=> 'slug',
            ) );
            if ( $this->polyLang->options['hide_default'] ) {
                $languages = array_diff( $languages, array( $this->polyLang->options['default_lang'] ) );
            }
            if ( !empty($languages) ) {
                return $wp_rewrite->root . (( $this->polyLang->options['rewrite'] ? '' : 'language/' )) . '(' . implode( '|', $languages ) . ')/';
            }
        }
        
        return false;
    }
    
    private function getProductBase()
    {
        
        if ( is_null( $this->productBase ) ) {
            $permalinkStructure = wc_get_permalink_structure();
            $this->productBase = $permalinkStructure['product_rewrite_slug'];
        }
        
        return $this->productBase;
    }
    
    private function addPostParentLink( $permalink, $post, $hierarchical )
    {
        if ( false === strpos( $permalink, '%product_cat%' ) ) {
            return $permalink;
        }
        $term = $this->getProductCategory( $post );
        
        if ( $term ) {
            $slug = $this->buildTermPath( $term, $hierarchical );
            $permalink = str_replace( '%product_cat%', $slug, $permalink );
        }
        
        return $permalink;
    }
    
    private function buildTermPath( $term, $hierarchical, $suffix = false )
    {
        //urldecode used here to fix copied url via ctrl+c
        $slug = urldecode( $term->slug );
        
        if ( $hierarchical && $term->parent ) {
            $ancestors = get_ancestors( $term->term_id, 'product_cat' );
            foreach ( $ancestors as $ancestor ) {
                $ancestor_object = get_term( $ancestor, 'product_cat' );
                $slug = urldecode( $ancestor_object->slug ) . '/' . $slug;
            }
        }
        
        return ( $suffix ? $slug . $suffix : $slug );
    }
    
    private function getProductCategory( $product )
    {
        $term = null;
        if ( !empty($this->options['use_primary_category']) ) {
            $term = $this->getSeoPrimaryTerm( $product );
        }
        if ( !$term instanceof \WP_Term ) {
            $term = $this->getWcPrimaryTerm( $product );
        }
        if ( $term instanceof \WP_Term ) {
            return $term;
        }
        return null;
    }
    
    private function getSeoPrimaryTerm( $product )
    {
        
        if ( $this->checkSeoPlugin() ) {
            $primaryTerm = yoast_get_primary_term_id( self::WOO_CAT, $product->ID );
            return get_term( $primaryTerm );
        }
        
        return null;
    }
    
    private function getWcPrimaryTerm( $product )
    {
        $terms = get_the_terms( $product->ID, 'product_cat' );
        if ( empty($terms) ) {
            return null;
        }
        
        if ( function_exists( 'wp_list_sort' ) ) {
            $terms = wp_list_sort( $terms, 'term_id', 'DESC' );
        } else {
            usort( $terms, '_usort_terms_by_ID' );
        }
        
        $category_object = apply_filters(
            'wc_product_post_type_link_product_cat',
            $terms[0],
            $terms,
            $product
        );
        $category_object = get_term( $category_object, 'product_cat' );
        return $category_object;
    }
    
    private function isHierarchical( $type )
    {
        return 'hierarchical' === $type;
    }
    
    /**
     * Check that seo plugin is enabled and available to use
     *
     * @return bool
     */
    protected function checkSeoPlugin()
    {
        if ( !function_exists( 'is_plugin_active' ) ) {
            include_once ABSPATH . 'wp-admin/includes/plugin.php';
        }
        return function_exists( 'is_plugin_active' ) && defined( 'WPSEO_BASENAME' ) && is_plugin_active( WPSEO_BASENAME ) && function_exists( 'yoast_get_primary_term_id' );
    }
    
    /**
     * Check that WPML plugin is enabled and available to use
     *
     * @return bool
     */
    protected function checkWpmlPlugin()
    {
        return class_exists( 'SitePress' );
    }
    
    /**
     * Replace current post slug with woocommerce SKU
     *
     * @param string $permalink
     * @param integer $postID
     *
     * @return string
     */
    protected function replaceSlugWithSku( $permalink, $postID )
    {
        $skuString = get_post_meta( $postID, '_sku', true );
        if ( '' !== $skuString ) {
            if ( 'sku' === $this->options['sku'] ) {
                return str_replace( basename( $permalink ), $skuString, $permalink );
            }
        }
        return $permalink;
    }
    
    /**
     * Add parameters to permalink
     *
     * @param string $permalink
     *
     * @return string
     */
    protected function addParamsToPermalink( $permalink )
    {
        $parsedUrl = parse_url( $permalink, PHP_URL_QUERY );
        parse_str( $parsedUrl, $output );
        if ( isset( $output['lang'] ) ) {
            return $permalink;
        }
        global  $sitepress ;
        $isGetParamUrlFormat = apply_filters( 'wpml_setting', 0, 'language_negotiation_type' ) == '3';
        if ( $sitepress->get_default_language() != ICL_LANGUAGE_CODE && $isGetParamUrlFormat ) {
            return add_query_arg( array(
                'lang' => ICL_LANGUAGE_CODE,
            ), $permalink );
        }
        return $permalink;
    }

}