#1167 Use retrofit also for capabilities endpoint

10 files changed, 286 insertions, 126 deletions

diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/CapabilitiesClient.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/CapabilitiesClient.java
index b053227e..ecf9dfcf 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/persistence/CapabilitiesClient.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/persistence/CapabilitiesClient.java
@@ -1,19 +1,24 @@
 package it.niedermann.owncloud.notes.persistence;
 
 import android.content.Context;
+import android.util.Log;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.WorkerThread;
 
 import com.google.gson.JsonParseException;
+import com.nextcloud.android.sso.api.NextcloudAPI;
+import com.nextcloud.android.sso.api.ParsedResponse;
 import com.nextcloud.android.sso.exceptions.NextcloudHttpRequestFailedException;
 import com.nextcloud.android.sso.model.SingleSignOnAccount;
 
 import java.io.IOException;
+import java.util.Map;
 
-import it.niedermann.owncloud.notes.persistence.sync.ApiProvider;
+import it.niedermann.owncloud.notes.persistence.sync.OcsAPI;
 import it.niedermann.owncloud.notes.shared.model.Capabilities;
+import retrofit2.NextcloudRetrofitApiBuilder;
 import retrofit2.Response;
 
 import static java.net.HttpURLConnection.HTTP_UNAVAILABLE;
@@ -21,14 +26,23 @@ import static java.net.HttpURLConnection.HTTP_UNAVAILABLE;
 @WorkerThread
 public class CapabilitiesClient {
 
-    protected static final String HEADER_KEY_ETAG = "ETag";
+    private static final String TAG = CapabilitiesClient.class.getSimpleName();
+
+    private static final String API_ENDPOINT_OCS = "/ocs/v2.php/cloud/";
+    private static final String HEADER_KEY_ETAG = "ETag";
 
     public static Capabilities getCapabilities(@NonNull Context context, @NonNull SingleSignOnAccount ssoAccount, @Nullable String lastETag) throws NextcloudHttpRequestFailedException, IOException {
-        final ApiProvider provider = new ApiProvider(context, ssoAccount);
-        final Response<Capabilities> response = provider.getOcsAPI().getCapabilities(lastETag).execute();
+        final NextcloudAPI nextcloudAPI = SSOClient.getNextcloudAPI(context.getApplicationContext(), ssoAccount);
+        final OcsAPI ocsAPI = new NextcloudRetrofitApiBuilder(nextcloudAPI, API_ENDPOINT_OCS).create(OcsAPI.class);
+        final Response<ParsedResponse<Capabilities>> response = ocsAPI.getCapabilities(lastETag).execute();
         try {
-            final Capabilities capabilities = response.body();
-            capabilities.setETag(response.headers().get(HEADER_KEY_ETAG));
+            final Capabilities capabilities = response.body().getResponse();
+            final Map<String, String> headers = response.body().getHeaders();
+            if (headers != null) {
+                capabilities.setETag(headers.get(HEADER_KEY_ETAG));
+            } else {
+                Log.w(TAG, "Response headers of capabilities are null");
+            }
             return capabilities;
         } catch (JsonParseException e) {
             if (e.getCause() instanceof NextcloudHttpRequestFailedException && ((NextcloudHttpRequestFailedException) e.getCause()).getStatusCode() == HTTP_UNAVAILABLE) {
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/NotesServerSyncTask.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/NotesServerSyncTask.java
index b3af4ab7..79e844ae 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/persistence/NotesServerSyncTask.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/persistence/NotesServerSyncTask.java
@@ -6,6 +6,8 @@ import android.util.Log;
 import androidx.annotation.NonNull;
 
 import com.nextcloud.android.sso.AccountImporter;
+import com.nextcloud.android.sso.api.NextcloudAPI;
+import com.nextcloud.android.sso.api.ParsedResponse;
 import com.nextcloud.android.sso.exceptions.NextcloudFilesAppAccountNotFoundException;
 import com.nextcloud.android.sso.exceptions.NextcloudHttpRequestFailedException;
 import com.nextcloud.android.sso.exceptions.TokenMismatchException;
@@ -23,7 +25,7 @@ import java.util.Set;
 
