public function actionSetMain()
 {
     /** @var File $file */
     Yii::$app->response->format = Response::FORMAT_JSON;
     $file = File::findOne(Yii::$app->request->post('id', 0));
     $result = [];
     if ($file) {
         $status = Yii::$app->request->post('value', 'false');
         if ($status === 'true') {
             File::updateAll(['is_main' => 0], ['model' => $file->model, 'itemId' => $file->itemId]);
             $file->is_main = File::MAIN;
         } else {
             $file->is_main = File::NOT_MAIN;
         }
         if ($file->save() && $file->is_main) {
             $result = ['id' => $file->id];
         }
     }
     return $result;
 }