filters( 'premmerce_permalink_manager_canonical', $this->getCanonical() );
            if ( !empty($canonical) ) {
                echo  '<link rel="canonical" href="' . esc_url( $canonical ) . '" />' . "\n" ;
            }
        }
    
    }
    
    private function getCanonical( $useCommentsPagination = false )
    {
        global  $wp_rewrite ;
        $qo = get_queried_object();
        $canonical = null;
        
        if ( $qo instanceof WP_Term ) {
            $canonical = get_term_link( $qo );
            $paged = get_query_var( 'paged' );
            if ( $paged > 1 ) {
                $canonical = trailingslashit( $canonical ) . trailingslashit( $wp_rewrite->pagination_base ) . $paged;
            }
        } elseif ( $qo instanceof WP_Post ) {
            $canonical = get_permalink( $qo );
            
            if ( $useCommentsPagination ) {
                $page = get_query_var( 'cpage' );
                if ( $page > 1 ) {
                    $canonical = trailingslashit( $canonical ) . $wp_rewrite->comments_pagination_base . '-' . $page;
                }
            }
        
        }
        
        if ( $canonical ) {
            return user_trailingslashit( $canonical );
        }
    }
    
    /**
     * Find current slug by product SKU
     *
     * @param string $sku
     *
     * @return string
     */
    protected function findSlugBySku( $sku )
    {
        global  $wpdb ;
        $skuId = $wpdb->get_row( $wpdb->prepare( "SELECT post_id FROM {$wpdb->postmeta} WHERE meta_value = %s AND meta_key = '_sku'", array( $sku ) ), ARRAY_A );
        
        if ( isset( $skuId['post_id'] ) ) {
            $postSlug = get_post_field( 'post_name', $skuId['post_id'] );
            if ( '' !== $postSlug ) {
                return $postSlug;
            }
        }
        
        return $sku;
    }
    
    /**
     * Check if woocommerce category exists in request
     *
     * @param array $request
     *
     * @return boolean
     */
    protected function checkIfWooCategoryExists( $request )
    {
        if ( !empty($this->options['category']) && in_array( $this->options['product'], array( 'category_slug', 'hierarchical' ) ) ) {
            if ( array_key_exists( self::WOO_CATEGORY, $request ) ) {
                return true;
            }
        }
        return false;
    }

}