<?php

namespace App\Services;

use App\Models\User;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Str;

class WeChatService
{
    private string $appId;
    private string $appSecret;

    public function __construct()
    {
        $this->appId = config('services.wechat_open.app_id', env('WECHAT_OPEN_APP_ID', ''));
        $this->appSecret = config('services.wechat_open.app_secret', env('WECHAT_OPEN_APP_SECRET', ''));
    }

    /**
     * 获取微信登录二维码
     *
     * @return array ['success' => bool, 'data' => ['scene_str' => string, 'qr_url' => string, 'ticket' => string]]
     */
    public function getLoginQr(): array
    {
        if (!$this->isConfigured()) {
            // 未配置时返回模拟二维码
            return $this->getMockQr();
        }

        try {
            // 获取 Access Token (用于生成二维码)
            $accessToken = $this->getAccessToken();
            if (!$accessToken) {
                return ['success' => false, 'message' => '获取access_token失败'];
            }

            // 创建二维码 ticket
            $sceneStr = 'wx_' . Str::random(16);
            $expireSeconds = 300; // 5分钟

            $response = Http::post("https://api.weixin.qq.com/cgi-bin/qrcode/create?access_token={$accessToken}", [
                'expire_seconds' => $expireSeconds,
                'action_name' => 'QR_STR',
                'action_info' => [
                    'scene' => [
                        'scene_str' => $sceneStr
                    ]
                ]
            ]);

            $result = $response->json();

            if (isset($result['ticket'])) {
                $qrUrl = "https://mp.weixin.qq.com/cgi-bin/showqrcode?ticket=" . urlencode($result['ticket']);

                // 缓存 ticket -> scene_str 映射，用于后续验证
                Cache::put("wechat_qr:{$result['ticket']}", [
                    'scene_str' => $sceneStr,
                    'created_at' => time(),
                ], $expireSeconds);

                return [
                    'success' => true,
                    'data' => [
                        'scene_str' => $sceneStr,
                        'qr_url' => $qrUrl,
                        'ticket' => $result['ticket'],
                    ]
                ];
            }

            return ['success' => false, 'message' => $result['errmsg'] ?? '创建二维码失败'];

        } catch (\Exception $e) {
            Log::error('微信获取二维码异常: ' . $e->getMessage());
            return ['success' => false, 'message' => '微信服务异常'];
        }
    }

    /**
     * 通过 ticket 换取二维码链接
     */
    public function getQrUrlByTicket(string $ticket): ?string
    {
        try {
            $response = Http::get("https://mp.weixin.qq.com/cgi-bin/showqrcode", [
                'ticket' => $ticket
            ]);

            if ($response->status() === 200) {
                return $response->header('Location') ?? null;
            }
        } catch (\Exception $e) {
            Log::error('获取二维码URL失败: ' . $e->getMessage());
        }

        return null;
    }

    /**
     * 轮询检查扫码状态 (模拟 - 实际项目中微信需要使用被动回调)
     *
     * @param string $sceneStr 场景字符串
     * @return array
     */
    public function checkScanStatus(string $sceneStr): array
    {
        // 实际项目中，微信扫码后是回调到开发者服务器
        // 这里提供模拟实现，用于开发和测试

        // 模拟：检查是否有模拟登录标记
        $mockScanKey = "wechat_mock_scan:{$sceneStr}";
        $mockData = Cache::get($mockScanKey);

        if ($mockData) {
            Cache::forget($mockScanKey);
            return [
                'success' => true,
                'data' => [
                    'scanned' => true,
                    'openid' => $mockData['openid'],
                    'unionid' => $mockData['unionid'] ?? null,
                    'nickname' => $mockData['nickname'] ?? '微信用户',
                ]
            ];
        }

        return [
            'success' => true,
            'data' => [
                'scanned' => false,
            ]
        ];
    }

    /**
     * 模拟扫码（开发测试用）
     *
     * @param string $sceneStr 场景字符串
     * @param string $openid 模拟的openid
     */
    public function mockScan(string $sceneStr, string $openid = 'mock_openid_123456'): void
    {
        Cache::put("wechat_mock_scan:{$sceneStr}", [
            'openid' => $openid,
            'unionid' => 'mock_unionid_' . substr(md5($openid), 0, 16),
            'nickname' => '测试用户',
        ], now()->addMinutes(5));
    }

    /**
     * 处理微信开放平台回调
     *
     * @param string $code 授权码
     * @return array ['success' => bool, 'data' => [...]]
     */
    public function handleCallback(string $code): array
    {
        if (!$this->isConfigured()) {
            return ['success' => false, 'message' => '微信未配置'];
        }

        try {
            // 通过 code 获取 access_token 和 openid
            $tokenResponse = Http::get("https://api.weixin.qq.com/sns/oauth2/access_token", [
                'appid' => $this->appId,
                'secret' => $this->appSecret,
                'code' => $code,
                'grant_type' => 'authorization_code',
            ]);

