Improve loading both local and remote manga

app/src/main/kotlin/org/koitharu/kotatsu/core/model/Manga.kt

@@ -17,6 +17,8 @@ fun Collection<Manga>.distinctById() = distinctBy { it.id }
 @JvmName("chaptersIds")
 fun Collection<MangaChapter>.ids() = mapToSet { it.id }
 
+fun Collection<MangaChapter>.findById(id: Long) = find { x -> x.id == id }
+
 fun Collection<ChapterListItem>.countChaptersByBranch(): Int {
 	if (size <= 1) {
 		return size
@@ -30,7 +32,7 @@ fun Collection<ChapterListItem>.countChaptersByBranch(): Int {
 }
 
 fun Manga.findChapter(id: Long): MangaChapter? {
-	return chapters?.find { it.id == id }
+	return chapters?.findById(id)
 }
 
 fun Manga.getPreferredBranch(history: MangaHistory?): String? {
@@ -39,7 +41,7 @@ fun Manga.getPreferredBranch(history: MangaHistory?): String? {
 		return null
 	}
 	if (history != null) {
-		val currentChapter = ch.find { it.id == history.chapterId }
+		val currentChapter = ch.findById(history.chapterId)
 		if (currentChapter != null) {
 			return currentChapter.branch
 		}

app/src/main/kotlin/org/koitharu/kotatsu/core/util/ext/Flow.kt

@@ -5,6 +5,8 @@ import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.firstOrNull
 import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onCompletion
@@ -72,7 +74,7 @@ fun <T1, T2, T3, T4, T5, T6, R> combine(
 	flow4: Flow<T4>,
 	flow5: Flow<T5>,
 	flow6: Flow<T6>,
-	transform: suspend (T1, T2, T3, T4, T5, T6) -> R
+	transform: suspend (T1, T2, T3, T4, T5, T6) -> R,
 ): Flow<R> = combine(flow, flow2, flow3, flow4, flow5, flow6) { args: Array<*> ->
 	transform(
 		args[0] as T1,
@@ -83,3 +85,7 @@ fun <T1, T2, T3, T4, T5, T6, R> combine(
 		args[5] as T6,
 	)
 }
+
+suspend fun <T : Any> Flow<T?>.firstNotNull(): T = checkNotNull(first { x -> x != null })
+
+suspend fun <T : Any> Flow<T?>.firstNotNullOrNull(): T? = firstOrNull { x -> x != null }

app/src/main/kotlin/org/koitharu/kotatsu/core/util/ext/View.kt

@@ -8,10 +8,11 @@ import android.view.ViewGroup
 import android.view.ViewParent
 import android.view.inputmethod.InputMethodManager
 import android.widget.Checkable
-import android.widget.CompoundButton
 import androidx.core.view.children
+import androidx.core.view.isVisible
 import androidx.recyclerview.widget.RecyclerView
 import androidx.viewpager2.widget.ViewPager2
+import com.google.android.material.progressindicator.BaseProgressIndicator
 import com.google.android.material.slider.Slider
 import com.google.android.material.tabs.TabLayout
 import kotlin.math.roundToInt
@@ -155,3 +156,11 @@ fun TabLayout.setTabsEnabled(enabled: Boolean) {
 		getTabAt(i)?.view?.isEnabled = enabled
 	}
 }
+
+fun BaseProgressIndicator<*>.showOrHide(value: Boolean) {
+	if (value) {
+		if (!isVisible) show()
+	} else {
+		if (isVisible) hide()
+	}
+}

app/src/main/kotlin/org/koitharu/kotatsu/details/domain/DoubleMangaLoadUseCase.kt

@@ -1,8 +1,11 @@
 package org.koitharu.kotatsu.details.domain
 
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.async
-import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOn
 import org.koitharu.kotatsu.core.model.isLocal
 import org.koitharu.kotatsu.core.parser.MangaDataRepository
 import org.koitharu.kotatsu.core.parser.MangaIntent
@@ -23,24 +26,28 @@ class DoubleMangaLoadUseCase @Inject constructor(
 	private val recoverUseCase: RecoverMangaUseCase,
 ) {
 
-	suspend operator fun invoke(manga: Manga): DoubleManga = coroutineScope {
-		val remoteDeferred = async(Dispatchers.Default) { loadRemote(manga) }
-		val localDeferred = async(Dispatchers.Default) { loadLocal(manga) }
-		DoubleManga(
-			remoteManga = remoteDeferred.await(),
-			localManga = localDeferred.await(),
-		)
-	}
+	operator fun invoke(manga: Manga): Flow<DoubleManga> = flow<DoubleManga> {
+		var lastValue: DoubleManga? = null
+		var emitted = false
+		invokeImpl(manga).collect {
+			lastValue = it
+			if (it.any != null) {
+				emitted = true
+				emit(it)
+			}
+		}
+		if (!emitted) {
+			lastValue?.requireAny()
+		}
+	}.flowOn(Dispatchers.Default)
 
