import 'dart:convert';
import 'package:dio/dio.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'package:sales_chat/models/user.dart';
import 'package:sales_chat/models/group.dart';
import 'package:sales_chat/models/message.dart';
import 'package:sales_chat/models/invite.dart';
import 'package:sales_chat/models/stats.dart';

/// 与 Tailchat 后端通信的 API 服务。
///
/// 关键约定：
/// - 所有 API 路由都在 `/api/`（网关路径）下。
/// - Tailchat 核心用户路由：`/api/user/<action>`
/// - 插件路由：`/api/plugin:com.msgbyte.saleschat/<action>`（冒号用于分隔 Moleculer 服务名段）
/// - 认证使用 `X-Token` 请求头（非 Authorization: Bearer）。
/// - 网关响应格式为 `{ "code": <int>, "data": <payload> }`。
class ApiService {
  late final Dio _dio;
  final FlutterSecureStorage _storage;

  static const String _baseUrl = 'http://localhost:3000/api';
  static const String _tokenKey = 'auth_token';
  static const String _userKey = 'user_data';

  ApiService() : _storage = const FlutterSecureStorage(
    aOptions: AndroidOptions(encryptedSharedPreferences: true),
    iOptions: IOSOptions(
      accessibility: KeychainAccessibility.first_unlock_this_device,
    ),
  ) {
    _dio = Dio(BaseOptions(
      baseUrl: _baseUrl,
      connectTimeout: const Duration(seconds: 10),
      receiveTimeout: const Duration(seconds: 30),
      headers: {
        'Content-Type': 'application/json',
      },
    ));

    _dio.interceptors.add(InterceptorsWrapper(
      onRequest: (options, handler) async {
        // Tailchat 使用 X-Token 请求头进行认证
        final token = await _storage.read(key: _tokenKey);
        if (token != null) {
          options.headers['X-Token'] = token;
        }
        return handler.next(options);
      },
      onError: (error, handler) async {
        if (error.response?.statusCode == 401) {
          await _storage.delete(key: _tokenKey);
          await _storage.delete(key: _userKey);
        }
        return handler.next(error);
      },
    ));
  }

  Future<String?> get token => _storage.read(key: _tokenKey);

  Future<bool> get isAuthenticated async =>
      await _storage.read(key: _tokenKey) != null;

  /// 解包网关响应：{ "code": 200, "data": ... }
  dynamic _unwrapResponse(Response response) {
    final body = response.data;
    if (body is Map<String, dynamic> && body.containsKey('data')) {
      return body['data'];
    }
    return body;
  }

  // ============================================================
  // 认证 API - Tailchat 核心用户服务
  // ============================================================

  /// 使用邮箱或用户名 + 密码登录。
  /// 后端接口：POST /api/user/login  {email|username, password}
  /// 响应（已解包）：{ ...userFields, token: "jwt..." }
  Future<AuthResponse> login({
    String? email,
    String? username,
    required String password,
  }) async {
    final data = <String, dynamic>{
      'password': password,
    };
    if (email != null && email.isNotEmpty) {
      data['email'] = email;
    } else if (username != null && username.isNotEmpty) {
      data['username'] = username;
    }

    final response = await _dio.post('/user/login', data: data);
    final unwrapped = _unwrapResponse(response);

    // 登录响应是用户对象附加了 `token`
    final authResponse = AuthResponse.fromJson({
      'data': unwrapped,
    });

    await _storage.write(key: _tokenKey, value: authResponse.token);
    await _storage.write(
        key: _userKey, value: jsonEncode(authResponse.user.toJson()));

    return authResponse;
  }

  /// 注册新用户。
  /// 后端接口：POST /api/user/register  {username, email, nickname, password}
  /// 响应（已解包）：{ ...userFields, token: "jwt..." }
  Future<AuthResponse> register({
    String? username,
    String? email,
    String? nickname,
    required String password,
  }) async {
    final data = <String, dynamic>{
      'password': password,
    };
    if (username != null && username.isNotEmpty) data['username'] = username;
    if (email != null && email.isNotEmpty) data['email'] = email;
    if (nickname != null && nickname.isNotEmpty) data['nickname'] = nickname;

    final response = await _dio.post('/user/register', data: data);
    final unwrapped = _unwrapResponse(response);

    final authResponse = AuthResponse.fromJson({
      'data': unwrapped,
    });

    await _storage.write(key: _tokenKey, value: authResponse.token);
    await _storage.write(
        key: _userKey, value: jsonEncode(authResponse.user.toJson()));

    return authResponse;
  }

  /// 创建临时（访客）用户。
  /// 后端接口：POST /api/user/createTemporaryUser  {nickname}
  Future<AuthResponse> createTemporaryUser({required String nickname}) async {
    final response = await _dio.post('/user/createTemporaryUser', data: {
      'nickname': nickname,
    });
    final unwrapped = _unwrapResponse(response);

    final authResponse = AuthResponse.fromJson({
      'data': unwrapped,
    });

    await _storage.write(key: _tokenKey, value: authResponse.token);
    await _storage.write(
        key: _userKey, value: jsonEncode(authResponse.user.toJson()));

    return authResponse;
  }

  /// 登出（仅本地 - JWT 是无状态的）
  Future<void> logout() async {
    await _storage.delete(key: _tokenKey);
    await _storage.delete(key: _userKey);
  }

