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

const _kAccessToken = 'access_token';
const _kRefreshToken = 'refresh_token';
const _kUsername = 'username';
const _kRealName = 'real_name';
const _kHotelNo = 'hotel_no';
const _kHotelId = 'hotel_id';

class AuthUser {
  final String accessToken;
  final String refreshToken;
  final String username;
  final String realName;
  final String hotelNo;
  final int hotelId;

  const AuthUser({
    required this.accessToken,
    required this.refreshToken,
    required this.username,
    required this.realName,
    required this.hotelNo,
    required this.hotelId,
  });

  // Kept for ApiClient compatibility
  String get token => accessToken;
}

class AuthState {
  final AuthUser? user;
  final bool initialized;
  const AuthState({this.user, this.initialized = false});
  bool get isLoggedIn => user != null;
}

class AuthNotifier extends StateNotifier<AuthState> {
  AuthNotifier() : super(const AuthState());

  /// Called at app startup to restore persisted session.
  Future<void> restore() async {
    try {
      final prefs = await SharedPreferences.getInstance();
      final accessToken = prefs.getString(_kAccessToken);
      final refreshToken = prefs.getString(_kRefreshToken);
      final username = prefs.getString(_kUsername);
      final realName = prefs.getString(_kRealName);
      final hotelNo = prefs.getString(_kHotelNo);
      final hotelIdStr = prefs.getString(_kHotelId);

      if (accessToken != null && refreshToken != null && username != null) {
        state = AuthState(
          initialized: true,
          user: AuthUser(
            accessToken: accessToken,
            refreshToken: refreshToken,
            username: username,
            realName: realName ?? username,
            hotelNo: hotelNo ?? '',
            hotelId: int.tryParse(hotelIdStr ?? '') ?? 0,
          ),
        );
        return;
      }
    } catch (_) {
      // Storage unavailable — fall through to logged-out state
    }
    state = const AuthState(initialized: true);
  }

  Future<void> login(AuthUser user) async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.setString(_kAccessToken, user.accessToken);
    await prefs.setString(_kRefreshToken, user.refreshToken);
    await prefs.setString(_kUsername, user.username);
    await prefs.setString(_kRealName, user.realName);
    await prefs.setString(_kHotelNo, user.hotelNo);
    await prefs.setString(_kHotelId, user.hotelId.toString());
    state = AuthState(initialized: true, user: user);
  }

  void updateAccessToken(String newToken) {
    if (state.user == null) return;
    SharedPreferences.getInstance()
        .then((prefs) => prefs.setString(_kAccessToken, newToken));
    state = AuthState(
      initialized: true,
      user: AuthUser(
        accessToken: newToken,
        refreshToken: state.user!.refreshToken,
        username: state.user!.username,
        realName: state.user!.realName,
        hotelNo: state.user!.hotelNo,
        hotelId: state.user!.hotelId,
      ),
    );
  }

  Future<void> logout() async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.remove(_kAccessToken);
    await prefs.remove(_kRefreshToken);
    await prefs.remove(_kUsername);
    await prefs.remove(_kRealName);
    await prefs.remove(_kHotelNo);
    await prefs.remove(_kHotelId);
    state = const AuthState(initialized: true);
  }
}

final authStateProvider = StateNotifierProvider<AuthNotifier, AuthState>(
  (ref) => AuthNotifier(),
);