loadTrending.kt

fun <A : ListAction> Observable<ActionState<A, ListState>>.loadTrending(
    mode: ListState.Mode,
    offset: Int = 0,
    limit: Int = 10,
    listStateFunction: (ListState.Screen, List<GiphyItem>) -> ListState.Screen
): Observable<ListState> = this
    .map { it.state as ListState.Screen }
    .flatMap { state ->
        repository.getTrending(offset, limit)
            .map { giphies ->
                val items = giphies.map { it.mapToItem() }
                listStateFunction(state, items)
            }
            .startWith(state.copy(loadingMode = mode))
    }
    .ofType(ListState::class.java)
    .onErrorReturn {
        Timber.e(it, "Error loading gifs")
        ListState.Error(R.string.error_loading)
    }
    .applySchedulers()