql );
		$exist_safe = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'token'";
		$query = $this->db->query( $sql );
		$exist_token = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'code'";
		$query = $this->db->query( $sql );
		$exist_code = ($query->num_rows > 0) ? true : false;
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."customer` LIKE 'approved'";
		$query = $this->db->query( $sql );
		$exist_approved = ($query->num_rows > 0) ? true : false;

		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('customer_id')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('customer_group')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('store_id'),2)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('firstname'),20)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('lastname'),20)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('email'),30)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('telephone'),14)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('fax'),14)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('password'),40)+1);
		if ($exist_salt) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('salt'),12)+1);
		}
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('cart'),14)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('wishlist'),20)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('newsletter'),5)+1);
		if ($exist_custom_field) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('custom_field'),20)+1);
		}
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('ip'),15)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('status'),5)+1);
		if ($exist_approved) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('approved'),5)+1);
		}
		if ($exist_safe) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('safe'),5)+1);
		}
		if ($exist_token) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('token'),20)+1);
		}
		if ($exist_code) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('code'),20)+1);
		}
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('date_added'),19)+1);

		// The heading row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'customer_id';
		$styles[$j] = &$text_format;
		$data[$j++] = 'customer_group';
		$data[$j++] = 'store_id';
		$styles[$j] = &$text_format;
		$data[$j++] = 'firstname';
		$styles[$j] = &$text_format;
		$data[$j++] = 'lastname';
		$styles[$j] = &$text_format;
		$data[$j++] = 'email';
		$styles[$j] = &$text_format;
		$data[$j++] = 'telephone';
		$styles[$j] = &$text_format;
		$data[$j++] = 'fax';
		$styles[$j] = &$text_format;
		$data[$j++] = 'password';
		if ($exist_salt) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'salt';
		}
		$styles[$j] = &$text_format;
		$data[$j++] = 'cart';
		$styles[$j] = &$text_format;
		$data[$j++] = 'wishlist';
		$data[$j++] = 'newsletter';
		if ($exist_custom_field) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'custom_field';
		}
		$styles[$j] = &$text_format;
		$data[$j++] = 'ip';
		$data[$j++] = 'status';
		if ($exist_approved) {
			$data[$j++] = 'approved';
		}
		if ($exist_safe) {
			$data[$j++] = 'safe';
		}
		if ($exist_token) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'token';
		}
		if ($exist_code) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'code';
		}
		$styles[$j] = &$text_format;
		$data[$j++] = 'date_added';
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual customers data
		$i += 1;
		$j = 1;
		$customers = $this->getCustomers( $exist_custom_field, $exist_salt, $exist_safe, $exist_token, $exist_code, $offset, $rows, $min_id, $max_id );
		$len = count($customers);
		$min_id = ($len>0) ? $customers[0]['customer_id'] : 0;
		$max_id = ($len>0) ? $customers[$len-1]['customer_id'] : 0;
		foreach ($customers as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(26);
			$data = array();
			$data[$j++] = $row['customer_id'];
			$data[$j++] = $row['customer_group'];
			$data[$j++] = $row['store_id'];
			$data[$j++] = $row['firstname'];
			$data[$j++] = $row['lastname'];
			$data[$j++] = $row['email'];
			$data[$j++] = $row['telephone'];
			$data[$j++] = $row['fax'];
			$data[$j++] = $row['password'];
			if ($exist_salt) {
				$data[$j++] = $row['salt'];
			}
			$data[$j++] = $row['cart'];
			$data[$j++] = $row['wishlist'];
			$data[$j++] = ($row['newsletter']==0) ? 'no' : 'yes';
			if ($exist_custom_field) {
				$data[$j++] = $row['custom_field'];
			}
			$data[$j++] = $row['ip'];
			$data[$j++] = ($row['status']==0) ? 'false' : 'true';
			if ($exist_approved) {
				$data[$j++] = ($row['approved']==0) ? 'false' : 'true';
			}
			if ($exist_safe) {
				$data[$j++] = ($row['safe']==0) ? 'false' : 'true';
			}
			if ($exist_token) {
				$data[$j++] = $row['token'];
			}
			if ($exist_code) {
				$data[$j++] = $row['code'];
			}
			$data[$j++] = $row['date_added'];
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function getAddresses( $min_id, $max_id ) {
		// DB query for getting the addresses
		$sql  = "SELECT a.*, c.name AS country, z.name AS zone, (cu.address_id=a.address_id) AS `default` FROM `".DB_PREFIX."address` a ";
		$sql .= "INNER JOIN `".DB_PREFIX."country` c ON c.country_id=a.country_id ";
		$sql .= "LEFT JOIN `".DB_PREFIX."zone` z ON z.country_id=a.country_id AND z.zone_id=a.zone_id ";
		$sql .= "INNER JOIN `".DB_PREFIX."customer` cu ON cu.customer_id=a.customer_id ";
		if (isset($min_id) && isset($max_id)) {
			$sql .= "  WHERE a.customer_id BETWEEN $min_id AND $max_id ";
		}
		$sql .= "  ORDER BY a.customer_id ASC, a.address_id ASC;";
		$query = $this->db->query( $sql );
		return $query->rows;
	}


