<?php

declare(strict_types=1);

namespace Aether\Traits;

use Aether\AetherModel;
use Hyperf\Database\Model\Collection;
use LogicException;

trait AetherTree
{
    // 初始化时检查当前类是否继承AetherModel
    public function __construct(array $attributes = [])
    {
        parent::__construct($attributes);

        if (! $this instanceof AetherModel) {
            throw new LogicException(
                '使用AetherTree trait的类必须继承AetherModel，当前类: ' . get_class($this)
            );
        }
    }

    /**
     * 构建树形结构.
     * @param mixed $items
     */
    public static function buildTree($items, int $parentId = 0): array
    {
        $self = new static();
        $parentField = $self->getParentIdField();
        $sortField = $self->getSortField();

        $items = $items instanceof Collection ? $items->toArray() : $items;
        $tree = [];

        foreach ($items as $item) {
            if ($item[$parentField] == $parentId) {
                $children = static::buildTree($items, $item['id']);
                if (! empty($children)) {
                    $item['children'] = $children;
                }
                $tree[] = $item;
            }
        }

        $self->sortTreeItems($tree, $sortField);
        return $tree;
    }

    /**
     * 获取指定节点的所有子节点ID.
     */
    public function getChildIds(int $id): array
    {
        $parentField = $this->getParentIdField();
        // 现在可以安全调用newQuery()，因为已通过继承检查
        $allItems = $this->newQuery()->get(['id', $parentField])->toArray();
        $ids = [$id];

        $this->collectChildIds($allItems, $id, $parentField, $ids);
        return $ids;
    }

    /**
     * 获取节点的完整路径.
     */
    public function getPath(int $id): array
    {
        $parentField = $this->getParentIdField();
        // 安全调用newQuery()
        $node = $this->newQuery()->find($id);
        if (! $node) {
            return [];
        }

        $path = [$node->toArray()];
        $parentId = $node[$parentField];

        while ($parentId > 0) {
            $parent = $this->newQuery()->find($parentId);
            if (! $parent) {
                break;
            }
            array_unshift($path, $parent->toArray());
            $parentId = $parent[$parentField];
        }

        return $path;
    }

    /**
     * 抽象方法：获取父ID字段名（由子类实现）.
     */
    abstract protected function getParentIdField(): string;

    /**
     * 抽象方法：获取排序字段名（由子类实现）.
     */
    abstract protected function getSortField(): string;

    /**
     * 树形节点排序.
     */
    protected function sortTreeItems(array &$items, string $sortField): void
    {
        usort($items, function ($a, $b) use ($sortField) {
            $direction = $this->treeSortDirection ?? 'asc';
            return $direction === 'desc'
                ? $b[$sortField] <=> $a[$sortField]
                : $a[$sortField] <=> $b[$sortField];
        });
    }

    /**
     * 递归收集子节点ID.
     */
    private function collectChildIds(array $items, int $parentId, string $parentField, array &$ids): void
    {
        foreach ($items as $item) {
            if ($item[$parentField] == $parentId) {
                $ids[] = $item['id'];
                $this->collectChildIds($items, $item['id'], $parentField, $ids);
            }
        }
    }
}