 import it.niedermann.owncloud.notes.persistence.entity.Account;
 import it.niedermann.owncloud.notes.persistence.entity.Note;
-import it.niedermann.owncloud.notes.persistence.sync.ApiProvider;
+import it.niedermann.owncloud.notes.persistence.sync.NotesAPI;
 import it.niedermann.owncloud.notes.shared.model.DBStatus;
 import it.niedermann.owncloud.notes.shared.model.ISyncCallback;
 import it.niedermann.owncloud.notes.shared.model.SyncResultStatus;
@@ -49,7 +51,7 @@ abstract class NotesServerSyncTask extends Thread {
     @NonNull
     private final Context context;
     @NonNull
-    private ApiProvider notesClient;
+    private NotesAPI notesAPI;
     @NonNull
     private final NotesRepository repo;
     @NonNull
@@ -78,18 +80,21 @@ abstract class NotesServerSyncTask extends Thread {
     @Override
     public void run() {
         onPreExecute();
-        notesClient = new ApiProvider(context, ssoAccount);
-        new Thread(() -> {
-            Log.i(TAG, "STARTING SYNCHRONIZATION");
-            final SyncResultStatus status = new SyncResultStatus();
-            status.pushSuccessful = pushLocalChanges();
-            if (!onlyLocalChanges) {
-                status.pullSuccessful = pullRemoteChanges();
-            }
-            Log.i(TAG, "SYNCHRONIZATION FINISHED");
 
-            onPostExecute(status);
-        }).start();
+        final NextcloudAPI nextcloudAPI = SSOClient.getNextcloudAPI(context.getApplicationContext(), ssoAccount);
+        notesAPI = new NotesAPI(nextcloudAPI, localAccount.getPreferredApiVersion());
+
+        Log.i(TAG, "STARTING SYNCHRONIZATION");
+
+        final SyncResultStatus status = new SyncResultStatus();
+        status.pushSuccessful = pushLocalChanges();
+        if (!onlyLocalChanges) {
+            status.pullSuccessful = pullRemoteChanges();
+        }
+
+        Log.i(TAG, "SYNCHRONIZATION FINISHED");
+
+        onPostExecute(status);
     }
 
     abstract void onPreExecute();
@@ -113,13 +118,13 @@ abstract class NotesServerSyncTask extends Thread {
                         Log.v(TAG, "   ...create/edit");
                         if (note.getRemoteId() != null) {
                             Log.v(TAG, "   ...Note has remoteId → try to edit");
-                            final Response<Note> editResponse = notesClient.getNotesAPI().editNote(note, note.getRemoteId()).execute();
+                            final Response<Note> editResponse = notesAPI.editNote(note, note.getRemoteId()).execute();
                             if (editResponse.isSuccessful()) {
                                 remoteNote = editResponse.body();
                             } else {
                                 if (editResponse.code() == HTTP_NOT_FOUND) {
                                     Log.v(TAG, "   ...Note does no longer exist on server → recreate");
-                                    final Response<Note> createResponse = notesClient.getNotesAPI().createNote(note).execute();
+                                    final Response<Note> createResponse = notesAPI.createNote(note).execute();
                                     if (createResponse.isSuccessful()) {
                                         remoteNote = createResponse.body();
                                     } else {
@@ -131,7 +136,7 @@ abstract class NotesServerSyncTask extends Thread {
                             }
                         } else {
                             Log.v(TAG, "   ...Note does not have a remoteId yet → create");
-                            final Response<Note> createResponse = notesClient.getNotesAPI().createNote(note).execute();
+                            final Response<Note> createResponse = notesAPI.createNote(note).execute();
                             if (createResponse.isSuccessful()) {
                                 remoteNote = createResponse.body();
                                 repo.updateRemoteId(note.getId(), remoteNote.getRemoteId());
@@ -147,7 +152,7 @@ abstract class NotesServerSyncTask extends Thread {
                             Log.v(TAG, "   ...delete (only local, since it has never been synchronized)");
                         } else {
                             Log.v(TAG, "   ...delete (from server and local)");
-                            final Response<Note> deleteResponse = notesClient.getNotesAPI().deleteNote(note.getRemoteId()).execute();
+                            final Response<Note> deleteResponse = notesAPI.deleteNote(note.getRemoteId()).execute();
                             if (!deleteResponse.isSuccessful()) {
                                 if (deleteResponse.code() == HTTP_NOT_FOUND) {
                                     Log.v(TAG, "   ...delete (note has already been deleted remotely)");
@@ -197,9 +202,9 @@ abstract class NotesServerSyncTask extends Thread {
             localAccount.setModified(accountFromDatabase.getModified());
             localAccount.setETag(accountFromDatabase.getETag());
 