	protected function populateAddressesWorksheet( &$worksheet, &$box_format, &$text_format, $min_id=null, $max_id=null ) {
		// Some Opencart 1.5.x versions also have company_id
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."address` LIKE 'company_id'";
		$query = $this->db->query( $sql );
		$exist_company_id = ($query->num_rows > 0) ? true : false;

		// Some Opencart 1.5.x versions also have tax_id
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."address` LIKE 'tax_id'";
		$query = $this->db->query( $sql );
		$exist_tax_id = ($query->num_rows > 0) ? true : false;

		// Opencart 2.x versions have custom_field
		$sql = "SHOW COLUMNS FROM `".DB_PREFIX."address` LIKE 'custom_field'";
		$query = $this->db->query( $sql );
		$exist_custom_field = ($query->num_rows > 0) ? true : false;

		// Set the column widths
		$j = 1;
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(strlen('customer_id')+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('firstname'),20)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('lastname'),20)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('company'),30)+1);
		if ($exist_company_id) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('company_id'),10)+1);
		}
		if ($exist_tax_id) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('tax_id'),15)+1);
		}
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('address_1'),30)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('address_2'),30)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('city'),30)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('postcode'),10)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('zone'),20)+1);
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('country'),20)+1);
		if ($exist_custom_field) {
			$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('custom_field'),20)+1);
		}
		$worksheet->getColumnDimensionByColumn($j++)->setWidth(max(strlen('default'),5)+1);

		// The heading row and column styles
		$styles = array();
		$data = array();
		$i = 1;
		$j = 1;
		$data[$j++] = 'customer_id';
		$styles[$j] = &$text_format;
		$data[$j++] = 'firstname';
		$styles[$j] = &$text_format;
		$data[$j++] = 'lastname';
		$styles[$j] = &$text_format;
		$data[$j++] = 'company';
		if ($exist_company_id) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'company_id';
		}
		if ($exist_tax_id) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'tax_id';
		}
		$styles[$j] = &$text_format;
		$data[$j++] = 'address_1';
		$styles[$j] = &$text_format;
		$data[$j++] = 'address_2';
		$styles[$j] = &$text_format;
		$data[$j++] = 'city';
		$styles[$j] = &$text_format;
		$data[$j++] = 'postcode';
		$styles[$j] = &$text_format;
		$data[$j++] = 'zone';
		$styles[$j] = &$text_format;
		$data[$j++] = 'country';
		if ($exist_custom_field) {
			$styles[$j] = &$text_format;
			$data[$j++] = 'custom_field';
		}
		$data[$j++] = 'default';
		$worksheet->getRowDimension($i)->setRowHeight(30);
		$this->setCellRow( $worksheet, $i, $data, $box_format );

