/**
  * Авторизация
  * @return array|string|Response
  */
 public function actionLogin()
 {
     if (!Yii::$app->user->isGuest) {
         $this->goHome();
     }
     $model = new models\LoginForm(['scenario' => 'admin']);
     if ($model->load(Yii::$app->request->post())) {
         if ($model->validate()) {
             if ($model->login()) {
                 return $this->goHome();
             }
         } else {
             if (Yii::$app->request->isAjax) {
                 Yii::$app->response->format = Response::FORMAT_JSON;
                 return ActiveForm::validate($model);
             }
         }
     }
     return $this->render('login', ['model' => $model]);
 }