better localId

Signed-off-by: tobiasKaminsky <tobias@kaminsky.me>

src/main/java/com/owncloud/android/datamodel/OCFile.java

@@ -552,7 +552,8 @@ public class OCFile implements Parcelable, Comparable<OCFile>, ServerFileInterfa
      * @return file fileId, unique within the instance
      */
     public String getLocalId() {
-        return getRemoteId().substring(0, 8).replaceAll("^0*", "");
+        // fileId, instanceId. instanceId is 12 chars long
+        return getRemoteId().substring(0, getRemoteId().length() - 12).replaceAll("^0*", "");
     }
 
     public boolean isInConflict() {

src/test/java/com/owncloud/android/datamodel/OCFileTest.java

@@ -0,0 +1,43 @@
+/*
+ *
+ * Nextcloud Android client application
+ *
+ * @author Tobias Kaminsky
+ * Copyright (C) 2021 Tobias Kaminsky
+ * Copyright (C) 2021 Nextcloud GmbH
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.owncloud.android.datamodel;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class OCFileTest {
+
+    @Test
+    public void testLongIds() {
+        OCFile sut = new OCFile("/", "12345678ocjycgrudn78");
+        assertEquals("12345678", sut.getLocalId());
+
+        sut.setRemoteId("00000008ocjycgrudn78");
+        assertEquals("8", sut.getLocalId());
+
+        sut.setRemoteId("1234567891011ocjycgrudn78");
+        assertEquals("1234567891011", sut.getLocalId());
+    }
+
+}