		// The actual addresses data
		$i += 1;
		$j = 1;
		$addresses = $this->getAddresses( $min_id, $max_id );
		foreach ($addresses as $row) {
			$worksheet->getRowDimension($i)->setRowHeight(13);
			$data = array();
			$data[$j++] = $row['customer_id'];
			$data[$j++] = $row['firstname'];
			$data[$j++] = $row['lastname'];
			$data[$j++] = $row['company'];
			if ($exist_company_id) {
				$data[$j++] = $row['company_id'];
			}
			if ($exist_tax_id) {
				$data[$j++] = $row['tax_id'];
			}
			$data[$j++] = $row['address_1'];
			$data[$j++] = $row['address_2'];
			$data[$j++] = $row['city'];
			$data[$j++] = $row['postcode'];
			$data[$j++] = html_entity_decode( $row['zone'], ENT_QUOTES, 'UTF-8' );
			$data[$j++] = $row['country'];
			if ($exist_custom_field) {
				$data[$j++] = $row['custom_field'];
			}
			$data[$j++] = ($row['default']==0) ? 'no' : 'yes';
			$this->setCellRow( $worksheet, $i, $data, $this->null_array, $styles );
			$i += 1;
			$j = 1;
		}
	}


	protected function clearSpreadsheetCache() {
		$files = glob(DIR_CACHE . 'Spreadsheet_Excel_Writer' . '*');
		
		if ($files) {
			foreach ($files as $file) {
				if (file_exists($file)) {
					@unlink($file);
					clearstatcache();
				}
			}
		}
	}
   

	public function getMaxProductId() {
		$query = $this->db->query( "SELECT MAX(product_id) as max_product_id FROM `".DB_PREFIX."product`" );
		if (isset($query->row['max_product_id'])) {
			$max_id = $query->row['max_product_id'];
		} else {
			$max_id = 0;
		}
		return $max_id;
	}


	public function getMinProductId() {
		$query = $this->db->query( "SELECT MIN(product_id) as min_product_id FROM `".DB_PREFIX."product`" );
		if (isset($query->row['min_product_id'])) {
			$min_id = $query->row['min_product_id'];
		} else {
			$min_id = 0;
		}
		return $min_id;
	}


	public function getCountProduct() {
		$sql  = "SELECT COUNT(DISTINCT p.product_id) as count_product ";
		$sql .= "FROM `".DB_PREFIX."product` p ";
		$posted_categories = $this->getPostedCategories();
		$posted_manufacturers = $this->getPostedManufacturers();
		if ($posted_categories) {
			$sql .= "LEFT JOIN `".DB_PREFIX."product_to_category` pc ON pc.product_id=p.product_id ";
			$sql .= "WHERE pc.category_id IN $posted_categories ";
		}
		if ($posted_manufacturers) {
			$sql .= (strpos($sql," WHERE ",0)===false) ? " WHERE " : " AND ";
			$sql .= "p.manufacturer_id IN ".$posted_manufacturers." ";
		}

		$query = $this->db->query( $sql );
		if (isset($query->row['count_product'])) {
			$count = $query->row['count_product'];
		} else {
			$count = 0;
		}
		return $count;
	}  

 
	public function getMaxCategoryId() {
		$query = $this->db->query( "SELECT MAX(category_id) as max_category_id FROM `".DB_PREFIX."category`" );
		if (isset($query->row['max_category_id'])) {
			$max_id = $query->row['max_category_id'];
		} else {
			$max_id = 0;
		}
		return $max_id;
	}


	public function getMinCategoryId() {
		$query = $this->db->query( "SELECT MIN(category_id) as min_category_id FROM `".DB_PREFIX."category`" );
		if (isset($query->row['min_category_id'])) {
			$min_id = $query->row['min_category_id'];
		} else {
			$min_id = 0;
		}
		return $min_id;
	}


