Fix default branch selection #527 #528

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

@@ -26,6 +26,17 @@ fun <T> Flow<T>.onFirst(action: suspend (T) -> Unit): Flow<T> {
 	}
 }
 
+fun <T> Flow<T>.onEachWhile(action: suspend (T) -> Boolean): Flow<T> {
+	var isCalled = false
+	return onEach {
+		if (!isCalled) {
+			isCalled = action(it)
+		}
+	}.onCompletion {
+		isCalled = false
+	}
+}
+
 inline fun <T, R> Flow<List<T>>.mapItems(crossinline transform: (T) -> R): Flow<List<R>> {
 	return map { list -> list.map(transform) }
 }

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

@@ -33,7 +33,7 @@ import org.koitharu.kotatsu.core.ui.BaseViewModel
 import org.koitharu.kotatsu.core.util.ext.MutableEventFlow
 import org.koitharu.kotatsu.core.util.ext.call
 import org.koitharu.kotatsu.core.util.ext.computeSize
-import org.koitharu.kotatsu.core.util.ext.onFirst
+import org.koitharu.kotatsu.core.util.ext.onEachWhile
 import org.koitharu.kotatsu.core.util.ext.requireValue
 import org.koitharu.kotatsu.details.data.MangaDetails
 import org.koitharu.kotatsu.details.domain.BranchComparator
@@ -313,11 +313,15 @@ class DetailsViewModel @Inject constructor(
 
 	private fun doLoad() = launchLoadingJob(Dispatchers.Default) {
 		detailsLoadUseCase.invoke(intent)
-			.onFirst {
+			.onEachWhile {
+				if (it.allChapters.isEmpty()) {
+					return@onEachWhile false
+				}
 				val manga = it.toManga()
 				// find default branch
 				val hist = historyRepository.getOne(manga)
 				selectedBranch.value = manga.getPreferredBranch(hist)
+				true
 			}.collect {
 				details.value = it
 			}