三、第一步：SDK 层（最底层，只负责 fluwx）

1️⃣ wechat_sdk_datasource.dart

import 'package:fluwx/fluwx.dart';

class WechatSdkDataSource {
  final Fluwx _fluwx;

  WechatSdkDataSource(this._fluwx);

  Future<bool> isInstalled() async {
    return await _fluwx.isWeChatInstalled;
  }

  Future<void> requestAuth() async {
    await _fluwx.authBy(
      which: NormalAuth(
        scope: 'snsapi_userinfo',
        state: 'login',
      ),
    );
  }

  void listenAuth(void Function(String code) onCode) {
    _fluwx.addSubscriber((resp) {
      if (resp is WeChatAuthResponse && resp.isSuccessful) {
        onCode(resp.code!);
      }
    });
  }
}

📌 注意

• ❌ 不调后端

• ❌ 不存 token

• ❌ 不跳页面

👉 这里只和 fluwx 打交道

---

四、Domain 层（真正的业务核心）

2️⃣ wechat_auth_result.dart

class WechatAuthResult {
  final bool isNewUser;
  final String? accessToken;
  final String? openId;

  WechatAuthResult({
    required this.isNewUser,
    this.accessToken,
    this.openId,
  });
}

---

3️⃣ wechat_auth_repository.dart（抽象）

abstract class WechatAuthRepository {
  Future<WechatAuthResult> loginByCode(String code);
}

---

五、Data → Repository 实现（真正调你后端）

4️⃣ wechat_auth_repository_impl.dart

import '../../domain/entity/wechat_auth_result.dart';
import '../../domain/repository/wechat_auth_repository.dart';
import '../../http/http.dart';

class WechatAuthRepositoryImpl implements WechatAuthRepository {
  @override
  Future<WechatAuthResult> loginByCode(String code) async {
    final res = await HttpUtil.dio.post(
      "/api/auth/wechat/login",
      data: {"code": code},
    );

    final data = res.data;

    if (data["isNewUser"] == true) {
      return WechatAuthResult(
        isNewUser: true,
        openId: data["openId"],
      );
    }

    return WechatAuthResult(
      isNewUser: false,
      accessToken: data["accessToken"],
    );
  }
}

📌 关键点

• Flutter 不再关心微信细节

• 后端是唯一微信接口调用者

---

六、UseCase（业务动作封装）

5️⃣ wechat_login_usecase.dart

import '../entity/wechat_auth_result.dart';
import '../repository/wechat_auth_repository.dart';

class WechatLoginUseCase {
  final WechatAuthRepository repository;

  WechatLoginUseCase(this.repository);

  Future<WechatAuthResult> execute(String code) {
    return repository.loginByCode(code);
  }
}

👉 这一步的价值：
以后你要接 Apple / Google 登录，只换 UseCase

---

七、Presentation 层（UI & 跳转）

6️⃣ wechat_login_controller.dart（GetX / Bloc 都行）

import 'package:get/get.dart';
import '../../domain/usecase/wechat_login_usecase.dart';
import '../../domain/entity/wechat_auth_result.dart';
import '../pages/wechat_bind_phone_page.dart';
import '../../main.dart';

class WechatLoginController extends GetxController {
  final WechatLoginUseCase useCase;

  WechatLoginController(this.useCase);

  Future<void> handleWechatCode(String code) async {
    final result = await useCase.execute(code);

    if (result.isNewUser) {
      Get.to(() => WechatBindPhonePage(
            openId: result.openId!,
          ));
    } else {
      storage.write("token", result.accessToken);
      Get.offAll(() => const MainPage());
    }
  }
}

📌 注意

• 跳转只在 Presentation 层

• Domain 层完全不依赖 Flutter

---

八、初始化 & 注入（你现在 registerApi 的正确位置）

7️⃣ wechat_initializer.dart

import 'package:fluwx/fluwx.dart';

class WechatInitializer {
  static Future<void> init() async {
    await Fluwx().registerApi(
      appId: "wx_xxxxx",
      universalLink: "https://xxxx.com/wechat/",
    );
  }
}

在 main()：

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await WechatInitializer.init();
  runApp(MyApp());
}