	public function getCountCategory() {
		$query = $this->db->query( "SELECT COUNT(category_id) as count_category FROM `".DB_PREFIX."category`" );
		if (isset($query->row['count_category'])) {
			$count = $query->row['count_category'];
		} else {
			$count = 0;
		}
		return $count;
	}  

 
	public function getMaxCustomerId() {
		$query = $this->db->query( "SELECT MAX(customer_id) as max_customer_id FROM `".DB_PREFIX."customer`" );
		if (isset($query->row['max_customer_id'])) {
			$max_id = $query->row['max_customer_id'];
		} else {
			$max_id = 0;
		}
		return $max_id;
	}


	public function getMinCustomerId() {
		$query = $this->db->query( "SELECT MIN(customer_id) as min_customer_id FROM `".DB_PREFIX."customer`" );
		if (isset($query->row['min_customer_id'])) {
			$min_id = $query->row['min_customer_id'];
		} else {
			$min_id = 0;
		}
		return $min_id;
	}


	public function getCountCustomer() {
		$query = $this->db->query( "SELECT COUNT(customer_id) as count_customer FROM `".DB_PREFIX."customer`" );
		if (isset($query->row['count_customer'])) {
			$count = $query->row['count_customer'];
		} else {
			$count = 0;
		}
		return $count;
	}  


	public function download( $export_type, $offset=null, $rows=null, $min_id=null, $max_id=null) {
		// we use our own error handler
		global $registry;
		$registry = $this->registry;
		set_error_handler('error_handler_for_export_import',E_ALL);
		register_shutdown_function('fatal_error_shutdown_handler_for_export_import');

		try {
			if (version_compare(phpversion(), '7.2.', '<')) {
				// php version isn't high enough
				throw new Exception( $this->language->get( 'error_php_version' ) );
			}

			// enable auto_load from system/library/export_import
			require( DIR_SYSTEM.'library/export_import/vendor/autoload.php' );
		
			// Use the PhoOffice/PhpSpreadsheet package from https://github.com/PHPOffice/PhpSpreadsheet
			$workbook = new PhpOffice\PhpSpreadsheet\Spreadsheet();

			// find out whether all data is to be downloaded
			$all = !isset($offset) && !isset($rows) && !isset($min_id) && !isset($max_id);

			$this->posted_categories = $this->getPostedCategories();
			$this->posted_manufacturers = $this->getPostedManufacturers();

			// set appropriate timeout limit
			set_time_limit( 1800 );

			$languages = $this->getLanguages();
			$default_language_id = $this->getDefaultLanguageId();

			// create a new workbook
			$workbook = new PhpOffice\PhpSpreadsheet\Spreadsheet();

			// set some default styles
			$workbook->getDefaultStyle()->getFont()->setName('Arial');
			$workbook->getDefaultStyle()->getFont()->setSize(10);
			//$workbook->getDefaultStyle()->getAlignment()->setIndent(0.5);
			$workbook->getDefaultStyle()->getAlignment()->setHorizontal(PhpOffice\PhpSpreadsheet\Style\Alignment::HORIZONTAL_LEFT);
			$workbook->getDefaultStyle()->getAlignment()->setVertical(PhpOffice\PhpSpreadsheet\Style\Alignment::VERTICAL_CENTER);
			$workbook->getDefaultStyle()->getNumberFormat()->setFormatCode(PhpOffice\PhpSpreadsheet\Style\NumberFormat::FORMAT_GENERAL);

