Blog/content/posts/mvi_architecture.md

+++ title = 'MVI Architecture Helper' date = 2024-09-27T13:45:09+02:00 tags = ['kotlin', 'kmp', 'android', 'mvi'] draft = true +++ Something smart to talk about this helper class

{{< highlight kotlin >}} interface StateReceiver {

suspend fun updateState(transform: suspend (STATE) -> STATE)
suspend fun withState(block: suspend (STATE) -> Unit)

}

suspend inline fun StateReceiver.withType(crossinline block: suspend (TYPE) -> Unit) {

withState { state ->
    if (state is TYPE) {
        block(state)
    }
}

}

suspend inline fun StateReceiver.updateWithType(crossinline transform: suspend (TYPE) -> TYPE) {

withType<TYPE, STATE> { state -> updateState { transform(state) } }

}

interface StateProvider {

val state: StateFlow<STATE>

}

interface IntentReceiver {

fun handleIntent(intent: INTENT)

}

interface ActionProvider {

val action: Flow<ACTION>

}

interface ActionReceiver {

suspend fun sendAction(block: suspend () -> ACTION)

}

interface StateModule : StateReceiver, StateProvider interface IntentModule : IntentReceiver interface ActionModule : ActionReceiver, ActionProvider

interface MVIViewModel :

StateModule<STATE>,
IntentModule<INTENT>,
ActionModule<ACTION>

class MVIViewModelDelegate(

initial: STATE

) : MVIViewModel {

private val _state = MutableStateFlow(initial)
override val state: StateFlow<STATE> = _state.asStateFlow()

private val _action = Channel<ACTION>()
override val action: Flow<ACTION> = _action.receiveAsFlow()

override suspend fun updateState(transform: suspend (STATE) -> STATE) {
    _state.update { transform(it) }
}

override suspend fun withState(block: suspend (STATE) -> Unit) {
    block(_state.value)
}

override suspend fun sendAction(block: suspend () -> ACTION) {
    _action.trySend(block())
}

override fun handleIntent(intent: INTENT) {
    throw NotImplementedError()
}

} {{< / highlight >}}