<?php
/**
 * Copyright since 2007 PrestaShop SA and Contributors
 * PrestaShop is an International Registered Trademark & Property of PrestaShop SA
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the Open Software License (OSL 3.0)
 * that is bundled with this package in the file LICENSE.md.
 * It is also available through the world-wide-web at this URL:
 * https://opensource.org/licenses/OSL-3.0
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@prestashop.com so we can send you a copy immediately.
 *
 * DISCLAIMER
 *
 * Do not edit or add to this file if you wish to upgrade PrestaShop to newer
 * versions in the future. If you wish to customize PrestaShop for your
 * needs please refer to https://devdocs.prestashop.com/ for more information.
 *
 * @author    PrestaShop SA and Contributors <contact@prestashop.com>
 * @copyright Since 2007 PrestaShop SA and Contributors
 * @license   https://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
 */
function attribute_group_clean_combinations()
{
    $attributeCombinations = Db::getInstance()->executeS('SELECT
		pac.`id_attribute`, pa.`id_product_attribute`
		FROM `' . _DB_PREFIX_ . 'product_attribute` pa
		LEFT JOIN `' . _DB_PREFIX_ . 'product_attribute_combination` pac
			ON (pa.`id_product_attribute` = pac.`id_product_attribute`)');
    $toRemove = [];
    foreach ($attributeCombinations as $attributeCombination) {
        if ((int) ($attributeCombination['id_attribute']) == 0) {
            $toRemove[] = (int) ($attributeCombination['id_product_attribute']);
        }
    }

    if (!empty($toRemove)) {
        $res = Db::getInstance()->execute('DELETE FROM `' . _DB_PREFIX_ . 'product_attribute`
			WHERE `id_product_attribute` IN (' . implode(', ', $toRemove) . ')');

        return $res;
    }

    return true;
}