<?php

namespace App\Module\Friend\Logics;

use App\Module\Friend\Enums\ERROR_CODE;
use App\Module\Friend\Enums\READ_STATUS;
use App\Module\Friend\Enums\REQUEST_STATUS;
use App\Module\Friend\Models\FriendRequest;
use App\Module\User\Models\User;
use Carbon\Carbon;
use Illuminate\Support\Facades\Log;

/**
 * 好友申请逻辑类
 *
 * 实现好友申请的核心业务逻辑，包括申请发送、处理等功能。
 * 该类仅供内部使用，不对外提供服务。
 */
class RequestLogic
{
    /**
     * 申请有效期（天）
     *
     * @var int
     */
    protected $requestExpireDays = 30;

    /**
     * 发送好友申请
     *
     * @param int $senderId 发送者ID
     * @param int $receiverId 接收者ID
     * @param string|null $message 申请消息
     * @return \UCore\Dto\Res 操作结果
     */
    public function sendFriendRequest(int $senderId, int $receiverId, ?string $message = null): \UCore\Dto\Res
    {
        try {
            // 检查接收者是否存在
            $receiver = User::find($receiverId);
            if (!$receiver) {
                return \UCore\Dto\Res::error('用户不存在', [
                    'code' => ERROR_CODE::USER_NOT_EXIST
                ]);
            }

            // 检查是否已经是好友
            $isFriend = DB::table('friend_relations')
                ->where('user_id', $senderId)
                ->where('friend_id', $receiverId)
                ->exists();

            if ($isFriend) {
                return \UCore\Dto\Res::error('已经是好友关系', [
                    'code' => ERROR_CODE::ALREADY_FRIEND
                ]);
            }

            // 检查是否已经发送过申请且未处理
            $existingRequest = FriendRequest::where('sender_id', $senderId)
                ->where('receiver_id', $receiverId)
                ->where('status', REQUEST_STATUS::PENDING)
                ->first();

            if ($existingRequest) {
                return \UCore\Dto\Res::error('已发送过申请，请等待对方处理', [
                    'code' => ERROR_CODE::REQUEST_ALREADY_SENT
                ]);
            }

            // 创建新的申请
            $request = FriendRequest::create([
                'sender_id' => $senderId,
                'receiver_id' => $receiverId,
                'message' => $message,
                'status' => REQUEST_STATUS::PENDING,
                'read_status' => READ_STATUS::UNREAD,
                'expired_at' => Carbon::now()->addDays($this->requestExpireDays),
            ]);

            // TODO: 发送通知给接收者

            return \UCore\Dto\Res::success('好友申请发送成功', [
                'request' => $request
            ]);
        } catch (\Exception $e) {
            Log::error('发送好友申请失败: ' . $e->getMessage());

            return \UCore\Dto\Res::error('发送好友申请失败', [
                'code' => ERROR_CODE::PARAM_ERROR,
                'error' => $e->getMessage()
            ]);
        }
    }

    /**
     * 获取收到的好友申请列表
     *
     * @param int $userId 用户ID
     * @param int $page 页码
     * @param int $limit 每页数量
     * @return array 申请列表数据
     */
    public function getReceivedRequests(int $userId, int $page = 1, int $limit = 20): array
    {
        // 查询收到的申请
        $requests = FriendRequest::where('receiver_id', $userId)
            ->where('status', REQUEST_STATUS::PENDING)
            ->where('expired_at', '>', Carbon::now())
            ->with('sender')
            ->orderBy('id', 'desc')
            ->paginate($limit, ['*'], 'page', $page);

        // 更新为已读状态
        FriendRequest::where('receiver_id', $userId)
            ->where('read_status', READ_STATUS::UNREAD)
            ->update(['read_status' => READ_STATUS::READ]);

        // 格式化数据
        $items = [];
        foreach ($requests as $request) {
            if (!$request->sender) {
                continue;
            }

            $items[] = [
                'id' => $request->id,
                'sender_id' => $request->sender_id,
                'nickname' => $request->sender->nickname ?? '',
                'avatar' => $request->sender->avatar ?? '',
                'level' => $request->sender->level ?? 1,
                'message' => $request->message,
                'apply_time' => $request->created_at->timestamp,
            ];
        }

        return [
            'total' => $requests->total(),
            'per_page' => $requests->perPage(),
            'current_page' => $requests->currentPage(),
            'last_page' => $requests->lastPage(),
            'items' => $items
        ];
    }

    /**
     * 获取发送的好友申请列表
     *
     * @param int $userId 用户ID
     * @param int $page 页码
     * @param int $limit 每页数量
     * @return array 申请列表数据
     */
    public function getSentRequests(int $userId, int $page = 1, int $limit = 20): array
    {
        // 查询发送的申请
        $requests = FriendRequest::where('sender_id', $userId)
            ->where(function($query) {
                $query->where('status', REQUEST_STATUS::PENDING)
                    ->orWhere('created_at', '>', Carbon::now()->subDays(7));
            })
            ->with('receiver')
            ->orderBy('id', 'desc')
            ->paginate($limit, ['*'], 'page', $page);

