water-management-system/lib/services/auth_service.dart

import 'package:shared_preferences/shared_preferences.dart';
import 'package:dio/dio.dart';
import 'package:flutter/material.dart';

class AuthService extends ChangeNotifier {
  static const String _tokenKey = 'auth_token';
  static const String _userKey = 'user_info';
  
  String? _token;
  String? _userId;
  String? _userName;
  bool _isAuthenticated = false;
  bool _isLoading = false;
  final Dio _dio = Dio();

  String? get token => _token;
  String? get userId => _userId;
  String? get userName => _userName;
  bool get isAuthenticated => _isAuthenticated;
  bool get isLoading => _isLoading;

  AuthService() {
    _dio.options.baseUrl = 'http://your-api-domain.com/api';
    _dio.interceptors.add(
      InterceptorsWrapper(
        onRequest: (options, handler) {
          if (_token != null) {
            options.headers['Authorization'] = 'Bearer $_token';
          }
          handler.next(options);
        },
      ),
    );
  }

  Future<void> init() async {
    await loadStoredAuth();
  }

  Future<void> loadStoredAuth() async {
    try {
      final prefs = await SharedPreferences.getInstance();
      final token = prefs.getString(_tokenKey);
      final userJson = prefs.getString(_userKey);
      
      if (token != null && userJson != null) {
        _token = token;
        _parseUserInfo(userJson);
        _isAuthenticated = true;
      }
    } catch (e) {
      print('加载认证信息失败: $e');
    }
    notifyListeners();
  }

  void _parseUserInfo(String userJson) {
    try {
      // 这里解析用户信息，根据实际的API响应格式
      final user = userJson;
      _userId = 'user_id_from_json'; // 从JSON解析
      _userName = 'username_from_json'; // 从JSON解析
    } catch (e) {
      print('解析用户信息失败: $e');
    }
  }

  Future<bool> login(String username, String password) async {
    _isLoading = true;
    notifyListeners();

    try {
      final response = await _dio.post('/auth/login', data: {
        'username': username,
        'password': password,
      });

      if (response.statusCode == 200) {
        final data = response.data;
        _token = data['token'];
        _userId = data['user_id'];
        _userName = data['username'];
        _isAuthenticated = true;

        // 保存到本地存储
        final prefs = await SharedPreferences.getInstance();
        await prefs.setString(_tokenKey, _token!);
        await prefs.setString(_userKey, data.toString());

        notifyListeners();
        return true;
      } else {
        throw Exception('登录失败');
      }
    } catch (e) {
      print('登录错误: $e');
      return false;
    } finally {
      _isLoading = false;
      notifyListeners();
    }
  }

  Future<void> logout() async {
    try {
      // 调用登出API
      await _dio.post('/auth/logout');
    } catch (e) {
      print('登出API调用失败: $e');
    }

    // 清除本地数据
    _token = null;
    _userId = null;
    _userName = null;
    _isAuthenticated = false;

    final prefs = await SharedPreferences.getInstance();
    await prefs.remove(_tokenKey);
    await prefs.remove(_userKey);

    notifyListeners();
  }
}