Show not downloaded chapters in local manga

app/src/main/java/org/koitharu/kotatsu/details/ui/ChaptersFragment.kt

@@ -15,7 +15,6 @@ import org.koin.androidx.viewmodel.ext.android.sharedViewModel
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.base.ui.BaseFragment
 import org.koitharu.kotatsu.base.ui.list.OnListItemClickListener
-import org.koitharu.kotatsu.core.model.MangaChapter
 import org.koitharu.kotatsu.core.model.MangaSource
 import org.koitharu.kotatsu.databinding.FragmentChaptersBinding
 import org.koitharu.kotatsu.details.ui.adapter.BranchesAdapter
@@ -27,7 +26,9 @@ import org.koitharu.kotatsu.reader.ui.ReaderActivity
 import org.koitharu.kotatsu.reader.ui.ReaderState
 
 class ChaptersFragment : BaseFragment<FragmentChaptersBinding>(),
-	OnListItemClickListener<MangaChapter>, ActionMode.Callback, AdapterView.OnItemSelectedListener {
+	OnListItemClickListener<ChapterListItem>,
+	ActionMode.Callback,
+	AdapterView.OnItemSelectedListener {
 
 	private val viewModel by sharedViewModel<DetailsViewModel>()
 
@@ -105,9 +106,9 @@ class ChaptersFragment : BaseFragment<FragmentChaptersBinding>(),
 		else -> super.onOptionsItemSelected(item)
 	}
 
-	override fun onItemClick(item: MangaChapter, view: View) {
+	override fun onItemClick(item: ChapterListItem, view: View) {
 		if (selectionDecoration?.checkedItemsCount != 0) {
-			selectionDecoration?.toggleItemChecked(item.id)
+			selectionDecoration?.toggleItemChecked(item.chapter.id)
 			if (selectionDecoration?.checkedItemsCount == 0) {
 				actionMode?.finish()
 			} else {
@@ -116,6 +117,10 @@ class ChaptersFragment : BaseFragment<FragmentChaptersBinding>(),
 			}
 			return
 		}
+		if (item.isMissing) {
+			(activity as? DetailsActivity)?.showChapterMissingDialog(item.chapter.id)
+			return
+		}
 		val options = ActivityOptions.makeScaleUpAnimation(
 			view,
 			0,
@@ -127,17 +132,17 @@ class ChaptersFragment : BaseFragment<FragmentChaptersBinding>(),
 			ReaderActivity.newIntent(
 				view.context,
 				viewModel.manga.value ?: return,
-				ReaderState(item.id, 0, 0)
+				ReaderState(item.chapter.id, 0, 0)
 			), options.toBundle()
 		)
 	}
 
-	override fun onItemLongClick(item: MangaChapter, view: View): Boolean {
+	override fun onItemLongClick(item: ChapterListItem, view: View): Boolean {
 		if (actionMode == null) {
 			actionMode = (activity as? AppCompatActivity)?.startSupportActionMode(this)
 		}
 		return actionMode?.also {
-			selectionDecoration?.setItemIsChecked(item.id, true)
+			selectionDecoration?.setItemIsChecked(item.chapter.id, true)
 			binding.recyclerViewChapters.invalidateItemDecorations()
 			it.invalidate()
 		} != null
@@ -148,7 +153,7 @@ class ChaptersFragment : BaseFragment<FragmentChaptersBinding>(),
 			R.id.action_save -> {
 				DownloadService.start(
 					context ?: return false,
-					viewModel.manga.value ?: return false,
+					viewModel.getRemoteManga() ?: viewModel.manga.value ?: return false,
 					selectionDecoration?.checkedItemsIds
 				)
 				mode.finish()
@@ -174,17 +179,20 @@ class ChaptersFragment : BaseFragment<FragmentChaptersBinding>(),
 	override fun onCreateActionMode(mode: ActionMode, menu: Menu): Boolean {
 		val manga = viewModel.manga.value
 		mode.menuInflater.inflate(R.menu.mode_chapters, menu)
-		menu.findItem(R.id.action_save).isVisible = manga?.source != MangaSource.LOCAL
 		mode.title = manga?.title
 		return true
 	}
 
