Improve loading both local and remote manga

app/src/main/kotlin/org/koitharu/kotatsu/reader/domain/ChaptersLoader.kt

@@ -2,6 +2,12 @@ package org.koitharu.kotatsu.reader.domain
 
 import android.util.LongSparseArray
 import dagger.hilt.android.scopes.ViewModelScoped
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.firstOrNull
+import kotlinx.coroutines.flow.mapNotNull
+import kotlinx.coroutines.launch
 import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
 import org.koitharu.kotatsu.core.parser.MangaRepository
@@ -17,24 +23,32 @@ class ChaptersLoader @Inject constructor(
 	private val mangaRepositoryFactory: MangaRepository.Factory,
 ) {
 
-	private val chapters = LongSparseArray<MangaChapter>()
+	private val chapters = MutableStateFlow(LongSparseArray<MangaChapter>(0))
 	private val chapterPages = ChapterPages()
 	private val mutex = Mutex()
 
-	val size: Int
-		get() = chapters.size()
+	val size: Int // TODO flow
+		get() = chapters.value.size()
 
-	suspend fun init(manga: DoubleManga) = mutex.withLock {
-		chapters.clear()
-		manga.chapters?.forEach {
-			chapters.put(it.id, it)
+	fun init(scope: CoroutineScope, manga: Flow<DoubleManga>) = scope.launch {
+		manga.collect {
+			val ch = it.chapters.orEmpty()
+			val longSparseArray = LongSparseArray<MangaChapter>(ch.size)
+			ch.forEach { x -> longSparseArray.put(x.id, x) }
+			mutex.withLock {
+				chapters.value = longSparseArray
+			}
 		}
 	}
 
 	suspend fun loadPrevNextChapter(manga: DoubleManga, currentId: Long, isNext: Boolean) {
 		val chapters = manga.chapters ?: return
 		val predicate: (MangaChapter) -> Boolean = { it.id == currentId }
-		val index = if (isNext) chapters.indexOfFirst(predicate) else chapters.indexOfLast(predicate)
+		val index = if (isNext) {
+			chapters.indexOfFirst(predicate)
+		} else {
+			chapters.indexOfLast(predicate)
+		}
 		if (index == -1) return
 		val newChapter = chapters.getOrNull(if (isNext) index + 1 else index - 1) ?: return
 		val newPages = loadChapter(newChapter.id)
@@ -65,7 +79,11 @@ class ChaptersLoader @Inject constructor(
 		}
 	}
 
-	fun peekChapter(chapterId: Long): MangaChapter? = chapters[chapterId]
+	fun peekChapter(chapterId: Long): MangaChapter? = chapters.value[chapterId]
+
+	suspend fun awaitChapter(chapterId: Long): MangaChapter? = chapters.mapNotNull { x ->
+		x[chapterId]
+	}.firstOrNull()
 
 	fun getPages(chapterId: Long): List<ReaderPage> {
 		return chapterPages.subList(chapterId)
@@ -82,7 +100,7 @@ class ChaptersLoader @Inject constructor(
 	fun snapshot() = chapterPages.toList()
 
 	private suspend fun loadChapter(chapterId: Long): List<ReaderPage> {
-		val chapter = checkNotNull(chapters[chapterId]) { "Requested chapter not found" }
+		val chapter = checkNotNull(awaitChapter(chapterId)) { "Requested chapter not found" }
 		val repo = mangaRepositoryFactory.create(chapter.source)
 		return repo.getPages(chapter).mapIndexed { index, page ->
 			ReaderPage(page, index, chapterId)

