asasasasasff.kt

class MainViewModel : BaseViewModel<MainContract.Event, MainContract.State, MainContract.Effect>() {
    /**
     * Create initial State of Views
     */
    override fun createInitialState(): MainContract.State {

        val currentTime = Calendar.getInstance().getTime()
        return MainContract.State("sajjad-agha-gole-bagha + $currentTime")
    }

    override fun handleEvent(event: MainContract.Event) {
        viewModelScope.launch {
            setState {
                copy(variable = (Calendar.getInstance().getTime().toString()))
            }
        }
    }


}



class MainContract {
    // Events that user performed
    sealed class Event : UiEvent {
        data object OnButtonClicked : Event()
    }

    // Ui View States
    data class State(
        val variable: String
    ) : UiState

    // View State that related to Random Number
    sealed class GettingValue {
        data class ReceiveValue(val value: String) : GettingValue()
    }

    // Side effects
    sealed class Effect : UiEffect {
        data object ShowSnack : Effect()

    }


}



public abstract class BaseViewModel<Event : UiEvent, State : UiState, Effect : UiEffect> :
    ViewModel() {
    // Create Initial State of View
    private val initialState: State by lazy { createInitialState() }

    abstract fun createInitialState(): State

    // Get Current State
    val currentState: State
        get() = uiState.value

    private val _uiState: MutableStateFlow<State> = MutableStateFlow(initialState)

    val uiState = _uiState.asStateFlow()

    private val _event: MutableSharedFlow<Event> = MutableSharedFlow()
    val event = _event.asSharedFlow()

    private val _effect: Channel<Effect> = Channel()
    val effect = _effect.receiveAsFlow()

    /**
     * Set new Event
     */
    protected fun setEvent(event: Event) {
        val newEvent = event
        viewModelScope.launch { _event.emit(newEvent) }
    }


    /**
     * Set new Ui State
     */
    protected fun setState(reduce: State.() -> State) {
        val newState = currentState.reduce()
        _uiState.value = newState
    }

    /**
     * Set new Effect
     */
    protected fun setEffect(builder: () -> Effect) {
        val effectValue = builder()
        viewModelScope.launch { _effect.send(effectValue) }
    }

    init {
        subscribeEvents()
    }

    /**
     * Start listening to Event
     */
    private fun subscribeEvents() {
        viewModelScope.launch {
            event.collect {
                handleEvent(it)
            }
        }
    }

    /**
     * Handle each event
     */
    abstract fun handleEvent(event: Event)
}


interface UiState

interface UiEvent

interface UiEffect



class MainActivity : ComponentActivity() {


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContent {
            // A surface container using the 'background' color from the theme
            MaterialTheme {
                Surface(
                    modifier = Modifier.fillMaxSize(), color = MaterialTheme.colorScheme.background
                ) {
                    CallbackCatcher(this)
                }
            }
        }
    }
}

private val viewModel = MainViewModel()

@Composable
fun CallbackCatcher(context: Context) {

    Column {
        Button(modifier = Modifier.requiredSize(200.dp, 150.dp), onClick = {
            viewModel.handleEvent(MainContract.Event.OnButtonClicked)
        }) {
            Text("sajjad agha gole bagha")
        }
    }
    MyTextField()
}


@Composable
fun MyTextField() {

    val textState = viewModel.uiState.collectAsState().value.variable

    val viewModel = MainViewModel()

    Text(
        text = textState,
    )
}