			// pre-define some commonly used styles
			$box_format = array(
				'fill' => array(
					'fillType'   => PhpOffice\PhpSpreadsheet\Style\Fill::FILL_SOLID,
					'startColor' => array( 'rgb' => 'F0F0F0'),
					'endColor'   => array( 'rgb' => 'F0F0F0')
				),
				'borders' => array(
					'right' => array( 
						'borderStyle' => PhpOffice\PhpSpreadsheet\Style\Border::BORDER_THIN, 
						'color'       => array('rgb' => 'F0F0F0') 
					)
				)
				/*
				'alignment' => array(
					'horizontal' => PhpOffice\PhpSpreadsheet\Style\Alignment::HORIZONTAL_LEFT,
					'vertical'   => PhpOffice\PhpSpreadsheet\Style\Alignment::VERTICAL_CENTER,
					'wrap'       => false,
					'indent'     => 0
				)
				*/
			);
			$text_format = array(
				'numberFormat' => array(
					'formatCode' => PhpOffice\PhpSpreadsheet\Style\NumberFormat::FORMAT_TEXT
				),
				/*
				'alignment' => array(
					'horizontal' => PhpOffice\PhpSpreadsheet\Style\Alignment::HORIZONTAL_LEFT,
					'vertical'   => PhpOffice\PhpSpreadsheet\Style\Alignment::VERTICAL_CENTER,
					'wrap'       => false,
					'indent'     => 0
				)
				*/
			);
			$price_format = array(
				'numberFormat' => array(
					'formatCode' => '######0.00'
				),
				'alignment' => array(
					'horizontal' => PhpOffice\PhpSpreadsheet\Style\Alignment::HORIZONTAL_RIGHT,
					/*
					'vertical'   => PhpOffice\PhpSpreadsheet\Style\Alignment::VERTICAL_CENTER,
					'wrap'       => false,
					'indent'     => 0
					*/
				)
			);
			$weight_format = array(
				'numberFormat' => array(
					'formatCode' => '##0.00'
				),
				'alignment' => array(
					'horizontal' => PhpOffice\PhpSpreadsheet\Style\Alignment::HORIZONTAL_RIGHT,
					/*
					'vertical'   => PhpOffice\PhpSpreadsheet\Style\Alignment::VERTICAL_CENTER,
					'wrap'       => false,
					'indent'     => 0
					*/
				)
			);

			// create the worksheets
			$worksheet_index = 0;
			switch ($export_type) {
				case 'c':
					// creating the Categories worksheet
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'Categories' );
					$this->populateCategoriesWorksheet( $worksheet, $languages, $box_format, $text_format, $offset, $rows, $min_id, $max_id );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );

					// creating the CategoryFilters worksheet
					if ($this->existFilter()) {
						$workbook->createSheet();
						$workbook->setActiveSheetIndex($worksheet_index++);
						$worksheet = $workbook->getActiveSheet();
						$worksheet->setTitle( 'CategoryFilters' );
						$this->populateCategoryFiltersWorksheet( $worksheet, $languages, $default_language_id, $box_format, $text_format, $min_id, $max_id );
						$worksheet->freezePaneByColumnAndRow( 2, 2 );
					}

					// creating the CategorySEOKeywords worksheet
					if ($this->use_table_seo_url) {
						$workbook->createSheet();
						$workbook->setActiveSheetIndex($worksheet_index++);
						$worksheet = $workbook->getActiveSheet();
						$worksheet->setTitle( 'CategorySEOKeywords' );
						$this->populateCategorySEOKeywordsWorksheet( $worksheet, $languages, $box_format, $text_format, $min_id, $max_id );
						$worksheet->freezePaneByColumnAndRow( 2, 2 );
					}
					break;

				case 'p':
					// creating the Products worksheet
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'Products' );
					$this->populateProductsWorksheet( $worksheet, $languages, $default_language_id, $price_format, $box_format, $weight_format, $text_format, $offset, $rows, $min_id, $max_id );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );

					// creating the AdditionalImages worksheet
					$workbook->createSheet();
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'AdditionalImages' );
					$this->populateAdditionalImagesWorksheet( $worksheet, $box_format, $text_format, $min_id, $max_id );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );

					// creating the Specials worksheet
					$workbook->createSheet();
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'Specials' );
					$this->populateSpecialsWorksheet( $worksheet, $default_language_id, $price_format, $box_format, $text_format, $min_id, $max_id );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );

