Auto Download: Exponential backoff when file 404s

4 files changed, 62 insertions, 14 deletions

diff --git a/core/src/main/java/de/danoeh/antennapod/core/feed/FeedItem.java b/core/src/main/java/de/danoeh/antennapod/core/feed/FeedItem.java
index c54cc1d5b..00b32de5f 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/feed/FeedItem.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/feed/FeedItem.java
@@ -11,6 +11,7 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.Callable;
+import java.util.concurrent.TimeUnit;
 
 import de.danoeh.antennapod.core.asynctask.ImageResource;
 import de.danoeh.antennapod.core.storage.DBReader;
@@ -75,7 +76,13 @@ public class FeedItem extends FeedComponent implements ShownotesProvider, Flattr
     private List<Chapter> chapters;
     private FeedImage image;
 
-    private boolean autoDownload = true;
+    /*
+     *   0: auto download disabled
+     *   1: auto download enabled
+     * > 1: auto download enabled, (approx.) timestamp of the last failed attempt
+     *      where last digit denotes the number of failed attempts
+     */
+    private long autoDownload = 0;
 
     /**
      * Any tags assigned to this item
@@ -93,7 +100,7 @@ public class FeedItem extends FeedComponent implements ShownotesProvider, Flattr
      * */
     public FeedItem(long id, String title, String link, Date pubDate, String paymentLink, long feedId,
                     FlattrStatus flattrStatus, boolean hasChapters, FeedImage image, int state,
-                    String itemIdentifier, boolean autoDownload) {
+                    String itemIdentifier, long autoDownload) {
         this.id = id;
         this.title = title;
         this.link = link;
@@ -162,7 +169,7 @@ public class FeedItem extends FeedComponent implements ShownotesProvider, Flattr
         FlattrStatus flattrStatus = new FlattrStatus(cursor.getLong(indexFlattrStatus));
         int state = cursor.getInt(indexRead);
         String itemIdentifier = cursor.getString(indexItemIdentifier);
-        boolean autoDownload = cursor.getInt(indexAutoDownload) > 0;
+        long autoDownload = cursor.getLong(indexAutoDownload);
 
         FeedItem item = new FeedItem(id, title, link, pubDate, paymentLink, feedId, flattrStatus,
                 hasChapters, null, state, itemIdentifier, autoDownload);
@@ -449,18 +456,37 @@ public class FeedItem extends FeedComponent implements ShownotesProvider, Flattr
     }
 
     public void setAutoDownload(boolean autoDownload) {
-        this.autoDownload = autoDownload;
+        this.autoDownload = autoDownload ? 1 : 0;
     }
 
     public boolean getAutoDownload() {
-        return this.autoDownload;
+        return this.autoDownload > 0;
+    }
+
+    public int getFailedAutoDownloadAttempts() {
+        if (autoDownload <= 1) {
+            return 0;
+        }
+        int failedAttempts = (int)(autoDownload % 10);
+        if (failedAttempts == 0) {
+            failedAttempts = 10;
+        }
+        return failedAttempts;
     }
 
     public boolean isAutoDownloadable() {
-        return this.hasMedia() &&
-                false == this.getMedia().isPlaying() &&
-                false == this.getMedia().isDownloaded() &&
-                this.getAutoDownload();
+        if (media == null || media.isPlaying() || media.isDownloaded() || autoDownload == 0) {
+            return false;
+        }
+        if (autoDownload == 1) {
+            return true;
+        }
+        int failedAttempts = getFailedAutoDownloadAttempts();
+        double magicValue = 1.767; // 1.767^(10[=#maxNumAttempts]-1) = 168 hours / 7 days
+        int millisecondsInHour = 3600000;
+        long waitingTime = (long) (Math.pow(magicValue, failedAttempts - 1) * millisecondsInHour);
+        long grace = TimeUnit.MINUTES.toMillis(5);
+        return System.currentTimeMillis() > (autoDownload + waitingTime - grace);
     }
 