  /// 从本地缓存获取当前用户
  Future<User?> getCurrentUser() async {
    final userData = await _storage.read(key: _userKey);
    if (userData == null) return null;

    try {
      return User.fromJson(jsonDecode(userData));
    } catch (e) {
      return null;
    }
  }

  // ============================================================
  // 群组 API - Tailchat 核心群组服务
  // ============================================================

  /// 获取当前用户加入的群组。
  /// 后端接口：GET /api/group/getUserGroups
  Future<List<Group>> getGroups() async {
    final response = await _dio.get('/group/getUserGroups');
    final data = _unwrapResponse(response);
    return (data as List).map((e) => Group.fromJson(e)).toList();
  }

  /// 获取单个群组的基本信息。
  /// 后端接口：GET /api/group/getGroupBasicInfo  {groupId}
  Future<GroupBasicInfo> getGroupBasicInfo(String groupId) async {
    final response =
        await _dio.get('/group/getGroupBasicInfo', queryParameters: {
      'groupId': groupId,
    });
    final data = _unwrapResponse(response);
    return GroupBasicInfo.fromJson(data);
  }

  /// 获取完整群组信息。
  /// 后端接口：GET /api/group/getGroupInfo  {groupId}
  Future<Group> getGroupInfo(String groupId) async {
    final response = await _dio.get('/group/getGroupInfo', queryParameters: {
      'groupId': groupId,
    });
    final data = _unwrapResponse(response);
    return Group.fromJson(data);
  }

  /// 创建新群组。
  /// 后端接口：POST /api/group/createGroup  {name, panels}
  Future<Group> createGroup(String name, {String? description}) async {
    // Tailchat 创建群组时至少需要一个文本面板
    final response = await _dio.post('/group/createGroup', data: {
      'name': name,
      'panels': [
        {
          'id': 'default',
          'name': 'General',
          'type': 0, // GroupPanelType.TEXT（文本面板类型）
        }
      ],
    });
    final data = _unwrapResponse(response);
    return Group.fromJson(data);
  }

  // ============================================================
  // 消息 API - Tailchat 核心 chat.message 服务
  // ============================================================

  /// 获取会话消息。
  /// 后端接口：GET /api/chat.message/fetchConverseMessage  {converseId, startId?}
  Future<List<Message>> getMessages(String converseId,
      {int limit = 50, String? before}) async {
    final response = await _dio.get(
        '/chat.message/fetchConverseMessage',
        queryParameters: {
          'converseId': converseId,
          if (before != null) 'startId': before,
        });
    final data = _unwrapResponse(response);
    return (data as List).map((e) => Message.fromJson(e)).toList();
  }

  /// 发送消息。
  /// 后端接口：POST /api/chat.message/sendMessage  {converseId, content, groupId?, meta?}
  Future<Message> sendMessage(String converseId, String content,
      {String? groupId}) async {
    final response =
        await _dio.post('/chat.message/sendMessage', data: {
      'converseId': converseId,
      'content': content,
      if (groupId != null) 'groupId': groupId,
    });
    final data = _unwrapResponse(response);
    return Message.fromJson(data);
  }

  /// 撤回消息（2 分钟内）。
  /// 后端接口：POST /api/chat.message/recallMessage  {messageId}
  Future<void> recallMessage(String messageId) async {
    await _dio.post('/chat.message/recallMessage', data: {
      'messageId': messageId,
    });
  }

  /// 删除消息（管理员）。
  /// 后端接口：POST /api/chat.message/deleteMessage  {messageId}
  Future<void> deleteMessage(String messageId) async {
    await _dio.post('/chat.message/deleteMessage', data: {
      'messageId': messageId,
    });
  }

  // ============================================================
  // 插件 API - plugin:com.msgbyte.saleschat
  // Tailchat 网关路由：/api/plugin:<pluginName>/<action>
  // ============================================================

  /// 创建邀请。
  Future<Invite> createInvite({
    required String groupId,
    int? expiresInDays,
  }) async {
    final data = <String, dynamic>{
      'groupId': groupId,
    };
    if (expiresInDays != null) {
      data['expiresIn'] = expiresInDays;
    }

    final response = await _dio.post(
        '/plugin:com.msgbyte.saleschat/inviteCreate',
        data: data);
    final unwrapped = _unwrapResponse(response);
    return Invite.fromJson(unwrapped);
  }

  /// 获取我的邀请。
  Future<List<Invite>> getMyInvites() async {
    final response = await _dio
        .get('/plugin:com.msgbyte.saleschat/inviteGetMyInvites');
    final data = _unwrapResponse(response);
    return (data as List).map((e) => Invite.fromJson(e)).toList();
  }