					// creating the Discounts worksheet
					$workbook->createSheet();
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'Discounts' );
					$this->populateDiscountsWorksheet( $worksheet, $default_language_id, $price_format, $box_format, $text_format, $min_id, $max_id );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );

					// creating the Rewards worksheet
					$workbook->createSheet();
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'Rewards' );
					$this->populateRewardsWorksheet( $worksheet, $default_language_id, $box_format, $text_format, $min_id, $max_id );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );

					// creating the ProductOptions worksheet
					$workbook->createSheet();
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'ProductOptions' );
					$this->populateProductOptionsWorksheet( $worksheet, $box_format, $text_format, $min_id, $max_id );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );

					// creating the ProductOptionValues worksheet
					$workbook->createSheet();
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'ProductOptionValues' );
					$this->populateProductOptionValuesWorksheet( $worksheet, $price_format, $box_format, $weight_format, $text_format, $min_id, $max_id );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );

					// creating the ProductAttributes worksheet
					$workbook->createSheet();
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'ProductAttributes' );
					$this->populateProductAttributesWorksheet( $worksheet, $languages, $default_language_id, $box_format, $text_format, $min_id, $max_id );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );

					// creating the ProductFilters worksheet
					if ($this->existFilter()) {
						$workbook->createSheet();
						$workbook->setActiveSheetIndex($worksheet_index++);
						$worksheet = $workbook->getActiveSheet();
						$worksheet->setTitle( 'ProductFilters' );
						$this->populateProductFiltersWorksheet( $worksheet, $languages, $default_language_id, $box_format, $text_format, $min_id, $max_id );
						$worksheet->freezePaneByColumnAndRow( 2, 2 );
					}

					// creating the ProductSEOKeywords worksheet
					if ($this->use_table_seo_url) {
						$workbook->createSheet();
						$workbook->setActiveSheetIndex($worksheet_index++);
						$worksheet = $workbook->getActiveSheet();
						$worksheet->setTitle( 'ProductSEOKeywords' );
						$this->populateProductSEOKeywordsWorksheet( $worksheet, $languages, $box_format, $text_format, $min_id, $max_id );
						$worksheet->freezePaneByColumnAndRow( 2, 2 );
					}
					break;

				case 'o':
					// creating the Options worksheet
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'Options' );
					$this->populateOptionsWorksheet( $worksheet, $languages, $box_format, $text_format );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );

					// creating the OptionValues worksheet
					$workbook->createSheet();
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'OptionValues' );
					$this->populateOptionValuesWorksheet( $worksheet, $languages, $box_format, $text_format );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );
					break;

				case 'a':
					// creating the AttributeGroups worksheet
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'AttributeGroups' );
					$this->populateAttributeGroupsWorksheet( $worksheet, $languages, $box_format, $text_format );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );

					// creating the Attributes worksheet
					$workbook->createSheet();
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'Attributes' );
					$this->populateAttributesWorksheet( $worksheet, $languages, $box_format, $text_format );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );
					break;

				case 'f':
					if (!$this->existFilter()) {
						throw new Exception( $this->language->get( 'error_filter_not_supported' ) );
						break;
					}

					// creating the FilterGroups worksheet
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'FilterGroups' );
					$this->populateFilterGroupsWorksheet( $worksheet, $languages, $box_format, $text_format );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );

					// creating the Filters worksheet
					$workbook->createSheet();
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'Filters' );
					$this->populateFiltersWorksheet( $worksheet, $languages, $box_format, $text_format );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );
					break;

				case 'u':
					// creating the Customers worksheet
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'Customers' );
					$this->populateCustomersWorksheet( $worksheet, $box_format, $text_format, $offset, $rows, $min_id, $max_id );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );

					// creating the Addresses worksheet
					$workbook->createSheet();
					$workbook->setActiveSheetIndex($worksheet_index++);
					$worksheet = $workbook->getActiveSheet();
					$worksheet->setTitle( 'Addresses' );
					$this->populateAddressesWorksheet( $worksheet, $box_format, $text_format, $min_id, $max_id );
					$worksheet->freezePaneByColumnAndRow( 2, 2 );
					break;

				default:
					break;
			}

			$workbook->setActiveSheetIndex(0);

