@HiltViewModel
class UserViewModel @Inject constructor(
    private val repository: UserRepository
) : ViewModel() {
    private val _state = MutableLiveData<UiState>()
    val state: LiveData<UiState> = _state
    
    fun loadUser(id: Int) {
        viewModelScope.launch {
            _state.value = repository.getUser(id)
        }
    }
}

interface UserRepository {
    suspend fun getUser(id: Int): User
}

class UserRepositoryImpl(
    private val dao: UserDao,
    private val api: UserApi
) : UserRepository {
    override suspend fun getUser(id: Int): User {
        return dao.getUser(id) ?: api.fetchUser(id)
    }
}

@Module
@InstallIn(SingletonComponent::class)
object RepositoryModule {
    @Provides
    fun provideUserRepository(dao: UserDao, api: UserApi): UserRepository {
        return UserRepositoryImpl(dao, api)
    }
}