Follow chapter sort setting when downloading next n chapters (closes #4725)

app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaController.kt

@@ -1003,9 +1003,10 @@ class MangaController :
     // OVERFLOW MENU DIALOGS
 
     private fun getUnreadChaptersSorted() = presenter.chapters
+        .sortedWith(presenter.getChapterSort())
         .filter { !it.read && it.status == Download.State.NOT_DOWNLOADED }
         .distinctBy { it.name }
-        .sortedByDescending { it.source_order }
+        .reversed()
 
     private fun downloadChapters(choice: Int) {
         val chaptersToDownload = when (choice) {

app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaPresenter.kt

@@ -429,7 +429,11 @@ class MangaPresenter(
             observable = observable.filter { !it.bookmark }
         }
 
-        val sortFunction: (Chapter, Chapter) -> Int = when (manga.sorting) {
+        return observable.toSortedList(getChapterSort())
+    }
+
+    fun getChapterSort(): (Chapter, Chapter) -> Int {
+        return when (manga.sorting) {
             Manga.SORTING_SOURCE -> when (sortDescending()) {
                 true -> { c1, c2 -> c1.source_order.compareTo(c2.source_order) }
                 false -> { c1, c2 -> c2.source_order.compareTo(c1.source_order) }
@@ -444,8 +448,6 @@ class MangaPresenter(
             }
             else -> throw NotImplementedError("Unimplemented sorting method")
         }
-
-        return observable.toSortedList(sortFunction)
     }
 
     /**