#1167 Use retrofit also for capabilities endpoint

14 files changed, 174 insertions, 561 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 9a08bc1e..b053227e 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
@@ -1,87 +1,38 @@
 package it.niedermann.owncloud.notes.persistence;
 
 import android.content.Context;
-import android.content.pm.PackageInfo;
-import android.util.Log;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.WorkerThread;
 
-import com.nextcloud.android.sso.aidl.NextcloudRequest;
-import com.nextcloud.android.sso.api.AidlNetworkRequest;
-import com.nextcloud.android.sso.api.Response;
-import com.nextcloud.android.sso.exceptions.NextcloudFilesAppNotSupportedException;
+import com.google.gson.JsonParseException;
+import com.nextcloud.android.sso.exceptions.NextcloudHttpRequestFailedException;
 import com.nextcloud.android.sso.model.SingleSignOnAccount;
 
-import java.io.BufferedReader;
-import java.io.InputStreamReader;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
+import java.io.IOException;
 
+import it.niedermann.owncloud.notes.persistence.sync.ApiProvider;
 import it.niedermann.owncloud.notes.shared.model.Capabilities;
+import retrofit2.Response;
+
+import static java.net.HttpURLConnection.HTTP_UNAVAILABLE;
 
 @WorkerThread
 public class CapabilitiesClient {
 
-    private static final String TAG = CapabilitiesClient.class.getSimpleName();
-
-    private static final int MIN_NEXTCLOUD_FILES_APP_VERSION_CODE = 30090000;
-
-    protected static final String HEADER_KEY_IF_NONE_MATCH = "If-None-Match";
     protected static final String HEADER_KEY_ETAG = "ETag";
 