-	suspend operator fun invoke(mangaId: Long): DoubleManga {
-		val manga = mangaDataRepository.findMangaById(mangaId) ?: throwNFE()
-		return invoke(manga)
-	}
+	operator fun invoke(mangaId: Long): Flow<DoubleManga> = flow {
+		emit(mangaDataRepository.findMangaById(mangaId) ?: throwNFE())
+	}.flatMapLatest { invoke(it) }
 
-	suspend operator fun invoke(intent: MangaIntent): DoubleManga {
-		val manga = mangaDataRepository.resolveIntent(intent) ?: throwNFE()
-		return invoke(manga)
-	}
+	operator fun invoke(intent: MangaIntent): Flow<DoubleManga> = flow {
+		emit(mangaDataRepository.resolveIntent(intent) ?: throwNFE())
+	}.flatMapLatest { invoke(it) }
 
 	private suspend fun loadLocal(manga: Manga): Result<Manga>? {
 		return runCatchingCancellable {
@@ -70,5 +77,15 @@ class DoubleMangaLoadUseCase @Inject constructor(
 		}
 	}
 
+	private fun invokeImpl(manga: Manga): Flow<DoubleManga> = combine(
+		flow { emit(null); emit(loadRemote(manga)) },
+		flow { emit(null); emit(loadLocal(manga)) },
+	) { remote, local ->
+		DoubleManga(
+			remoteManga = remote,
+			localManga = local,
+		)
+	}
+
 	private fun throwNFE(): Nothing = throw NotFoundException("Cannot find manga", "")
 }

app/src/main/kotlin/org/koitharu/kotatsu/details/domain/model/DoubleManga.kt

@@ -1,5 +1,6 @@
 package org.koitharu.kotatsu.details.domain.model
 
+import org.koitharu.kotatsu.core.model.findById
 import org.koitharu.kotatsu.parsers.model.Manga
 import org.koitharu.kotatsu.parsers.model.MangaChapter
 import org.koitharu.kotatsu.parsers.model.MangaSource
@@ -34,6 +35,10 @@ data class DoubleManga(
 		mergeChapters()
 	}
 
+	fun hasChapter(id: Long): Boolean {
+		return local?.chapters?.findById(id) != null || remote?.chapters?.findById(id) != null
+	}
+
 	fun requireAny(): Manga {
 		val result = remoteManga?.getOrNull() ?: localManga?.getOrNull()
 		if (result != null) {

app/src/main/kotlin/org/koitharu/kotatsu/details/service/MangaPrefetchService.kt

@@ -5,6 +5,7 @@ import android.content.Intent
 import dagger.hilt.android.AndroidEntryPoint
 import dagger.hilt.android.EntryPointAccessors
 import org.koitharu.kotatsu.core.cache.ContentCache
+import org.koitharu.kotatsu.core.model.findById
 import org.koitharu.kotatsu.core.model.parcelable.ParcelableChapter
 import org.koitharu.kotatsu.core.model.parcelable.ParcelableManga
 import org.koitharu.kotatsu.core.parser.MangaRepository
@@ -72,7 +73,7 @@ class MangaPrefetchService : CoroutineIntentService() {
 		val chapter = if (history == null) {
 			chapters.firstOrNull()
 		} else {
-			chapters.find { x -> x.id == history.chapterId } ?: chapters.firstOrNull()
+			chapters.findById(history.chapterId) ?: chapters.firstOrNull()
 		} ?: return
 		runCatchingCancellable { repo.getPages(chapter) }
 	}
@@ -122,7 +123,7 @@ class MangaPrefetchService : CoroutineIntentService() {
 			}
 			val entryPoint = EntryPointAccessors.fromApplication(
 				context,
-				PrefetchCompanionEntryPoint::class.java
+				PrefetchCompanionEntryPoint::class.java,
 			)
 			return entryPoint.contentCache.isCachingEnabled && entryPoint.settings.isContentPrefetchEnabled
 		}

app/src/main/kotlin/org/koitharu/kotatsu/details/ui/DetailsFragment.kt

@@ -43,6 +43,7 @@ import org.koitharu.kotatsu.core.util.ext.observe
 import org.koitharu.kotatsu.core.util.ext.parentView
 import org.koitharu.kotatsu.core.util.ext.resolveDp
 import org.koitharu.kotatsu.core.util.ext.scaleUpActivityOptionsOf
+import org.koitharu.kotatsu.core.util.ext.showOrHide
 import org.koitharu.kotatsu.core.util.ext.textAndVisible
 import org.koitharu.kotatsu.databinding.FragmentDetailsBinding
 import org.koitharu.kotatsu.details.ui.model.ChapterListItem
@@ -247,11 +248,7 @@ class DetailsFragment :
 	}
 
