Prevent renaming system folders

Fixes #123

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

@@ -76,6 +76,7 @@ public class EntityFolder implements Parcelable {
     static final String TRASH = "Trash";
     static final String JUNK = "Junk";
     static final String SENT = "Sent";
+    static final String SYSTEM = "System";
     static final String USER = "User";
 
     static final List<String> SYSTEM_FOLDER_ATTR = Arrays.asList(
@@ -83,14 +84,18 @@ public class EntityFolder implements Parcelable {
             "Drafts",
             "Trash",
             "Junk",
-            "Sent"
+            "Sent",
+            "Important",
+            "Flagged"
     );
     static final List<String> SYSTEM_FOLDER_TYPE = Arrays.asList(
             ARCHIVE,
             DRAFTS,
             TRASH,
             JUNK,
-            SENT
+            SENT,
+            SYSTEM,
+            SYSTEM
     ); // MUST match SYSTEM_FOLDER_ATTR
 
     static final List<String> FOLDER_SORT_ORDER = Arrays.asList(
@@ -101,6 +106,7 @@ public class EntityFolder implements Parcelable {
             ARCHIVE,
             TRASH,
             JUNK,
+            SYSTEM,
             USER
     );
 

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

@@ -310,6 +310,7 @@ public class FragmentFolder extends FragmentEx {
                 // Consider previous save as cancelled
                 pbWait.setVisibility(View.GONE);
                 Helper.setViewsEnabled(view, true);
+                etRename.setEnabled(folder == null || EntityFolder.USER.equals(folder.type));
                 btnSave.setEnabled(true);
                 ibDelete.setEnabled(true);
                 ibDelete.setVisibility(folder == null ? View.GONE : View.VISIBLE);

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

@@ -1239,17 +1239,23 @@ public class ServiceSynchronize extends LifecycleService {
 
             for (Folder ifolder : ifolders) {
                 String[] attrs = ((IMAPFolder) ifolder).getAttributes();
+                boolean system = false;
                 boolean selectable = true;
                 for (String attr : attrs) {
                     if ("\\Noselect".equals(attr)) { // TODO: is this attribute correct?
                         selectable = false;
                         break;
                     }
-                    if (attr.startsWith("\\"))
-                        if (EntityFolder.SYSTEM_FOLDER_ATTR.contains(attr.substring(1))) {
-                            selectable = false;
+                    if (attr.startsWith("\\")) {
+                        attr = attr.substring(1);
+                        if (EntityFolder.SYSTEM_FOLDER_ATTR.contains(attr)) {
+                            int index = EntityFolder.SYSTEM_FOLDER_ATTR.indexOf(attr);
+                            system = EntityFolder.SYSTEM.equals(EntityFolder.SYSTEM_FOLDER_TYPE.get(index));
+                            if (!system)
+                                selectable = false;
                             break;
                         }
+                    }
                 }
 
                 if (selectable) {
@@ -1259,13 +1265,16 @@ public class ServiceSynchronize extends LifecycleService {
                         folder = new EntityFolder();
                         folder.account = account.id;
                         folder.name = ifolder.getFullName();
-                        folder.type = EntityFolder.USER;
+                        folder.type = (system ? EntityFolder.SYSTEM : EntityFolder.USER);
                         folder.synchronize = false;
                         folder.after = EntityFolder.DEFAULT_USER_SYNC;
                         db.folder().insertFolder(folder);
                         Log.i(Helper.TAG, folder.name + " added");
-                    } else
+                    } else {
+                        if (system)
+                            db.folder().setFolderType(folder.id, EntityFolder.SYSTEM);
                         names.remove(folder.name);
+                    }
                 }
             }
 

app/src/main/res/values/strings.xml

@@ -145,6 +145,7 @@
     <string name="title_folder_trash">Trash</string>
     <string name="title_folder_junk">Spam</string>
     <string name="title_folder_sent">Sent</string>
+    <string name="title_folder_system">System</string>
     <string name="title_folder_user">User</string>
     <string name="title_folder_primary">Folders primary account</string>
     <string name="title_folder_thread">Conversation</string>