-    private static final String API_PATH = "/ocs/v2.php/cloud/capabilities";
-    private static final String METHOD_GET = "GET";
-    private static final String PARAM_KEY_FORMAT = "format";
-    private static final String PARAM_VALUE_JSON = "json";
-
-    private static final Map<String, String> parameters = new HashMap<>();
-
-    static {
-        parameters.put(PARAM_KEY_FORMAT, PARAM_VALUE_JSON);
-    }
-
-    public static Capabilities getCapabilities(@NonNull Context context, @NonNull SingleSignOnAccount ssoAccount, @Nullable String lastETag) throws Exception {
-        final NextcloudRequest.Builder requestBuilder = new NextcloudRequest.Builder()
-                .setMethod(METHOD_GET)
-                .setUrl(API_PATH)
-                .setParameter(parameters);
-
-        final Map<String, List<String>> header = new HashMap<>();
-        if (lastETag != null && !lastETag.isEmpty()) {
-            header.put(HEADER_KEY_IF_NONE_MATCH, Collections.singletonList('"' + lastETag + '"'));
-            requestBuilder.setHeader(header);
-        }
-
-        final NextcloudRequest nextcloudRequest = requestBuilder.build();
-        final StringBuilder result = new StringBuilder();
-
+    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();
         try {
-            Log.v(TAG, ssoAccount.name + " → " + nextcloudRequest.getMethod() + " " + nextcloudRequest.getUrl() + " ");
-            final Response response = SSOClient.requestFilesApp(context.getApplicationContext(), ssoAccount, nextcloudRequest);
-            Log.v(TAG, "NextcloudRequest: " + nextcloudRequest.toString());
-
-            final BufferedReader rd = new BufferedReader(new InputStreamReader(response.getBody()));
-            String line;
-            while ((line = rd.readLine()) != null) {
-                result.append(line);
-            }
-            response.getBody().close();
-
-            String etag = null;
-            final AidlNetworkRequest.PlainHeader eTagHeader = response.getPlainHeader(HEADER_KEY_ETAG);
-            if (eTagHeader != null) {
-                etag = eTagHeader.getValue().replace("\"", "");
-            }
-
-            return new Capabilities(result.toString(), etag);
-        } catch (NullPointerException e) {
-            final PackageInfo pInfo = context.getApplicationContext().getPackageManager().getPackageInfo("com.nextcloud.client", 0);
-            if (pInfo.versionCode < MIN_NEXTCLOUD_FILES_APP_VERSION_CODE) {
-                throw new NextcloudFilesAppNotSupportedException();
+            final Capabilities capabilities = response.body();
+            capabilities.setETag(response.headers().get(HEADER_KEY_ETAG));
+            return capabilities;
+        } catch (JsonParseException e) {
+            if (e.getCause() instanceof NextcloudHttpRequestFailedException && ((NextcloudHttpRequestFailedException) e.getCause()).getStatusCode() == HTTP_UNAVAILABLE) {
+                throw (NextcloudHttpRequestFailedException) e.getCause();
             } else {
                 throw e;
             }
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/NotesClient.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/NotesClient.java
deleted file mode 100644
index f5a8f189..00000000
--- a/app/src/main/java/it/niedermann/owncloud/notes/persistence/NotesClient.java
+++ /dev/null
@@ -1,217 +0,0 @@
-package it.niedermann.owncloud.notes.persistence;
-
-import android.content.Context;
-import android.content.pm.PackageInfo;
-import android.util.Log;
-
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-import androidx.annotation.WorkerThread;
-
-import com.nextcloud.android.sso.aidl.NextcloudRequest;
-import com.nextcloud.android.sso.api.AidlNetworkRequest;
-import com.nextcloud.android.sso.api.Response;
-import com.nextcloud.android.sso.exceptions.NextcloudFilesAppNotSupportedException;
-import com.nextcloud.android.sso.model.SingleSignOnAccount;
-
-import org.json.JSONObject;
-
-import java.io.BufferedReader;
-import java.io.InputStreamReader;
-import java.util.Calendar;
-import java.util.Collections;
-import java.util.Date;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Objects;
-
-import it.niedermann.owncloud.notes.persistence.entity.Note;
-import it.niedermann.owncloud.notes.shared.model.ApiVersion;
-import it.niedermann.owncloud.notes.shared.model.ServerResponse.NoteResponse;
-import it.niedermann.owncloud.notes.shared.model.ServerResponse.NotesResponse;
-
-@SuppressWarnings("WeakerAccess")
-@WorkerThread
-public abstract class NotesClient {
-
-    final static int MIN_NEXTCLOUD_FILES_APP_VERSION_CODE = 30090000;
-    private static final String TAG = NotesClient.class.getSimpleName();
-
-    protected final Context appContext;
-
-    protected static final String GET_PARAM_KEY_PRUNE_BEFORE = "pruneBefore";
-
-    protected static final String HEADER_KEY_ETAG = "ETag";
-    protected static final String HEADER_KEY_LAST_MODIFIED = "Last-Modified";
-    protected static final String HEADER_KEY_CONTENT_TYPE = "Content-Type";
-    protected static final String HEADER_KEY_IF_NONE_MATCH = "If-None-Match";
-    protected static final String HEADER_KEY_X_NOTES_API_VERSIONS = "X-Notes-API-Versions";
-
-    protected static final String HEADER_VALUE_APPLICATION_JSON = "application/json";
-
-    protected static final String METHOD_GET = "GET";
-    protected static final String METHOD_PUT = "PUT";
-    protected static final String METHOD_POST = "POST";
-    protected static final String METHOD_DELETE = "DELETE";
-
-    public static final String JSON_ID = "id";
-    public static final String JSON_TITLE = "title";
-    public static final String JSON_CONTENT = "content";
-    public static final String JSON_FAVORITE = "favorite";
-    public static final String JSON_CATEGORY = "category";
-    public static final String JSON_ETAG = "etag";
-    public static final String JSON_MODIFIED = "modified";
-
-    public static final ApiVersion[] SUPPORTED_API_VERSIONS = new ApiVersion[]{
-            new ApiVersion(1, 0),
-            new ApiVersion(0, 2)
-    };
-
-    public static NotesClient newInstance(@Nullable ApiVersion preferredApiVersion,
-                                          @NonNull Context appContext) {
-        if (preferredApiVersion == null) {
