Merge pull request #5133 from ByteHamster/sync-module

Moved synchronization to its own module

41 files changed, 261 insertions, 120 deletions

diff --git a/app/build.gradle b/app/build.gradle
index 6156d1536..2c622cd91 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -164,6 +164,8 @@ android {
 dependencies {
     implementation project(":core")
     implementation project(':model')
+    implementation project(':net:sync:gpoddernet')
+    implementation project(':net:sync:model')
     implementation project(':ui:app-start-intent')
     implementation project(':ui:common')
 
diff --git a/app/src/androidTest/java/de/test/antennapod/gpodnet/GPodnetServiceTest.java b/app/src/androidTest/java/de/test/antennapod/gpodnet/GPodnetServiceTest.java
index 9b3422a5d..f1d71b07a 100644
--- a/app/src/androidTest/java/de/test/antennapod/gpodnet/GPodnetServiceTest.java
+++ b/app/src/androidTest/java/de/test/antennapod/gpodnet/GPodnetServiceTest.java
@@ -6,10 +6,10 @@ import java.util.List;
 
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import de.danoeh.antennapod.core.service.download.AntennapodHttpClient;
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetService;
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetServiceException;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetDevice;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetTag;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetService;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetServiceException;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetDevice;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetTag;
 import org.junit.Before;
 import org.junit.Ignore;
 import org.junit.Test;
@@ -28,14 +28,16 @@ public class GPodnetServiceTest {
 
     private static final String USER = "";
     private static final String PW = "";
+    private static final String DEVICE_ID = "radio";
 
     @Before
     public void setUp() {
-        service = new GpodnetService(AntennapodHttpClient.getHttpClient(), GpodnetService.DEFAULT_BASE_HOST);
+        service = new GpodnetService(AntennapodHttpClient.getHttpClient(),
+                GpodnetService.DEFAULT_BASE_HOST, DEVICE_ID, USER, PW);
     }
 
     private void authenticate() throws GpodnetServiceException {
-        service.authenticate(USER, PW);
+        service.login();
     }
 
     @Test
@@ -43,7 +45,7 @@ public class GPodnetServiceTest {
         authenticate();
         ArrayList<String> l = new ArrayList<>();
         l.add("http://bitsundso.de/feed");
-        service.uploadSubscriptions("radio", l);
+        service.uploadSubscriptions(DEVICE_ID, l);
     }
 
     @Test
@@ -52,7 +54,7 @@ public class GPodnetServiceTest {
         ArrayList<String> l = new ArrayList<>();
         l.add("http://bitsundso.de/feed");
         l.add("http://gamesundso.de/feed");
-        service.uploadSubscriptions("radio", l);
+        service.uploadSubscriptions(DEVICE_ID, l);
     }
 
     @Test
@@ -62,14 +64,14 @@ public class GPodnetServiceTest {
         List<String> subscriptions = Arrays.asList(URLS[0], URLS[1]);
         List<String> removed = singletonList(URLS[0]);
         List<String> added = Arrays.asList(URLS[2], URLS[3]);
-        service.uploadSubscriptions("radio", subscriptions);
-        service.uploadChanges("radio", added, removed);
+        service.uploadSubscriptions(DEVICE_ID, subscriptions);
+        service.uploadSubscriptionChanges(added, removed);
     }
 
     @Test
     public void testGetSubscriptionChanges() throws GpodnetServiceException {
         authenticate();
-        service.getSubscriptionChanges("radio", 1362322610L);
+        service.getSubscriptionChanges(1362322610L);
     }
 
     @Test
@@ -83,7 +85,7 @@ public class GPodnetServiceTest {
     public void testGetSubscriptionsOfDevice()
             throws GpodnetServiceException {
         authenticate();
-        service.getSubscriptionsOfDevice("radio");
+        service.getSubscriptionsOfDevice(DEVICE_ID);
     }
 
     @Test
diff --git a/app/src/main/java/de/danoeh/antennapod/adapter/gpodnet/PodcastListAdapter.java b/app/src/main/java/de/danoeh/antennapod/adapter/gpodnet/PodcastListAdapter.java
index 25fc0a05c..a125515cc 100644
--- a/app/src/main/java/de/danoeh/antennapod/adapter/gpodnet/PodcastListAdapter.java
+++ b/app/src/main/java/de/danoeh/antennapod/adapter/gpodnet/PodcastListAdapter.java
@@ -13,7 +13,7 @@ import com.bumptech.glide.Glide;
 import com.bumptech.glide.load.resource.bitmap.FitCenter;
 import com.bumptech.glide.load.resource.bitmap.RoundedCorners;
 import com.bumptech.glide.request.RequestOptions;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetPodcast;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetPodcast;
 import org.apache.commons.lang3.StringUtils;
 
 
diff --git a/app/src/main/java/de/danoeh/antennapod/adapter/gpodnet/TagListAdapter.java b/app/src/main/java/de/danoeh/antennapod/adapter/gpodnet/TagListAdapter.java
index 698e43145..b0441688d 100644
--- a/app/src/main/java/de/danoeh/antennapod/adapter/gpodnet/TagListAdapter.java
+++ b/app/src/main/java/de/danoeh/antennapod/adapter/gpodnet/TagListAdapter.java
@@ -8,7 +8,7 @@ import android.widget.ArrayAdapter;
 import android.widget.TextView;
 
 import de.danoeh.antennapod.R;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetTag;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetTag;
 
 import java.util.List;
 
