// Android MVC示例：Model层实现
class UserModel {
    private val userRepository: UserRepository = UserRepository()

    fun getUser(id: String): User {
        return userRepository.getUserById(id)
    }

    fun updateUser(user: User) {
        userRepository.updateUser(user)
        // 通知视图更新
        // 这里暴露了MVC的问题：Model需要知道View的存在
    }
}

// View层（Activity/Fragment）
class UserActivity : AppCompatActivity() {
    private lateinit var userModel: UserModel
    private lateinit var nameTextView: TextView

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        userModel = UserModel()
        // Controller逻辑与View耦合
        loadUserData()
    }

    private fun loadUserData() {
        val user = userModel.getUser("123")
        nameTextView.text = user.name
    }
}

// iOS MVP示例：协议定义
protocol UserViewProtocol: AnyObject {
    func displayUser(name: String, email: String)
    func showError(message: String)
}

protocol UserPresenterProtocol {
    func loadUser()
    func updateUser(name: String)
}

// Presenter实现
class UserPresenter: UserPresenterProtocol {
    private weak var view: UserViewProtocol?
    private let userService: UserService

    init(view: UserViewProtocol, userService: UserService = UserService()) {
        self.view = view
        self.userService = userService
    }

    func loadUser() {
        userService.fetchUser { [weak self] result in
            switch result {
            case .success(let user):
                self?.view?.displayUser(name: user.name, email: user.email)
            case .failure(let error):
                self?.view?.showError(message: error.localizedDescription)
            }
        }
    }
}

// Android MVVM with LiveData示例
class UserViewModel : ViewModel() {
    private val userRepository = UserRepository()

    private val _user = MutableLiveData<User>()
    val user: LiveData<User> = _user

    private val _loading = MutableLiveData<Boolean>()
    val loading: LiveData<Boolean> = _loading

    fun loadUser(userId: String) {
        _loading.value = true
        viewModelScope.launch {
            try {
                val userData = userRepository.getUser(userId)
                _user.value = userData
            } catch (e: Exception) {
                // 错误处理
            } finally {
                _loading.value = false
            }
        }
    }
}

// 在Fragment中使用
class UserFragment : Fragment() {
    private lateinit var viewModel: UserViewModel

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        viewModel.user.observe(viewLifecycleOwner) { user ->
            // UI自动更新
            binding.nameText.text = user.name
        }

        viewModel.loading.observe(viewLifecycleOwner) { isLoading ->
            binding.progressBar.isVisible = isLoading
        }
    }
}

// MVI状态定义
sealed class UserState {
    object Loading : UserState()
    data class Success(val user: User) : UserState()
    data class Error(val message: String) : UserState()
}

// Intent定义
sealed class UserIntent {
    object LoadUser : UserIntent()
    data class UpdateUser(val name: String) : UserIntent()
}

// ViewModel实现
class UserViewModel : ViewModel() {
    private val _state = MutableStateFlow<UserState>(UserState.Loading)
    val state: StateFlow<UserState> = _state.asStateFlow()

    private val userRepository = UserRepository()

    fun processIntent(intent: UserIntent) {
        when (intent) {
            is UserIntent.LoadUser -> loadUser()
            is UserIntent.UpdateUser -> updateUser(intent.name)
        }
    }

    private fun loadUser() {
        viewModelScope.launch {
            _state.value = UserState.Loading
            try {
                val user = userRepository.getUser("123")
                _state.value = UserState.Success(user)
            } catch (e: Exception) {
                _state.value = UserState.Error(e.message ?: "Unknown error")
            }
        }
    }
}

@Module
@InstallIn(SingletonComponent::class)
object AppModule {
    @Provides
    @Singleton
    fun provideUserRepository(): UserRepository {
        return UserRepositoryImpl()
    }

    @Provides
    fun provideUserService(retrofit: Retrofit): UserService {
        return retrofit.create(UserService::class.java)
    }
}

@HiltViewModel
class UserViewModel @Inject constructor(
    private val userRepository: UserRepository
) : ViewModel() {
    // ViewModel逻辑
}

// Kotlin协程状态机反编译分析
public final Object loadUser(Continuation<? super User> $completion) {
    Object $result;
    label25: {
        // 状态机实现
        switch(this.label) {
            case 0:
                this.label = 1;
                $result = userRepository.getUser(this.arg$userId, this);
                if ($result == COROUTINE_SUSPENDED) {
                    return COROUTINE_SUSPENDED;
                }
                break;
            case 1:
                $result = this.result;
                break label25;
            default:
                throw new IllegalStateException("call to 'resume' before 'invoke' with coroutine");
        }
    }
    return $result;
}