-            Log.i(TAG, "apiVersion is null, using " + NotesClientV02.class.getSimpleName());
-            return new NotesClientV02(appContext);
-        } else if (preferredApiVersion.compareTo(SUPPORTED_API_VERSIONS[0]) == 0) {
-            Log.i(TAG, "Using " + NotesClientV1.class.getSimpleName());
-            return new NotesClientV1(appContext);
-        } else if (preferredApiVersion.compareTo(SUPPORTED_API_VERSIONS[1]) == 0) {
-            Log.i(TAG, "Using " + NotesClientV02.class.getSimpleName());
-            return new NotesClientV02(appContext);
-        }
-        Log.w(TAG, "Unsupported API version " + preferredApiVersion + " - try using " + NotesClientV02.class.getSimpleName());
-        return new NotesClientV02(appContext);
-    }
-
-    @SuppressWarnings("WeakerAccess")
-    protected NotesClient(@NonNull Context appContext) {
-        this.appContext = appContext;
-    }
-
-    /**
-     * Gets the list of notes from the server.
-     *
-     * @param ssoAccount   Account to be used
-     * @param lastModified Last modified time of a former response (Unix timestamp in seconds!). All notes older than this time will be skipped.
-     * @param lastETag     ETag of a former response. If nothing changed, the response will be 304 NOT MODIFIED.
-     * @return list of notes
-     * @throws Exception
-     */
-    abstract NotesResponse getNotes(SingleSignOnAccount ssoAccount, Calendar lastModified, String lastETag) throws Exception;
-
-    abstract NoteResponse createNote(SingleSignOnAccount ssoAccount, Note note) throws Exception;
-
-    abstract NoteResponse editNote(SingleSignOnAccount ssoAccount, Note note) throws Exception;
-
-    abstract void deleteNote(SingleSignOnAccount ssoAccount, long noteId) throws Exception;
-
-    /**
-     * This entity class is used to return relevant data of the HTTP reponse.
-     */
-    public static class ResponseData {
-        private final String content;
-        private final String etag;
-        private final String supportedApiVersions;
-        private final Calendar lastModified;
-
-        ResponseData(@NonNull String content, String etag, @NonNull Calendar lastModified, @Nullable String supportedApiVersions) {
-            this.content = content;
-            this.etag = etag;
-            this.lastModified = lastModified;
-            this.supportedApiVersions = supportedApiVersions;
-        }
-
-        public String getContent() {
-            return content;
-        }
-
-        public String getETag() {
-            return etag;
-        }
-
-        public Calendar getLastModified() {
-            return lastModified;
-        }
-
-        public String getSupportedApiVersions() {
-            return this.supportedApiVersions;
-        }
-    }
-
-    abstract protected String getApiPath();
-
-    /**
-     * Request-Method for POST, PUT with or without JSON-Object-Parameter
-     *
-     * @param target      Filepath to the wanted function
-     * @param method      GET, POST, DELETE or PUT
-     * @param parameter   optional headers to be sent
-     * @param requestBody JSON Object which shall be transferred to the server.
-     * @param lastETag    optional ETag of last response
-     * @return Body of answer
-     */
-    protected ResponseData requestServer(SingleSignOnAccount ssoAccount, String target, String method, Map<String, String> parameter, JSONObject requestBody, String lastETag) throws Exception {
-        final NextcloudRequest.Builder requestBuilder = new NextcloudRequest.Builder()
-                .setMethod(method)
-                .setUrl(getApiPath() + target);
-        if (parameter != null) {
-            requestBuilder.setParameter(parameter);
-        }
-
-        final Map<String, List<String>> header = new HashMap<>();
-        if (requestBody != null) {
-            header.put(HEADER_KEY_CONTENT_TYPE, Collections.singletonList(HEADER_VALUE_APPLICATION_JSON));
-            requestBuilder.setRequestBody(requestBody.toString());
-        }
-        if (lastETag != null && !lastETag.isEmpty() && METHOD_GET.equals(method)) {
-            header.put(HEADER_KEY_IF_NONE_MATCH, Collections.singletonList('"' + lastETag + '"'));
-            requestBuilder.setHeader(header);
-        }
-
-        final NextcloudRequest nextcloudRequest = requestBuilder.build();
-        final StringBuilder result = new StringBuilder();
-
-        try {
-            Log.v(TAG, ssoAccount.name + " → " + nextcloudRequest.getMethod() + " " + nextcloudRequest.getUrl() + " ");
-            Log.d(TAG, "NextcloudRequest: " + nextcloudRequest.toString());
-            final Response response = SSOClient.requestFilesApp(appContext, ssoAccount, nextcloudRequest);
-
-            final BufferedReader rd = new BufferedReader(new InputStreamReader(response.getBody()));
-            String line;
-            while ((line = rd.readLine()) != null) {
-                result.append(line);
-            }
-            response.getBody().close();
-
-            String etag = "";
-            final AidlNetworkRequest.PlainHeader eTagHeader = response.getPlainHeader(HEADER_KEY_ETAG);
-            if (eTagHeader != null) {
-                etag = Objects.requireNonNull(eTagHeader.getValue()).replace("\"", "");
-            }
-
-            final Calendar lastModified = Calendar.getInstance();
-            lastModified.setTimeInMillis(0);
-            final AidlNetworkRequest.PlainHeader lastModifiedHeader = response.getPlainHeader(HEADER_KEY_LAST_MODIFIED);
-            if (lastModifiedHeader != null)
-                lastModified.setTimeInMillis(Date.parse(lastModifiedHeader.getValue()));
-            Log.d(TAG, "ETag: " + etag + "; Last-Modified: " + lastModified + " (" + lastModified + ")");
-
-            String supportedApiVersions = null;
-            final AidlNetworkRequest.PlainHeader supportedApiVersionsHeader = response.getPlainHeader(HEADER_KEY_X_NOTES_API_VERSIONS);
-            if (supportedApiVersionsHeader != null) {
-                supportedApiVersions = "[" + Objects.requireNonNull(supportedApiVersionsHeader.getValue()) + "]";
-            }
-
-            // return these header fields since they should only be saved after successful processing the result!
-            return new ResponseData(result.toString(), etag, lastModified, supportedApiVersions);