diff --git a/app/src/main/java/de/danoeh/antennapod/discovery/GpodnetPodcastSearcher.java b/app/src/main/java/de/danoeh/antennapod/discovery/GpodnetPodcastSearcher.java
index 6de2186e0..f97c1c7ab 100644
--- a/app/src/main/java/de/danoeh/antennapod/discovery/GpodnetPodcastSearcher.java
+++ b/app/src/main/java/de/danoeh/antennapod/discovery/GpodnetPodcastSearcher.java
@@ -2,9 +2,9 @@ package de.danoeh.antennapod.discovery;
 
 import de.danoeh.antennapod.core.preferences.GpodnetPreferences;
 import de.danoeh.antennapod.core.service.download.AntennapodHttpClient;
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetService;
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetServiceException;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetPodcast;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetService;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetServiceException;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetPodcast;
 import io.reactivex.Single;
 import io.reactivex.SingleOnSubscribe;
 import io.reactivex.android.schedulers.AndroidSchedulers;
@@ -18,7 +18,8 @@ public class GpodnetPodcastSearcher implements PodcastSearcher {
         return Single.create((SingleOnSubscribe<List<PodcastSearchResult>>) subscriber -> {
             try {
                 GpodnetService service = new GpodnetService(AntennapodHttpClient.getHttpClient(),
-                        GpodnetPreferences.getHosturl());
+                        GpodnetPreferences.getHosturl(), GpodnetPreferences.getDeviceID(),
+                        GpodnetPreferences.getUsername(), GpodnetPreferences.getPassword());
                 List<GpodnetPodcast> gpodnetPodcasts = service.searchPodcasts(query, 0);
                 List<PodcastSearchResult> results = new ArrayList<>();
                 for (GpodnetPodcast podcast : gpodnetPodcasts) {
diff --git a/app/src/main/java/de/danoeh/antennapod/discovery/PodcastSearchResult.java b/app/src/main/java/de/danoeh/antennapod/discovery/PodcastSearchResult.java
index bba438d1d..767845cb4 100644
--- a/app/src/main/java/de/danoeh/antennapod/discovery/PodcastSearchResult.java
+++ b/app/src/main/java/de/danoeh/antennapod/discovery/PodcastSearchResult.java
@@ -1,7 +1,7 @@
 package de.danoeh.antennapod.discovery;
 
 import androidx.annotation.Nullable;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetPodcast;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetPodcast;
 import de.mfietz.fyydlin.SearchHit;
 import org.json.JSONArray;
 import org.json.JSONException;
diff --git a/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/PodcastListFragment.java b/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/PodcastListFragment.java
index 7ee0936d0..c813cbf7a 100644
--- a/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/PodcastListFragment.java
+++ b/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/PodcastListFragment.java
@@ -17,9 +17,9 @@ import de.danoeh.antennapod.activity.OnlineFeedViewActivity;
 import de.danoeh.antennapod.adapter.gpodnet.PodcastListAdapter;
 import de.danoeh.antennapod.core.preferences.GpodnetPreferences;
 import de.danoeh.antennapod.core.service.download.AntennapodHttpClient;
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetService;
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetServiceException;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetPodcast;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetService;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetServiceException;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetPodcast;
 import io.reactivex.Observable;
 import io.reactivex.android.schedulers.AndroidSchedulers;
 import io.reactivex.disposables.Disposable;
@@ -76,7 +76,8 @@ public abstract class PodcastListFragment extends Fragment {
         disposable = Observable.fromCallable(
                 () -> {
                     GpodnetService service = new GpodnetService(AntennapodHttpClient.getHttpClient(),
-                            GpodnetPreferences.getHosturl());
+                            GpodnetPreferences.getHosturl(), GpodnetPreferences.getDeviceID(),
+                            GpodnetPreferences.getUsername(), GpodnetPreferences.getPassword());
                     return loadPodcastData(service);
                 })
                 .subscribeOn(Schedulers.io())
diff --git a/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/PodcastTopListFragment.java b/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/PodcastTopListFragment.java
index 64261493d..f51ab032f 100644
--- a/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/PodcastTopListFragment.java
+++ b/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/PodcastTopListFragment.java
@@ -1,8 +1,8 @@
 package de.danoeh.antennapod.fragment.gpodnet;
 
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetService;
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetServiceException;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetPodcast;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetService;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetServiceException;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetPodcast;
 
 import java.util.List;
 
diff --git a/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/SuggestionListFragment.java b/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/SuggestionListFragment.java
index 41b99cdfc..e3cdb8959 100644
--- a/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/SuggestionListFragment.java
+++ b/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/SuggestionListFragment.java
@@ -4,9 +4,9 @@ import java.util.Collections;
 import java.util.List;
 
 import de.danoeh.antennapod.core.preferences.GpodnetPreferences;
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetService;
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetServiceException;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetPodcast;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetService;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetServiceException;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetPodcast;
 
 /**
  * Displays suggestions from gpodder.net
@@ -17,7 +17,7 @@ public class SuggestionListFragment extends PodcastListFragment {
     @Override
     protected List<GpodnetPodcast> loadPodcastData(GpodnetService service) throws GpodnetServiceException {
         if (GpodnetPreferences.loggedIn()) {
-            service.authenticate(GpodnetPreferences.getUsername(), GpodnetPreferences.getPassword());
+            service.login();
             return service.getSuggestions(SUGGESTIONS_COUNT);
         } else {
             return Collections.emptyList();
diff --git a/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/TagFragment.java b/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/TagFragment.java
index c6c00eb34..62e2e30d1 100644
--- a/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/TagFragment.java
+++ b/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/TagFragment.java
@@ -5,10 +5,10 @@ import androidx.annotation.NonNull;
 
 import java.util.List;
 
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetService;
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetServiceException;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetPodcast;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetTag;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetService;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetServiceException;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetPodcast;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetTag;
 