-            final Response<List<Note>> fetchResponse = notesClient.getNotesAPI().getNotes(localAccount.getModified().getTimeInMillis() / 1_000, localAccount.getETag()).execute();
+            final Response<ParsedResponse<List<Note>>> fetchResponse = notesAPI.getNotes(localAccount.getModified().getTimeInMillis() / 1_000, localAccount.getETag()).execute();
             if (fetchResponse.isSuccessful()) {
-                final List<Note> remoteNotes = fetchResponse.body();
+                final List<Note> remoteNotes = fetchResponse.body().getResponse();
                 final Set<Long> remoteIDs = new HashSet<>();
                 // pull remote changes: update or create each remote note
                 for (Note remoteNote : remoteNotes) {
@@ -231,14 +236,14 @@ abstract class NotesServerSyncTask extends Thread {
                 }
 
                 // update ETag and Last-Modified in order to reduce size of next response
-                localAccount.setETag(fetchResponse.headers().get(HEADER_KEY_ETAG));
+                localAccount.setETag(fetchResponse.body().getHeaders().get(HEADER_KEY_ETAG));
 
                 final Calendar lastModified = Calendar.getInstance();
                 lastModified.setTimeInMillis(0);
-                final String lastModifiedHeader = fetchResponse.headers().get(HEADER_KEY_LAST_MODIFIED);
+                final String lastModifiedHeader = fetchResponse.body().getHeaders().get(HEADER_KEY_LAST_MODIFIED);
                 if (lastModifiedHeader != null)
                     lastModified.setTimeInMillis(Date.parse(lastModifiedHeader));
-                Log.d(TAG, "ETag: " + fetchResponse.headers().get(HEADER_KEY_ETAG) + "; Last-Modified: " + lastModified + " (" + lastModified + ")");
+                Log.d(TAG, "ETag: " + fetchResponse.body().getHeaders().get(HEADER_KEY_ETAG) + "; Last-Modified: " + lastModified + " (" + lastModified + ")");
 
                 localAccount.setModified(lastModified);
 
