AutoValidationViewModel.kt

@HiltViewModel
class InputValidationAutoViewModel @Inject constructor(
    private val savedStateHandle: SavedStateHandle
) : ViewModel() {

    val name = handle.getStateFlow(NAME, InputWrapper())
    val creditCardNumber = handle.getStateFlow(CREDIT_CARD_NUMBER, InputWrapper())
    val areInputsValid = combine(name, creditCardNumber) { name, cardNumber ->
        name.value.isNotEmpty() && name.errorId == null && cardNumber.value.isNotEmpty() && cardNumber.errorId == null
    }.stateIn(viewModelScope, SharingStarted.WhileSubscribed(5000L), false)
   
    private val _events = Channel<ScreenEvent>()
    val events = _events.receiveAsFlow()
    
    fun onNameEntered(input: String) {
        val errorId = InputValidator.getNameErrorIdOrNull(input)
        handle[NAME] = name.value.copy(value = input, errorId = errorId)
    }

    fun onCardNumberEntered(input: String) {
        val errorId = InputValidator.getCardNumberErrorIdOrNull(input)
        handle[CREDIT_CARD_NUMBER] = creditCardNumber.value.copy(value = input, errorId = errorId)
    }
    
    fun onContinueClick() {
        viewModelScope.launch(Dispatchers.Default) {
            val resId = if (areInputsValid.value) R.string.success else R.string.validation_error
            _events.send(ScreenEvent.ShowToast(resId))
        }
    }
}