 	override fun onPrepareActionMode(mode: ActionMode, menu: Menu): Boolean {
-		val count = selectionDecoration?.checkedItemsCount ?: return false
+		val selectedIds = selectionDecoration?.checkedItemsIds ?: return false
+		val items = chaptersAdapter?.items?.filter { x -> x.chapter.id in selectedIds }.orEmpty()
+		menu.findItem(R.id.action_save).isVisible = items.none { x ->
+			x.chapter.source == MangaSource.LOCAL
+		}
 		mode.subtitle = resources.getQuantityString(
 			R.plurals.chapters_from_x,
-			count,
+			items.size,
-			count,
+			items.size,
 			chaptersAdapter?.itemCount ?: 0
 		)
 		return true

app/src/main/java/org/koitharu/kotatsu/details/ui/DetailsActivity.kt

@@ -34,8 +34,11 @@ import org.koitharu.kotatsu.core.model.MangaSource
 import org.koitharu.kotatsu.core.os.ShortcutsRepository
 import org.koitharu.kotatsu.databinding.ActivityDetailsBinding
 import org.koitharu.kotatsu.download.ui.service.DownloadService
+import org.koitharu.kotatsu.reader.ui.ReaderActivity
+import org.koitharu.kotatsu.reader.ui.ReaderState
 import org.koitharu.kotatsu.search.ui.global.GlobalSearchActivity
 import org.koitharu.kotatsu.utils.ShareHelper
+import org.koitharu.kotatsu.utils.ext.buildAlertDialog
 import org.koitharu.kotatsu.utils.ext.getDisplayMessage
 
 class DetailsActivity : BaseActivity<ActivityDetailsBinding>(),
@@ -228,6 +231,33 @@ class DetailsActivity : BaseActivity<ActivityDetailsBinding>(),
 		binding.pager.isUserInputEnabled = true
 	}
 
+	fun showChapterMissingDialog(chapterId: Long) {
+		val remoteManga = viewModel.getRemoteManga()
+		if (remoteManga == null) {
+			Snackbar.make(binding.pager, R.string.chapter_is_missing, Snackbar.LENGTH_LONG)
+				.show()
+			return
+		}
+		buildAlertDialog(this) {
+			setMessage(R.string.chapter_is_missing_text)
+			setTitle(R.string.chapter_is_missing)
+			setNegativeButton(android.R.string.cancel, null)
+			setPositiveButton(R.string.read) { _, _ ->
+				startActivity(
+					ReaderActivity.newIntent(
+						this@DetailsActivity,
+						remoteManga,
+						ReaderState(chapterId, 0, 0)
+					)
+				)
+			}
+			setNeutralButton(R.string.download) { _, _ ->
+				DownloadService.start(this@DetailsActivity, remoteManga, setOf(chapterId))
+			}
+			setCancelable(true)
+		}.show()
+	}
+
 	companion object {
 
 		const val ACTION_MANGA_VIEW = "${BuildConfig.APPLICATION_ID}.action.VIEW_MANGA"

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

@@ -128,23 +128,32 @@ class DetailsFragment : BaseFragment<FragmentDetailsBinding>(), View.OnClickList
 	}
 
 	private fun onLoadingStateChanged(isLoading: Boolean) {
-		binding.progressBar.isVisible = isLoading
+		if (isLoading) {
+			binding.progressBar.show()
+		} else {
+			binding.progressBar.hide()
+		}
 	}
 
 	override fun onClick(v: View) {
-		val manga = viewModel.manga.value
+		val manga = viewModel.manga.value ?: return
 		when (v.id) {
 			R.id.button_favorite -> {
-				FavouriteCategoriesDialog.show(childFragmentManager, manga ?: return)
+				FavouriteCategoriesDialog.show(childFragmentManager, manga)
 			}
 			R.id.button_read -> {
-				startActivity(
+				val chapterId = viewModel.readingHistory.value?.chapterId
-					ReaderActivity.newIntent(
+				if (chapterId != null && manga.chapters?.none { x -> x.id == chapterId } == true) {
-						context ?: return,
+					(activity as? DetailsActivity)?.showChapterMissingDialog(chapterId)
-						manga ?: return,
+				} else {
-						null
+					startActivity(
+						ReaderActivity.newIntent(
+							context ?: return,
+							manga,
+							null
+						)
 					)
-				)
+				}
 			}
 		}
 	}