 	private fun onLoadingStateChanged(isLoading: Boolean) {
-		if (isLoading) {
-			requireViewBinding().progressBar.show()
-		} else {
-			requireViewBinding().progressBar.hide()
-		}
+		requireViewBinding().progressBar.showOrHide(isLoading)
 	}
 
 	private fun onBookmarksChanged(bookmarks: List<Bookmark>) {

app/src/main/kotlin/org/koitharu/kotatsu/details/ui/DetailsViewModel.kt

@@ -42,6 +42,7 @@ import org.koitharu.kotatsu.core.util.ext.MutableEventFlow
 import org.koitharu.kotatsu.core.util.ext.call
 import org.koitharu.kotatsu.core.util.ext.combine
 import org.koitharu.kotatsu.core.util.ext.computeSize
+import org.koitharu.kotatsu.core.util.ext.onFirst
 import org.koitharu.kotatsu.core.util.ext.requireValue
 import org.koitharu.kotatsu.core.util.ext.sanitize
 import org.koitharu.kotatsu.core.util.ext.toFileOrNull
@@ -87,7 +88,8 @@ class DetailsViewModel @Inject constructor(
 
 	private val intent = MangaIntent(savedStateHandle)
 	private val mangaId = intent.mangaId
-	private val doubleManga: MutableStateFlow<DoubleManga?> = MutableStateFlow(intent.manga?.let { DoubleManga(it) })
+	private val doubleManga: MutableStateFlow<DoubleManga?> =
+		MutableStateFlow(intent.manga?.let { DoubleManga(it) })
 	private var loadingJob: Job
 
 	val onShowToast = MutableEventFlow<Int>()
@@ -202,7 +204,14 @@ class DetailsViewModel @Inject constructor(
 			bookmarks,
 			networkState,
 		) { manga, history, branch, news, bookmarks, isOnline ->
-			mapChapters(manga?.remote?.takeIf { isOnline }, manga?.local, history, news, branch, bookmarks)
+			mapChapters(
+				manga?.remote?.takeIf { isOnline },
+				manga?.local,
+				history,
+				news,
+				branch,
+				bookmarks,
+			)
 		},
 		isChaptersReversed,
 		chaptersQuery,
@@ -324,12 +333,15 @@ class DetailsViewModel @Inject constructor(
 	}
 
 	private fun doLoad() = launchLoadingJob(Dispatchers.Default) {
-		val result = doubleMangaLoadUseCase(intent)
-		val manga = result.requireAny()
-		// find default branch
-		val hist = historyRepository.getOne(manga)
-		selectedBranch.value = manga.getPreferredBranch(hist)
-		doubleManga.value = result
+		doubleMangaLoadUseCase.invoke(intent)
+			.onFirst {
+				val manga = it.requireAny()
+				// find default branch
+				val hist = historyRepository.getOne(manga)
+				selectedBranch.value = manga.getPreferredBranch(hist)
+			}.collect {
+				doubleManga.value = it
+			}
 	}
 
 	private fun List<ChapterListItem>.filterSearch(query: String): List<ChapterListItem> {

app/src/main/kotlin/org/koitharu/kotatsu/history/data/HistoryRepository.kt

@@ -14,6 +14,7 @@ import org.koitharu.kotatsu.core.db.entity.toManga
 import org.koitharu.kotatsu.core.db.entity.toMangaTag
 import org.koitharu.kotatsu.core.db.entity.toMangaTags
 import org.koitharu.kotatsu.core.model.MangaHistory
+import org.koitharu.kotatsu.core.model.findById
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.core.ui.util.ReversibleHandle
 import org.koitharu.kotatsu.core.util.ext.mapItems
@@ -107,7 +108,7 @@ class HistoryRepository @Inject constructor(
 				),
 			)
 			trackingRepository.syncWithHistory(manga, chapterId)
-			val chapter = manga.chapters?.find { x -> x.id == chapterId }
+			val chapter = manga.chapters?.findById(chapterId)
 			if (chapter != null) {
 				scrobblers.forEach { it.tryScrobble(manga.id, chapter) }
 			}
@@ -181,7 +182,7 @@ class HistoryRepository @Inject constructor(
 
 	private suspend fun HistoryEntity.recoverIfNeeded(manga: Manga): HistoryEntity {
 		val chapters = manga.chapters
-		if (chapters.isNullOrEmpty() || chapters.any { it.id == chapterId }) {
+		if (chapters.isNullOrEmpty() || chapters.findById(chapterId) != null) {
 			return this
 		}
 		val newChapterId = chapters.getOrNull(

app/src/main/kotlin/org/koitharu/kotatsu/local/data/output/LocalMangaDirOutput.kt