-        } catch (NullPointerException e) {
-            final PackageInfo pInfo = appContext.getPackageManager().getPackageInfo("com.nextcloud.client", 0);
-            if (pInfo.versionCode < MIN_NEXTCLOUD_FILES_APP_VERSION_CODE) {
-                throw new NextcloudFilesAppNotSupportedException();
-            } else {
-                throw e;
-            }
-        }
-    }
-}
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/NotesClientV02.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/NotesClientV02.java
deleted file mode 100644
index 31a4de39..00000000
--- a/app/src/main/java/it/niedermann/owncloud/notes/persistence/NotesClientV02.java
+++ /dev/null
@@ -1,63 +0,0 @@
-package it.niedermann.owncloud.notes.persistence;
-
-import android.content.Context;
-
-import androidx.annotation.NonNull;
-import androidx.annotation.WorkerThread;
-
-import com.nextcloud.android.sso.model.SingleSignOnAccount;
-
-import org.json.JSONObject;
-
-import java.util.Calendar;
-import java.util.HashMap;
-import java.util.Map;
-
-import it.niedermann.owncloud.notes.persistence.entity.Note;
-import it.niedermann.owncloud.notes.shared.model.ServerResponse.NoteResponse;
-import it.niedermann.owncloud.notes.shared.model.ServerResponse.NotesResponse;
-
-@WorkerThread
-public class NotesClientV02 extends NotesClient {
-
-    private static final String API_PATH = "/index.php/apps/notes/api/v0.2/";
-
-    NotesClientV02(@NonNull Context appContext) {
-        super(appContext);
-    }
-
-    NotesResponse getNotes(SingleSignOnAccount ssoAccount, Calendar lastModified, String lastETag) throws Exception {
-        final Map<String, String> parameter = new HashMap<>();
-        parameter.put(GET_PARAM_KEY_PRUNE_BEFORE, Long.toString(lastModified == null ? 0 : lastModified.getTimeInMillis() / 1_000));
-        return new NotesResponse(requestServer(ssoAccount, "notes", METHOD_GET, parameter, null, lastETag));
-    }
-
-    private NoteResponse putNote(SingleSignOnAccount ssoAccount, Note note, String path, String method) throws Exception {
-        JSONObject paramObject = new JSONObject();
-        paramObject.accumulate(JSON_CONTENT, note.getContent());
-        paramObject.accumulate(JSON_MODIFIED, note.getModified().getTimeInMillis() / 1_000);
-        paramObject.accumulate(JSON_FAVORITE, note.getFavorite());
-        paramObject.accumulate(JSON_CATEGORY, note.getCategory());
-        return new NoteResponse(requestServer(ssoAccount, path, method, null, paramObject, null));
-    }
-
-    @Override
-    NoteResponse createNote(SingleSignOnAccount ssoAccount, Note note) throws Exception {
-        return putNote(ssoAccount, note, "notes", METHOD_POST);
-    }
-
-    @Override
-    NoteResponse editNote(SingleSignOnAccount ssoAccount, Note note) throws Exception {
-        return putNote(ssoAccount, note, "notes/" + note.getRemoteId(), METHOD_PUT);
-    }
-
-    @Override
-    void deleteNote(SingleSignOnAccount ssoAccount, long noteId) throws Exception {
-        this.requestServer(ssoAccount, "notes/" + noteId, METHOD_DELETE, null, null, null);
-    }
-
-    @Override
-    protected String getApiPath() {
-        return API_PATH;
-    }
-}
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/NotesClientV1.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/NotesClientV1.java
deleted file mode 100644
index 56661543..00000000
--- a/app/src/main/java/it/niedermann/owncloud/notes/persistence/NotesClientV1.java
+++ /dev/null
@@ -1,64 +0,0 @@
-package it.niedermann.owncloud.notes.persistence;
-
-import android.content.Context;
-
-import androidx.annotation.NonNull;
-import androidx.annotation.WorkerThread;
-
-import com.nextcloud.android.sso.model.SingleSignOnAccount;
-
-import org.json.JSONObject;
-
-import java.util.Calendar;
-import java.util.HashMap;
-import java.util.Map;
-
-import it.niedermann.owncloud.notes.persistence.entity.Note;
-import it.niedermann.owncloud.notes.shared.model.ServerResponse.NoteResponse;
-import it.niedermann.owncloud.notes.shared.model.ServerResponse.NotesResponse;
-
-@WorkerThread
-public class NotesClientV1 extends NotesClient {
-
-    private static final String API_PATH = "/index.php/apps/notes/api/v1/";
-
-    NotesClientV1(@NonNull Context appContext) {
-        super(appContext);
-    }
-
-    NotesResponse getNotes(SingleSignOnAccount ssoAccount, Calendar lastModified, String lastETag) throws Exception {
-        final Map<String, String> parameter = new HashMap<>();
-        parameter.put(GET_PARAM_KEY_PRUNE_BEFORE, Long.toString(lastModified == null ? 0 : lastModified.getTimeInMillis() / 1_000));
-        return new NotesResponse(requestServer(ssoAccount, "notes", METHOD_GET, parameter, null, lastETag));
-    }
-
-    private NoteResponse putNote(SingleSignOnAccount ssoAccount, Note note, String path, String method) throws Exception {
-        JSONObject paramObject = new JSONObject();
-        paramObject.accumulate(JSON_TITLE, note.getTitle());
-        paramObject.accumulate(JSON_CONTENT, note.getContent());
-        paramObject.accumulate(JSON_MODIFIED, note.getModified().getTimeInMillis() / 1_000);
-        paramObject.accumulate(JSON_FAVORITE, note.getFavorite());
-        paramObject.accumulate(JSON_CATEGORY, note.getCategory());
-        return new NoteResponse(requestServer(ssoAccount, path, method, null, paramObject, null));
-    }
-
-    @Override
-    NoteResponse createNote(SingleSignOnAccount ssoAccount, Note note) throws Exception {
-        return putNote(ssoAccount, note, "notes", METHOD_POST);
-    }
-
-    @Override
-    NoteResponse editNote(SingleSignOnAccount ssoAccount, Note note) throws Exception {
-        return putNote(ssoAccount, note, "notes/" + note.getRemoteId(), METHOD_PUT);
-    }
-
-    @Override
-    void deleteNote(SingleSignOnAccount ssoAccount, long noteId) throws Exception {
-        this.requestServer(ssoAccount, "notes/" + noteId, METHOD_DELETE, null, null, null);
-    }
-
-    @Override
-    protected String getApiPath() {
-        return API_PATH;
-    }
-}
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 d5901496..9f28cfff 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
@@ -1,24 +1,40 @@
 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 {
@@ -27,10 +43,6 @@ public class SSOClient {
 
