WorkoutSummaryController.kt

class WorkoutSummaryController : TypedEpoxyController<WorkoutSummaryViewState>(
    EpoxyAsyncUtil.getAsyncBackgroundHandler(),
    EpoxyAsyncUtil.getAsyncBackgroundHandler()) {

    override fun buildModels(viewState: WorkoutSummaryViewState) {
        addLikes(viewState)
        
        addLoadingIndicatorIfNeed(viewState)
    }

    private fun addLikes(viewState: WorkoutSummaryViewState) {
        val likesItem = viewState.likesItem.data
        // We verify that the state is loaded, we can use the state to show a loading indicator
        // only for this item if we want
        if (viewState.likesItem is ViewState.Loaded && likesItem != null) {
            likes {
                id("likes")
                likesItem(likesItem)
                onLikeClicked { model, _, _, _ ->
                    model.likesItem().onClickHandler(viewState.workoutId)
                }
            }
        } else if (viewState.likesItem is ViewState.Error) {
            // Instead of adding the likes item, we can use the state of the item to add
            // a generic error item instead
            addErrorItem(/* pass here some data to decide the message */)
        }
    }
}