Fix list items reorder

app/src/main/kotlin/org/koitharu/kotatsu/core/ui/ReorderableListAdapter.kt

@@ -0,0 +1,75 @@
+package org.koitharu.kotatsu.core.ui
+
+import androidx.recyclerview.widget.AsyncListDiffer.ListListener
+import androidx.recyclerview.widget.DiffUtil
+import com.hannesdorfmann.adapterdelegates4.AdapterDelegate
+import com.hannesdorfmann.adapterdelegates4.ListDelegationAdapter
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.FlowCollector
+import kotlinx.coroutines.withContext
+import org.koitharu.kotatsu.list.ui.adapter.ListItemType
+import org.koitharu.kotatsu.list.ui.model.ListModel
+import java.util.Collections
+import java.util.LinkedList
+
+open class ReorderableListAdapter<T : ListModel> : ListDelegationAdapter<List<T>>(), FlowCollector<List<T>?> {
+
+	private val listListeners = LinkedList<ListListener<T>>()
+
+	override suspend fun emit(value: List<T>?) {
+		val oldList = items.orEmpty()
+		val newList = value.orEmpty()
+		val diffResult = withContext(Dispatchers.Default) {
+			val diffCallback = DiffCallback(oldList, newList)
+			DiffUtil.calculateDiff(diffCallback)
+		}
+		super.setItems(newList)
+		diffResult.dispatchUpdatesTo(this)
+		listListeners.forEach { it.onCurrentListChanged(oldList, newList) }
+	}
+
+	@Deprecated("Use emit() to dispatch list updates", level = DeprecationLevel.ERROR)
+	override fun setItems(items: List<T>?) {
+		super.setItems(items)
+	}
+
+	fun reorderItems(oldPos: Int, newPos: Int) {
+		Collections.swap(items ?: return, oldPos, newPos)
+		notifyItemMoved(oldPos, newPos)
+	}
+
+	fun addDelegate(type: ListItemType, delegate: AdapterDelegate<List<T>>): ReorderableListAdapter<T> {
+		delegatesManager.addDelegate(type.ordinal, delegate)
+		return this
+	}
+
+	fun addListListener(listListener: ListListener<T>) {
+		listListeners.add(listListener)
+	}
+
+	fun removeListListener(listListener: ListListener<T>) {
+		listListeners.remove(listListener)
+	}
+
+	protected class DiffCallback<T : ListModel>(
+		val oldList: List<T>,
+		val newList: List<T>,
+	) : DiffUtil.Callback() {
+
+		override fun getOldListSize(): Int = oldList.size
+
+		override fun getNewListSize(): Int = newList.size
+
+		override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
+			val oldItem = oldList[oldItemPosition]
+			val newItem = newList[newItemPosition]
+			return newItem.areItemsTheSame(oldItem)
+		}
+
+		override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
+			val oldItem = oldList[oldItemPosition]
+			val newItem = newList[newItemPosition]
+			return newItem == oldItem
+		}
+	}
+}

app/src/main/kotlin/org/koitharu/kotatsu/favourites/ui/categories/FavouriteCategoriesActivity.kt

@@ -142,7 +142,11 @@ class FavouriteCategoriesActivity :
 			}
 			val fromPos = viewHolder.bindingAdapterPosition
 			val toPos = target.bindingAdapterPosition
-			return fromPos != toPos && fromPos != RecyclerView.NO_POSITION && toPos != RecyclerView.NO_POSITION
+			if (fromPos == toPos || fromPos == RecyclerView.NO_POSITION || toPos == RecyclerView.NO_POSITION) {
+				return false
+			}
+			adapter.reorderItems(fromPos, toPos)
+			return true
 		}
 
 		override fun canDropOver(
@@ -151,25 +155,16 @@ class FavouriteCategoriesActivity :
 			target: RecyclerView.ViewHolder,
 		): Boolean = current.itemViewType == target.itemViewType
 
-		override fun onMoved(
-			recyclerView: RecyclerView,
-			viewHolder: RecyclerView.ViewHolder,
-			fromPos: Int,
-			target: RecyclerView.ViewHolder,
-			toPos: Int,
-			x: Int,
-			y: Int,
-		) {
-			super.onMoved(recyclerView, viewHolder, fromPos, target, toPos, x, y)
-			viewModel.reorderCategories(fromPos, toPos)
-		}
-
 		override fun isLongPressDragEnabled(): Boolean = false
 
 		override fun onSelectedChanged(viewHolder: RecyclerView.ViewHolder?, actionState: Int) {
 			super.onSelectedChanged(viewHolder, actionState)
-			viewBinding.recyclerView.isNestedScrollingEnabled =
-				actionState == ItemTouchHelper.ACTION_STATE_IDLE
+			viewBinding.recyclerView.isNestedScrollingEnabled = actionState == ItemTouchHelper.ACTION_STATE_IDLE
+		}
+
+		override fun clearView(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder) {
+			super.clearView(recyclerView, viewHolder)
+			viewModel.saveOrder(adapter.items ?: return)
 		}
 	}
 

app/src/main/kotlin/org/koitharu/kotatsu/favourites/ui/categories/FavouritesCategoriesViewModel.kt

