public function mentionHandler($post)
 {
     $usernames = MentionHelper::find($post->message);
     if (!empty($usernames)) {
         foreach ($usernames as $username) {
             /** @var UserModels $mentioned */
             $mentioned = UserModels::findByUsername($username);
             if (!$mentioned instanceof UserModels) {
                 continue;
             }
             $exist = UserMention::find()->where(['post_id' => $post->id, 'mention_user_id' => $mentioned->id, 'status' => UserMention::MENTION_SATUS_UNVIEWED])->exists();
             if ($exist) {
                 continue;
             }
             $currentUser = Yii::$app->getUser()->getIdentity();
             $model = new UserMention();
             $model->user_id = $currentUser->id;
             $model->mention_user_id = $mentioned->id;
             $model->post_id = $post->id;
             $model->topic_id = $post->topic->id;
             $model->status = UserMention::MENTION_SATUS_UNVIEWED;
             if ($mentioned->notify_mention_web == 1) {
                 $model->save();
             }
             if ($mentioned->notify_mention_email == 1) {
                 \Yii::$app->mailer->compose(['text' => 'mention'], ['model' => $model, 'topic' => $post->topic])->setFrom([Yii::$app->config->get('support_email') => Yii::$app->config->get('site_title')])->setTo([$model->mentionUser->email => $model->mentionUser->username])->setSubject('#' . $post->id . ' ' . $post->topic->subject)->send();
             }
         }
         return true;
     }
     return false;
 }
 /**
  * @inheritdoc
  */
 public static function notifications($user)
 {
     $userMentions = UserMention::find()->with(['post' => function ($query) {
         $query->andWhere(['status' => UserMention::MENTION_STATUS_UNVIEWED]);
     }, 'topic'])->where(['mention_user_id' => $user->id])->andWhere(['status' => UserMention::MENTION_STATUS_UNVIEWED])->all();
     return $userMentions;
 }