Amity Support

messages.kt

class ChannelDetailViewModel : BaseViewModel() {

    private var _messagesUiState = MutableStateFlow<ChatsUiState>(ChatsUiState.Loading)
    var messagesUiState: StateFlow<ChatsUiState> = _messagesUiState

    fun getChannelMessages(subChannelId: String) {
        messagesUiState =
            AmityChatClient.newMessageRepository().getMessages(subChannelId).includeDeleted(false)
                .build().query()
                .asFlow().cachedIn(viewModelScope)
                .map { ChatsUiState.Success(data = flowOf(it)) }
                .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5000), ChatsUiState.Loading)
    }
}

sealed interface ChatsUiState {
    object Loading : ChatsUiState
    data class Success(val data: Flow<PagingData<AmityMessage>>) : ChatsUiState
}

@Composable
fun StatefulMessagesParent(
    viewModel: ChannelDetailViewModel,
    subChannelId: String,
    modifier: Modifier
) {
    LaunchedEffect(key1 = subChannelId) {
        viewModel.getChannelMessages(subChannelId)
    }

    val lifecycle = LocalLifecycleOwner.current.lifecycle
    val uiState by produceState<ChatsUiState>(
        initialValue = ChatsUiState.Loading,
        key1 = lifecycle,
        key2 = viewModel
    ) {
        lifecycle.repeatOnLifecycle(state = Lifecycle.State.STARTED) {
            viewModel.messagesUiState.collect {
                value = it
            }
        }
    }

    if (uiState is ChatsUiState.Success) {
        val messages: LazyPagingItems<AmityMessage> =
            (uiState as ChatsUiState.Success).data.collectAsLazyPagingItems()
        MessagesParent(
            messages = messages,
            modifier = modifier
        )
    }
}

@Composable
fun MessagesParent(
    messages: LazyPagingItems<AmityMessage>,
    state: LazyListState = rememberLazyListState(),
    modifier: Modifier
) {
    LazyColumn(state = state, modifier = modifier, reverseLayout = true) {
        items(
            messages.itemCount,
            key = messages.itemKey { it.getMessageId() },
            contentType = messages.itemContentType { it.getDataType() }
        ) { index ->
            messages[index]?.let { message ->
                MessageCard(message)
            }
        }
    }
}