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

@@ -11,7 +11,11 @@ import org.koitharu.kotatsu.base.domain.MangaIntent
 import org.koitharu.kotatsu.base.ui.BaseViewModel
 import org.koitharu.kotatsu.core.exceptions.MangaNotFoundException
 import org.koitharu.kotatsu.core.model.Manga
+import org.koitharu.kotatsu.core.model.MangaChapter
+import org.koitharu.kotatsu.core.model.MangaSource
+import org.koitharu.kotatsu.core.parser.MangaRepository
 import org.koitharu.kotatsu.core.prefs.AppSettings
+import org.koitharu.kotatsu.details.ui.model.ChapterListItem
 import org.koitharu.kotatsu.details.ui.model.toListItem
 import org.koitharu.kotatsu.favourites.domain.FavouritesRepository
 import org.koitharu.kotatsu.history.domain.ChapterExtra
@@ -29,7 +33,7 @@ class DetailsViewModel(
 	private val localMangaRepository: LocalMangaRepository,
 	private val trackingRepository: TrackingRepository,
 	private val mangaDataRepository: MangaDataRepository,
-	private val settings: AppSettings
+	private val settings: AppSettings,
 ) : BaseViewModel() {
 
 	private val mangaData = MutableStateFlow<Manga?>(intent.manga)
@@ -53,6 +57,18 @@ class DetailsViewModel(
 			trackingRepository.getNewChaptersCount(mangaId)
 		}.stateIn(viewModelScope + Dispatchers.Default, SharingStarted.Eagerly, 0)
 
+	private val remoteManga = MutableStateFlow<Manga?>(null)
+	/*private val remoteManga = mangaData.mapLatest {
+		if (it?.source == MangaSource.LOCAL) {
+			runCatching {
+				val m = localMangaRepository.getRemoteManga(it) ?: return@mapLatest null
+				MangaRepository(m.source).getDetails(m)
+			}.getOrNull()
+		} else {
+			null
+		}
+	}.stateIn(viewModelScope + Dispatchers.Default, SharingStarted.Eagerly, null)*/
+
 	private val chaptersReversed = settings.observe()
 		.filter { it == AppSettings.KEY_REVERSE_CHAPTERS }
 		.map { settings.chaptersReverse }
@@ -85,24 +101,19 @@ class DetailsViewModel(
 
 	val chapters = combine(
 		mangaData.map { it?.chapters.orEmpty() },
+		remoteManga,
 		history.map { it?.chapterId },
 		newChapters,
-		chaptersReversed,
 		selectedBranch
-	) { chapters, currentId, newCount, reversed, branch ->
+	) { chapters, sourceManga, currentId, newCount, branch ->
-		val currentIndex = chapters.indexOfFirst { it.id == currentId }
+		val sourceChapters = sourceManga?.chapters
-		val firstNewIndex = chapters.size - newCount
+		if (sourceChapters.isNullOrEmpty()) {
-		val res = chapters.mapIndexed { index, chapter ->
+			mapChapters(chapters, currentId, newCount, branch)
-			chapter.toListItem(
+		} else {
-				when {
+			mapChaptersWithSource(chapters, sourceChapters, currentId, newCount, branch)
-					index >= firstNewIndex -> ChapterExtra.NEW
+		}
-					index == currentIndex -> ChapterExtra.CURRENT
+	}.combine(chaptersReversed) { list, reversed ->
-					index < currentIndex -> ChapterExtra.READ
+		if (reversed) list.asReversed() else list
-					else -> ChapterExtra.UNREAD
-				}
-			)
-		}.filter { it.chapter.branch == branch }
-		if (reversed) res.asReversed() else res
 	}.asLiveData(viewModelScope.coroutineContext + Dispatchers.Default)
 
 	init {
@@ -121,6 +132,12 @@ class DetailsViewModel(
 					?.maxByOrNull { it.value.size }?.key
 			}
 			mangaData.value = manga
+			if (manga.source == MangaSource.LOCAL) {
+				remoteManga.value = runCatching {
+					val m = localMangaRepository.getRemoteManga(manga) ?: return@runCatching null
+					MangaRepository(m.source).getDetails(m)
+				}.getOrNull()
+			}
 		}
 	}
 