  /// 通过邀请码获取邀请（公开，无需认证）。
  Future<Invite> getInviteByCode(String code) async {
    final response = await _dio.get(
        '/plugin:com.msgbyte.saleschat/inviteGetByCode',
        queryParameters: {'code': code});
    final data = _unwrapResponse(response);
    return Invite.fromJson(data);
  }

  /// 获取邀请统计。
  Future<InviteStats> getInviteStats(String code) async {
    final response = await _dio.get(
        '/plugin:com.msgbyte.saleschat/inviteGetStats',
        queryParameters: {'code': code});
    final data = _unwrapResponse(response);
    return InviteStats.fromJson(data);
  }

  /// 停用邀请。
  Future<void> deactivateInvite(String code) async {
    await _dio.post(
        '/plugin:com.msgbyte.saleschat/inviteDeactivate',
        data: {'code': code});
  }

  /// 通过邀请码加入。
  Future<Map<String, dynamic>> joinInvite(String code) async {
    final response = await _dio.post(
        '/plugin:com.msgbyte.saleschat/inviteJoin',
        data: {'code': code});
    return _unwrapResponse(response);
  }

  /// 获取我的统计数据。
  Future<MyStats> getMyStats() async {
    final response =
        await _dio.get('/plugin:com.msgbyte.saleschat/statsGetMyStats');
    final data = _unwrapResponse(response);
    return MyStats.fromJson(data);
  }

  /// 获取排行榜。
  Future<List<RankingEntry>> getRanking({String period = 'monthly'}) async {
    final response = await _dio.get(
        '/plugin:com.msgbyte.saleschat/statsGetRanking',
        queryParameters: {'period': period});
    final data = _unwrapResponse(response);
    return (data as List).map((e) => RankingEntry.fromJson(e)).toList();
  }

  /// 获取趋势数据。
  Future<List<Map<String, dynamic>>> getTrend({
    required String salesId,
    String period = 'daily',
  }) async {
    final response = await _dio.get(
        '/plugin:com.msgbyte.saleschat/statsGetTrend',
        queryParameters: {
          'salesId': salesId,
          'period': period,
        });
    final data = _unwrapResponse(response);
    return (data as List).cast<Map<String, dynamic>>();
  }

  /// 获取团队统计（仅管理员）。
  Future<List<Map<String, dynamic>>> getTeamStats() async {
    final response = await _dio
        .get('/plugin:com.msgbyte.saleschat/statsGetTeamStats');
    final data = _unwrapResponse(response);
    return (data as List).cast<Map<String, dynamic>>();
  }

  /// 获取平台统计（仅超级管理员）。
  Future<PlatformStats> getPlatformStats() async {
    final response = await _dio
        .get('/plugin:com.msgbyte.saleschat/statsGetPlatformStats');
    final data = _unwrapResponse(response);
    return PlatformStats.fromJson(data);
  }

  /// 获取用户列表（仅管理员）。
  Future<List<Map<String, dynamic>>> getUsers() async {
    final response = await _dio
        .get('/plugin:com.msgbyte.saleschat/adminGetUserList');
    final data = _unwrapResponse(response);
    return (data as List).cast<Map<String, dynamic>>();
  }

  /// 更新用户角色（仅超级管理员）。
  Future<void> updateUserRole(String userId, String role) async {
    await _dio.post(
        '/plugin:com.msgbyte.saleschat/adminUpdateUserRole',
        data: {'userId': userId, 'role': role});
  }

  /// 删除用户（仅超级管理员）。
  Future<void> deleteUser(String userId,
      {String type = 'soft', String reason = ''}) async {
    await _dio.post(
        '/plugin:com.msgbyte.saleschat/adminDeleteUser',
        data: {
          'userId': userId,
          'type': type,
          if (reason.isNotEmpty) 'reason': reason,
        });
  }

  /// 获取群组列表（仅管理员）。
  Future<List<Map<String, dynamic>>> getAdminGroups() async {
    final response = await _dio
        .get('/plugin:com.msgbyte.saleschat/adminGetGroupList');
    final data = _unwrapResponse(response);
    return (data as List).cast<Map<String, dynamic>>();
  }

  /// 获取群组统计（仅管理员）。
  Future<Map<String, dynamic>> getGroupStats(String groupId) async {
    final response = await _dio.get(
        '/plugin:com.msgbyte.saleschat/adminGetGroupStats',
        queryParameters: {'groupId': groupId});
    return _unwrapResponse(response);
  }

  /// 踢出群组成员（仅管理员）。
  Future<void> kickGroupMember(String groupId, String userId,
      {String? reason}) async {
    await _dio.post(
        '/plugin:com.msgbyte.saleschat/adminKickUser',
        data: {
          'groupId': groupId,
          'userId': userId,
          if (reason != null) 'reason': reason,
        });
  }
}