Current branch indicator

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

@@ -4,7 +4,9 @@ import android.content.Context
 import android.content.Intent
 import android.graphics.Color
 import android.os.Bundle
+import android.text.style.DynamicDrawableSpan
 import android.text.style.ForegroundColorSpan
+import android.text.style.ImageSpan
 import android.text.style.RelativeSizeSpan
 import android.transition.AutoTransition
 import android.transition.Slide
@@ -318,6 +320,18 @@ class DetailsActivity :
 		val branches = viewModel.branches.value
 		for ((i, branch) in branches.withIndex()) {
 			val title = buildSpannedString {
+				if (branch.isCurrent) {
+					inSpans(
+						ImageSpan(
+							this@DetailsActivity,
+							R.drawable.ic_current_chapter,
+							DynamicDrawableSpan.ALIGN_BASELINE,
+						),
+					) {
+						append(' ')
+					}
+					append(' ')
+				}
 				append(branch.name ?: getString(R.string.system_default))
 				append(' ')
 				append(' ')

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

@@ -25,6 +25,7 @@ import okio.FileNotFoundException
 import org.koitharu.kotatsu.R
 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.model.getPreferredBranch
 import org.koitharu.kotatsu.core.parser.MangaIntent
 import org.koitharu.kotatsu.core.prefs.AppSettings
@@ -171,10 +172,21 @@ class DetailsViewModel @Inject constructor(
 	val branches: StateFlow<List<MangaBranch>> = combine(
 		details,
 		selectedBranch,
-	) { m, b ->
-		(m?.chapters ?: return@combine emptyList())
-			.map { x -> MangaBranch(x.key, x.value.size, x.key == b) }
-			.sortedWith(BranchComparator())
+		history,
+	) { m, b, h ->
+		val c = m?.chapters
+		if (c.isNullOrEmpty()) {
+			return@combine emptyList()
+		}
+		val currentBranch = h?.let { m.allChapters.findById(it.chapterId) }?.branch
+		c.map { x ->
+			MangaBranch(
+				name = x.key,
+				count = x.value.size,
+				isSelected = x.key == b,
+				isCurrent = h != null && x.key == currentBranch,
+			)
+		}.sortedWith(BranchComparator())
 	}.stateIn(viewModelScope + Dispatchers.Default, SharingStarted.Eagerly, emptyList())
 
 	val isChaptersEmpty: StateFlow<Boolean> = details.map {

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

@@ -7,6 +7,7 @@ data class MangaBranch(
 	val name: String?,
 	val count: Int,
 	val isSelected: Boolean,
+	val isCurrent: Boolean,
 ) : ListModel {
 
 	override fun areItemsTheSame(other: ListModel): Boolean {