public function actionMark($id = null)
    {
        $model = Subscription::find()->where(['id' => $id, 'user_id' => User::loggedId()])->limit(1)->one();
        if (empty($model)) {
            $this->error(Yii::t('podium/flash', 'Sorry! We can not find Subscription with this ID.'));
            return $this->redirect(['profile/subscriptions']);
        }
        if ($model->post_seen == Subscription::POST_SEEN) {
            if ($model->unseen()) {
                $this->success(Yii::t('podium/flash', 'Thread has been marked unseen.'));
            } else {
                Log::error('Error while marking thread', $model->id, __METHOD__);
                $this->error(Yii::t('podium/flash', 'Sorry! There was some error while marking the thread.'));
            }
            return $this->redirect(['profile/subscriptions']);
        }
        if ($model->post_seen == Subscription::POST_NEW) {
            if ($model->seen()) {
                $this->success(Yii::t('podium/flash', 'Thread has been marked seen.'));
            } else {
                Log::error('Error while marking thread', $model->id, __METHOD__);
                $this->error(Yii::t('podium/flash', 'Sorry! There was some error while marking the thread.'));
            }
            return $this->redirect(['profile/subscriptions']);
        }
        $this->error(Yii::t('podium/flash', 'Sorry! Subscription has got the wrong status.'));
        return $this->redirect(['profile/subscriptions']);
    }