 /**
  * Shows all podcasts from gpodder.net that belong to a specific tag.
diff --git a/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/TagListFragment.java b/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/TagListFragment.java
index 9d0f99aa9..f961e30bb 100644
--- a/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/TagListFragment.java
+++ b/app/src/main/java/de/danoeh/antennapod/fragment/gpodnet/TagListFragment.java
@@ -10,8 +10,8 @@ import de.danoeh.antennapod.activity.MainActivity;
 import de.danoeh.antennapod.adapter.gpodnet.TagListAdapter;
 import de.danoeh.antennapod.core.preferences.GpodnetPreferences;
 import de.danoeh.antennapod.core.service.download.AntennapodHttpClient;
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetService;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetTag;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetService;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetTag;
 import io.reactivex.Observable;
 import io.reactivex.android.schedulers.AndroidSchedulers;
 import io.reactivex.disposables.Disposable;
@@ -51,7 +51,8 @@ public class TagListFragment extends ListFragment {
         disposable = Observable.fromCallable(
             () -> {
                 GpodnetService service = new GpodnetService(AntennapodHttpClient.getHttpClient(),
-                        GpodnetPreferences.getHosturl());
+                        GpodnetPreferences.getHosturl(), GpodnetPreferences.getDeviceID(),
+                        GpodnetPreferences.getUsername(), GpodnetPreferences.getPassword());
                 return service.getTopTags(COUNT);
             })
                 .subscribeOn(Schedulers.io())
diff --git a/app/src/main/java/de/danoeh/antennapod/fragment/preferences/GpodderAuthenticationFragment.java b/app/src/main/java/de/danoeh/antennapod/fragment/preferences/GpodderAuthenticationFragment.java
index 6eb19aff2..c0bf3e0ea 100644
--- a/app/src/main/java/de/danoeh/antennapod/fragment/preferences/GpodderAuthenticationFragment.java
+++ b/app/src/main/java/de/danoeh/antennapod/fragment/preferences/GpodderAuthenticationFragment.java
@@ -25,8 +25,8 @@ import de.danoeh.antennapod.R;
 import de.danoeh.antennapod.core.preferences.GpodnetPreferences;
 import de.danoeh.antennapod.core.service.download.AntennapodHttpClient;
 import de.danoeh.antennapod.core.sync.SyncService;
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetService;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetDevice;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetService;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetDevice;
 import de.danoeh.antennapod.core.util.FileNameGenerator;
 import de.danoeh.antennapod.core.util.IntentUtils;
 import io.reactivex.Completable;
@@ -96,7 +96,9 @@ public class GpodderAuthenticationFragment extends DialogFragment {
             } else {
                 GpodnetPreferences.setHosturl(GpodnetService.DEFAULT_BASE_HOST);
             }
-            service = new GpodnetService(AntennapodHttpClient.getHttpClient(), GpodnetPreferences.getHosturl());
+            service = new GpodnetService(AntennapodHttpClient.getHttpClient(),
+                    GpodnetPreferences.getHosturl(), GpodnetPreferences.getDeviceID(),
+                    GpodnetPreferences.getUsername(), GpodnetPreferences.getPassword());
             getDialog().setTitle(GpodnetPreferences.getHosturl());
             advance();
         });
@@ -138,7 +140,8 @@ public class GpodderAuthenticationFragment extends DialogFragment {
             inputManager.hideSoftInputFromWindow(login.getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS);
 
             Completable.fromAction(() -> {
-                service.authenticate(usernameStr, passwordStr);
+                service.setCredentials(usernameStr, passwordStr);
+                service.login();
                 devices = service.getDevices();
                 GpodderAuthenticationFragment.this.username = usernameStr;
                 GpodderAuthenticationFragment.this.password = passwordStr;
diff --git a/app/src/main/java/de/danoeh/antennapod/menuhandler/FeedItemMenuHandler.java b/app/src/main/java/de/danoeh/antennapod/menuhandler/FeedItemMenuHandler.java
index 7cf483052..d478c581d 100644
--- a/app/src/main/java/de/danoeh/antennapod/menuhandler/FeedItemMenuHandler.java
+++ b/app/src/main/java/de/danoeh/antennapod/menuhandler/FeedItemMenuHandler.java
@@ -20,7 +20,7 @@ import de.danoeh.antennapod.core.preferences.UserPreferences;
 import de.danoeh.antennapod.core.service.playback.PlaybackService;
 import de.danoeh.antennapod.core.storage.DBWriter;
 import de.danoeh.antennapod.core.sync.SyncService;
-import de.danoeh.antennapod.core.sync.model.EpisodeAction;
+import de.danoeh.antennapod.net.sync.model.EpisodeAction;
 import de.danoeh.antennapod.core.util.FeedItemUtil;
 import de.danoeh.antennapod.core.util.IntentUtils;
 import de.danoeh.antennapod.core.util.ShareUtils;
diff --git a/core/build.gradle b/core/build.gradle
index e5ab13bcd..f9c09c7bc 100644
--- a/core/build.gradle
+++ b/core/build.gradle
@@ -75,6 +75,8 @@ android {
 dependencies {
     implementation project(':model')
     implementation project(':net:ssl')
+    implementation project(':net:sync:gpoddernet')
+    implementation project(':net:sync:model')
     implementation project(':ui:app-start-intent')
     implementation project(':ui:common')
     implementation project(':ui:png-icons')
diff --git a/core/src/main/java/de/danoeh/antennapod/core/preferences/GpodnetPreferences.java b/core/src/main/java/de/danoeh/antennapod/core/preferences/GpodnetPreferences.java
index 209558b19..e338e0d01 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/preferences/GpodnetPreferences.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/preferences/GpodnetPreferences.java
@@ -6,7 +6,7 @@ import android.util.Log;
 import de.danoeh.antennapod.core.BuildConfig;
 import de.danoeh.antennapod.core.ClientConfig;
 import de.danoeh.antennapod.core.sync.SyncService;
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetService;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetService;
 
