public function actionIndex()
 {
     $this->link_canonical = Url::to(['index'], true);
     $product_collections = ProductCollection::find()->where(['is_active' => 1])->orderBy('position asc')->all();
     if ($this->is_mobile && !$this->is_tablet) {
         $product_collection_image_suffix = ProductCollection::$image_resizes['mobile'];
     } else {
         if ($this->is_tablet) {
             $product_collection_image_suffix = ProductCollection::$image_resizes['tablet'];
         } else {
             $product_collection_image_suffix = ProductCollection::$image_resizes['desktop'];
         }
     }
     return $this->render('index', ['product_collection_image_suffix' => $product_collection_image_suffix, 'product_collections' => $product_collections]);
 }