			// redirect output to client browser
			$datetime = date('Y-m-d');
			switch ($export_type) {
				case 'c':
					$filename = 'categories-'.$datetime;
					if (!$all) {
						if (isset($offset)) {
							$filename .= "-offset-$offset";
						} else if (isset($min_id)) {
							$filename .= "-start-$min_id";
						}
						if (isset($rows)) {
							$filename .= "-rows-$rows";
						} else if (isset($max_id)) {
							$filename .= "-end-$max_id";
						}
					}
					$filename .= '.xlsx';
					break;
				case 'p':
					$filename = 'products-'.$datetime;
					if (!$all) {
						if (isset($offset)) {
							$filename .= "-offset-$offset";
						} else if (isset($min_id)) {
							$filename .= "-start-$min_id";
						}
						if (isset($rows)) {
							$filename .= "-rows-$rows";
						} else if (isset($max_id)) {
							$filename .= "-end-$max_id";
						}
					}
					$filename .= '.xlsx';
					break;
				case 'o':
					$filename = 'options-'.$datetime.'.xlsx';
					break;
				case 'a':
					$filename = 'attributes-'.$datetime.'.xlsx';
					break;
				case 'f':
					if (!$this->existFilter()) {
						throw new Exception( $this->language->get( 'error_filter_not_supported' ) );
						break;
					}
					$filename = 'filters-'.$datetime.'.xlsx';
					break;
				case 'u':
					$filename = 'customers-'.$datetime;
					if (!$all) {
						if (isset($offset)) {
							$filename .= "-offset-$offset";
						} else if (isset($min_id)) {
							$filename .= "-start-$min_id";
						}
						if (isset($rows)) {
							$filename .= "-rows-$rows";
						} else if (isset($max_id)) {
							$filename .= "-end-$max_id";
						}
					}
					$filename .= '.xlsx';
					break;
				default:
					$filename = $datetime.'.xlsx';
					break;
			}
			header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
			header('Content-Disposition: attachment;filename="'.$filename.'"');
			header('Cache-Control: max-age=0');
			$objWriter = PhpOffice\PhpSpreadsheet\IOFactory::createWriter($workbook, 'Xlsx');
			$objWriter->setPreCalculateFormulas(false);
			$objWriter->save('php://output');

			// Clear the spreadsheet caches
			$this->clearSpreadsheetCache();
			exit;

		} catch (Exception $e) {
			$errstr = $e->getMessage();
			$errline = $e->getLine();
			$errfile = $e->getFile();
			$errno = $e->getCode();
			$this->session->data['export_import_error'] = array( 'errstr'=>$errstr, 'errno'=>$errno, 'errfile'=>$errfile, 'errline'=>$errline );
			if ($this->config->get('config_error_log')) {
				$this->log->write('PHP ' . get_class($e) . ':  ' . $errstr . ' in ' . $errfile . ' on line ' . $errline);
			}
			return;
		}
	}


	protected function curl_get_contents($url) {
		$ch = curl_init();
		curl_setopt($ch, CURLOPT_URL, $url);
		curl_setopt($ch, CURLOPT_HEADER, 0);
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
		curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 2);
		$output = curl_exec($ch);
		curl_close($ch);
		return $output;
	}


	public function getNotifications() {
		$language_code = $this->config->get( 'config_admin_language' );
		$result = $this->curl_get_contents("https://www.mhccorp.com/index.php?route=information/message&type=tool_export_import_".str_replace('.','_',$this->version)."&language_code=$language_code");
		if (stripos($result,'<html') !== false) {
			return '';
		}
		return $result;
	}


	public function getVersion() {
		return $this->version;
	}


	public function getOptionNameCounts() {
		$default_language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT `name`, COUNT(option_id) AS `count` FROM `".DB_PREFIX."option_description` ";
		$sql .= "WHERE language_id='".(int)$default_language_id."' ";
		$sql .= "GROUP BY `name`";
		$query = $this->db->query( $sql );
		return $query->rows;
	}