@@ -142,4 +159,80 @@ class DetailsViewModel(
 	fun setSelectedBranch(branch: String?) {
 		selectedBranch.value = branch
 	}
+
+	fun getRemoteManga(): Manga? {
+		return remoteManga.value
+	}
+
+	private fun mapChapters(
+		chapters: List<MangaChapter>,
+		currentId: Long?,
+		newCount: Int,
+		branch: String?,
+	): List<ChapterListItem> {
+		val result = ArrayList<ChapterListItem>(chapters.size)
+		val currentIndex = chapters.indexOfFirst { it.id == currentId }
+		val firstNewIndex = chapters.size - newCount
+		for (i in chapters.indices) {
+			val chapter = chapters[i]
+			if (chapter.branch != branch) {
+				continue
+			}
+			result += chapter.toListItem(
+				extra = when {
+					i >= firstNewIndex -> ChapterExtra.NEW
+					i == currentIndex -> ChapterExtra.CURRENT
+					i < currentIndex -> ChapterExtra.READ
+					else -> ChapterExtra.UNREAD
+				},
+				isMissing = false
+			)
+		}
+		return result
+	}
+
+	private fun mapChaptersWithSource(
+		chapters: List<MangaChapter>,
+		sourceChapters: List<MangaChapter>,
+		currentId: Long?,
+		newCount: Int,
+		branch: String?,
+	): List<ChapterListItem> {
+		val chaptersMap = chapters.associateByTo(HashMap(chapters.size)) { it.id }
+		val result = ArrayList<ChapterListItem>(sourceChapters.size)
+		val currentIndex = sourceChapters.indexOfFirst { it.id == currentId }
+		val firstNewIndex = sourceChapters.size - newCount
+		for (i in sourceChapters.indices) {
+			val chapter = sourceChapters[i]
+			if (chapter.branch != branch) {
+				continue
+			}
+			val localChapter = chaptersMap.remove(chapter.id)
+			result += localChapter?.toListItem(
+				extra = when {
+					i >= firstNewIndex -> ChapterExtra.NEW
+					i == currentIndex -> ChapterExtra.CURRENT
+					i < currentIndex -> ChapterExtra.READ
+					else -> ChapterExtra.UNREAD
+				},
+				isMissing = false
+			) ?: chapter.toListItem(
+				extra = when {
+					i >= firstNewIndex -> ChapterExtra.NEW
+					i == currentIndex -> ChapterExtra.CURRENT
+					i < currentIndex -> ChapterExtra.READ
+					else -> ChapterExtra.UNREAD
+				},
+				isMissing = true
+			)
+		}
+		if (chaptersMap.isNotEmpty()) { // some chapters on device but not online source
+			result.ensureCapacity(result.size + chaptersMap.size)
+			chaptersMap.values.mapTo(result) {
+				it.toListItem(ChapterExtra.UNREAD, false)
+			}
+			result.sortBy { it.chapter.number }
+		}
+		return result
+	}
 }

app/src/main/java/org/koitharu/kotatsu/details/ui/adapter/ChapterListItemAD.kt

@@ -3,23 +3,22 @@ package org.koitharu.kotatsu.details.ui.adapter
 import com.hannesdorfmann.adapterdelegates4.dsl.adapterDelegateViewBinding
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.base.ui.list.OnListItemClickListener
-import org.koitharu.kotatsu.core.model.MangaChapter
 import org.koitharu.kotatsu.databinding.ItemChapterBinding
 import org.koitharu.kotatsu.details.ui.model.ChapterListItem
 import org.koitharu.kotatsu.history.domain.ChapterExtra
 import org.koitharu.kotatsu.utils.ext.getThemeColor
 
