LoginViewModel.kt

class LoginViewModel(val repository: AuthRepository): ViewMode() {
    private val _state = mutableStateOf(LoginUiState())
    val state = _state.asStateFlow()

    fun onLoginAttemp(user: User) {
    viewModelScope.launch {
repository.isRegistered(user).collect { registered ->
                when (registered) {
                    is Result.Loading -> {
                        _state.update { it.copy(loading = true) }
                    }
                    is Result.Error -> {
                        showUserMessage(registered.message)
                    }
                    is Result.Success -> {
                     repository.signIn(user).collect { signedIn ->
                when (signedIn) {
                    is Result.Loading -> {
                        _state.update { it.copy(loading = true) }
                    }
                    is Result.Error -> {
                        showUserMessage(signedIn.message)
                    }
                    is Result.Success -> {
                     _state.update {
                         loading = false,
                         // User is registered and signing in was successful
                         navigateToHome = registered.value && signedIn.value 
                        // User is not registered and this is the first sign in
                         navigateToRegistration = !registered.value && signedIn.value 
                                   }
                               }
                           }
                       }
                   }
                }
            }
        }
    }

    fun showUserMessage(message: String) {
        _state.update {
        val messages = it.errorMessages + message
        it.copy(errorMessages = messages)
        }
    }

    fun userMessageShown() {
        _state.update{
            // Remove last message
            val messages = it.messages.subList(0, it.messages.size -1)
            it.copy(errorMessages = messages)
        }
    }
}