Allow to delete downloaded chapters

app/src/main/java/eu/kanade/mangafeed/data/helpers/DownloadManager.java

@@ -226,4 +226,8 @@ public class DownloadManager {
         return new File(preferences.getDownloadsDirectory(), chapterRelativePath);
     }
 
+    public void deleteChapter(Source source, Manga manga, Chapter chapter) {
+        File path = getAbsoluteChapterDirectory(source, manga, chapter);
+        DiskUtils.deleteFiles(path);
+    }
 }

app/src/main/java/eu/kanade/mangafeed/presenter/MangaChaptersPresenter.java

@@ -41,6 +41,7 @@ public class MangaChaptersPresenter extends BasePresenter<MangaChaptersFragment>
 
     private Subscription markReadSubscription;
     private Subscription downloadSubscription;
+    private Subscription deleteSubscription;
 
     @Override
     protected void onCreate(Bundle savedState) {
@@ -118,9 +119,6 @@ public class MangaChaptersPresenter extends BasePresenter<MangaChaptersFragment>
     }
 
     public void markChaptersRead(Observable<Chapter> selectedChapters, boolean read) {
-        if (markReadSubscription != null)
-            remove(markReadSubscription);
-
         add(markReadSubscription = selectedChapters
                 .subscribeOn(Schedulers.io())
                 .map(chapter -> {
@@ -130,16 +128,14 @@ public class MangaChaptersPresenter extends BasePresenter<MangaChaptersFragment>
                 .toList()
                 .flatMap(db::insertChapters)
                 .observeOn(AndroidSchedulers.mainThread())
+                .doOnCompleted( () -> remove(markReadSubscription) )
                 .subscribe(result -> {
-
                 }));
     }
 
     public void downloadChapters(Observable<Chapter> selectedChapters) {
-        if (downloadSubscription != null)
-            remove(downloadSubscription);
-
         add(downloadSubscription = selectedChapters
+                .doOnCompleted(() -> remove(downloadSubscription))
                 .subscribe(chapter -> {
                     EventBus.getDefault().post(
                             new DownloadChapterEvent(manga, chapter));
@@ -155,4 +151,13 @@ public class MangaChaptersPresenter extends BasePresenter<MangaChaptersFragment>
             chapter.downloaded = Chapter.NOT_DOWNLOADED;
         }
     }
+
+    public void deleteChapters(Observable<Chapter> selectedChapters) {
+        deleteSubscription = selectedChapters
+                .doOnCompleted( () -> remove(deleteSubscription) )
+                .subscribe(chapter -> {
+                    downloadManager.deleteChapter(source, manga, chapter);
+                    chapter.downloaded = Chapter.NOT_DOWNLOADED;
+                });
+    }
 }

app/src/main/java/eu/kanade/mangafeed/presenter/ReaderPresenter.java

@@ -34,6 +34,7 @@ public class ReaderPresenter extends BasePresenter<ReaderActivity> {
     private Manga manga;
     private Chapter chapter;
     private List<Page> pageList;
+    private boolean isDownloaded;
     @State int currentPage;
 
     private static final int GET_PAGE_LIST = 1;
@@ -52,13 +53,11 @@ public class ReaderPresenter extends BasePresenter<ReaderActivity> {
                     if (currentPage != 0)
                         view.setSelectedPage(currentPage);
                 },
-                (view, error) -> Timber.e("An error occurred while downloading page list")
-        );
+                (view, error) -> Timber.e("An error occurred while downloading page list"));
 
         restartableReplay(GET_PAGE_IMAGES,
                 this::getPageImagesObservable,
-                (view, page) -> {
-                },
+                (view, page) -> {},
                 (view, error) -> Timber.e("An error occurred while downloading an image"));
 
     }
@@ -77,8 +76,9 @@ public class ReaderPresenter extends BasePresenter<ReaderActivity> {
 
     @Override
     protected void onDestroy() {
-        source.savePageList(chapter.url, pageList);
-        saveChapter();
+        if (!isDownloaded)
+            source.savePageList(chapter.url, pageList);
+        saveChapterProgress();
         super.onDestroy();
     }
 
@@ -87,6 +87,7 @@ public class ReaderPresenter extends BasePresenter<ReaderActivity> {
         source = event.getSource();
         manga = event.getManga();
         chapter = event.getChapter();
+        isDownloaded = chapter.downloaded == Chapter.DOWNLOADED;
         if (chapter.last_page_read != 0 && !chapter.read)
             currentPage = chapter.last_page_read;
 
@@ -96,7 +97,7 @@ public class ReaderPresenter extends BasePresenter<ReaderActivity> {
     }
 
     private Observable<List<Page>> getPageListObservable() {
-        if (chapter.downloaded != Chapter.DOWNLOADED)
+        if (!isDownloaded)
             return source.pullPageListFromNetwork(chapter.url)
                     .subscribeOn(Schedulers.io())
                     .observeOn(AndroidSchedulers.mainThread());
@@ -107,7 +108,7 @@ public class ReaderPresenter extends BasePresenter<ReaderActivity> {
     private Observable<Page> getPageImagesObservable() {
         Observable<Page> pages;
 
-        if (chapter.downloaded != Chapter.DOWNLOADED) {
+        if (!isDownloaded) {
             pages = Observable
                     .merge(Observable.from(pageList).filter(page -> page.getImageUrl() != null),
                             source.getRemainingImageUrlsFromPageList(pageList))
@@ -129,7 +130,7 @@ public class ReaderPresenter extends BasePresenter<ReaderActivity> {
         this.currentPage = currentPage;
     }
 
-    private void saveChapter() {
+    private void saveChapterProgress() {
         chapter.last_page_read = currentPage;
         if (currentPage == pageList.size() - 1) {
             chapter.read = true;

app/src/main/java/eu/kanade/mangafeed/ui/fragment/MangaChaptersFragment.java

@@ -144,6 +144,10 @@ public class MangaChaptersFragment extends BaseRxFragment<MangaChaptersPresenter
                 getPresenter().downloadChapters(getSelectedChapters());
                 closeActionMode();
                 return true;
+            case R.id.action_delete:
+                getPresenter().deleteChapters(getSelectedChapters());
+                closeActionMode();
+                return true;
         }
         return false;
     }

app/src/main/res/menu/chapter_selection.xml

@@ -8,6 +8,11 @@
         android:icon="@drawable/ic_file_download"
         app:showAsAction="ifRoom"/>
 
+    <item android:id="@+id/action_delete"
+        android:title="@string/action_delete"
+        android:icon="@drawable/ic_action_delete"
+        app:showAsAction="ifRoom"/>
+
     <item android:id="@+id/action_mark_as_read"
         android:title="@string/action_mark_as_read"
         android:icon="@drawable/ic_action_done_all"