 fun chapterListItemAD(
-	clickListener: OnListItemClickListener<MangaChapter>
+	clickListener: OnListItemClickListener<ChapterListItem>,
 ) = adapterDelegateViewBinding<ChapterListItem, ChapterListItem, ItemChapterBinding>(
 	{ inflater, parent -> ItemChapterBinding.inflate(inflater, parent, false) }
 ) {
 
 	itemView.setOnClickListener {
-		clickListener.onItemClick(item.chapter, it)
+		clickListener.onItemClick(item, it)
 	}
 	itemView.setOnLongClickListener {
-		clickListener.onItemLongClick(item.chapter, it)
+		clickListener.onItemLongClick(item, it)
 	}
 
 	bind { payload ->
@@ -43,5 +42,7 @@ fun chapterListItemAD(
 				binding.textViewNumber.setTextColor(context.getThemeColor(android.R.attr.textColorPrimaryInverse))
 			}
 		}
+		binding.textViewTitle.alpha = if (item.isMissing) 0.3f else 1f
+		binding.textViewNumber.alpha = if (item.isMissing) 0.3f else 1f
 	}
 }

app/src/main/java/org/koitharu/kotatsu/details/ui/adapter/ChaptersAdapter.kt

@@ -3,12 +3,11 @@ package org.koitharu.kotatsu.details.ui.adapter
 import androidx.recyclerview.widget.DiffUtil
 import com.hannesdorfmann.adapterdelegates4.AsyncListDifferDelegationAdapter
 import org.koitharu.kotatsu.base.ui.list.OnListItemClickListener
-import org.koitharu.kotatsu.core.model.MangaChapter
 import org.koitharu.kotatsu.details.ui.model.ChapterListItem
 import kotlin.jvm.internal.Intrinsics
 
 class ChaptersAdapter(
-	onItemClickListener: OnListItemClickListener<MangaChapter>
+	onItemClickListener: OnListItemClickListener<ChapterListItem>,
 ) :	AsyncListDifferDelegationAdapter<ChapterListItem>(DiffCallback()) {
 
 	init {
@@ -38,7 +37,7 @@ class ChaptersAdapter(
 		}
 
 		override fun getChangePayload(oldItem: ChapterListItem, newItem: ChapterListItem): Any? {
-			if (oldItem.extra != newItem.extra) {
+			if (oldItem.extra != newItem.extra && oldItem.chapter == newItem.chapter) {
 				return newItem.extra
 			}
 			return null

app/src/main/java/org/koitharu/kotatsu/details/ui/model/ChapterListItem.kt

@@ -5,5 +5,6 @@ import org.koitharu.kotatsu.history.domain.ChapterExtra
 
 data class ChapterListItem(
 	val chapter: MangaChapter,
-	val extra: ChapterExtra
+	val extra: ChapterExtra,
+	val isMissing: Boolean,
 )

app/src/main/java/org/koitharu/kotatsu/details/ui/model/ListModelConversionExt.kt

@@ -3,7 +3,11 @@ package org.koitharu.kotatsu.details.ui.model
 import org.koitharu.kotatsu.core.model.MangaChapter
 import org.koitharu.kotatsu.history.domain.ChapterExtra
 
-fun MangaChapter.toListItem(extra: ChapterExtra) = ChapterListItem(
+fun MangaChapter.toListItem(
+	extra: ChapterExtra,
+	isMissing: Boolean,
+) = ChapterListItem(
 	chapter = this,
-	extra = extra
+	extra = extra,
+	isMissing = isMissing,
 )

app/src/main/java/org/koitharu/kotatsu/download/ui/service/DownloadService.kt

@@ -47,6 +47,7 @@ class DownloadService : BaseService() {
 	private val jobCount = MutableStateFlow(0)
 	private val mutex = Mutex()
 	private val controlReceiver = ControlReceiver()
+	private var binder: DownloadBinder? = null
 
 	override fun onCreate() {
 		super.onCreate()
@@ -75,11 +76,12 @@ class DownloadService : BaseService() {
 
 	override fun onBind(intent: Intent): IBinder {
 		super.onBind(intent)
-		return DownloadBinder()
+		return binder ?: DownloadBinder(this).also { binder = it }
 	}
 
 	override fun onDestroy() {
 		unregisterReceiver(controlReceiver)
+		binder = null
 		super.onDestroy()
 	}
 
