/*
Получение товаров по параметрам фильтров.
В пределах одного родителя между параметрами "или". Между родителями "и".
Модель ProductFilter ('product_id', 'category_id', 'filter_id', 'filter_item_id')

https://github.com/DmitrySkibitsky
*/

/**
 * @param $filters // Коллекция с filter_item_id
 * @param null $category_id // Категория
 * @return array // массив с product_id
 */
public static function getProductsByFilters($filters, $category_id = null) {
    $flatten_filters = $filters;

    // $filters = [int, int, int] => [[int, int], [int]] - по родителю
    $filter_models = Filter::getItems($category_id, $flatten_filters->toArray()); // спикок с фильтров и его параметров
    $filters = $filter_models->map(function ($filter) {
        $children_id = [];
        $filter->children->map(function($children) use (&$children_id) {
            $children_id[] = $children->id;
        });
        return $children_id;
    })->values();

    $query = ProductFilter::query();

    if ($category_id !== null) {
        $query->where('category_id', $category_id);
    }
    $query->whereIn('filter_item_id', $flatten_filters->toArray());

    $products = $query->get();

    $id_products = [];

    $products->groupBy('product_id')->each(function ($product, $key) use ($filters, &$id_products) {
        $id_item_filters = [];
        $product->each(function ($item) use (&$id_item_filters) {
            $id_item_filters[] = $item->filter_item_id;
        });
        $id_item_filters = array_unique($id_item_filters);

        $check_exist_filters = [];
        $filters->each(function ($filter) use (&$check_exist_filters, $id_item_filters) {
            if (is_array($filter)) {
                $check_exist_filters[] = (count(array_intersect($filter, $id_item_filters)) > 0) ? true : false;
            }
        });

        if (!in_array(false, $check_exist_filters)) {
            $id_products[] = $key;
        }
    });

    return $id_products;
}