/**
  * @param $id
  * @return mixed
  */
 public function deletePublishedFile($id)
 {
     $file = $this->getActivityPublishedFile($id);
     if (Gate::denies('ownership', $file)) {
         return redirect()->route('activity.index')->withResponse($this->getNoPrivilegesMessage());
     }
     $this->authorize('delete_activity', $file);
     $result = $this->activityManager->deletePublishedFile($id);
     $message = $result ? 'File deleted successfully' : 'File couldn\'t be deleted.';
     $type = $result ? 'success' : 'danger';
     $response = ['type' => $type, 'code' => ['transfer_message', ['name' => $message]]];
     return redirect()->back()->withResponse($response);
 }