        // 格式化数据
        $items = [];
        foreach ($requests as $request) {
            if (!$request->receiver) {
                continue;
            }

            $items[] = [
                'id' => $request->id,
                'receiver_id' => $request->receiver_id,
                'nickname' => $request->receiver->nickname ?? '',
                'avatar' => $request->receiver->avatar ?? '',
                'level' => $request->receiver->level ?? 1,
                'message' => $request->message,
                'status' => $request->status,
                'apply_time' => $request->created_at->timestamp,
            ];
        }

        return [
            'total' => $requests->total(),
            'per_page' => $requests->perPage(),
            'current_page' => $requests->currentPage(),
            'last_page' => $requests->lastPage(),
            'items' => $items
        ];
    }

    /**
     * 获取已发送申请的用户ID列表
     *
     * @param int $userId 用户ID
     * @return array 用户ID数组
     */
    public function getSentRequestUserIds(int $userId): array
    {
        return FriendRequest::where('sender_id', $userId)
            ->where('status', REQUEST_STATUS::PENDING)
            ->where('expired_at', '>', Carbon::now())
            ->pluck('receiver_id')
            ->toArray();
    }

    /**
     * 同意好友申请
     *
     * @param int $userId 当前用户ID
     * @param int $requestId 申请ID
     * @return \UCore\Dto\Res 操作结果
     */
    public function acceptFriendRequest(int $userId, int $requestId): \UCore\Dto\Res
    {
        try {
            // 查询申请记录
            $request = FriendRequest::where('id', $requestId)
                ->where('receiver_id', $userId)
                ->where('status', REQUEST_STATUS::PENDING)
                ->where('expired_at', '>', Carbon::now())
                ->first();

            if (!$request) {
                return \UCore\Dto\Res::error('申请不存在或已过期', [
                    'code' => ERROR_CODE::REQUEST_NOT_EXIST
                ]);
            }

            // 检查事务是否已开启
            \UCore\Db\Helper::check_tr();

            // 更新申请状态
            $request->status = REQUEST_STATUS::ACCEPTED;
            $request->save();

            // 创建好友关系
            $friendLogic = new FriendLogic();
            $result = $friendLogic->createFriendRelation($userId, $request->sender_id);

            if (!$result['success']) {
                return \UCore\Dto\Res::error($result['message'] ?? '创建好友关系失败', [
                    'code' => $result['code'] ?? ERROR_CODE::PARAM_ERROR
                ]);
            }

            // 获取好友信息
            $friend = User::find($request->sender_id);
            $friendData = null;

            if ($friend) {
                $friendData = [
                    'user_id' => $friend->id,
                    'nickname' => $friend->nickname ?? '',
                    'avatar' => $friend->avatar ?? '',
                    'level' => $friend->level ?? 1,
                    'status' => 2, // 默认离线
                    'last_login' => $friend->last_login_at ?? 0,
                    'remark' => null,
                    'intimacy' => 0,
                ];
            }

            // TODO: 发送通知给申请者

            return \UCore\Dto\Res::success('好友申请已接受', [
                'friend' => $friendData
            ]);
        } catch (\Exception $e) {
            DB::rollBack();
            Log::error('同意好友申请失败: ' . $e->getMessage());

            return \UCore\Dto\Res::error('同意好友申请失败', [
                'code' => ERROR_CODE::PARAM_ERROR,
                'error' => $e->getMessage()
            ]);
        }
    }

    /**
     * 拒绝好友申请
     *
     * @param int $userId 当前用户ID
     * @param int $requestId 申请ID
     * @return \UCore\Dto\Res 操作结果
     */
    public function rejectFriendRequest(int $userId, int $requestId): \UCore\Dto\Res
    {
        try {
            // 查询申请记录
            $request = FriendRequest::where('id', $requestId)
                ->where('receiver_id', $userId)
                ->where('status', REQUEST_STATUS::PENDING)
                ->first();

            if (!$request) {
                return \UCore\Dto\Res::error('申请不存在或已处理', [
                    'code' => ERROR_CODE::REQUEST_NOT_EXIST
                ]);
            }

            // 更新申请状态
            $request->status = REQUEST_STATUS::REJECTED;
            $request->save();

            // TODO: 发送通知给申请者

            return \UCore\Dto\Res::success('好友申请已拒绝');
        } catch (\Exception $e) {
            Log::error('拒绝好友申请失败: ' . $e->getMessage());

            return \UCore\Dto\Res::error('拒绝好友申请失败', [
                'code' => ERROR_CODE::PARAM_ERROR,
                'error' => $e->getMessage()
            ]);
        }
    }
}