     private static final Map<String, NextcloudAPI> mNextcloudAPIs = new HashMap<>();
 
-    public static Response requestFilesApp(@NonNull Context context, @NonNull SingleSignOnAccount ssoAccount, @NonNull NextcloudRequest nextcloudRequest) throws Exception {
-        return getNextcloudAPI(context.getApplicationContext(), ssoAccount).performNetworkRequestV2(nextcloudRequest);
-    }
-
     public static NextcloudAPI getNextcloudAPI(Context appContext, SingleSignOnAccount ssoAccount) {
         if (mNextcloudAPIs.containsKey(ssoAccount.name)) {
             return mNextcloudAPIs.get(ssoAccount.name);
@@ -45,6 +57,7 @@ public class SSOClient {
                                 calendar.setTimeInMillis(src.getAsLong() * 1_000);
                                 return calendar;
                             })
+                            .registerTypeAdapter(Capabilities.class, new CapabilitiesDeserializer())
                             .create(),
                     new NextcloudAPI.ApiConnectedListener() {
                         @Override
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/entity/Account.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/entity/Account.java
index ed6dcd6c..5317ed33 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/persistence/entity/Account.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/persistence/entity/Account.java
@@ -7,7 +7,6 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.room.ColumnInfo;
 import androidx.room.Entity;
-import androidx.room.Ignore;
 import androidx.room.Index;
 import androidx.room.PrimaryKey;
 