 /**
  * Manages preferences for accessing gpodder.net service
diff --git a/core/src/main/java/de/danoeh/antennapod/core/service/download/handler/MediaDownloadedHandler.java b/core/src/main/java/de/danoeh/antennapod/core/service/download/handler/MediaDownloadedHandler.java
index 2d0efd22a..8c9035621 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/service/download/handler/MediaDownloadedHandler.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/service/download/handler/MediaDownloadedHandler.java
@@ -19,7 +19,7 @@ import de.danoeh.antennapod.core.storage.DBWriter;
 import de.danoeh.antennapod.core.util.ChapterUtils;
 import de.danoeh.antennapod.core.util.DownloadError;
 import de.danoeh.antennapod.core.sync.SyncService;
-import de.danoeh.antennapod.core.sync.model.EpisodeAction;
+import de.danoeh.antennapod.net.sync.model.EpisodeAction;
 import org.greenrobot.eventbus.EventBus;
 
 /**
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 cf3983910..3231c3779 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
@@ -8,7 +8,7 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
 import de.danoeh.antennapod.core.sync.SyncService;
-import de.danoeh.antennapod.core.sync.model.EpisodeAction;
+import de.danoeh.antennapod.net.sync.model.EpisodeAction;
 import org.greenrobot.eventbus.EventBus;
 
 import java.io.File;
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/SyncService.java b/core/src/main/java/de/danoeh/antennapod/core/sync/SyncService.java
index 21b217e66..4736a2c33 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/SyncService.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/sync/SyncService.java
@@ -32,17 +32,17 @@ import de.danoeh.antennapod.core.storage.DBTasks;
 import de.danoeh.antennapod.core.storage.DBWriter;
 import de.danoeh.antennapod.core.storage.DownloadRequestException;
 import de.danoeh.antennapod.core.storage.DownloadRequester;
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetService;
-import de.danoeh.antennapod.core.sync.model.EpisodeAction;
-import de.danoeh.antennapod.core.sync.model.EpisodeActionChanges;
-import de.danoeh.antennapod.core.sync.model.ISyncService;
-import de.danoeh.antennapod.core.sync.model.SubscriptionChanges;
-import de.danoeh.antennapod.core.sync.model.SyncServiceException;
-import de.danoeh.antennapod.core.sync.model.UploadChangesResponse;
 import de.danoeh.antennapod.core.util.FeedItemUtil;
 import de.danoeh.antennapod.core.util.LongList;
 import de.danoeh.antennapod.core.util.URLChecker;
 import de.danoeh.antennapod.core.util.gui.NotificationUtils;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetService;
+import de.danoeh.antennapod.net.sync.model.EpisodeAction;
+import de.danoeh.antennapod.net.sync.model.EpisodeActionChanges;
+import de.danoeh.antennapod.net.sync.model.ISyncService;
+import de.danoeh.antennapod.net.sync.model.SubscriptionChanges;
+import de.danoeh.antennapod.net.sync.model.SyncServiceException;
+import de.danoeh.antennapod.net.sync.model.UploadChangesResponse;
 import io.reactivex.Completable;
 import io.reactivex.schedulers.Schedulers;
 import org.apache.commons.lang3.StringUtils;
@@ -81,7 +81,9 @@ public class SyncService extends Worker {
         if (!GpodnetPreferences.loggedIn()) {
             return Result.success();
         }
-        syncServiceImpl = new GpodnetService(AntennapodHttpClient.getHttpClient(), GpodnetPreferences.getHosturl());
+        syncServiceImpl = new GpodnetService(AntennapodHttpClient.getHttpClient(),
+                GpodnetPreferences.getHosturl(), GpodnetPreferences.getDeviceID(),
+                GpodnetPreferences.getUsername(), GpodnetPreferences.getPassword());
         SharedPreferences.Editor prefs = getApplicationContext().getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE)
                 .edit();
         prefs.putLong(PREF_LAST_SYNC_ATTEMPT_TIMESTAMP, System.currentTimeMillis()).apply();
diff --git a/net/sync/README.md b/net/sync/README.md
new file mode 100644
index 000000000..ec3a5d3a7
--- /dev/null
+++ b/net/sync/README.md
@@ -0,0 +1,3 @@
+# :net:sync
+
+This folder contains modules related to external services for synchronization. The module `model` provides the basic interfaces for implementing a synchronization backend. The other modules contains backends for specific synchronization services.
diff --git a/net/sync/gpoddernet/README.md b/net/sync/gpoddernet/README.md
new file mode 100644
index 000000000..1f8bb95bd
--- /dev/null
+++ b/net/sync/gpoddernet/README.md
@@ -0,0 +1,3 @@
+# :net:sync:gpoddernet
+
+This module contains the sync backend for the open-source podcast synchronization service "Gpodder.net".
diff --git a/net/sync/gpoddernet/build.gradle b/net/sync/gpoddernet/build.gradle
new file mode 100644
index 000000000..cd6d8d04c
--- /dev/null
+++ b/net/sync/gpoddernet/build.gradle
@@ -0,0 +1,57 @@
+apply plugin: "com.android.library"
+
+android {
+    compileSdkVersion rootProject.ext.compileSdkVersion
+
+    defaultConfig {
+        minSdkVersion rootProject.ext.minSdkVersion
+        targetSdkVersion rootProject.ext.targetSdkVersion
+
+        multiDexEnabled false
+
+        testApplicationId "de.danoeh.antennapod.core.tests"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+    }
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile("proguard-android.txt")
+        }
+        debug {
+            // debug build has method count over 64k single-dex threshold.
+            // For building debug build to use on Android < 21 (pre-Android 5) devices,
+            // you need to manually change class
+            // de.danoeh.antennapod.PodcastApp to extend MultiDexApplication .
+            // See Issue #2813
+            multiDexEnabled true
+        }
+    }
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+
+    testOptions {
+        unitTests {
+            includeAndroidResources = true
+        }
+    }
+
+    lintOptions {
+        disable 'GradleDependency'
+        checkDependencies true
+        warningsAsErrors true
+        abortOnError true
+    }
+}
+
+dependencies {
+    implementation project(':net:sync:model')
+
+    annotationProcessor "androidx.annotation:annotation:$annotationVersion"
+    implementation "androidx.appcompat:appcompat:$appcompatVersion"
+
+    implementation "com.squareup.okhttp3:okhttp:$okhttpVersion"
+    implementation "org.apache.commons:commons-lang3:$commonslangVersion"
+}
diff --git a/net/sync/gpoddernet/src/main/AndroidManifest.xml b/net/sync/gpoddernet/src/main/AndroidManifest.xml
new file mode 100644
index 000000000..df37bed3c
--- /dev/null
+++ b/net/sync/gpoddernet/src/main/AndroidManifest.xml
@@ -0,0 +1 @@
+<manifest package="de.danoeh.antennapod.net.sync.gpoddernet" />
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/GpodnetService.java b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/GpodnetService.java
index cd0fc93ea..d41f613a7 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/GpodnetService.java
+++ b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/GpodnetService.java
@@ -1,20 +1,18 @@
-package de.danoeh.antennapod.core.sync.gpoddernet;
+package de.danoeh.antennapod.net.sync.gpoddernet;
 
