Initial download manager

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

@@ -0,0 +1,128 @@
+package eu.kanade.mangafeed.data.helpers;
+
+import android.content.Context;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.List;
+
+import eu.kanade.mangafeed.data.models.Chapter;
+import eu.kanade.mangafeed.data.models.Manga;
+import eu.kanade.mangafeed.data.models.Page;
+import eu.kanade.mangafeed.events.DownloadChapterEvent;
+import eu.kanade.mangafeed.sources.base.Source;
+import eu.kanade.mangafeed.util.DiskUtils;
+import rx.Observable;
+import rx.Subscription;
+import rx.schedulers.Schedulers;
+import rx.subjects.PublishSubject;
+
+public class DownloadManager {
+
+    private PublishSubject<DownloadChapterEvent> downloadsSubject;
+    private Subscription downloadsSubscription;
+
+    private Context context;
+    private SourceManager sourceManager;
+
+    public DownloadManager(Context context, SourceManager sourceManager) {
+        this.context = context;
+        this.sourceManager = sourceManager;
+
+        initializeDownloadSubscription();
+    }
+
+    private void initializeDownloadSubscription() {
+        if (downloadsSubscription != null && !downloadsSubscription.isUnsubscribed()) {
+            downloadsSubscription.unsubscribe();
+        }
+
+        downloadsSubject = PublishSubject.create();
+
+        downloadsSubscription = downloadsSubject
+                .subscribeOn(Schedulers.io())
+                .concatMap(event -> downloadChapter(event.getManga(), event.getChapter()))
+                .onBackpressureBuffer()
+                .subscribe();
+    }
+
+    private Observable<Page> downloadChapter(Manga manga, Chapter chapter) {
+        final Source source = sourceManager.get(manga.source);
+        final File chapterDirectory = new File(getDownloadsDirectory(), getChapterDirectory(chapter));
+
+        return source
+                .pullPageListFromNetwork(chapter.url)
+                // Ensure we don't download a chapter already downloaded
+                .filter(pages -> !isChapterDownloaded(chapterDirectory, pages))
+                // Get all the URLs to the source images, fetch pages if necessary
+                .flatMap(pageList -> Observable.merge(
+                        Observable.from(pageList).filter(page -> page.getImageUrl() != null),
+                        source.getRemainingImageUrlsFromPageList(pageList)))
+                // Start downloading images
+                .flatMap(page -> getDownloadedImage(page, source, chapterDirectory));
+    }
+
+    private File getDownloadsDirectory() {
+        // TODO
+        return new File(DiskUtils.getStorageDirectories(context)[0]);
+    }
+
+    private String getChapterDirectory(Chapter chapter) {
+        return chapter.name.replaceAll("[^a-zA-Z0-9.-]", "_");
+    }
+
+    private String getImageFilename(Page page) {
+        return page.getImageUrl().substring(
+                page.getImageUrl().lastIndexOf("/") + 1,
+                page.getImageUrl().length());
+    }
+
+    private boolean isChapterDownloaded(File chapterDir, List<Page> pages) {
+        return chapterDir.exists() && chapterDir.listFiles().length == pages.size();
+    }
+
+    private boolean isImageDownloaded(File imagePath) {
+        return imagePath.exists() && !imagePath.isDirectory();
+    }
+
+    public Observable<Page> getDownloadedImage(final Page page, Source source, File chapterDir) {
+        Observable<Page> obs = Observable.just(page);
+        if (page.getImageUrl() == null)
+            return obs;
+
+        String imageFilename = getImageFilename(page);
+        File imagePath = new File(chapterDir, imageFilename);
+
+        if (!isImageDownloaded(imagePath)) {
+            page.setStatus(Page.DOWNLOAD_IMAGE);
+            obs = downloadImage(page, source, chapterDir, imageFilename);
+        }
+
+        return obs.flatMap(p -> {
+            page.setImagePath(imagePath.getAbsolutePath());
+            page.setStatus(Page.READY);
+            return Observable.just(page);
+        }).onErrorResumeNext(e -> {
+            page.setStatus(Page.ERROR);
+            return Observable.just(page);
+        });
+    }
+
+    private Observable<Page> downloadImage(final Page page, Source source, File chapterDir, String imageFilename) {
+        return source.getImageProgressResponse(page)
+                .flatMap(resp -> {
+                    try {
+                        DiskUtils.saveBufferedSourceToDirectory(resp.body().source(), chapterDir, imageFilename);
+                    } catch (IOException e) {
+                        e.printStackTrace();
+                        throw new IllegalStateException("Unable to save image");
+                    }
+                    return Observable.just(page);
+                });
+    }
+
+    public PublishSubject<DownloadChapterEvent> getDownloadsSubject() {
+        return downloadsSubject;
+    }
+
+}

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

@@ -6,6 +6,7 @@ import android.preference.PreferenceManager;
 
 import eu.kanade.mangafeed.R;
 import eu.kanade.mangafeed.sources.base.Source;
+import eu.kanade.mangafeed.util.DiskUtils;
 
 public class PreferencesHelper {
 
@@ -53,4 +54,9 @@ public class PreferencesHelper {
                 .apply();
     }
 
+    public String getDownloadsDirectory() {
+        return mPref.getString(getKey(R.string.pref_download_directory_key),
+                DiskUtils.getStorageDirectories(context)[0]);
+    }
+
 }

app/src/main/java/eu/kanade/mangafeed/data/services/DownloadService.java

@@ -0,0 +1,58 @@
+package eu.kanade.mangafeed.data.services;
+
+import android.app.Service;
+import android.content.Context;
+import android.content.Intent;
+import android.os.IBinder;
+
+import javax.inject.Inject;
+
+import de.greenrobot.event.EventBus;
+import eu.kanade.mangafeed.App;
+import eu.kanade.mangafeed.data.helpers.DownloadManager;
+import eu.kanade.mangafeed.events.DownloadChapterEvent;
+import eu.kanade.mangafeed.util.AndroidComponentUtil;
+import eu.kanade.mangafeed.util.EventBusHook;
+
+public class DownloadService extends Service {
+
+    @Inject DownloadManager downloadManager;
+
+    public static Intent getStartIntent(Context context) {
+        return new Intent(context, DownloadService.class);
+    }
+
+    public static boolean isRunning(Context context) {
+        return AndroidComponentUtil.isServiceRunning(context, DownloadService.class);
+    }
+
+    @Override
+    public void onCreate() {
+        super.onCreate();
+        App.get(this).getComponent().inject(this);
+
+        EventBus.getDefault().register(this);
+    }
+
+    @Override
+    public int onStartCommand(Intent intent, int flags, int startId) {
+        return START_STICKY;
+    }
+
+    @Override
+    public IBinder onBind(Intent intent) {
+        return null;
+    }
+
+    @EventBusHook
+    public void onEvent(DownloadChapterEvent event) {
+        downloadManager.getDownloadsSubject().onNext(event);
+    }
+
+    @Override
+    public void onDestroy() {
+        EventBus.getDefault().unregister(this);
+        super.onDestroy();
+    }
+
+}