Add ability to download unread chapters from library

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryController.kt

@@ -28,6 +28,7 @@ import eu.kanade.tachiyomi.data.library.LibraryUpdateService
 import eu.kanade.tachiyomi.data.preference.PreferencesHelper
 import eu.kanade.tachiyomi.data.preference.asImmediateFlow
 import eu.kanade.tachiyomi.databinding.LibraryControllerBinding
+import eu.kanade.tachiyomi.source.LocalSource
 import eu.kanade.tachiyomi.ui.base.controller.NucleusController
 import eu.kanade.tachiyomi.ui.base.controller.RootController
 import eu.kanade.tachiyomi.ui.base.controller.TabbedController
@@ -441,6 +442,7 @@ class LibraryController(
             mode.title = count.toString()
 
             binding.actionToolbar.findItem(R.id.action_edit_cover)?.isVisible = count == 1
+            binding.actionToolbar.findItem(R.id.action_download_unread)?.isVisible = selectedMangas.any { it.source != LocalSource.ID }
         }
         return false
     }
@@ -453,6 +455,7 @@ class LibraryController(
         when (item.itemId) {
             R.id.action_edit_cover -> handleChangeCover()
             R.id.action_move_to_category -> showChangeMangaCategoriesDialog()
+            R.id.action_download_unread -> downloadUnreadChapters()
             R.id.action_delete -> showDeleteMangaDialog()
             R.id.action_select_all -> selectAllCategoryManga()
             R.id.action_select_inverse -> selectInverseCategoryManga()
@@ -546,6 +549,12 @@ class LibraryController(
             .showDialog(router)
     }
 
+    private fun downloadUnreadChapters() {
+        val mangas = selectedMangas.toList()
+        presenter.downloadUnreadChapters(mangas)
+        destroyActionModeIfNeeded()
+    }
+
     private fun showDeleteMangaDialog() {
         DeleteLibraryMangasDialog(this, selectedMangas.toList()).showDialog(router)
     }

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt

@@ -313,6 +313,22 @@ class LibraryPresenter(
             .reduce { set1: Iterable<Category>, set2 -> set1.intersect(set2).toMutableList() }
     }
 
+    /**
+     * Queues all unread chapters from the given list of manga.
+     *
+     * @param mangas the list of manga.
+     */
+    fun downloadUnreadChapters(mangas: List<Manga>) {
+        mangas.forEach { manga ->
+            launchIO {
+                val chapters = db.getChapters(manga).executeAsBlocking()
+                    .filter { !it.read }
+
+                downloadManager.downloadChapters(manga, chapters)
+            }
+        }
+    }
+
     /**
      * Remove the selected manga from the library.
      *