@@ -247,7 +252,7 @@ abstract class NotesServerSyncTask extends Thread {
 
 
                 String supportedApiVersions = null;
-                final String supportedApiVersionsHeader = fetchResponse.headers().get(HEADER_KEY_X_NOTES_API_VERSIONS);
+                final String supportedApiVersionsHeader = fetchResponse.body().getHeaders().get(HEADER_KEY_X_NOTES_API_VERSIONS);
                 if (supportedApiVersionsHeader != null) {
                     supportedApiVersions = "[" + Objects.requireNonNull(supportedApiVersionsHeader) + "]";
                 }
@@ -260,16 +265,17 @@ abstract class NotesServerSyncTask extends Thread {
                 }
                 return true;
             } else {
-                throw new Exception(fetchResponse.errorBody().string());
-            }
-        } catch (NextcloudHttpRequestFailedException e) {
-            Log.d(TAG, "Server returned HTTP Status Code " + e.getStatusCode() + " - " + e.getMessage());
-            if (e.getStatusCode() == HTTP_NOT_MODIFIED) {
-                return true;
-            } else {
-                exceptions.add(e);
+                exceptions.add(new Exception(fetchResponse.errorBody().string()));
                 return false;
             }
+//        } catch (NextcloudHttpRequestFailedException e) {
+//            Log.d(TAG, "Server returned HTTP Status Code " + e.getStatusCode() + " - " + e.getMessage());
+//            if (e.getStatusCode() == HTTP_NOT_MODIFIED) {
+//                return true;
+//            } else {
+//                exceptions.add(e);
+//                return false;
+//            }
         } catch (Exception e) {
             if (e instanceof TokenMismatchException) {
                 SSOClient.invalidateAPICache(ssoAccount);
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/SSOClient.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/SSOClient.java
index 9f28cfff..d110c8a0 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/persistence/SSOClient.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/persistence/SSOClient.java
@@ -1,40 +1,25 @@
 package it.niedermann.owncloud.notes.persistence;
 
 import android.content.Context;
-import android.graphics.Color;
 import android.util.Log;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.WorkerThread;
 
-import com.bumptech.glide.load.HttpException;
 import com.google.gson.GsonBuilder;
-import com.google.gson.JsonDeserializationContext;
 import com.google.gson.JsonDeserializer;
-import com.google.gson.JsonElement;
-import com.google.gson.JsonParseException;
 import com.google.gson.JsonPrimitive;
 import com.google.gson.JsonSerializer;
-import com.nextcloud.android.sso.aidl.NextcloudRequest;
 import com.nextcloud.android.sso.api.NextcloudAPI;
-import com.nextcloud.android.sso.api.Response;
-import com.nextcloud.android.sso.exceptions.NextcloudHttpRequestFailedException;
 import com.nextcloud.android.sso.model.SingleSignOnAccount;
 
-import org.json.JSONException;
-import org.json.JSONObject;
-
-import java.lang.reflect.Type;
 import java.util.Calendar;
 import java.util.HashMap;
 import java.util.Map;
 
-import it.niedermann.android.util.ColorUtil;
 import it.niedermann.owncloud.notes.persistence.sync.CapabilitiesDeserializer;
 import it.niedermann.owncloud.notes.shared.model.Capabilities;
 
-import static java.net.HttpURLConnection.HTTP_UNAVAILABLE;
-
 @SuppressWarnings("WeakerAccess")
 @WorkerThread
 public class SSOClient {
@@ -43,7 +28,7 @@ public class SSOClient {
 
     private static final Map<String, NextcloudAPI> mNextcloudAPIs = new HashMap<>();
 
-    public static NextcloudAPI getNextcloudAPI(Context appContext, SingleSignOnAccount ssoAccount) {
+    public static synchronized NextcloudAPI getNextcloudAPI(@NonNull Context appContext, @NonNull SingleSignOnAccount ssoAccount) {
         if (mNextcloudAPIs.containsKey(ssoAccount.name)) {
             return mNextcloudAPIs.get(ssoAccount.name);
         } else {
@@ -58,18 +43,18 @@ public class SSOClient {
                                 return calendar;
                             })
                             .registerTypeAdapter(Capabilities.class, new CapabilitiesDeserializer())
-                            .create(),
-                    new NextcloudAPI.ApiConnectedListener() {
-                        @Override
-                        public void onConnected() {
-                            Log.i(TAG, "SSO API connected for " + ssoAccount);
-                        }
+                            .create(), new NextcloudAPI.ApiConnectedListener() {
+                @Override
+                public void onConnected() {
+                    Log.i(TAG, "SSO API connected for " + ssoAccount);
+                }
 
