water-management-system/mobile/lib/services/api_service.dart

import 'package:dio/dio.dart';
import 'package:flutter/foundation.dart';
import 'auth_service.dart';

/// 全局 HTTP 客户端 —— Dio 封装 + Token 拦截器
class ApiService {
  ApiService._internal();
  static final ApiService instance = ApiService._internal();

  late final Dio dio;
  AuthService? _authService;

  /// 在 app 启动时调用一次，注入 AuthService 以便拦截器读取 token
  void init(AuthService auth) {
    _authService = auth;
  }

  /// 工厂方法：外部通过 ApiService.instance 使用
  factory ApiService() => instance;

  // --------------- Dio 初始化 ---------------

  Dio _createDio() {
    final d = Dio(BaseOptions(
      baseUrl: 'http://10.0.2.2:8080/api',
      connectTimeout: const Duration(seconds: 15),
      receiveTimeout: const Duration(seconds: 15),
      headers: {'Content-Type': 'application/json'},
    ));

    // ---------- Token 拦截器 ----------
    d.interceptors.add(InterceptorsWrapper(
      onRequest: (options, handler) {
        final token = _authService?.token ?? '';
        if (token.isNotEmpty) {
          options.headers['Authorization'] = 'Bearer $token';
        }
        debugPrint('→ ${options.method} ${options.uri}');
        handler.next(options);
      },
      onResponse: (response, handler) {
        debugPrint('← ${response.statusCode} ${response.requestOptions.uri}');
        handler.next(response);
      },
      onError: (error, handler) async {
        debugPrint('✗ ${error.message} ${error.requestOptions.uri}');

        // 401 → Token 过期，自动清除登录态
        if (error.response?.statusCode == 401) {
          await _authService?.logout();
        }

        handler.next(error);
      },
    ));

    // ---------- 日志拦截器（仅 debug） ----------
    if (kDebugMode) {
      d.interceptors.add(LogInterceptor(
        requestBody: true,
        responseBody: true,
        logPrint: (obj) => debugPrint(obj.toString()),
      ));
    }

    return d;
  }

  /// 懒加载 Dio 实例
  Dio get client {
    dio = _createDio();
    return dio;
  }

  // --------------- 便捷方法 ---------------

  Future<Response> get(String path, {Map<String, dynamic>? queryParameters}) {
    return client.get(path, queryParameters: queryParameters);
  }

  Future<Response> post(String path, {dynamic data, Map<String, dynamic>? queryParameters}) {
    return client.post(path, data: data, queryParameters: queryParameters);
  }

  Future<Response> put(String path, {dynamic data, Map<String, dynamic>? queryParameters}) {
    return client.put(path, data: data, queryParameters: queryParameters);
  }

  Future<Response> delete(String path, {dynamic data, Map<String, dynamic>? queryParameters}) {
    return client.delete(path, data: data, queryParameters: queryParameters);
  }

  Future<Response> patch(String path, {dynamic data, Map<String, dynamic>? queryParameters}) {
    return client.patch(path, data: data, queryParameters: queryParameters);
  }
}