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/ReaderViewModel.kt

@@ -87,7 +87,8 @@ class ReaderViewModel @Inject constructor(
 	private var pageSaveJob: Job? = null
 	private var bookmarkJob: Job? = null
 	private var stateChangeJob: Job? = null
-	private val currentState = MutableStateFlow<ReaderState?>(savedStateHandle[ReaderActivity.EXTRA_STATE])
+	private val currentState =
+		MutableStateFlow<ReaderState?>(savedStateHandle[ReaderActivity.EXTRA_STATE])
 	private val mangaData = MutableStateFlow(intent.manga?.let { DoubleManga(it) })
 	private val mangaFlow: Flow<Manga?>
 		get() = mangaData.map { it?.any }
@@ -317,8 +318,9 @@ class ReaderViewModel @Inject constructor(
 					?: throw NotFoundException("Cannot find manga", ""),
 			)
 			mangaData.value = manga
-			manga = doubleMangaLoadUseCase(intent)
-			chaptersLoader.init(manga)
+			val mangaFlow = doubleMangaLoadUseCase(intent)
+			manga = mangaFlow.first { x -> x.any != null }
+			chaptersLoader.init(viewModelScope, mangaFlow)
 			// determine mode
 			val singleManga = manga.requireAny()
 			// obtain state
@@ -328,7 +330,7 @@ class ReaderViewModel @Inject constructor(
 				} ?: ReaderState(singleManga, preselectedBranch)
 			}
 			val mode = detectReaderModeUseCase.invoke(singleManga, currentState.value)
-			val branch = chaptersLoader.peekChapter(currentState.value?.chapterId ?: 0L)?.branch
+			val branch = chaptersLoader.awaitChapter(currentState.value?.chapterId ?: 0L)?.branch
 			mangaData.value = manga.filterChapters(branch)
 			readerMode.value = mode
 

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/thumbnails/PagesThumbnailsSheet.kt

@@ -24,6 +24,7 @@ import org.koitharu.kotatsu.core.util.ext.observe
 import org.koitharu.kotatsu.core.util.ext.observeEvent
 import org.koitharu.kotatsu.core.util.ext.plus
 import org.koitharu.kotatsu.core.util.ext.showDistinct
+import org.koitharu.kotatsu.core.util.ext.showOrHide
 import org.koitharu.kotatsu.core.util.ext.withArgs
 import org.koitharu.kotatsu.databinding.SheetPagesBinding
 import org.koitharu.kotatsu.list.ui.MangaListSpanResolver
@@ -84,6 +85,7 @@ class PagesThumbnailsSheet :
 		viewModel.thumbnails.observe(viewLifecycleOwner, ::onThumbnailsChanged)
 		viewModel.branch.observe(viewLifecycleOwner, ::updateTitle)
 		viewModel.onError.observeEvent(viewLifecycleOwner, SnackbarErrorObserver(binding.recyclerView, this))
+		viewModel.isLoading.observe(viewLifecycleOwner) { binding.progressBar.showOrHide(it) }
 	}
 
 	override fun onDestroyView() {

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/thumbnails/PagesThumbnailsViewModel.kt

@@ -1,19 +1,26 @@
 package org.koitharu.kotatsu.reader.ui.thumbnails
 
 import androidx.lifecycle.SavedStateHandle
+import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.filterNotNull
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.stateIn
+import org.koitharu.kotatsu.core.model.findById
 import org.koitharu.kotatsu.core.model.parcelable.ParcelableManga
 import org.koitharu.kotatsu.core.parser.MangaRepository
 import org.koitharu.kotatsu.core.ui.BaseViewModel
+import org.koitharu.kotatsu.core.util.ext.firstNotNull
+import org.koitharu.kotatsu.core.util.ext.firstNotNullOrNull
 import org.koitharu.kotatsu.core.util.ext.require
 import org.koitharu.kotatsu.details.domain.DoubleMangaLoadUseCase
 import org.koitharu.kotatsu.list.ui.model.ListHeader
 import org.koitharu.kotatsu.list.ui.model.ListModel
-import org.koitharu.kotatsu.list.ui.model.LoadingFooter
-import org.koitharu.kotatsu.parsers.util.SuspendLazy
 import org.koitharu.kotatsu.reader.domain.ChaptersLoader
 import javax.inject.Inject
 
@@ -30,13 +37,12 @@ class PagesThumbnailsViewModel @Inject constructor(
 	val manga = savedStateHandle.require<ParcelableManga>(PagesThumbnailsSheet.ARG_MANGA).manga
 
 	private val repository = mangaRepositoryFactory.create(manga.source)
-	private val mangaDetails = SuspendLazy {
-		doubleMangaLoadUseCase(manga).let {
-			val b = manga.chapters?.find { ch -> ch.id == initialChapterId }?.branch
-			branch.value = b
-			it.filterChapters(b)
-		}
-	}
+	private val mangaDetails = doubleMangaLoadUseCase(manga).map {
+		val b = manga.chapters?.findById(initialChapterId)?.branch
+		branch.value = b
+		it.filterChapters(b)
+	}.withErrorHandling()
+		.stateIn(viewModelScope, SharingStarted.Lazily, null)
 	private var loadingJob: Job? = null
 	private var loadingPrevJob: Job? = null
 	private var loadingNextJob: Job? = null
@@ -46,8 +52,9 @@ class PagesThumbnailsViewModel @Inject constructor(
 	val branch = MutableStateFlow<String?>(null)
 