@@ -1,13 +1,14 @@
 package org.koitharu.kotatsu.favourites.ui.categories
 
+import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.cancelAndJoin
-import kotlinx.coroutines.delay
-import kotlinx.coroutines.flow.MutableStateFlow
-import kotlinx.coroutines.flow.collectLatest
-import kotlinx.coroutines.yield
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.plus
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.model.FavouriteCategory
 import org.koitharu.kotatsu.core.prefs.AppSettings
@@ -19,7 +20,6 @@ import org.koitharu.kotatsu.favourites.ui.categories.adapter.CategoryListModel
 import org.koitharu.kotatsu.list.ui.model.EmptyState
 import org.koitharu.kotatsu.list.ui.model.ListModel
 import org.koitharu.kotatsu.list.ui.model.LoadingState
-import org.koitharu.kotatsu.parsers.util.move
 import javax.inject.Inject
 
 @HiltViewModel
@@ -30,17 +30,9 @@ class FavouritesCategoriesViewModel @Inject constructor(
 
 	private var commitJob: Job? = null
 
-	val content = MutableStateFlow<List<ListModel>>(listOf(LoadingState))
-
-	init {
-		launchJob(Dispatchers.Default) {
-			repository.observeCategoriesWithCovers()
-				.collectLatest {
-					commitJob?.join()
-					updateContent(it)
-				}
-		}
-	}
+	val content = repository.observeCategoriesWithCovers()
+		.map { it.toUiList() }
+		.stateIn(viewModelScope + Dispatchers.Default, SharingStarted.Eagerly, listOf(LoadingState))
 
 	fun deleteCategories(ids: Set<Long>) {
 		launchJob(Dispatchers.Default) {
@@ -54,11 +46,17 @@ class FavouritesCategoriesViewModel @Inject constructor(
 
 	fun isEmpty(): Boolean = content.value.none { it is CategoryListModel }
 
-	fun reorderCategories(oldPos: Int, newPos: Int) {
-		val snapshot = content.requireValue().toMutableList()
-		snapshot.move(oldPos, newPos)
-		content.value = snapshot
-		commit(snapshot)
+	fun saveOrder(snapshot: List<ListModel>) {
+		val prevJob = commitJob
+		commitJob = launchJob {
+			prevJob?.cancelAndJoin()
+			val ids = snapshot.mapNotNullTo(ArrayList(snapshot.size)) {
+				(it as? CategoryListModel)?.category?.id
+			}
+			if (ids.isNotEmpty()) {
+				repository.reorderCategories(ids)
+			}
+		}
 	}
 
 	fun setIsVisible(ids: Set<Long>, isVisible: Boolean) {
@@ -76,36 +74,21 @@ class FavouritesCategoriesViewModel @Inject constructor(
 		}
 	}
 
-	private fun commit(snapshot: List<ListModel>) {
-		val prevJob = commitJob
-		commitJob = launchJob {
-			prevJob?.cancelAndJoin()
-			delay(500)
-			val ids = snapshot.mapNotNullTo(ArrayList(snapshot.size)) {
-				(it as? CategoryListModel)?.category?.id
-			}
-			repository.reorderCategories(ids)
-			yield()
-		}
-	}
-
-	private fun updateContent(categories: Map<FavouriteCategory, List<Cover>>) {
-		content.value = categories.map { (category, covers) ->
-			CategoryListModel(
-				mangaCount = covers.size,
-				covers = covers.take(3),
-				category = category,
-				isTrackerEnabled = settings.isTrackerEnabled && AppSettings.TRACK_FAVOURITES in settings.trackSources,
-			)
-		}.ifEmpty {
-			listOf(
-				EmptyState(
-					icon = R.drawable.ic_empty_favourites,
-					textPrimary = R.string.text_empty_holder_primary,
-					textSecondary = R.string.empty_favourite_categories,
-					actionStringRes = 0,
-				),
-			)
-		}
+	private fun Map<FavouriteCategory, List<Cover>>.toUiList(): List<ListModel> = map { (category, covers) ->
+		CategoryListModel(
+			mangaCount = covers.size,
+			covers = covers.take(3),
+			category = category,
+			isTrackerEnabled = settings.isTrackerEnabled && AppSettings.TRACK_FAVOURITES in settings.trackSources,
+		)
+	}.ifEmpty {
+		listOf(
+			EmptyState(
+				icon = R.drawable.ic_empty_favourites,
+				textPrimary = R.string.text_empty_holder_primary,
+				textSecondary = R.string.empty_favourite_categories,
+				actionStringRes = 0,
+			),
+		)
 	}
 }

app/src/main/kotlin/org/koitharu/kotatsu/favourites/ui/categories/adapter/CategoriesAdapter.kt

