import 'package:flutter_web_auth_2/flutter_web_auth_2.dart';
import 'package:shared_preferences/shared_preferences.dart';
import '../config/api_config.dart';

class AuthService {
  static const String _tokenKey = 'access_token';
  static const String _accountKey = 'selected_account';

  Future<String?> getStoredToken() async {
    final prefs = await SharedPreferences.getInstance();
    return prefs.getString(_tokenKey);
  }

  Future<String?> getStoredAccount() async {
    final prefs = await SharedPreferences.getInstance();
    return prefs.getString(_accountKey);
  }

  Future<String?> login() async {
    final result = await FlutterWebAuth2.authenticate(
      url: '${ApiConfig.baseUrl}/login?redirect_uri=${Uri.encodeComponent('myice://callback')}',
      callbackUrlScheme: 'myice',
    );

    final uri = Uri.parse(result);
    // Check for authorization errors first
    final error = uri.queryParameters['error'];
    if (error != null) {
      throw Exception('Authorization failed: $error');
    }
    // Extract token from fragment (#access_token=...)
    final fragment = uri.fragment;
    final params = Uri.splitQueryString(fragment);
    final token = params['access_token'];

    if (token != null) {
      final prefs = await SharedPreferences.getInstance();
      await prefs.setString(_tokenKey, token);
    }

    return token;
  }

  Future<void> setAccount(String account) async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.setString(_accountKey, account);
  }

  Future<void> logout() async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.remove(_tokenKey);
    await prefs.remove(_accountKey);
  }
}