-                        @Override
-                        public void onError(Exception ex) {
-                            ex.printStackTrace();
-                        }
-                    });
+                @Override
+                public void onError(Exception ex) {
+                    ex.printStackTrace();
+                    SSOClient.invalidateAPICache(ssoAccount);
+                }
+            });
             mNextcloudAPIs.put(ssoAccount.name, nextcloudAPI);
             return nextcloudAPI;
         }
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/ApiProvider.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/ApiProvider.java
deleted file mode 100644
index 538afd89..00000000
--- a/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/ApiProvider.java
+++ /dev/null
@@ -1,38 +0,0 @@
-package it.niedermann.owncloud.notes.persistence.sync;
-
-import android.content.Context;
-
-import androidx.annotation.NonNull;
-
-import com.google.gson.GsonBuilder;
-import com.nextcloud.android.sso.api.NextcloudAPI;
-import com.nextcloud.android.sso.model.SingleSignOnAccount;
-
-import it.niedermann.owncloud.notes.persistence.SSOClient;
-import retrofit2.NextcloudRetrofitApiBuilder;
-
-/**
- * Created by david on 26.05.17.
- */
-public class ApiProvider {
-
-    private static final String API_ENDPOINT_OCS = "/ocs/v2.php/cloud/";
-    private static final String API_ENDPOINT_NOTES = "/index.php/apps/notes/api/v1/";
-
-    private final OcsAPI ocsAPI;
-    private final NotesAPI notesAPI;
-
-    public ApiProvider(@NonNull Context appContext, @NonNull SingleSignOnAccount ssoAccount) {
-        final NextcloudAPI nextcloudAPI = SSOClient.getNextcloudAPI(appContext, ssoAccount);
-        ocsAPI = new NextcloudRetrofitApiBuilder(nextcloudAPI, API_ENDPOINT_OCS).create(OcsAPI.class);
-        notesAPI = new NextcloudRetrofitApiBuilder(nextcloudAPI, API_ENDPOINT_NOTES).create(NotesAPI.class);
-    }
-
-    public NotesAPI getNotesAPI() {
-        return notesAPI;
-    }
-
-    public OcsAPI getOcsAPI() {
-        return ocsAPI;
-    }
-}
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/NotesAPI.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/NotesAPI.java
index 92130664..29f3119c 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/NotesAPI.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/NotesAPI.java
@@ -1,34 +1,97 @@
 package it.niedermann.owncloud.notes.persistence.sync;
 
 
-import java.util.Calendar;
+import android.util.Log;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.nextcloud.android.sso.api.NextcloudAPI;
+import com.nextcloud.android.sso.api.ParsedResponse;
+
 import java.util.List;
 
 import it.niedermann.owncloud.notes.persistence.entity.Note;
+import it.niedermann.owncloud.notes.shared.model.ApiVersion;
 import retrofit2.Call;
-import retrofit2.http.Body;
-import retrofit2.http.DELETE;
-import retrofit2.http.GET;
-import retrofit2.http.POST;
-import retrofit2.http.PUT;
-import retrofit2.http.Path;
-import retrofit2.http.Query;
+import retrofit2.NextcloudRetrofitApiBuilder;
 
 /**
- * @link <a href="https://deck.readthedocs.io/en/latest/API/">Deck REST API</a>
+ * Compatibility layer to support multiple API versions
  */
-public interface NotesAPI {
+public class NotesAPI {
+
+    private static final String TAG = NotesAPI.class.getSimpleName();
+
+    private static final String API_ENDPOINT_NOTES_1_0 = "/index.php/apps/notes/api/v1/";
+    private static final String API_ENDPOINT_NOTES_0_2 = "/index.php/apps/notes/api/v0.2/";
+
+    @NonNull
+    private final ApiVersion usedApiVersion;
+    private final NotesAPI_0_2 notesAPI_0_2;
+    private final NotesAPI_1_0 notesAPI_1_0;
 