 	init {
-		loadingJob = launchJob(Dispatchers.Default) {
-			chaptersLoader.init(mangaDetails.get())
+		loadingJob = launchLoadingJob(Dispatchers.Default) {
+			chaptersLoader.init(viewModelScope, mangaDetails.filterNotNull())
+			mangaDetails.first { x -> x?.hasChapter(initialChapterId) == true }
 			chaptersLoader.loadSingleChapter(initialChapterId)
 			updateList()
 		}
@@ -55,7 +62,7 @@ class PagesThumbnailsViewModel @Inject constructor(
 
 	fun allowLoadAbove() {
 		if (!isLoadAboveAllowed) {
-			loadingJob = launchJob(Dispatchers.Default) {
+			loadingJob = launchLoadingJob(Dispatchers.Default) {
 				isLoadAboveAllowed = true
 				updateList()
 			}
@@ -78,23 +85,18 @@ class PagesThumbnailsViewModel @Inject constructor(
 
 	private fun loadPrevNextChapter(isNext: Boolean): Job = launchLoadingJob(Dispatchers.Default) {
 		val currentId = (if (isNext) chaptersLoader.last() else chaptersLoader.first()).chapterId
-		chaptersLoader.loadPrevNextChapter(mangaDetails.get(), currentId, isNext)
+		chaptersLoader.loadPrevNextChapter(mangaDetails.firstNotNull(), currentId, isNext)
 		updateList()
 	}
 
 	private suspend fun updateList() {
 		val snapshot = chaptersLoader.snapshot()
-		val mangaChapters = mangaDetails.tryGet().getOrNull()?.chapters.orEmpty()
-		val hasPrevChapter = isLoadAboveAllowed && snapshot.firstOrNull()?.chapterId != mangaChapters.firstOrNull()?.id
-		val hasNextChapter = snapshot.lastOrNull()?.chapterId != mangaChapters.lastOrNull()?.id
+		val mangaChapters = mangaDetails.firstNotNullOrNull()?.chapters.orEmpty()
 		val pages = buildList(snapshot.size + chaptersLoader.size + 2) {
-			if (hasPrevChapter) {
-				add(LoadingFooter(-1))
-			}
 			var previousChapterId = 0L
 			for (page in snapshot) {
 				if (page.chapterId != previousChapterId) {
-					chaptersLoader.peekChapter(page.chapterId)?.let {
+					chaptersLoader.awaitChapter(page.chapterId)?.let {
 						add(ListHeader(it.name))
 					}
 					previousChapterId = page.chapterId
@@ -105,9 +107,6 @@ class PagesThumbnailsViewModel @Inject constructor(
 					page = page,
 				)
 			}
-			if (hasNextChapter) {
-				add(LoadingFooter(1))
-			}
 		}
 		thumbnails.value = pages
 	}

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/thumbnails/adapter/PageThumbnailAdapter.kt

@@ -8,7 +8,6 @@ import org.koitharu.kotatsu.core.ui.list.OnListItemClickListener
 import org.koitharu.kotatsu.core.ui.list.fastscroll.FastScroller
 import org.koitharu.kotatsu.list.ui.adapter.ListItemType
 import org.koitharu.kotatsu.list.ui.adapter.listHeaderAD
-import org.koitharu.kotatsu.list.ui.adapter.loadingFooterAD
 import org.koitharu.kotatsu.list.ui.model.ListHeader
 import org.koitharu.kotatsu.list.ui.model.ListModel
 import org.koitharu.kotatsu.reader.ui.thumbnails.PageThumbnail
@@ -22,7 +21,6 @@ class PageThumbnailAdapter(
 	init {
 		addDelegate(ListItemType.PAGE_THUMB, pageThumbnailAD(coil, lifecycleOwner, clickListener))
 		addDelegate(ListItemType.HEADER, listHeaderAD(null))
-		addDelegate(ListItemType.FOOTER_LOADING, loadingFooterAD())
 	}
 
 	override fun getSectionText(context: Context, position: Int): CharSequence? {