Support multiple branches in saved manga

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

@@ -41,6 +41,7 @@ import org.koitharu.kotatsu.details.ui.adapter.BranchesAdapter
 import org.koitharu.kotatsu.download.ui.service.DownloadService
 import org.koitharu.kotatsu.parsers.model.Manga
 import org.koitharu.kotatsu.parsers.model.MangaSource
+import org.koitharu.kotatsu.parsers.util.mapNotNullToSet
 import org.koitharu.kotatsu.reader.ui.ReaderActivity
 import org.koitharu.kotatsu.reader.ui.ReaderState
 import org.koitharu.kotatsu.search.ui.global.GlobalSearchActivity
@@ -193,23 +194,9 @@ class DetailsActivity :
 		R.id.action_save -> {
 			viewModel.manga.value?.let {
 				val chaptersCount = it.chapters?.size ?: 0
-				if (chaptersCount > 5) {
-					MaterialAlertDialogBuilder(this)
-						.setTitle(R.string.save_manga)
-						.setMessage(
-							getString(
-								R.string.large_manga_save_confirm,
-								resources.getQuantityString(
-									R.plurals.chapters,
-									chaptersCount,
-									chaptersCount
-								)
-							)
-						)
-						.setNegativeButton(android.R.string.cancel, null)
-						.setPositiveButton(R.string.save) { _, _ ->
-							DownloadService.start(this, it)
-						}.show()
+				val branches = viewModel.branches.value.orEmpty()
+				if (chaptersCount > 5 || branches.size > 1) {
+					showSaveConfirmation(it, chaptersCount, branches)
 				} else {
 					DownloadService.start(this, it)
 				}
@@ -335,6 +322,36 @@ class DetailsActivity :
 		}
 	}
 
+	private fun showSaveConfirmation(manga: Manga, chaptersCount: Int, branches: List<String?>) {
+		val dialogBuilder = MaterialAlertDialogBuilder(this)
+			.setTitle(R.string.save_manga)
+			.setNegativeButton(android.R.string.cancel, null)
+		if (branches.size > 1) {
+			val items = Array(branches.size) { i -> branches[i].orEmpty() }
+			val currentBranch = viewModel.selectedBranchIndex.value ?: -1
+			val checkedIndices = BooleanArray(branches.size) { i -> i == currentBranch }
+			dialogBuilder.setMultiChoiceItems(items, checkedIndices) { _, i, checked ->
+				checkedIndices[i] = checked
+			}.setPositiveButton(R.string.save) { _, _ ->
+				val selectedBranches = branches.filterIndexedTo(HashSet()) { i, _ -> checkedIndices[i] }
+				val chaptersIds = manga.chapters?.mapNotNullToSet { c ->
+					if (c.branch in selectedBranches) c.id else null
+				}
+				DownloadService.start(this, manga, chaptersIds)
+			}
+		} else {
+			dialogBuilder.setMessage(
+				getString(
+					R.string.large_manga_save_confirm,
+					resources.getQuantityString(R.plurals.chapters, chaptersCount, chaptersCount)
+				)
+			).setPositiveButton(R.string.save) { _, _ ->
+				DownloadService.start(this, manga)
+			}
+		}
+		dialogBuilder.show()
+	}
+
 	companion object {
 
 		fun newIntent(context: Context, manga: Manga): Intent {

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

@@ -267,10 +267,10 @@ class DetailsViewModel(
 		val dateFormat = settings.getDateFormat()
 		for (i in sourceChapters.indices) {
 			val chapter = sourceChapters[i]
+			val localChapter = chaptersMap.remove(chapter.id)
 			if (chapter.branch != branch) {
 				continue
 			}
-			val localChapter = chaptersMap.remove(chapter.id)
 			result += localChapter?.toListItem(
 				isCurrent = i == currentIndex,
 				isUnread = i > currentIndex,
@@ -289,15 +289,19 @@ class DetailsViewModel(
 		}
 		if (chaptersMap.isNotEmpty()) { // some chapters on device but not online source
 			result.ensureCapacity(result.size + chaptersMap.size)
-			chaptersMap.values.mapTo(result) {
-				it.toListItem(
-					isCurrent = false,
-					isUnread = true,
-					isNew = false,
-					isMissing = false,
-					isDownloaded = false,
-					dateFormat = dateFormat,
-				)
+			chaptersMap.values.mapNotNullTo(result) {
+				if (it.branch == branch) {
+					it.toListItem(
+						isCurrent = false,
+						isUnread = true,
+						isNew = false,
+						isMissing = false,
+						isDownloaded = false,
+						dateFormat = dateFormat,
+					)
+				} else {
+					null
+				}
 			}
 			result.sortBy { it.chapter.number }
 		}

app/src/main/java/org/koitharu/kotatsu/local/data/MangaIndex.kt

@@ -87,7 +87,7 @@ class MangaIndex(source: String?) {
 			jo.put("uploadDate", chapter.uploadDate)
 			jo.put("scanlator", chapter.scanlator)
 			jo.put("branch", chapter.branch)
-			jo.put("entries", "%03d\\d{3}".format(chapter.number))
+			jo.put("entries", "%08d_%03d\\d{3}".format(chapter.branch.hashCode(), chapter.number))
 			chapters.put(chapter.id.toString(), jo)
 		}
 	}

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

@@ -36,7 +36,7 @@ class CbzMangaOutput(
 
 	suspend fun addCover(file: File, ext: String) {
 		val name = buildString {
-			append(FILENAME_PATTERN.format(0, 0))
+			append(FILENAME_PATTERN.format(0, 0, 0))
 			if (ext.isNotEmpty() && ext.length <= 4) {
 				append('.')
 				append(ext)
@@ -50,7 +50,7 @@ class CbzMangaOutput(
 
 	suspend fun addPage(chapter: MangaChapter, file: File, pageNumber: Int, ext: String) {
 		val name = buildString {
-			append(FILENAME_PATTERN.format(chapter.number, pageNumber))
+			append(FILENAME_PATTERN.format(chapter.branch.hashCode(), chapter.number, pageNumber))
 			if (ext.isNotEmpty() && ext.length <= 4) {
 				append('.')
 				append(ext)
@@ -105,7 +105,7 @@ class CbzMangaOutput(
 
 	companion object {
 
-		private const val FILENAME_PATTERN = "%03d%03d"
+		private const val FILENAME_PATTERN = "%08d_%03d%03d"
 
 		const val ENTRY_NAME_INDEX = "index.json"