@@ -141,10 +143,10 @@ class DownloadService : BaseService() {
 		}
 	}
 
-	inner class DownloadBinder : Binder() {
+	class DownloadBinder(private val service: DownloadService) : Binder() {
 
 		val downloads: Flow<Collection<JobStateFlow<DownloadManager.State>>>
-			get() = jobCount.mapLatest { jobs.values }
+			get() = service.jobCount.mapLatest { service.jobs.values }
 	}
 
 	companion object {
@@ -160,6 +162,9 @@ class DownloadService : BaseService() {
 		private const val EXTRA_CANCEL_ID = "cancel_id"
 
 		fun start(context: Context, manga: Manga, chaptersIds: Collection<Long>? = null) {
+			if (chaptersIds?.isEmpty() == true) {
+				return
+			}
 			confirmDataTransfer(context) {
 				val intent = Intent(context, DownloadService::class.java)
 				intent.putExtra(EXTRA_MANGA, manga)

app/src/main/java/org/koitharu/kotatsu/local/domain/LocalMangaRepository.kt

@@ -98,7 +98,10 @@ class LocalMangaRepository(private val context: Context) : MangaRepository {
 					entryName = index.getCoverEntry()
 						?: findFirstEntry(zip.entries(), isImage = true)?.name.orEmpty()
 				),
-				chapters = info.chapters?.map { c -> c.copy(url = fileUri) }
+				chapters = info.chapters?.map { c ->
+					c.copy(url = fileUri,
+						source = MangaSource.LOCAL)
+				}
 			)
 		}
 		// fallback

app/src/main/java/org/koitharu/kotatsu/reader/ui/ChaptersDialog.kt

@@ -15,16 +15,17 @@ import org.koitharu.kotatsu.base.ui.list.OnListItemClickListener
 import org.koitharu.kotatsu.core.model.MangaChapter
 import org.koitharu.kotatsu.databinding.DialogChaptersBinding
 import org.koitharu.kotatsu.details.ui.adapter.ChaptersAdapter
+import org.koitharu.kotatsu.details.ui.model.ChapterListItem
 import org.koitharu.kotatsu.details.ui.model.toListItem
 import org.koitharu.kotatsu.history.domain.ChapterExtra
 import org.koitharu.kotatsu.utils.ext.withArgs
 
 class ChaptersDialog : AlertDialogFragment<DialogChaptersBinding>(),
-	OnListItemClickListener<MangaChapter> {
+	OnListItemClickListener<ChapterListItem> {
 
 	override fun onInflateView(
 		inflater: LayoutInflater,
-		container: ViewGroup?
+		container: ViewGroup?,
 	) = DialogChaptersBinding.inflate(inflater, container, false)
 
 	override fun onBuildDialog(builder: AlertDialog.Builder) {
@@ -51,7 +52,8 @@ class ChaptersDialog : AlertDialogFragment<DialogChaptersBinding>(),
 						index < currentPosition -> ChapterExtra.READ
 						index == currentPosition -> ChapterExtra.CURRENT
 						else -> ChapterExtra.UNREAD
-					}
+					},
+					isMissing = false
 				)
 			}) {
 				if (currentPosition >= 0) {
@@ -66,11 +68,11 @@ class ChaptersDialog : AlertDialogFragment<DialogChaptersBinding>(),
 		}
 	}
 
-	override fun onItemClick(item: MangaChapter, view: View) {
+	override fun onItemClick(item: ChapterListItem, view: View) {
 		((parentFragment as? OnChapterChangeListener)
 			?: (activity as? OnChapterChangeListener))?.let {
 			dismiss()
-			it.onChapterChanged(item)
+			it.onChapterChanged(item.chapter)
 		}
 	}
 

app/src/main/java/org/koitharu/kotatsu/utils/ext/AndroidExt.kt

@@ -1,8 +1,10 @@
 package org.koitharu.kotatsu.utils.ext
 
+import android.content.Context
 import android.net.ConnectivityManager
 import android.net.Network
 import android.net.NetworkRequest
+import androidx.appcompat.app.AlertDialog
 import kotlinx.coroutines.suspendCancellableCoroutine
 import kotlin.coroutines.resume
 