@@ -21,7 +20,6 @@ import java.util.Collections;
 import java.util.HashSet;
 import java.util.NoSuchElementException;
 
-import it.niedermann.owncloud.notes.persistence.NotesClient;
 import it.niedermann.owncloud.notes.shared.model.ApiVersion;
 import it.niedermann.owncloud.notes.shared.model.Capabilities;
 
@@ -83,7 +81,7 @@ public class Account implements Serializable {
             final Collection<ApiVersion> supportedApiVersions = new HashSet<>(versionsArray.length());
             for (int i = 0; i < versionsArray.length(); i++) {
                 final ApiVersion parsedApiVersion = ApiVersion.of(versionsArray.getString(i));
-                for (ApiVersion temp : NotesClient.SUPPORTED_API_VERSIONS) {
+                for (ApiVersion temp : ApiVersion.SUPPORTED_API_VERSIONS) {
                     if (temp.compareTo(parsedApiVersion) == 0) {
                         supportedApiVersions.add(parsedApiVersion);
                         break;
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
index cbb0687b..538afd89 100644
--- 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
@@ -16,16 +16,23 @@ import retrofit2.NextcloudRetrofitApiBuilder;
  */
 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/CapabilitiesDeserializer.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/CapabilitiesDeserializer.java
new file mode 100644
index 00000000..c9bf78da
--- /dev/null
+++ b/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/CapabilitiesDeserializer.java
@@ -0,0 +1,81 @@
+package it.niedermann.owncloud.notes.persistence.sync;
+
+import android.graphics.Color;
+import android.util.Log;
+
+import com.bumptech.glide.load.HttpException;
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParseException;
+import com.nextcloud.android.sso.exceptions.NextcloudHttpRequestFailedException;
+
+import java.lang.reflect.Type;
+
+import it.niedermann.android.util.ColorUtil;
+import it.niedermann.owncloud.notes.shared.model.Capabilities;
+
+import static java.net.HttpURLConnection.HTTP_UNAVAILABLE;
+
+public class CapabilitiesDeserializer implements JsonDeserializer<Capabilities> {
+
+    private static final String TAG = CapabilitiesDeserializer.class.getSimpleName();
+
+    private static final String JSON_OCS = "ocs";
+    private static final String JSON_OCS_META = "meta";
+    private static final String JSON_OCS_META_STATUSCODE = "statuscode";
+    private static final String JSON_OCS_DATA = "data";
+    private static final String JSON_OCS_DATA_CAPABILITIES = "capabilities";
+    private static final String JSON_OCS_DATA_CAPABILITIES_NOTES = "notes";
+    private static final String JSON_OCS_DATA_CAPABILITIES_NOTES_API_VERSION = "api_version";
+    private static final String JSON_OCS_DATA_CAPABILITIES_THEMING = "theming";
+    private static final String JSON_OCS_DATA_CAPABILITIES_THEMING_COLOR = "color";
+    private static final String JSON_OCS_DATA_CAPABILITIES_THEMING_COLOR_TEXT = "color-text";
+
+    @Override
+    public Capabilities deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
+        final Capabilities response = new Capabilities();
+        final JsonObject ocs = json.getAsJsonObject().getAsJsonObject(JSON_OCS);
+        if (ocs.has(JSON_OCS_META)) {
+            final JsonObject meta = ocs.getAsJsonObject(JSON_OCS_META);
+            if (meta.has(JSON_OCS_META_STATUSCODE)) {
+                if (meta.get(JSON_OCS_META_STATUSCODE).getAsInt() == HTTP_UNAVAILABLE) {
+                    Log.i(TAG, "Capabilities Endpoint: This instance is currently in maintenance mode.");
+                    throw new JsonParseException(new NextcloudHttpRequestFailedException(HTTP_UNAVAILABLE, new HttpException(HTTP_UNAVAILABLE)));
+                }
+            }
+        }
+        if (ocs.has(JSON_OCS_DATA)) {
+            final JsonObject data = ocs.getAsJsonObject(JSON_OCS_DATA);
+            if (data.has(JSON_OCS_DATA_CAPABILITIES)) {
+                final JsonObject capabilities = data.getAsJsonObject(JSON_OCS_DATA_CAPABILITIES);
+                if (capabilities.has(JSON_OCS_DATA_CAPABILITIES_NOTES)) {
+                    final JsonObject notes = capabilities.getAsJsonObject(JSON_OCS_DATA_CAPABILITIES_NOTES);
+                    if (notes.has(JSON_OCS_DATA_CAPABILITIES_NOTES_API_VERSION)) {
+                        final JsonElement apiVersion = notes.get(JSON_OCS_DATA_CAPABILITIES_NOTES_API_VERSION);
+                        response.setApiVersion(apiVersion.isJsonArray() ? apiVersion.toString() : null);
+                    }
+                }
+                if (capabilities.has(JSON_OCS_DATA_CAPABILITIES_THEMING)) {
+                    final JsonObject theming = capabilities.getAsJsonObject(JSON_OCS_DATA_CAPABILITIES_THEMING);
+                    if (theming.has(JSON_OCS_DATA_CAPABILITIES_THEMING_COLOR)) {
+                        try {
+                            response.setColor(Color.parseColor(ColorUtil.INSTANCE.formatColorToParsableHexString(theming.get(JSON_OCS_DATA_CAPABILITIES_THEMING_COLOR).getAsString())));
+                        } catch (Exception e) {
+                            e.printStackTrace();
+                        }
+                    }
+                    if (theming.has(JSON_OCS_DATA_CAPABILITIES_THEMING_COLOR_TEXT)) {
+                        try {
+                            response.setTextColor(Color.parseColor(ColorUtil.INSTANCE.formatColorToParsableHexString(theming.get(JSON_OCS_DATA_CAPABILITIES_THEMING_COLOR_TEXT).getAsString())));
+                        } catch (Exception e) {
+                            e.printStackTrace();
+                        }
+                    }
+                }
+            }
+        }
+        return response;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/NextcloudAPI.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/NextcloudAPI.java
deleted file mode 100644
index 9ddb5941..00000000
--- a/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/NextcloudAPI.java
+++ /dev/null
@@ -1,33 +0,0 @@
-package it.niedermann.owncloud.notes.persistence.sync;
-
-
-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://deck.readthedocs.io/en/latest/API/">Deck REST API</a>
- */
-public interface NextcloudAPI {
-
-    @GET("notes")
-    Call<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
new file mode 100644
index 00000000..17bc3c4f
--- /dev/null
+++ b/app/src/main/java/it/niedermann/owncloud/notes/persistence/sync/OcsAPI.java
@@ -0,0 +1,16 @@
+package it.niedermann.owncloud.notes.persistence.sync;
+
+
+import it.niedermann.owncloud.notes.shared.model.Capabilities;
+import retrofit2.Call;
+import retrofit2.http.GET;
+import retrofit2.http.Query;
+
+/**
+ * @link <a href="https://deck.readthedocs.io/en/latest/API/">Deck REST API</a>
+ */
+public interface OcsAPI {
+
+    @GET("capabilities?format=json")
+    Call<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 b27afd7a..761d0dc3 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
@@ -10,6 +10,11 @@ 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[] SUPPORTED_API_VERSIONS = new ApiVersion[]{
+            new ApiVersion(1, 0),
+            new ApiVersion(0, 2)
+    };
+
     private String originalVersion = "?";
     private int major;
     private int minor;
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/shared/model/Capabilities.java b/app/src/main/java/it/niedermann/owncloud/notes/shared/model/Capabilities.java
index 1c1bed3d..5514a91b 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/shared/model/Capabilities.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/shared/model/Capabilities.java
@@ -6,6 +6,7 @@ import android.util.Log;
 import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.annotation.VisibleForTesting;
 
