import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:shared_preferences/shared_preferences.dart';
import '../../data/datasources/remote/auth_remote_datasource.dart';
import '../../core/di/injection.dart';

class UserState {
  final String? accountSequence;
  final String? nickname;
  final String? phone;
  final String? kycStatus;
  final String? source;
  final String? accessToken;
  final String? refreshToken;
  final bool isLoggedIn;
  final bool isLoading;
  final String? error;

  UserState({
    this.accountSequence,
    this.nickname,
    this.phone,
    this.kycStatus,
    this.source,
    this.accessToken,
    this.refreshToken,
    this.isLoggedIn = false,
    this.isLoading = false,
    this.error,
  });

  UserState copyWith({
    String? accountSequence,
    String? nickname,
    String? phone,
    String? kycStatus,
    String? source,
    String? accessToken,
    String? refreshToken,
    bool? isLoggedIn,
    bool? isLoading,
    String? error,
  }) {
    return UserState(
      accountSequence: accountSequence ?? this.accountSequence,
      nickname: nickname ?? this.nickname,
      phone: phone ?? this.phone,
      kycStatus: kycStatus ?? this.kycStatus,
      source: source ?? this.source,
      accessToken: accessToken ?? this.accessToken,
      refreshToken: refreshToken ?? this.refreshToken,
      isLoggedIn: isLoggedIn ?? this.isLoggedIn,
      isLoading: isLoading ?? this.isLoading,
      error: error,
    );
  }
}

class UserNotifier extends StateNotifier<UserState> {
  final AuthRemoteDataSource _authDataSource;

  UserNotifier(this._authDataSource) : super(UserState()) {
    _loadFromStorage();
  }

  Future<void> _loadFromStorage() async {
    final prefs = await SharedPreferences.getInstance();
    final accessToken = prefs.getString('access_token');
    final refreshToken = prefs.getString('refresh_token');
    final accountSequence = prefs.getString('account_sequence');
    final phone = prefs.getString('phone');

    if (accessToken != null && refreshToken != null && accountSequence != null) {
      state = state.copyWith(
        accessToken: accessToken,
        refreshToken: refreshToken,
        accountSequence: accountSequence,
        phone: phone,
        isLoggedIn: true,
      );
    }
  }

  Future<void> _saveToStorage(AuthResult result) async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.setString('access_token', result.accessToken);
    await prefs.setString('refresh_token', result.refreshToken);
    await prefs.setString('account_sequence', result.user.accountSequence);
    await prefs.setString('phone', result.user.phone);
  }

  Future<void> _clearStorage() async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.remove('access_token');
    await prefs.remove('refresh_token');
    await prefs.remove('account_sequence');
    await prefs.remove('phone');
  }

  Future<void> sendSmsCode(String phone, String type) async {
    state = state.copyWith(isLoading: true, error: null);
    try {
      await _authDataSource.sendSmsCode(phone, type);
      state = state.copyWith(isLoading: false);
    } catch (e) {
      state = state.copyWith(isLoading: false, error: e.toString());
      rethrow;
    }
  }

  Future<void> register(String phone, String password, String smsCode) async {
    state = state.copyWith(isLoading: true, error: null);
    try {
      final result = await _authDataSource.register(phone, password, smsCode);
      await _saveToStorage(result);
      state = state.copyWith(
        accessToken: result.accessToken,
        refreshToken: result.refreshToken,
        accountSequence: result.user.accountSequence,
        phone: result.user.phone,
        kycStatus: result.user.kycStatus,
        source: result.user.source,
        isLoggedIn: true,
        isLoading: false,
      );
    } catch (e) {
      state = state.copyWith(isLoading: false, error: e.toString());
      rethrow;
    }
  }

  Future<void> loginWithPassword(String phone, String password) async {
    state = state.copyWith(isLoading: true, error: null);
    try {
      final result = await _authDataSource.loginWithPassword(phone, password);
      await _saveToStorage(result);
      state = state.copyWith(
        accessToken: result.accessToken,
        refreshToken: result.refreshToken,
        accountSequence: result.user.accountSequence,
        phone: result.user.phone,
        kycStatus: result.user.kycStatus,
        source: result.user.source,
        isLoggedIn: true,
        isLoading: false,
      );
    } catch (e) {
      state = state.copyWith(isLoading: false, error: e.toString());
      rethrow;
    }
  }

  Future<void> loginWithSms(String phone, String smsCode) async {
    state = state.copyWith(isLoading: true, error: null);
    try {
      final result = await _authDataSource.loginWithSms(phone, smsCode);
      await _saveToStorage(result);
      state = state.copyWith(
        accessToken: result.accessToken,
        refreshToken: result.refreshToken,
        accountSequence: result.user.accountSequence,
        phone: result.user.phone,
        kycStatus: result.user.kycStatus,
        source: result.user.source,
        isLoggedIn: true,
        isLoading: false,
      );
    } catch (e) {
      state = state.copyWith(isLoading: false, error: e.toString());
      rethrow;
    }
  }

  Future<void> logout() async {
    if (state.refreshToken != null) {
      try {
        await _authDataSource.logout(state.refreshToken!);
      } catch (_) {}
    }
    await _clearStorage();
    state = UserState();
  }

  Future<void> refreshTokenIfNeeded() async {
    if (state.refreshToken == null) return;
    try {
      final newAccessToken = await _authDataSource.refreshToken(state.refreshToken!);
      final prefs = await SharedPreferences.getInstance();
      await prefs.setString('access_token', newAccessToken);
      state = state.copyWith(accessToken: newAccessToken);
    } catch (e) {
      await logout();
    }
  }

  Future<void> resetPassword(String phone, String smsCode, String newPassword) async {
    state = state.copyWith(isLoading: true, error: null);
    try {
      await _authDataSource.resetPassword(phone, smsCode, newPassword);
      state = state.copyWith(isLoading: false);
    } catch (e) {
      state = state.copyWith(isLoading: false, error: e.toString());
      rethrow;
    }
  }

  Future<void> changePassword(String oldPassword, String newPassword) async {
    state = state.copyWith(isLoading: true, error: null);
    try {
      await _authDataSource.changePassword(oldPassword, newPassword);
      state = state.copyWith(isLoading: false);
    } catch (e) {
      state = state.copyWith(isLoading: false, error: e.toString());
      rethrow;
    }
  }

  // Legacy method for compatibility
  void login({
    required String accountSequence,
    String? nickname,
    String? phone,
  }) {
    state = state.copyWith(
      accountSequence: accountSequence,
      nickname: nickname,
      phone: phone,
      isLoggedIn: true,
    );
  }

  // Legacy mock method for development
  void setMockUser() {
    state = state.copyWith(
      accountSequence: '1001',
      nickname: '测试用户',
      phone: '138****8888',
      isLoggedIn: true,
    );
  }
}

final userNotifierProvider = StateNotifierProvider<UserNotifier, UserState>(
  (ref) => UserNotifier(getIt<AuthRemoteDataSource>()),
);

final currentAccountSequenceProvider = Provider<String?>((ref) {
  return ref.watch(userNotifierProvider).accountSequence;
});

final isLoggedInProvider = Provider<bool>((ref) {
  return ref.watch(userNotifierProvider).isLoggedIn;
});

final accessTokenProvider = Provider<String?>((ref) {
  return ref.watch(userNotifierProvider).accessToken;
});