@@ -2,7 +2,7 @@ package org.koitharu.kotatsu.favourites.ui.categories.adapter
 
 import androidx.lifecycle.LifecycleOwner
 import coil.ImageLoader
-import org.koitharu.kotatsu.core.ui.BaseListAdapter
+import org.koitharu.kotatsu.core.ui.ReorderableListAdapter
 import org.koitharu.kotatsu.favourites.ui.categories.FavouriteCategoriesListListener
 import org.koitharu.kotatsu.list.ui.adapter.ListItemType
 import org.koitharu.kotatsu.list.ui.adapter.ListStateHolderListener
@@ -15,7 +15,7 @@ class CategoriesAdapter(
 	lifecycleOwner: LifecycleOwner,
 	onItemClickListener: FavouriteCategoriesListListener,
 	listListener: ListStateHolderListener,
-) : BaseListAdapter<ListModel>() {
+) : ReorderableListAdapter<ListModel>() {
 
 	init {
 		addDelegate(ListItemType.CATEGORY_LARGE, categoryAD(coil, lifecycleOwner, onItemClickListener))

app/src/main/kotlin/org/koitharu/kotatsu/settings/sources/adapter/SourceConfigAdapter.kt

@@ -2,14 +2,14 @@ package org.koitharu.kotatsu.settings.sources.adapter
 
 import androidx.lifecycle.LifecycleOwner
 import coil.ImageLoader
-import org.koitharu.kotatsu.core.ui.BaseListAdapter
+import org.koitharu.kotatsu.core.ui.ReorderableListAdapter
 import org.koitharu.kotatsu.settings.sources.model.SourceConfigItem
 
 class SourceConfigAdapter(
 	listener: SourceConfigListener,
 	coil: ImageLoader,
 	lifecycleOwner: LifecycleOwner,
-) : BaseListAdapter<SourceConfigItem>() {
+) : ReorderableListAdapter<SourceConfigItem>() {
 
 	init {
 		with(delegatesManager) {

app/src/main/kotlin/org/koitharu/kotatsu/settings/sources/manage/SourcesManageFragment.kt

@@ -54,6 +54,7 @@ class SourcesManageFragment :
 	lateinit var shortcutManager: AppShortcutManager
 
 	private var reorderHelper: ItemTouchHelper? = null
+	private var sourcesAdapter: SourceConfigAdapter? = null
 	private val viewModel by viewModels<SourcesManageViewModel>()
 
 	override val recyclerView: RecyclerView
@@ -69,7 +70,7 @@ class SourcesManageFragment :
 		savedInstanceState: Bundle?,
 	) {
 		super.onViewBindingCreated(binding, savedInstanceState)
-		val sourcesAdapter = SourceConfigAdapter(this, coil, viewLifecycleOwner)
+		sourcesAdapter = SourceConfigAdapter(this, coil, viewLifecycleOwner)
 		with(binding.recyclerView) {
 			setHasFixedSize(true)
 			adapter = sourcesAdapter
@@ -77,7 +78,7 @@ class SourcesManageFragment :
 				it.attachToRecyclerView(this)
 			}
 		}
-		viewModel.content.observe(viewLifecycleOwner, sourcesAdapter)
+		viewModel.content.observe(viewLifecycleOwner, checkNotNull(sourcesAdapter))
 		viewModel.onActionDone.observeEvent(
 			viewLifecycleOwner,
 			ReversibleActionObserver(binding.recyclerView),
@@ -91,6 +92,7 @@ class SourcesManageFragment :
 	}
 
 	override fun onDestroyView() {
+		sourcesAdapter = null
 		reorderHelper = null
 		super.onDestroyView()
 	}
@@ -204,7 +206,7 @@ class SourcesManageFragment :
 			y: Int,
 		) {
 			super.onMoved(recyclerView, viewHolder, fromPos, target, toPos, x, y)
-			viewModel.reorderSources(fromPos, toPos)
+			sourcesAdapter?.reorderItems(fromPos, toPos)
 		}
 
 		override fun canDropOver(
@@ -248,5 +250,10 @@ class SourcesManageFragment :
 		}
 
 		override fun isLongPressDragEnabled() = true
+
+		override fun clearView(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder) {
+			super.clearView(recyclerView, viewHolder)
+			viewModel.saveSourcesOrder(sourcesAdapter?.items ?: return)
+		}
 	}
 }

app/src/main/kotlin/org/koitharu/kotatsu/settings/sources/manage/SourcesManageViewModel.kt