 import android.util.Log;
 import androidx.annotation.NonNull;
-import de.danoeh.antennapod.core.BuildConfig;
-import de.danoeh.antennapod.core.preferences.GpodnetPreferences;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetDevice;
-import de.danoeh.antennapod.core.sync.model.EpisodeAction;
-import de.danoeh.antennapod.core.sync.model.EpisodeActionChanges;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetEpisodeActionPostResponse;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetPodcast;
-import de.danoeh.antennapod.core.sync.model.ISyncService;
-import de.danoeh.antennapod.core.sync.model.SubscriptionChanges;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetTag;
-import de.danoeh.antennapod.core.sync.gpoddernet.model.GpodnetUploadChangesResponse;
-import de.danoeh.antennapod.core.sync.model.SyncServiceException;
-import de.danoeh.antennapod.core.sync.model.UploadChangesResponse;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetDevice;
+import de.danoeh.antennapod.net.sync.model.EpisodeAction;
+import de.danoeh.antennapod.net.sync.model.EpisodeActionChanges;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetEpisodeActionPostResponse;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetPodcast;
+import de.danoeh.antennapod.net.sync.model.ISyncService;
+import de.danoeh.antennapod.net.sync.model.SubscriptionChanges;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetTag;
+import de.danoeh.antennapod.net.sync.gpoddernet.model.GpodnetUploadChangesResponse;
+import de.danoeh.antennapod.net.sync.model.SyncServiceException;
+import de.danoeh.antennapod.net.sync.model.UploadChangesResponse;
 import okhttp3.Credentials;
 import okhttp3.MediaType;
 import okhttp3.OkHttpClient;
@@ -36,7 +34,6 @@ import java.net.URISyntaxException;
 import java.net.URL;
 import java.nio.charset.Charset;
 import java.util.ArrayList;
-import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
@@ -55,17 +52,24 @@ public class GpodnetService implements ISyncService {
     private static final MediaType TEXT = MediaType.parse("plain/text; charset=utf-8");
     private static final MediaType JSON = MediaType.parse("application/json; charset=utf-8");
     private String baseScheme;
-    private String baseHost;
     private int basePort;
+    private final String baseHost;
+    private final String deviceId;
+    private String username;
+    private String password;
+    private boolean loggedIn = false;
 
     private final OkHttpClient httpClient;
-    private String username = null;
 
     // split into schema, host and port - missing parts are null
     private static Pattern urlsplit_regex = Pattern.compile("(?:(https?)://)?([^:]+)(?::(\\d+))?");
 
-    public GpodnetService(OkHttpClient httpClient, String baseHosturl)  {
+    public GpodnetService(OkHttpClient httpClient, String baseHosturl,
+                          String deviceId, String username, String password)  {
         this.httpClient = httpClient;
+        this.deviceId = deviceId;
+        this.username = username;
+        this.password = password;
 
