Synchronize selectable folders only

app/src/main/java/eu/faircode/email/ServiceSynchronize.java

@@ -1436,6 +1436,14 @@ public class ServiceSynchronize extends LifecycleService {
             Log.i(Helper.TAG, "Remote folder count=" + ifolders.length);
 
             for (Folder ifolder : ifolders) {
+                boolean selectable = true;
+                String[] attrs = ((IMAPFolder) ifolder).getAttributes();
+                for (String attr : attrs) {
+                    if ("\\Noselect".equals(attr))
+                        selectable = false;
+                }
+
+                if (selectable) {
                     EntityFolder folder = db.folder().getFolderByName(account.id, ifolder.getFullName());
                     if (folder == null) {
                         folder = new EntityFolder();
@@ -1451,10 +1459,13 @@ public class ServiceSynchronize extends LifecycleService {
                         Log.i(Helper.TAG, folder.name + " exists");
                     }
                 }
+            }
 
             Log.i(Helper.TAG, "Delete local folder=" + names.size());
-            for (String name : names)
+            for (String name : names) {
                 db.folder().deleteFolder(account.id, name);
+                Log.i(Helper.TAG, name + " deleted");
+            }
 
             db.setTransactionSuccessful();
         } finally {