-    @GET("notes")
-    Call<List<Note>> getNotes(@Query(value = "pruneBefore") long lastModified, @Query("If-None-Match") String lastETag);
+    public NotesAPI(@NonNull NextcloudAPI nextcloudAPI, @Nullable ApiVersion preferredApiVersion) {
+        if (preferredApiVersion == null) {
+            Log.i(TAG, "Using " + ApiVersion.API_VERSION_0_2 + ", preferredApiVersion is null");
+            usedApiVersion = ApiVersion.API_VERSION_0_2;
+            notesAPI_0_2 = new NextcloudRetrofitApiBuilder(nextcloudAPI, API_ENDPOINT_NOTES_0_2).create(NotesAPI_0_2.class);
+            notesAPI_1_0 = null;
+        } else if (ApiVersion.API_VERSION_1_0.equals(preferredApiVersion)) {
+            Log.i(TAG, "Using " + ApiVersion.API_VERSION_1_0);
+            usedApiVersion = ApiVersion.API_VERSION_1_0;
+            notesAPI_0_2 = null;
+            notesAPI_1_0 = new NextcloudRetrofitApiBuilder(nextcloudAPI, API_ENDPOINT_NOTES_1_0).create(NotesAPI_1_0.class);
+        } else if (ApiVersion.API_VERSION_0_2.equals(preferredApiVersion)) {
+            Log.i(TAG, "Using " + ApiVersion.API_VERSION_0_2);
+            usedApiVersion = ApiVersion.API_VERSION_0_2;
+            notesAPI_0_2 = new NextcloudRetrofitApiBuilder(nextcloudAPI, API_ENDPOINT_NOTES_0_2).create(NotesAPI_0_2.class);
+            notesAPI_1_0 = null;
+        } else {
+            Log.w(TAG, "Unsupported API version " + preferredApiVersion + " - try using " + ApiVersion.API_VERSION_0_2);
+            usedApiVersion = ApiVersion.API_VERSION_0_2;
+            notesAPI_0_2 = new NextcloudRetrofitApiBuilder(nextcloudAPI, API_ENDPOINT_NOTES_0_2).create(NotesAPI_0_2.class);
+            notesAPI_1_0 = null;
+        }
+    }
 
-    @POST("notes")
-    Call<Note> createNote(@Body Note note);
+    public Call<ParsedResponse<List<Note>>> getNotes(long lastModified, String lastETag) {
+        if (ApiVersion.API_VERSION_1_0.equals(usedApiVersion)) {
+            return notesAPI_1_0.getNotes(lastModified, lastETag);
+        } else if (ApiVersion.API_VERSION_0_2.equals(usedApiVersion)) {
+            return notesAPI_0_2.getNotes(lastModified, lastETag);
+        } else {
+            throw new UnsupportedOperationException("Used API version " + usedApiVersion + " does not support getNotes().");
+        }
+    }
 
-    @PUT("notes/{remoteId}")
-    Call<Note> editNote(@Body Note note, @Path("remoteId") long remoteId);
+    public Call<Note> createNote(Note note) {
+        if (ApiVersion.API_VERSION_1_0.equals(usedApiVersion)) {
+            return notesAPI_1_0.createNote(note);
+        } else if (ApiVersion.API_VERSION_0_2.equals(usedApiVersion)) {
+            return notesAPI_0_2.createNote(note);
+        } else {
+            throw new UnsupportedOperationException("Used API version " + usedApiVersion + " does not support createNote().");
+        }
+    }
 
-    @DELETE("notes/{remoteId}")
-    Call<Note> deleteNote(@Path("remoteId") long noteId);
+    public Call<Note> editNote(Note note, long remoteId) {
+        if (ApiVersion.API_VERSION_1_0.equals(usedApiVersion)) {
+            return notesAPI_1_0.editNote(note, remoteId);
+        } else if (ApiVersion.API_VERSION_0_2.equals(usedApiVersion)) {
+            return notesAPI_0_2.editNote(note, remoteId);
+        } else {
+            throw new UnsupportedOperationException("Used API version " + usedApiVersion + " does not support editNote().");
+        }
+    }
 