	public function getOptionValueNameCounts() {
		$default_language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT option_id, `name`, COUNT(option_value_id) AS `count` FROM `".DB_PREFIX."option_value_description` ";
		$sql .= "WHERE language_id='".(int)$default_language_id."' ";
		$sql .= "GROUP BY option_id, `name`";
		$query = $this->db->query( $sql );
		return $query->rows;
	}


	public function getAttributeGroupNameCounts() {
		$default_language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT `name`, COUNT(attribute_group_id) AS `count` FROM `".DB_PREFIX."attribute_group_description` ";
		$sql .= "WHERE language_id='".(int)$default_language_id."' ";
		$sql .= "GROUP BY `name`";
		$query = $this->db->query( $sql );
		return $query->rows;
	}


	public function getAttributeNameCounts() {
		$default_language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT ag.attribute_group_id, ad.`name`, COUNT(ad.attribute_id) AS `count` FROM `".DB_PREFIX."attribute_description` ad ";
		$sql .= "INNER JOIN `".DB_PREFIX."attribute` a ON a.attribute_id=ad.attribute_id ";
		$sql .= "INNER JOIN `".DB_PREFIX."attribute_group` ag ON ag.attribute_group_id=a.attribute_group_id ";
		$sql .= "WHERE ad.language_id='".(int)$default_language_id."' ";
		$sql .= "GROUP BY ag.attribute_group_id, ad.`name`";
		$query = $this->db->query( $sql );
		return $query->rows;
	}


	public function getFilterGroupNameCounts() {
		$default_language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT `name`, COUNT(filter_group_id) AS `count` FROM `".DB_PREFIX."filter_group_description` ";
		$sql .= "WHERE language_id='".(int)$default_language_id."' ";
		$sql .= "GROUP BY `name`";
		$query = $this->db->query( $sql );
		return $query->rows;
	}


	public function getFilterNameCounts() {
		$default_language_id = $this->getDefaultLanguageId();
		$sql  = "SELECT fg.filter_group_id, fd.`name`, COUNT(fd.filter_id) AS `count` FROM `".DB_PREFIX."filter_description` fd ";
		$sql .= "INNER JOIN `".DB_PREFIX."filter` f ON f.filter_id=fd.filter_id ";
		$sql .= "INNER JOIN `".DB_PREFIX."filter_group` fg ON fg.filter_group_id=f.filter_group_id ";
		$sql .= "WHERE fd.language_id='".(int)$default_language_id."' ";
		$sql .= "GROUP BY fg.filter_group_id, fd.`name`";
		$query = $this->db->query( $sql );
		return $query->rows;
	}


	public function existFilter() {
		// only newer OpenCart versions support filters
		$query = $this->db->query( "SHOW TABLES LIKE '".DB_PREFIX."filter'" );
		$exist_table_filter = ($query->num_rows > 0);
		$query = $this->db->query( "SHOW TABLES LIKE '".DB_PREFIX."filter_group'" );
		$exist_table_filter_group = ($query->num_rows > 0);
		$query = $this->db->query( "SHOW TABLES LIKE '".DB_PREFIX."product_filter'" );
		$exist_table_product_filter = ($query->num_rows > 0);
		$query = $this->db->query( "SHOW TABLES LIKE '".DB_PREFIX."category_filter'" );
		$exist_table_category_filter = ($query->num_rows > 0);

		if (!$exist_table_filter) {
			return false;
		}
		if (!$exist_table_filter_group) {
			return false;
		}
		if (!$exist_table_product_filter) {
			return false;
		}
		if (!$exist_table_category_filter) {
			return false;
		}
		return true;
	}

}


if (version_compare(VERSION,'3.0','>=')) {
	class ModelExtensionExportImport extends ModelToolExportImport {
	}
}

?>