@@ -19,4 +21,8 @@ suspend fun ConnectivityManager.waitForNetwork(): Network {
 			unregisterNetworkCallback(callback)
 		}
 	}
+}
+
+inline fun buildAlertDialog(context: Context, block: AlertDialog.Builder.() -> Unit): AlertDialog {
+	return AlertDialog.Builder(context).apply(block).create()
 }

app/src/main/java/org/koitharu/kotatsu/utils/ext/FlowExt.kt

@@ -3,6 +3,7 @@ package org.koitharu.kotatsu.utils.ext
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.flow.transform
 
 fun <T> Flow<T>.onFirst(action: suspend (T) -> Unit): Flow<T> {
 	var isFirstCall = true
@@ -16,4 +17,10 @@ fun <T> Flow<T>.onFirst(action: suspend (T) -> Unit): Flow<T> {
 
 inline fun <T, R> Flow<List<T>>.mapItems(crossinline transform: (T) -> R): Flow<List<R>> {
 	return map { list -> list.map(transform) }
+}
+
+inline fun <T> Flow<T?>.filterNotNull(
+	crossinline predicate: suspend (T) -> Boolean,
+): Flow<T> = transform { value ->
+	if (value != null && predicate(value)) return@transform emit(value)
 }

app/src/main/res/layout-w600dp-land/fragment_details.xml

@@ -263,13 +263,15 @@
 
 		</LinearLayout>
 
-		<ProgressBar
+		<com.google.android.material.progressindicator.LinearProgressIndicator
 			android:id="@+id/progressBar"
 			style="@style/Widget.AppCompat.ProgressBar.Horizontal"
 			android:layout_width="0dp"
 			android:layout_height="wrap_content"
 			android:indeterminate="true"
 			android:visibility="gone"
+			app:showAnimationBehavior="inward"
+			app:hideAnimationBehavior="outward"
 			app:layout_constraintBottom_toTopOf="parent"
 			app:layout_constraintEnd_toEndOf="parent"
 			app:layout_constraintStart_toStartOf="parent"

app/src/main/res/layout-w600dp-port/fragment_details.xml

@@ -270,13 +270,15 @@
 			tools:ignore="UnusedAttribute"
 			tools:text="@tools:sample/lorem/random[25]" />
 
-		<ProgressBar
+		<com.google.android.material.progressindicator.LinearProgressIndicator
 			android:id="@+id/progressBar"
 			style="@style/Widget.AppCompat.ProgressBar.Horizontal"
 			android:layout_width="0dp"
 			android:layout_height="wrap_content"
 			android:indeterminate="true"
 			android:visibility="gone"
+			app:showAnimationBehavior="inward"
+			app:hideAnimationBehavior="outward"
 			app:layout_constraintBottom_toTopOf="parent"
 			app:layout_constraintEnd_toEndOf="parent"
 			app:layout_constraintStart_toStartOf="parent"

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

@@ -277,6 +277,8 @@
 			android:layout_height="wrap_content"
 			android:indeterminate="true"
 			android:visibility="gone"
+			app:showAnimationBehavior="inward"
+			app:hideAnimationBehavior="outward"
 			app:layout_constraintBottom_toTopOf="parent"
 			app:layout_constraintEnd_toEndOf="parent"
 			app:layout_constraintStart_toStartOf="parent"

app/src/main/res/values/strings.xml

@@ -222,4 +222,6 @@
 	<string name="read_more">Read more</string>
 	<string name="queued">Queued</string>
 	<string name="text_downloads_holder">There are currently no active downloads</string>
+	<string name="chapter_is_missing_text">This chapter is missing on your device. Download it or read online</string>
+	<string name="chapter_is_missing">Chapter is missing</string>
 </resources>