/**
  * Save  handler
  *
  * @param array $data
  * @param Form $form
  * @return HTTPResponse
  */
 public function save($data, $form)
 {
     $request = $this->getRequest();
     $className = $this->stat('tree_class');
     // Existing or new record?
     $id = $data['ID'];
     if (is_numeric($id) && $id > 0) {
         $record = DataObject::get_by_id($className, $id);
         if ($record && !$record->canEdit()) {
             return Security::permissionFailure($this);
         }
         if (!$record || !$record->ID) {
             $this->httpError(404, "Bad record ID #" . (int) $id);
         }
     } else {
         if (!singleton($this->stat('tree_class'))->canCreate()) {
             return Security::permissionFailure($this);
         }
         $record = $this->getNewItem($id, false);
     }
     // save form data into record
     $form->saveInto($record, true);
     $record->write();
     $this->extend('onAfterSave', $record);
     $this->setCurrentPageID($record->ID);
     $message = _t('LeftAndMain.SAVEDUP', 'Saved.');
     if ($request->getHeader('X-Formschema-Request')) {
         $schemaId = Controller::join_links($this->Link('schema/DetailEditForm'), $id);
         // Ensure that newly created records have all their data loaded back into the form.
         $form->loadDataFrom($record);
         $form->setMessage($message, 'good');
         $data = $this->getSchemaForForm($form, $schemaId);
         $response = new HTTPResponse(Convert::raw2json($data));
         $response->addHeader('Content-Type', 'application/json');
     } else {
         $response = $this->getResponseNegotiator()->respond($request);
     }
     $response->addHeader('X-Status', rawurlencode($message));
     return $response;
 }