 import com.bumptech.glide.load.HttpException;
 import com.nextcloud.android.sso.exceptions.NextcloudHttpRequestFailedException;
@@ -38,12 +39,17 @@ public class Capabilities {
     private String apiVersion = null;
 
     @ColorInt
-    private Integer color = -16743735;
+    private int color = -16743735;
     @ColorInt
-    private Integer textColor = -16777216;
+    private int textColor = -16777216;
     @Nullable
-    private final String eTag;
+    private String eTag;
 
+    public Capabilities() {
+
+    }
+
+    @VisibleForTesting
     public Capabilities(@NonNull String response, @Nullable String eTag) throws NextcloudHttpRequestFailedException {
         this.eTag = eTag;
         final JSONObject ocs;
@@ -92,6 +98,10 @@ public class Capabilities {
         }
     }
 
+    public void setApiVersion(String apiVersion) {
+        this.apiVersion = apiVersion;
+    }
+
     public String getApiVersion() {
         return apiVersion;
     }
@@ -101,14 +111,26 @@ public class Capabilities {
         return eTag;
     }
 
-    public Integer getColor() {
+    public void setETag(@Nullable String eTag) {
+        this.eTag = eTag;
+    }
+
+    public int getColor() {
         return color;
     }
 
-    public Integer getTextColor() {
+    public void setColor(@ColorInt int color) {
+        this.color = color;
+    }
+
+    public int getTextColor() {
         return textColor;
     }
 
