OpenCart 🇺🇦

if ($this->customer->isLogged()) {
	$customer_group_id = $this->customer->getCustomerGroupId();
} else {
	$customer_group_id = $this->config->get('config_customer_group_id');
}	

$product_data = $this->cache->get('product.bestseller.' . (int)$this->config->get('config_language_id') . '.' . (int)$this->config->get('config_store_id'). '.' . $customer_group_id . '.' . (int)$limit);

if (!$product_data) { 
	$product_data = array();

	$query = $this->db->query("SELECT op.product_id, COUNT(*) AS total FROM " . DB_PREFIX . "order_product op LEFT JOIN `" . DB_PREFIX . "order` o ON (op.order_id = o.order_id) LEFT JOIN `" . DB_PREFIX . "product` p ON (op.product_id = p.product_id) LEFT JOIN " . DB_PREFIX . "product_to_store p2s ON (p.product_id = p2s.product_id) WHERE o.order_status_id > '0' AND p.status = '1' AND p.date_available <= NOW() AND p2s.store_id = '" . (int)$this->config->get('config_store_id') . "' GROUP BY op.product_id ORDER BY total DESC LIMIT " . (int)$limit);

	foreach ($query->rows as $result) { 		
		$product_data[$result['product_id']] = $this->getProduct($result['product_id']);
	}

	$this->cache->set('product.bestseller.' . (int)$this->config->get('config_language_id') . '.' . (int)$this->config->get('config_store_id'). '.' . $customer_group_id . '.' . (int)$limit, $product_data);
}

return $product_data;