LoginViewModel.kt

inline fun <T> dependantLiveData(
    vararg dependencies: LiveData<*>,
    crossinline mapper: () -> T?
) = MediatorLiveData<T>().also { mediatorLiveData ->
    val observer = Observer<Any> { mediatorLiveData.value = mapper() }
    dependencies.forEach { dependencyLiveData ->
        mediatorLiveData.addSource(dependencyLiveData, observer)
    }
}

sealed class LoginUiStates
data class LoginUiStateSuccessfulLogin(val user: FirebaseUser) : LoginUiStates()
data class LoginUiStateSuccessfulRegister(val dataOkDialog: DataOkDialog) : LoginUiStates()
data class LoginUiStateError(val dataOkDialog: DataOkDialog) : LoginUiStates()

open class LoginViewModel @Inject constructor(private val dataManager: DataManager) :
    RxAwareViewModel() {

    val liveUiStates = MutableLiveData<LoginUiStates>()
    val liveSnackbar = SingleLiveEvent<String>()
    val liveOkDialog = SingleLiveEvent<DataOkDialog>()
        
    val liveEmail = MutableLiveData<String>()
    val livePass = MutableLiveData<String>()
    val displayName = dependantLiveData(liveEmail) {
        liveEmail.value ?: "null"
    }

    open fun login(
        email: String,
        password: String
    ) {
        disposables.add(dataManager.loginUser(email, password)
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe({
                Logger.i("Kullanıcı girişi başarılı.")
                liveSnackbar.value = "${it?.email} ile oturum açıldı."
                liveUiStates.value = LoginUiStateSuccessfulLogin(it)
            }, {
                it.printStackTrace()
                val dialog = DataOkDialog("SweetLoc", it?.message ?: "") {}
                liveUiStates.value = LoginUiStateError(dialog)
            })
        )
    }

    fun register(
        email: String,
        password: String
    ) {
        disposables.add(dataManager.registerUser(email, password)
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe({
                Logger.i("Kullanıcı kaydı başarılı.")
                liveSnackbar.value = "${it?.email} ile kayıt olundu."
                liveUiStates.value = LoginUiStateSuccessfulLogin(it)
            }, {
                it.printStackTrace()
                val dialog = DataOkDialog("SweetLoc", it?.message ?: "") {}
                liveUiStates.value = LoginUiStateError(dialog)
            })
        )
    }
}