+    public void setTextColor(@ColorInt int textColor) {
+        this.textColor = textColor;
+    }
+
     @NonNull
     @Override
     public String toString() {
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/shared/model/ServerResponse.java b/app/src/main/java/it/niedermann/owncloud/notes/shared/model/ServerResponse.java
deleted file mode 100644
index dca53fb9..00000000
--- a/app/src/main/java/it/niedermann/owncloud/notes/shared/model/ServerResponse.java
+++ /dev/null
@@ -1,103 +0,0 @@
-package it.niedermann.owncloud.notes.shared.model;
-
-import androidx.annotation.Nullable;
-
-import org.json.JSONArray;
-import org.json.JSONException;
-import org.json.JSONObject;
-
-import java.util.ArrayList;
-import java.util.Calendar;
-import java.util.List;
-
-import it.niedermann.owncloud.notes.persistence.NotesClient;
-import it.niedermann.owncloud.notes.persistence.entity.Note;
-
-/**
- * Provides entity classes for handling server responses with a single note ({@link NoteResponse}) or a list of notes ({@link NotesResponse}).
- */
-public class ServerResponse {
-
-    public static class NoteResponse extends ServerResponse {
-        public NoteResponse(NotesClient.ResponseData response) {
-            super(response);
-        }
-
-        public Note getNote() throws JSONException {
-            return getNoteFromJSON(new JSONObject(getContent()));
-        }
-    }
-
-    public static class NotesResponse extends ServerResponse {
-        public NotesResponse(NotesClient.ResponseData response) {
-            super(response);
-        }
-
-        public List<Note> getNotes() throws JSONException {
-            List<Note> notesList = new ArrayList<>();
-            JSONArray notes = new JSONArray(getContent());
-            for (int i = 0; i < notes.length(); i++) {
-                JSONObject json = notes.getJSONObject(i);
-                notesList.add(getNoteFromJSON(json));
-            }
-            return notesList;
-        }
-    }
-
-
-    private final NotesClient.ResponseData response;
-
-    ServerResponse(NotesClient.ResponseData response) {
-        this.response = response;
-    }
-
-    protected String getContent() {
-        return response == null ? null : response.getContent();
-    }
-
-    public String getETag() {
-        return response.getETag();
-    }
-
-    public Calendar getLastModified() {
-        return response.getLastModified();
-    }
-
-    @Nullable
-    public String getSupportedApiVersions() {
-        return response.getSupportedApiVersions();
-    }
-
-    Note getNoteFromJSON(JSONObject json) throws JSONException {
-        long remoteId = 0;
-        String title = "";
-        String content = "";
-        Calendar modified = null;
-        boolean favorite = false;
-        String category = "";
-        String etag = null;
-        if (!json.isNull(NotesClient.JSON_ID)) {
-            remoteId = json.getLong(NotesClient.JSON_ID);
-        }
-        if (!json.isNull(NotesClient.JSON_TITLE)) {
-            title = json.getString(NotesClient.JSON_TITLE);
-        }
-        if (!json.isNull(NotesClient.JSON_CONTENT)) {
-            content = json.getString(NotesClient.JSON_CONTENT);
-        }
-        if (!json.isNull(NotesClient.JSON_MODIFIED)) {
-            modified = Calendar.getInstance();
-            modified.setTimeInMillis(json.getLong(NotesClient.JSON_MODIFIED) * 1_000);
-        }
-        if (!json.isNull(NotesClient.JSON_FAVORITE)) {
-            favorite = json.getBoolean(NotesClient.JSON_FAVORITE);
-        }
-        if (!json.isNull(NotesClient.JSON_CATEGORY)) {
-            category = json.getString(NotesClient.JSON_CATEGORY);
-        }
-        if (!json.isNull(NotesClient.JSON_ETAG)) {
-            etag = json.getString(NotesClient.JSON_ETAG);
-        }
-        return new Note(remoteId, modified, title, content, category, favorite, etag);
-    }
-}
diff --git a/app/src/test/java/it/niedermann/owncloud/notes/shared/model/CapabilitiesTest.java b/app/src/test/java/it/niedermann/owncloud/notes/shared/model/CapabilitiesTest.java
index 6415bb39..5a30bd2a 100644
--- a/app/src/test/java/it/niedermann/owncloud/notes/shared/model/CapabilitiesTest.java
+++ b/app/src/test/java/it/niedermann/owncloud/notes/shared/model/CapabilitiesTest.java
@@ -48,8 +48,8 @@ public class CapabilitiesTest {
         final Capabilities capabilities = new Capabilities(response, null);
         assertNull(capabilities.getETag());
         assertNull(capabilities.getApiVersion());
-        assertEquals(Integer.valueOf(Color.parseColor("#1E4164")), capabilities.getColor());
-        assertEquals(Integer.valueOf(Color.parseColor("#ffffff")), capabilities.getTextColor());
+        assertEquals(Color.parseColor("#1E4164"), capabilities.getColor());
+        assertEquals(Color.parseColor("#ffffff"), capabilities.getTextColor());
     }
 
     @Test
@@ -86,8 +86,8 @@ public class CapabilitiesTest {
         final Capabilities capabilities = new Capabilities(response, null);
         assertNull(capabilities.getETag());
         assertEquals("1.0", capabilities.getApiVersion());
-        assertEquals(Integer.valueOf(Color.parseColor("#1E4164")), capabilities.getColor());
-        assertEquals(Integer.valueOf(Color.parseColor("#ffffff")), capabilities.getTextColor());
+        assertEquals(Color.parseColor("#1E4164"), capabilities.getColor());
+        assertEquals(Color.parseColor("#ffffff"), capabilities.getTextColor());
     }
 
     @Test