         Matcher m = urlsplit_regex.matcher(baseHosturl);
         if (m.matches()) {
@@ -97,7 +101,7 @@ public class GpodnetService implements ISyncService {
     }
 
     private void requireLoggedIn() {
-        if (username == null) {
+        if (!loggedIn) {
             throw new IllegalStateException("Not logged in");
         }
     }
@@ -454,7 +458,6 @@ public class GpodnetService implements ISyncService {
      * <p/>
      * This method requires authentication.
      *
-     * @param deviceId The ID of the device whose subscriptions should be updated.
      * @param added    Collection of feed URLs of added feeds. This Collection MUST NOT contain any duplicates
      * @param removed  Collection of feed URLs of removed feeds. This Collection MUST NOT contain any duplicates
      * @return a GpodnetUploadChangesResponse. See {@link GpodnetUploadChangesResponse}
@@ -462,8 +465,9 @@ public class GpodnetService implements ISyncService {
      * @throws GpodnetServiceException            if added or removed contain duplicates or if there
      *                                            is an authentication error.
      */
-    public GpodnetUploadChangesResponse uploadChanges(@NonNull String deviceId, @NonNull Collection<String> added,
-            @NonNull Collection<String> removed) throws GpodnetServiceException {
+    @Override
+    public UploadChangesResponse uploadSubscriptionChanges(List<String> added, List<String> removed)
+            throws GpodnetServiceException {
         requireLoggedIn();
         try {
             URL url = new URI(baseScheme, null, baseHost, basePort,
@@ -490,14 +494,12 @@ public class GpodnetService implements ISyncService {
      * <p/>
      * This method requires authentication.
      *
-     * @param deviceId  The ID of the device whose subscription changes should be
-     *                  downloaded.
      * @param timestamp A timestamp that can be used to receive all changes since a
      *                  specific point in time.
      * @throws GpodnetServiceAuthenticationException If there is an authentication error.
      */
-    public SubscriptionChanges getSubscriptionChanges(@NonNull String deviceId, long timestamp)
-            throws GpodnetServiceException {
+    @Override
+    public SubscriptionChanges getSubscriptionChanges(long timestamp) throws GpodnetServiceException {
         requireLoggedIn();
         String params = String.format(Locale.US, "since=%d", timestamp);
         String path = String.format("/api/2/subscriptions/%s/%s.json", username, deviceId);
@@ -552,7 +554,7 @@ public class GpodnetService implements ISyncService {
                 EpisodeAction episodeAction = episodeActions.get(i);
                 JSONObject obj = episodeAction.writeToJsonObject();
                 if (obj != null) {
-                    obj.put("device", GpodnetPreferences.getDeviceID());
+                    obj.put("device", deviceId);
                     list.put(obj);
                 }
             }
@@ -606,7 +608,8 @@ public class GpodnetService implements ISyncService {
      *
      * @throws IllegalArgumentException If username or password is null.
      */
-    public void authenticate(@NonNull String username, @NonNull String password) throws GpodnetServiceException {
+    @Override
+    public void login() throws GpodnetServiceException {
         URL url;
         try {
             url = new URI(baseScheme, null, baseHost, basePort,
@@ -623,7 +626,7 @@ public class GpodnetService implements ISyncService {
             Response response = httpClient.newCall(authRequest).execute();
             checkStatusCode(response);
             response.body().close();
-            this.username = username;
+            this.loggedIn = true;
         } catch (Exception e) {
             e.printStackTrace();
             throw new GpodnetServiceException(e);
@@ -804,23 +807,12 @@ public class GpodnetService implements ISyncService {
     }
 
     @Override
-    public void login() throws GpodnetServiceException {
-        authenticate(GpodnetPreferences.getUsername(), GpodnetPreferences.getPassword());
-    }
-
-    @Override
-    public SubscriptionChanges getSubscriptionChanges(long lastSync) throws GpodnetServiceException {
-        return getSubscriptionChanges(GpodnetPreferences.getDeviceID(), lastSync);
-    }
+    public void logout() {
 
-    @Override
-    public UploadChangesResponse uploadSubscriptionChanges(List<String> addedFeeds, List<String> removedFeeds)
-            throws GpodnetServiceException {
-        return uploadChanges(GpodnetPreferences.getDeviceID(), addedFeeds, removedFeeds);
     }
 
-    @Override
-    public void logout() {
-
+    public void setCredentials(String username, String password) {
+        this.username = username;
+        this.password = password;
     }
 }
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/GpodnetServiceAuthenticationException.java b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/GpodnetServiceAuthenticationException.java
index 0aec8e97e..d0a9c2dd6 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/GpodnetServiceAuthenticationException.java
+++ b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/GpodnetServiceAuthenticationException.java
@@ -1,4 +1,4 @@
-package de.danoeh.antennapod.core.sync.gpoddernet;
+package de.danoeh.antennapod.net.sync.gpoddernet;
 
 public class GpodnetServiceAuthenticationException extends GpodnetServiceException {
     private static final long serialVersionUID = 1L;
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/GpodnetServiceBadStatusCodeException.java b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/GpodnetServiceBadStatusCodeException.java
index c24b5fc0a..e403d8fff 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/GpodnetServiceBadStatusCodeException.java
+++ b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/GpodnetServiceBadStatusCodeException.java
@@ -1,4 +1,4 @@
-package de.danoeh.antennapod.core.sync.gpoddernet;
+package de.danoeh.antennapod.net.sync.gpoddernet;
 
 class GpodnetServiceBadStatusCodeException extends GpodnetServiceException {
     private static final long serialVersionUID = 1L;
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/GpodnetServiceException.java b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/GpodnetServiceException.java
index 10c4fdc11..298c59073 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/GpodnetServiceException.java
+++ b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/GpodnetServiceException.java
@@ -1,6 +1,6 @@
-package de.danoeh.antennapod.core.sync.gpoddernet;
+package de.danoeh.antennapod.net.sync.gpoddernet;
 
-import de.danoeh.antennapod.core.sync.model.SyncServiceException;
+import de.danoeh.antennapod.net.sync.model.SyncServiceException;
 
 public class GpodnetServiceException extends SyncServiceException {
     private static final long serialVersionUID = 1L;
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/model/GpodnetDevice.java b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/model/GpodnetDevice.java
index 454b3301d..ed7d80ee0 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/model/GpodnetDevice.java
+++ b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/model/GpodnetDevice.java
@@ -1,7 +1,9 @@
-package de.danoeh.antennapod.core.sync.gpoddernet.model;
+package de.danoeh.antennapod.net.sync.gpoddernet.model;
 
 import androidx.annotation.NonNull;
 