+    public Call<Note> deleteNote(long noteId) {
+        if (ApiVersion.API_VERSION_1_0.equals(usedApiVersion)) {
+            return notesAPI_1_0.deleteNote(noteId);
+        } else if (ApiVersion.API_VERSION_0_2.equals(usedApiVersion)) {
+            return notesAPI_0_2.deleteNote(noteId);
+        } else {
+            throw new UnsupportedOperationException("Used API version " + usedApiVersion + " does not support createNote().");
+        }
+    }
 }
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/NotesAPI_0_2.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/NotesAPI_0_2.java
new file mode 100644
index 00000000..9a77f8c4
--- /dev/null
+++ b/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/NotesAPI_0_2.java
@@ -0,0 +1,70 @@
+package it.niedermann.owncloud.notes.persistence.sync;
+
+
+import com.google.gson.annotations.Expose;
+import com.nextcloud.android.sso.api.ParsedResponse;
+
+import java.util.Calendar;
+import java.util.List;
+
+import it.niedermann.owncloud.notes.persistence.entity.Note;
+import retrofit2.Call;
+import retrofit2.http.Body;
+import retrofit2.http.DELETE;
+import retrofit2.http.GET;
+import retrofit2.http.POST;
+import retrofit2.http.PUT;
+import retrofit2.http.Path;
+import retrofit2.http.Query;
+
+/**
+ * @link <a href="https://github.com/nextcloud/notes/wiki/API-0.2">Notes API v0.2</a>
+ */
+public interface NotesAPI_0_2 {
+
+    @GET("notes")
+    Call<ParsedResponse<List<Note>>> getNotes(@Query(value = "pruneBefore") long lastModified, @Query("If-None-Match") String lastETag);
+
+    default Call<Note> createNote(@Body Note note) {
+        return createNote(new Note_0_2(note));
+    }
+
+    @POST("notes")
+    Call<Note> createNote(@Body Note_0_2 note);
+
+    @PUT("notes/{remoteId}")
+    Call<Note> editNote(@Body Note note, @Path("remoteId") long remoteId);
+
+    @DELETE("notes/{remoteId}")
+    Call<Note> deleteNote(@Path("remoteId") long noteId);
+
+    class Note_0_2 {
+        @Expose
+        public final long id;
+        @Expose
+        public final String title;
+        @Expose
+        public final String category;
+        @Expose
+        public final Calendar modified;
+        @Expose
+        public final String content;
+        @Expose
+        public final boolean favorite;
+        @Expose
+        public final String eTag;
+
+        private Note_0_2(Note note) {
+            if (note == null) {
+                throw new IllegalArgumentException(Note.class.getSimpleName() + " can not be converted to " + Note_0_2.class.getSimpleName() + " because it is null.");
+            }
+            this.id = note.getRemoteId();
+            this.title = note.getTitle();
+            this.category = note.getCategory();
+            this.modified = note.getModified();
+            this.content = note.getContent();
+            this.favorite = note.getFavorite();
+            this.eTag = note.getETag();
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/NotesAPI_1_0.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/NotesAPI_1_0.java
new file mode 100644
index 00000000..1c738ca7
--- /dev/null
+++ b/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/NotesAPI_1_0.java
@@ -0,0 +1,34 @@
+package it.niedermann.owncloud.notes.persistence.sync;
+
+
+import com.nextcloud.android.sso.api.ParsedResponse;
+
+import java.util.List;
+
+import it.niedermann.owncloud.notes.persistence.entity.Note;
+import retrofit2.Call;
+import retrofit2.http.Body;
+import retrofit2.http.DELETE;
+import retrofit2.http.GET;
+import retrofit2.http.POST;
+import retrofit2.http.PUT;
+import retrofit2.http.Path;
+import retrofit2.http.Query;
+
+/**
+ * @link <a href="https://github.com/nextcloud/notes/blob/master/docs/api/README.md">Notes API v1</a>
+ */
+public interface NotesAPI_1_0 {
+
+    @GET("notes")
+    Call<ParsedResponse<List<Note>>> getNotes(@Query(value = "pruneBefore") long lastModified, @Query("If-None-Match") String lastETag);
+
+    @POST("notes")
+    Call<Note> createNote(@Body Note note);
+
+    @PUT("notes/{remoteId}")
+    Call<Note> editNote(@Body Note note, @Path("remoteId") long remoteId);
+
+    @DELETE("notes/{remoteId}")
+    Call<Note> deleteNote(@Path("remoteId") long noteId);
+}
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/OcsAPI.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/OcsAPI.java
index 17bc3c4f..8923d50f 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/OcsAPI.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/OcsAPI.java
@@ -1,6 +1,8 @@
 package it.niedermann.owncloud.notes.persistence.sync;
 
