<?php
/**
 * For the full copyright and license information, please view the
 * docs/licenses/LICENSE.txt file that was distributed with this source code.
 */

declare(strict_types=1);

namespace PrestaShopBundle\Utils;

class Tree
{
    /**
     * @param array $elementlist
     * @param callable $getChildren; must return an array of children for the given element; signature function($element): array
     * @param callable $getId; must return the id of the given element; signature function($element): int
     * @param array $idStorage; store found ids (ensure recursion optimisation and avoiding infinite loop)
     *
     * @return array [ (int) 'id' => (int) 'id'] (make array construction easier)
     */
    public static function extractChildrenId(array $elementlist, callable $getChildren, callable $getId, array &$idStorage = []): array
    {
        foreach ($elementlist as $child) {
            $childId = $getId($child);
            // Test made to ensure avoiding unecessary recursive call
            if (!isset($idStorage[$childId])) {
                $idStorage[$childId] = $childId;
                static::extractChildrenId($getChildren($child), $getChildren, $getId, $idStorage);
            }
        }

        return $idStorage;
    }
}