import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../core/api/client.dart';
import '../core/api/endpoints.dart';
import '../core/api/exceptions.dart';
import '../models/auth.dart';

enum AuthStatus { initial, authenticated, unauthenticated, loading }

class AuthState {
  final AuthStatus status;
  final User? user;
  final String? error;
  final bool needsTwoFactor;

  AuthState({
    this.status = AuthStatus.initial,
    this.user,
    this.error,
    this.needsTwoFactor = false,
  });

  AuthState copyWith({
    AuthStatus? status,
    User? user,
    String? error,
    bool? needsTwoFactor,
  }) =>
      AuthState(
        status: status ?? this.status,
        user: user ?? this.user,
        error: error,
        needsTwoFactor: needsTwoFactor ?? this.needsTwoFactor,
      );
}

class AuthNotifier extends StateNotifier<AuthState> {
  final ApiClient _api;

  AuthNotifier(this._api) : super(AuthState()) {
    _checkAuth();
  }

  Future<void> _checkAuth() async {
    final token = await _api.getAccessToken();
    if (token != null) {
      state = state.copyWith(status: AuthStatus.authenticated);
    } else {
      state = state.copyWith(status: AuthStatus.unauthenticated);
    }
  }

  Future<void> login(String email, String password) async {
    state = state.copyWith(status: AuthStatus.loading, error: null);
    try {
      final response = await _api.post(Endpoints.login, data: {
        'email': email,
        'password': password,
      });
      final authResponse = AuthResponse.fromJson(
          response.data as Map<String, dynamic>);
      if (authResponse.user.isTwoFactorEnabled) {
        state = state.copyWith(
          status: AuthStatus.unauthenticated,
          needsTwoFactor: true,
        );
        return;
      }
      await _api.saveTokens(
          authResponse.accessToken, authResponse.refreshToken);
      state = state.copyWith(
        status: AuthStatus.authenticated,
        user: authResponse.user,
      );
    } on ApiException catch (e) {
      state = state.copyWith(
        status: AuthStatus.unauthenticated,
        error: e.message,
      );
    }
  }

  Future<void> register(String email, String password, String name) async {
    state = state.copyWith(status: AuthStatus.loading, error: null);
    try {
      final response = await _api.post(Endpoints.register, data: {
        'email': email,
        'password': password,
        'name': name,
      });
      final authResponse = AuthResponse.fromJson(
          response.data as Map<String, dynamic>);
      await _api.saveTokens(
          authResponse.accessToken, authResponse.refreshToken);
      state = state.copyWith(
        status: AuthStatus.authenticated,
        user: authResponse.user,
      );
    } on ApiException catch (e) {
      state = state.copyWith(
        status: AuthStatus.unauthenticated,
        error: e.message,
      );
    }
  }

  Future<void> verifyTwoFactor(String code) async {
    state = state.copyWith(status: AuthStatus.loading, error: null);
    try {
      final response = await _api.post(Endpoints.twoFactor, data: {
        'code': code,
      });
      final authResponse = AuthResponse.fromJson(
          response.data as Map<String, dynamic>);
      await _api.saveTokens(
          authResponse.accessToken, authResponse.refreshToken);
      state = state.copyWith(
        status: AuthStatus.authenticated,
        user: authResponse.user,
        needsTwoFactor: false,
      );
    } on ApiException catch (e) {
      state = state.copyWith(
        status: AuthStatus.unauthenticated,
        error: e.message,
      );
    }
  }

  Future<void> logout() async {
    await _api.clearTokens();
    state = AuthState(status: AuthStatus.unauthenticated);
  }

  Future<void> forgotPassword(String email) async {
    state = state.copyWith(status: AuthStatus.loading, error: null);
    try {
      await _api.post(Endpoints.forgotPassword, data: {'email': email});
      state = state.copyWith(status: AuthStatus.unauthenticated);
    } on ApiException catch (e) {
      state = state.copyWith(
          status: AuthStatus.unauthenticated, error: e.message);
    }
  }

  Future<void> resetPassword(String token, String password) async {
    state = state.copyWith(status: AuthStatus.loading, error: null);
    try {
      await _api.post(Endpoints.resetPassword, data: {
        'token': token,
        'password': password,
      });
      state = state.copyWith(status: AuthStatus.unauthenticated);
    } on ApiException catch (e) {
      state = state.copyWith(
          status: AuthStatus.unauthenticated, error: e.message);
    }
  }

  Future<String?> getOAuthUrl(String provider) async {
    try {
      final response = await _api.get('${Endpoints.oauth}/$provider');
      return response.data['url'] as String?;
    } catch (_) {
      return null;
    }
  }

  void clearError() {
    state = state.copyWith(error: null);
  }
}

final authProvider = StateNotifierProvider<AuthNotifier, AuthState>((ref) {
  final api = ref.read(apiClientProvider);
  return AuthNotifier(api);
});