 
+import com.nextcloud.android.sso.api.ParsedResponse;
+
 import it.niedermann.owncloud.notes.shared.model.Capabilities;
 import retrofit2.Call;
 import retrofit2.http.GET;
@@ -12,5 +14,5 @@ import retrofit2.http.Query;
 public interface OcsAPI {
 
     @GET("capabilities?format=json")
-    Call<Capabilities> getCapabilities(@Query("If-None-Match") String eTag);
+    Call<ParsedResponse<Capabilities>> getCapabilities(@Query("If-None-Match") String eTag);
 }
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/shared/model/ApiVersion.java b/app/src/main/java/it/niedermann/owncloud/notes/shared/model/ApiVersion.java
index 761d0dc3..94c5408d 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/shared/model/ApiVersion.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/shared/model/ApiVersion.java
@@ -3,6 +3,7 @@ package it.niedermann.owncloud.notes.shared.model;
 
 import androidx.annotation.NonNull;
 
+import java.util.Objects;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -10,14 +11,17 @@ import java.util.regex.Pattern;
 public class ApiVersion implements Comparable<ApiVersion> {
     private static final Pattern NUMBER_EXTRACTION_PATTERN = Pattern.compile("[0-9]+");
 
+    public static final ApiVersion API_VERSION_0_2 = new ApiVersion(0, 2);
+    public static final ApiVersion API_VERSION_1_0 = new ApiVersion(1, 0);
+
     public static final ApiVersion[] SUPPORTED_API_VERSIONS = new ApiVersion[]{
-            new ApiVersion(1, 0),
-            new ApiVersion(0, 2)
+            API_VERSION_1_0,
+            API_VERSION_0_2
     };
 
     private String originalVersion = "?";
-    private int major;
-    private int minor;
+    private final int major;
+    private final int minor;
 
     public ApiVersion(String originalVersion, int major, int minor) {
         this(major, minor);
@@ -70,7 +74,7 @@ public class ApiVersion implements Comparable<ApiVersion> {
      * 1 if the compared major version is <strong>lower</strong> than the current major version
      */
     @Override
-    public int compareTo(ApiVersion compare) {
+    public int compareTo(@NonNull ApiVersion compare) {
         if (compare.getMajor() > getMajor()) {
             return -1;
         } else if (compare.getMajor() < getMajor()) {
@@ -79,6 +83,19 @@ public class ApiVersion implements Comparable<ApiVersion> {
         return 0;
     }
 
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ApiVersion that = (ApiVersion) o;
+        return compareTo(that) == 0;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(major, minor);
+    }
+
     @NonNull
     @Override
     public String toString() {
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/shared/model/SyncResultStatus.java b/app/src/main/java/it/niedermann/owncloud/notes/shared/model/SyncResultStatus.java
index 2031568b..41ba850a 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/shared/model/SyncResultStatus.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/shared/model/SyncResultStatus.java
@@ -3,4 +3,11 @@ package it.niedermann.owncloud.notes.shared.model;
 public class SyncResultStatus {
     public boolean pullSuccessful = true;
     public boolean pushSuccessful = true;
+
+    public static final SyncResultStatus FAILED = new SyncResultStatus();
+
+    static {
+        FAILED.pullSuccessful = false;
+        FAILED.pushSuccessful = false;
+    }
 }