            $tokenResult = $tokenResponse->json();

            if (isset($tokenResult['errcode'])) {
                return ['success' => false, 'message' => $tokenResult['errmsg'] ?? '获取access_token失败'];
            }

            $openid = $tokenResult['openid'];
            $unionid = $tokenResult['unionid'] ?? null;
            $accessToken = $tokenResult['access_token'];

            // 获取用户信息
            $userInfo = $this->getUserInfo($accessToken, $openid);

            // 查找或创建用户
            $user = $this->findOrCreateUser($openid, $unionid, $userInfo);

            // 生成 token
            $token = $user->createToken('wechat_auth')->plainTextToken;

            return [
                'success' => true,
                'data' => [
                    'user' => $user,
                    'token' => $token,
                    'openid' => $openid,
                    'unionid' => $unionid,
                ]
            ];

        } catch (\Exception $e) {
            Log::error('微信回调处理异常: ' . $e->getMessage());
            return ['success' => false, 'message' => '处理失败'];
        }
    }

    /**
     * 获取用户信息
     */
    public function getUserInfo(string $accessToken, string $openid): array
    {
        try {
            $response = Http::get("https://api.weixin.qq.com/sns/userinfo", [
                'access_token' => $accessToken,
                'openid' => $openid,
            ]);

            return $response->json();
        } catch (\Exception $e) {
            Log::error('获取微信用户信息失败: ' . $e->getMessage());
            return [];
        }
    }

    /**
     * 查找或创建微信用户
     */
    public function findOrCreateUser(string $openid, ?string $unionid, array $userInfo): User
    {
        // 优先通过 unionid 查找
        if ($unionid) {
            $user = User::where('wechat_unionid', $unionid)->first();
            if ($user) {
                // 更新 openid（一个 unionid 可能对应多个 openid）
                $user->update(['wechat_openid' => $openid]);
                return $user;
            }
        }

        // 通过 openid 查找
        $user = User::where('wechat_openid', $openid)->first();
        if ($user) {
            return $user;
        }

        // 创建新用户
        $user = User::create([
            'name' => $userInfo['nickname'] ?? ('微信用户_' . substr($openid, 0, 8)),
            'email' => "wechat_{$openid}@wechat.local",
            'password' => bcrypt(Str::random(16)),
            'wechat_openid' => $openid,
            'wechat_unionid' => $unionid,
            'avatar' => $userInfo['headimgurl'] ?? null,
        ]);

        return $user;
    }

    /**
     * 绑定微信到已有账号
     */
    public function bindToUser(User $user, string $openid, ?string $unionid): bool
    {
        // 检查是否已被其他账号绑定
        $exists = User::where('wechat_openid', $openid)
            ->where('id', '!=', $user->id)
            ->exists();

        if ($exists) {
            return false;
        }

        $user->update([
            'wechat_openid' => $openid,
            'wechat_unionid' => $unionid,
        ]);

        return true;
    }

    /**
     * 解绑微信
     */
    public function unbind(User $user): bool
    {
        $user->update([
            'wechat_openid' => null,
            'wechat_unionid' => null,
        ]);

        return true;
    }

    /**
     * 获取 Access Token
     */
    private function getAccessToken(): ?string
    {
        $cacheKey = 'wechat_access_token';

        $token = Cache::get($cacheKey);
        if ($token) {
            return $token;
        }

        try {
            $response = Http::get("https://api.weixin.qq.com/cgi-bin/token", [
                'grant_type' => 'client_credential',
                'appid' => $this->appId,
                'secret' => $this->appSecret,
            ]);

            $result = $response->json();

            if (isset($result['access_token'])) {
                Cache::put($cacheKey, $result['access_token'], $result['expires_in'] - 200);
                return $result['access_token'];
            }
        } catch (\Exception $e) {
            Log::error('获取微信access_token失败: ' . $e->getMessage());
        }

        return null;
    }

    /**
     * 检查是否已配置
     */
    public function isConfigured(): bool
    {
        return !empty($this->appId) && !empty($this->appSecret);
    }

    /**
     * 获取模拟二维码（未配置时使用）
     */
    private function getMockQr(): array
    {
        $sceneStr = 'mock_' . Str::random(16);

        // 生成一个 data URI 格式的模拟二维码图片
        // 这是一个简单的模拟二维码，实际项目中应该显示真实二维码
        $mockQrData = [
            'scene_str' => $sceneStr,
            'qr_url' => null, // 前端可以自己生成二维码
            'ticket' => null,
            'mock' => true,
        ];

        return [
            'success' => true,
            'data' => $mockQrData,
        ];
    }
}