<?php

namespace Webkul\BagistoApi\Resolver;

use ApiPlatform\GraphQl\Resolver\QueryCollectionResolverInterface;
use Webkul\BagistoApi\Models\FrontMenuItem;

/**
 * Resolves the enabled front navigation menu as a hierarchical tree.
 */
class FrontMenuTreeResolver implements QueryCollectionResolverInterface
{
    public function __invoke(?iterable $collection, array $context): iterable
    {
        $items = FrontMenuItem::query()
            ->where('status', 1)
            ->orderBy('sort_order')
            ->orderBy('id')
            ->get();

        return $this->buildTree($items);
    }

    /**
     * Recursively build the menu tree from a flat collection.
     *
     * Only enabled (status = 1) items are kept at every level, so a disabled
     * item is excluded whether it is a root node or a nested child.
     */
    protected function buildTree($items, ?int $parentId = null): array
    {
        $tree = [];

        foreach ($items as $item) {
            // Exclude disabled items at every level.
            if (! $item->status) {
                continue;
            }

            $itemParentId = $item->parent_id === null ? null : (int) $item->parent_id;

            if ($itemParentId === $parentId) {
                $children = $this->buildTree($items, (int) $item->id);

                $item->setRelation('children', collect($children));

                $tree[] = $item;
            }
        }

        return $tree;
    }
}