+import java.util.Locale;
+
 public class GpodnetDevice {
 
     private final String id;
@@ -49,7 +51,7 @@ public class GpodnetDevice {
 
         @Override
         public String toString() {
-            return super.toString().toLowerCase();
+            return super.toString().toLowerCase(Locale.US);
         }
 
     }
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/model/GpodnetEpisodeActionPostResponse.java b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/model/GpodnetEpisodeActionPostResponse.java
index ae9ab9d70..6d573ebfc 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/model/GpodnetEpisodeActionPostResponse.java
+++ b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/model/GpodnetEpisodeActionPostResponse.java
@@ -1,8 +1,8 @@
-package de.danoeh.antennapod.core.sync.gpoddernet.model;
+package de.danoeh.antennapod.net.sync.gpoddernet.model;
 
 import androidx.collection.ArrayMap;
 
-import de.danoeh.antennapod.core.sync.model.UploadChangesResponse;
+import de.danoeh.antennapod.net.sync.model.UploadChangesResponse;
 import org.apache.commons.lang3.builder.ToStringBuilder;
 import org.apache.commons.lang3.builder.ToStringStyle;
 import org.json.JSONArray;
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/model/GpodnetPodcast.java b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/model/GpodnetPodcast.java
index bc4969758..f09ab1244 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/model/GpodnetPodcast.java
+++ b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/model/GpodnetPodcast.java
@@ -1,4 +1,4 @@
-package de.danoeh.antennapod.core.sync.gpoddernet.model;
+package de.danoeh.antennapod.net.sync.gpoddernet.model;
 
 import androidx.annotation.NonNull;
 
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/model/GpodnetTag.java b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/model/GpodnetTag.java
index 93abf4688..d3d683598 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/model/GpodnetTag.java
+++ b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/model/GpodnetTag.java
@@ -1,4 +1,4 @@
-package de.danoeh.antennapod.core.sync.gpoddernet.model;
+package de.danoeh.antennapod.net.sync.gpoddernet.model;
 
 import android.os.Parcel;
 import android.os.Parcelable;
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/model/GpodnetUploadChangesResponse.java b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/model/GpodnetUploadChangesResponse.java
index 790ba547f..7b09531a5 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/gpoddernet/model/GpodnetUploadChangesResponse.java
+++ b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/model/GpodnetUploadChangesResponse.java
@@ -1,9 +1,9 @@
-package de.danoeh.antennapod.core.sync.gpoddernet.model;
+package de.danoeh.antennapod.net.sync.gpoddernet.model;
 
 import androidx.collection.ArrayMap;
 
-import de.danoeh.antennapod.core.sync.gpoddernet.GpodnetService;
-import de.danoeh.antennapod.core.sync.model.UploadChangesResponse;
+import de.danoeh.antennapod.net.sync.gpoddernet.GpodnetService;
+import de.danoeh.antennapod.net.sync.model.UploadChangesResponse;
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
diff --git a/net/sync/model/README.md b/net/sync/model/README.md
new file mode 100644
index 000000000..21d842914
--- /dev/null
+++ b/net/sync/model/README.md
@@ -0,0 +1,3 @@
+# :net:sync:model
+
+This module contains the basic interfaces for implementing a sync backend.
diff --git a/net/sync/model/build.gradle b/net/sync/model/build.gradle
new file mode 100644
index 000000000..299359602
--- /dev/null
+++ b/net/sync/model/build.gradle
@@ -0,0 +1,54 @@
+apply plugin: "com.android.library"
+
+android {
+    compileSdkVersion rootProject.ext.compileSdkVersion
+
+    defaultConfig {
+        minSdkVersion rootProject.ext.minSdkVersion
+        targetSdkVersion rootProject.ext.targetSdkVersion
+
+        multiDexEnabled false
+
+        testApplicationId "de.danoeh.antennapod.core.tests"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+    }
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile("proguard-android.txt")
+        }
+        debug {
+            // debug build has method count over 64k single-dex threshold.
+            // For building debug build to use on Android < 21 (pre-Android 5) devices,
+            // you need to manually change class
+            // de.danoeh.antennapod.PodcastApp to extend MultiDexApplication .
+            // See Issue #2813
+            multiDexEnabled true
+        }
+    }
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+
+    testOptions {
+        unitTests {
+            includeAndroidResources = true
+        }
+    }
+
+    lintOptions {
+        disable 'GradleDependency'
+        checkDependencies true
+        warningsAsErrors true
+        abortOnError true
+    }
+}
+
+dependencies {
+    implementation project(':model')
+
+    annotationProcessor "androidx.annotation:annotation:$annotationVersion"
+    implementation "androidx.appcompat:appcompat:$appcompatVersion"
+}
diff --git a/net/sync/model/src/main/AndroidManifest.xml b/net/sync/model/src/main/AndroidManifest.xml
new file mode 100644
index 000000000..a7bd1e34b
--- /dev/null
+++ b/net/sync/model/src/main/AndroidManifest.xml
@@ -0,0 +1 @@
+<manifest package="de.danoeh.antennapod.net.sync.model" />
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/model/EpisodeAction.java b/net/sync/model/src/main/java/de/danoeh/antennapod/net/sync/model/EpisodeAction.java
index 7a97b7755..1aae5c811 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/model/EpisodeAction.java
+++ b/net/sync/model/src/main/java/de/danoeh/antennapod/net/sync/model/EpisodeAction.java
@@ -1,4 +1,4 @@
-package de.danoeh.antennapod.core.sync.model;
+package de.danoeh.antennapod.net.sync.model;
 
 import android.text.TextUtils;
 import android.util.Log;
@@ -6,10 +6,10 @@ import android.util.Log;
 import androidx.annotation.NonNull;
 import androidx.core.util.ObjectsCompat;
 import de.danoeh.antennapod.model.feed.FeedItem;
-import de.danoeh.antennapod.core.util.DateUtils;
 import org.json.JSONException;
 import org.json.JSONObject;
 
