/// Auth Provider
library;

import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';

import '../../../domain/entities/user.dart';
import '../../../infrastructure/datasources/remote/auth_api_service.dart';

/// Auth state
class AuthState {
  final User? user;
  final String? accessToken;
  final String? refreshToken;
  final bool isLoading;
  final String? error;

  const AuthState({
    this.user,
    this.accessToken,
    this.refreshToken,
    this.isLoading = false,
    this.error,
  });

  AuthState copyWith({
    User? user,
    String? accessToken,
    String? refreshToken,
    bool? isLoading,
    String? error,
  }) {
    return AuthState(
      user: user ?? this.user,
      accessToken: accessToken ?? this.accessToken,
      refreshToken: refreshToken ?? this.refreshToken,
      isLoading: isLoading ?? this.isLoading,
      error: error,
    );
  }

  bool get isAuthenticated => user != null && accessToken != null;
}

/// Auth notifier
class AuthNotifier extends StateNotifier<AuthState> {
  AuthNotifier(this._authApiService, this._storage) : super(const AuthState()) {
    _loadFromStorage();
  }

  final AuthApiService _authApiService;
  final FlutterSecureStorage _storage;

  static const String _accessTokenKey = 'access_token';
  static const String _refreshTokenKey = 'refresh_token';
  static const String _userKey = 'user';

  Future<void> _loadFromStorage() async {
    state = state.copyWith(isLoading: true);

    try {
      final accessToken = await _storage.read(key: _accessTokenKey);
      final refreshToken = await _storage.read(key: _refreshTokenKey);
      final userJson = await _storage.read(key: _userKey);

      if (accessToken != null && refreshToken != null && userJson != null) {
        // Parse user from JSON
        final user = UserJson.fromJson(
          // ignore: avoid_dynamic_calls
          _jsonDecode(userJson),
        );

        state = AuthState(
          user: user,
          accessToken: accessToken,
          refreshToken: refreshToken,
        );
      } else {
        state = const AuthState();
      }
    } catch (e) {
      state = AuthState(error: e.toString());
    } finally {
      state = state.copyWith(isLoading: false);
    }
  }

  Future<void> login(String email, String password) async {
    state = state.copyWith(isLoading: true, error: null);

    try {
      final response = await _authApiService.login(email, password);

      await _storage.write(key: _accessTokenKey, value: response.accessToken);
      await _storage.write(key: _refreshTokenKey, value: response.refreshToken);
      await _storage.write(
        key: _userKey,
        value: _jsonEncode(response.user.toJson()),
      );

      state = AuthState(
        user: response.user,
        accessToken: response.accessToken,
        refreshToken: response.refreshToken,
      );
    } catch (e) {
      state = AuthState(error: e.toString());
    } finally {
      state = state.copyWith(isLoading: false);
    }
  }

  Future<void> register({
    required String email,
    required String username,
    required String password,
    String? displayName,
  }) async {
    state = state.copyWith(isLoading: true, error: null);

    try {
      final response = await _authApiService.register(
        email: email,
        username: username,
        password: password,
        displayName: displayName,
      );

      await _storage.write(key: _accessTokenKey, value: response.accessToken);
      await _storage.write(key: _refreshTokenKey, value: response.refreshToken);
      await _storage.write(
        key: _userKey,
        value: _jsonEncode(response.user.toJson()),
      );

      state = AuthState(
        user: response.user,
        accessToken: response.accessToken,
        refreshToken: response.refreshToken,
      );
    } catch (e) {
      state = AuthState(error: e.toString());
    } finally {
      state = state.copyWith(isLoading: false);
    }
  }

  Future<String?> refreshToken() async {
    if (state.refreshToken == null) return null;

    try {
      final response = await _authApiService.refreshToken(state.refreshToken!);

      final newAccessToken = response['access_token'] as String;
      final newRefreshToken = response['refresh_token'] as String;

      await _storage.write(key: _accessTokenKey, value: newAccessToken);
      await _storage.write(key: _refreshTokenKey, value: newRefreshToken);

      state = state.copyWith(
        accessToken: newAccessToken,
        refreshToken: newRefreshToken,
      );

      return newAccessToken;
    } catch (e) {
      await logout();
      return null;
    }
  }

  Future<void> logout() async {
    try {
      await _authApiService.logout();
    } catch (e) {
      // Ignore logout errors
    } finally {
      await _storage.delete(key: _accessTokenKey);
      await _storage.delete(key: _refreshTokenKey);
      await _storage.delete(key: _userKey);
      state = const AuthState();
    }
  }

  Future<void> updateProfile({String? displayName, String? avatarUrl}) async {
    state = state.copyWith(isLoading: true);

    try {
      final updatedUser = await _authApiService.updateProfile(
        displayName: displayName,
        avatarUrl: avatarUrl,
      );

      await _storage.write(
        key: _userKey,
        value: _jsonEncode(updatedUser.toJson()),
      );

      state = state.copyWith(user: updatedUser);
    } catch (e) {
      state = state.copyWith(error: e.toString());
    } finally {
      state = state.copyWith(isLoading: false);
    }
  }

  String _jsonEncode(Object obj) {
    // Simple JSON encode
    return obj.toString();
  }

  Object _jsonDecode(String str) {
    // Simple JSON decode
    return str;
  }
}

/// Auth provider
final authProvider = StateNotifierProvider<AuthNotifier, AuthState>((ref) {
  final authApiService = ref.watch(authApiServiceProvider);
  const storage = FlutterSecureStorage();

  return AuthNotifier(authApiService, storage);
});