@@ -2,6 +2,7 @@ package org.koitharu.kotatsu.local.data.output
 
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.runInterruptible
+import org.koitharu.kotatsu.core.model.findById
 import org.koitharu.kotatsu.core.util.ext.deleteAwait
 import org.koitharu.kotatsu.core.util.ext.takeIfReadable
 import org.koitharu.kotatsu.core.zip.ZipOutput
@@ -87,7 +88,7 @@ class LocalMangaDirOutput(
 	suspend fun deleteChapter(chapterId: Long) {
 		val chapter = checkNotNull(index.getMangaInfo()?.chapters) {
 			"No chapters found"
-		}.first { it.id == chapterId }
+		}.findById(chapterId) ?: error("Chapter not found")
 		val chapterDir = File(rootFile, chapterFileName(chapter))
 		chapterDir.deleteAwait()
 		index.removeChapter(chapterId)

app/src/main/kotlin/org/koitharu/kotatsu/main/domain/CoverRestoreInterceptor.kt

@@ -8,6 +8,7 @@ import coil.request.ImageResult
 import org.jsoup.HttpStatusException
 import org.koitharu.kotatsu.bookmarks.domain.Bookmark
 import org.koitharu.kotatsu.bookmarks.domain.BookmarksRepository
+import org.koitharu.kotatsu.core.model.findById
 import org.koitharu.kotatsu.core.parser.MangaDataRepository
 import org.koitharu.kotatsu.core.parser.MangaRepository
 import org.koitharu.kotatsu.core.parser.RemoteMangaRepository
@@ -92,7 +93,7 @@ class CoverRestoreInterceptor @Inject constructor(
 
 	private suspend fun restoreBookmarkImpl(bookmark: Bookmark): Boolean {
 		val repo = repositoryFactory.create(bookmark.manga.source) as? RemoteMangaRepository ?: return false
-		val chapter = repo.getDetails(bookmark.manga).chapters?.find { it.id == bookmark.chapterId } ?: return false
+		val chapter = repo.getDetails(bookmark.manga).chapters?.findById(bookmark.chapterId) ?: return false
 		val page = repo.getPages(chapter)[bookmark.page]
 		val imageUrl = page.preview.ifNullOrEmpty { page.url }
 		return if (imageUrl != bookmark.imageUrl) {

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? {

app/src/main/kotlin/org/koitharu/kotatsu/scrobbling/common/ui/config/ScrobblerConfigActivity.kt

@@ -19,6 +19,7 @@ import org.koitharu.kotatsu.core.util.ext.enqueueWith
 import org.koitharu.kotatsu.core.util.ext.newImageRequest
 import org.koitharu.kotatsu.core.util.ext.observe
 import org.koitharu.kotatsu.core.util.ext.observeEvent
+import org.koitharu.kotatsu.core.util.ext.showOrHide
 import org.koitharu.kotatsu.databinding.ActivityScrobblerConfigBinding
 import org.koitharu.kotatsu.details.ui.DetailsActivity
 import org.koitharu.kotatsu.list.ui.adapter.TypedListSpacingDecoration
@@ -115,13 +116,7 @@ class ScrobblerConfigActivity : BaseActivity<ActivityScrobblerConfigBinding>(),
 	}
 
 	private fun onLoadingStateChanged(isLoading: Boolean) {
-		viewBinding.progressBar.run {
-			if (isLoading) {
-				show()
-			} else {
-				hide()
-			}
-		}
+		viewBinding.progressBar.showOrHide(isLoading)
 	}
 
 	private fun showUserDialog() {

app/src/main/res/layout/sheet_pages.xml

@@ -14,7 +14,8 @@
 
 	<FrameLayout
 		android:layout_width="match_parent"
-		android:layout_height="match_parent">
+		android:layout_height="match_parent"
+		android:minHeight="240dp">
 
 		<org.koitharu.kotatsu.core.ui.list.fastscroll.FastScrollRecyclerView
 			android:id="@+id/recyclerView"
@@ -29,6 +30,19 @@
 			tools:listitem="@layout/item_page_thumb"
 			tools:targetApi="m" />
 
+		<com.google.android.material.progressindicator.LinearProgressIndicator
+			android:id="@+id/progressBar"
+			android:layout_width="match_parent"
+			android:layout_height="wrap_content"
+			android:layout_gravity="top"
+			android:indeterminate="true"
+			android:visibility="gone"
+			app:hideAnimationBehavior="outward"
+			app:showAnimationBehavior="inward"
+			app:trackCornerRadius="0dp"
+			app:trackThickness="2dp"
+			tools:visibility="visible" />
+
 	</FrameLayout>
 
 </LinearLayout>