@@ -4,8 +4,6 @@ import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.cancelAndJoin
-import kotlinx.coroutines.delay
-import kotlinx.coroutines.yield
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.db.MangaDatabase
 import org.koitharu.kotatsu.core.db.removeObserverAsync
@@ -43,17 +41,19 @@ class SourcesManageViewModel @Inject constructor(
 		database.invalidationTracker.removeObserverAsync(listProducer)
 	}
 
-	fun reorderSources(oldPos: Int, newPos: Int) {
-		val snapshot = content.value.toMutableList()
-		if ((snapshot[oldPos] as? SourceConfigItem.SourceItem)?.isDraggable != true) {
-			return
+	fun saveSourcesOrder(snapshot: List<SourceConfigItem>) {
+		val prevJob = commitJob
+		commitJob = launchJob(Dispatchers.Default) {
+			prevJob?.cancelAndJoin()
+			val newSourcesList = snapshot.mapNotNull { x ->
+				if (x is SourceConfigItem.SourceItem && x.isDraggable) {
+					x.source
+				} else {
+					null
+				}
+			}
+			repository.setPositions(newSourcesList)
 		}
-		if ((snapshot[newPos] as? SourceConfigItem.SourceItem)?.isDraggable != true) {
-			return
-		}
-		snapshot.move(oldPos, newPos)
-		content.value = snapshot
-		commit(snapshot)
 	}
 
 	fun canReorder(oldPos: Int, newPos: Int): Boolean {
@@ -72,28 +72,31 @@ class SourcesManageViewModel @Inject constructor(
 	}
 
 	fun bringToTop(source: MangaSource) {
-		var oldPos = -1
-		var newPos = -1
 		val snapshot = content.value
-		for ((i, x) in snapshot.withIndex()) {
-			if (x !is SourceConfigItem.SourceItem) {
-				continue
+		launchJob(Dispatchers.Default) {
+			var oldPos = -1
+			var newPos = -1
+			for ((i, x) in snapshot.withIndex()) {
+				if (x !is SourceConfigItem.SourceItem) {
+					continue
+				}
+				if (newPos == -1) {
+					newPos = i
+				}
+				if (x.source == source) {
+					oldPos = i
+					break
+				}
 			}
-			if (newPos == -1) {
-				newPos = i
+			@Suppress("KotlinConstantConditions")
+			if (oldPos != -1 && newPos != -1) {
+				reorderSources(oldPos, newPos)
+				val revert = ReversibleAction(R.string.moved_to_top) {
+					reorderSources(newPos, oldPos)
+				}
+				commitJob?.join()
+				onActionDone.call(revert)
 			}
-			if (x.source == source) {
-				oldPos = i
-				break
-			}
-		}
-		@Suppress("KotlinConstantConditions")
-		if (oldPos != -1 && newPos != -1) {
-			reorderSources(oldPos, newPos)
-			val revert = ReversibleAction(R.string.moved_to_top) {
-				reorderSources(newPos, oldPos)
-			}
-			onActionDone.call(revert)
 		}
 	}
 
@@ -113,20 +116,15 @@ class SourcesManageViewModel @Inject constructor(
 		}
 	}
 
-	private fun commit(snapshot: List<SourceConfigItem>) {
-		val prevJob = commitJob
-		commitJob = launchJob {
-			prevJob?.cancelAndJoin()
-			delay(500)
-			val newSourcesList = snapshot.mapNotNull { x ->
-				if (x is SourceConfigItem.SourceItem && x.isDraggable) {
-					x.source
-				} else {
-					null
-				}
-			}
-			repository.setPositions(newSourcesList)
-			yield()
+	private fun reorderSources(oldPos: Int, newPos: Int) {
+		val snapshot = content.value.toMutableList()
+		if ((snapshot[oldPos] as? SourceConfigItem.SourceItem)?.isDraggable != true) {
+			return
 		}
+		if ((snapshot[newPos] as? SourceConfigItem.SourceItem)?.isDraggable != true) {
+			return
+		}
+		snapshot.move(oldPos, newPos)
+		saveSourcesOrder(snapshot)
 	}
 }