+import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.Locale;
@@ -17,6 +17,7 @@ import java.util.TimeZone;
 
 public class EpisodeAction {
     private static final String TAG = "EpisodeAction";
+    private static final String PATTERN_ISO_DATEFORMAT = "yyyy-MM-dd'T'HH:mm:ss";
     public static final Action NEW = Action.NEW;
     public static final Action DOWNLOAD = Action.DOWNLOAD;
     public static final Action PLAY = Action.PLAY;
@@ -56,14 +57,20 @@ public class EpisodeAction {
         }
         EpisodeAction.Action action;
         try {
-            action = EpisodeAction.Action.valueOf(actionString.toUpperCase());
+            action = EpisodeAction.Action.valueOf(actionString.toUpperCase(Locale.US));
         } catch (IllegalArgumentException e) {
             return null;
         }
         EpisodeAction.Builder builder = new EpisodeAction.Builder(podcast, episode, action);
         String utcTimestamp = object.optString("timestamp", null);
         if (!TextUtils.isEmpty(utcTimestamp)) {
-            builder.timestamp(DateUtils.parse(utcTimestamp));
+            try {
+                SimpleDateFormat parser = new SimpleDateFormat(PATTERN_ISO_DATEFORMAT, Locale.US);
+                parser.setTimeZone(TimeZone.getTimeZone("UTC"));
+                builder.timestamp(parser.parse(utcTimestamp));
+            } catch (ParseException e) {
+                e.printStackTrace();
+            }
         }
         if (action == EpisodeAction.Action.PLAY) {
             int started = object.optInt("started", -1);
@@ -92,7 +99,7 @@ public class EpisodeAction {
     }
 
     private String getActionString() {
-        return this.action.name().toLowerCase();
+        return this.action.name().toLowerCase(Locale.US);
     }
 
     public Date getTimestamp() {
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/model/EpisodeActionChanges.java b/net/sync/model/src/main/java/de/danoeh/antennapod/net/sync/model/EpisodeActionChanges.java
index 90af585af..570e012c5 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/model/EpisodeActionChanges.java
+++ b/net/sync/model/src/main/java/de/danoeh/antennapod/net/sync/model/EpisodeActionChanges.java
@@ -1,4 +1,4 @@
-package de.danoeh.antennapod.core.sync.model;
+package de.danoeh.antennapod.net.sync.model;
 
 
 import androidx.annotation.NonNull;
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/model/ISyncService.java b/net/sync/model/src/main/java/de/danoeh/antennapod/net/sync/model/ISyncService.java
index 473072b97..9c75e5dac 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/model/ISyncService.java
+++ b/net/sync/model/src/main/java/de/danoeh/antennapod/net/sync/model/ISyncService.java
@@ -1,4 +1,4 @@
-package de.danoeh.antennapod.core.sync.model;
+package de.danoeh.antennapod.net.sync.model;
 
 import java.util.List;
 
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/model/SubscriptionChanges.java b/net/sync/model/src/main/java/de/danoeh/antennapod/net/sync/model/SubscriptionChanges.java
index 51f2ed10d..2fbc8b45e 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/model/SubscriptionChanges.java
+++ b/net/sync/model/src/main/java/de/danoeh/antennapod/net/sync/model/SubscriptionChanges.java
@@ -1,4 +1,4 @@
-package de.danoeh.antennapod.core.sync.model;
+package de.danoeh.antennapod.net.sync.model;
 
 import androidx.annotation.NonNull;
 
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/model/SyncServiceException.java b/net/sync/model/src/main/java/de/danoeh/antennapod/net/sync/model/SyncServiceException.java
index d7e999b45..57262db17 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/model/SyncServiceException.java
+++ b/net/sync/model/src/main/java/de/danoeh/antennapod/net/sync/model/SyncServiceException.java
@@ -1,4 +1,4 @@
-package de.danoeh.antennapod.core.sync.model;
+package de.danoeh.antennapod.net.sync.model;
 
 public class SyncServiceException extends Exception {
     private static final long serialVersionUID = 1L;
diff --git a/core/src/main/java/de/danoeh/antennapod/core/sync/model/UploadChangesResponse.java b/net/sync/model/src/main/java/de/danoeh/antennapod/net/sync/model/UploadChangesResponse.java
index 44850bb03..7503f429b 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/sync/model/UploadChangesResponse.java
+++ b/net/sync/model/src/main/java/de/danoeh/antennapod/net/sync/model/UploadChangesResponse.java
@@ -1,4 +1,4 @@
-package de.danoeh.antennapod.core.sync.model;
+package de.danoeh.antennapod.net.sync.model;
 
 public abstract class UploadChangesResponse {
 
diff --git a/settings.gradle b/settings.gradle
index 1b3ecc497..27cc1a863 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -1,7 +1,11 @@
 include ':app'
 include ':core'
 include ':model'
+
 include ':net:ssl'
+include ':net:sync:gpoddernet'
+include ':net:sync:model'
+
 include ':ui:app-start-intent'
 include ':ui:common'
 include ':ui:png-icons'