     /**
diff --git a/core/src/main/java/de/danoeh/antennapod/core/service/download/DownloadService.java b/core/src/main/java/de/danoeh/antennapod/core/service/download/DownloadService.java
index bb7ff29d4..c3afff276 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/service/download/DownloadService.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/service/download/DownloadService.java
@@ -206,8 +206,7 @@ public class DownloadService extends Service {
                                     FeedItem item = media.getItem();
                                     if (status.getReason() == DownloadError.ERROR_HTTP_DATA_ERROR &&
                                             Integer.valueOf(status.getReasonDetailed()) == HttpURLConnection.HTTP_NOT_FOUND) {
-                                        item.setAutoDownload(false); // for event bus
-                                        DBWriter.setFeedItemAutoDownload(item, false);
+                                        DBWriter.saveFeedItemAutoDownloadFailed(item).get();
                                     }
                                     // to make lists reload the failed item, we fake an item update
                                     EventBus.getDefault().post(FeedItemEvent.updated(item));
diff --git a/core/src/main/java/de/danoeh/antennapod/core/storage/DBWriter.java b/core/src/main/java/de/danoeh/antennapod/core/storage/DBWriter.java
index f74064cfc..d1d6bd750 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/storage/DBWriter.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/storage/DBWriter.java
@@ -977,13 +977,35 @@ public class DBWriter {
      * Sets the 'auto_download'-attribute of specific FeedItem.
      *
      * @param feedItem  FeedItem.
+     * @param autoDownload true enables auto download, false disables it
      */
     public static Future<?> setFeedItemAutoDownload(final FeedItem feedItem,
                                                     final boolean autoDownload) {
-        Log.d(TAG, "FeedItem[id=" + feedItem.getId() + "] SET auto_download " + autoDownload);
         return dbExec.submit(() -> {
             final PodDBAdapter adapter = PodDBAdapter.getInstance();
             adapter.open();
+            adapter.setFeedItemAutoDownload(feedItem, autoDownload ? 1 : 0);
+            adapter.close();
+            EventDistributor.getInstance().sendUnreadItemsUpdateBroadcast();
+        });
+    }
+
+    public static Future<?> saveFeedItemAutoDownloadFailed(final FeedItem feedItem) {
+        return dbExec.submit(() -> {
+            int failedAttempts = feedItem.getFailedAutoDownloadAttempts() + 1;
+            Log.d(TAG, "failedAttempts: " + failedAttempts);
+            long autoDownload;
+            if(!feedItem.getAutoDownload() || failedAttempts >= 10) {
+                autoDownload = 0; // giving up, disable auto download
+                feedItem.setAutoDownload(false);
+            } else {
+                long now = System.currentTimeMillis();
+                autoDownload = (now / 10) * 10 + failedAttempts;
+                Log.d(TAG, "now: " + now);
+                Log.d(TAG, "autoDownload: " + autoDownload);
+            }
+            final PodDBAdapter adapter = PodDBAdapter.getInstance();
+            adapter.open();
             adapter.setFeedItemAutoDownload(feedItem, autoDownload);
             adapter.close();
             EventDistributor.getInstance().sendUnreadItemsUpdateBroadcast();
@@ -992,7 +1014,8 @@ public class DBWriter {
 
     /**
      * Sets the 'auto_download'-attribute of specific FeedItem.
-     *  @param feed This feed's episodes will be processed.
+     *
+     * @param feed         This feed's episodes will be processed.
      * @param autoDownload If true, auto download will be enabled for the feed's episodes. Else,
      */
     public static Future<?> setFeedsItemsAutoDownload(final Feed feed,
diff --git a/core/src/main/java/de/danoeh/antennapod/core/storage/PodDBAdapter.java b/core/src/main/java/de/danoeh/antennapod/core/storage/PodDBAdapter.java
index 629b73668..915ca14c7 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/storage/PodDBAdapter.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/storage/PodDBAdapter.java
@@ -794,7 +794,7 @@ public class PodDBAdapter {
         return status.getId();
     }
 
-    public void setFeedItemAutoDownload(FeedItem feedItem, boolean autoDownload) {
+    public void setFeedItemAutoDownload(FeedItem feedItem, long autoDownload) {
         ContentValues values = new ContentValues();
         values.put(KEY_AUTO_DOWNLOAD, autoDownload);
         db.update(TABLE_NAME_FEED_ITEMS, values, KEY_ID + "=?",