Support for partial fetches (for paginated APIs) about store HOT 1 OPEN

class FeedPager constructor(val singlePageStore: ThreadStore) {
  val page = AtomicInteger(-1)

  fun nextPage(): Single<List<Thread>> {
    Timber.e("getting page ${page.get() + 1}")
    return singlePageStore.get(page.incrementAndGet())
  }

  fun allCurrentPages() = Observable
      .range(0, page.get() + 1)
      .concatMapEager({
        singlePageStore.get(it)
            .toObservable()
      }, 10, 10)
      .toList()
      .map { it.flatten() }
  //refresh calls store.clear then store.fetch so that we clear the memory cache
  fun refresh(): Single<List<Thread>> {
    return singlePageStore.refresh()
        .doOnSubscribe { page.set(0) }
  }
}