wordpress: Dynamical wordpress pages menu with included ancestor

gistfile1.phtml

<?php   //ADD PAGES MENU
                        
$children = get_pages('child_of='.$post->ID);
$ancestors = get_post_ancestors($post->ID);

//Check if the page has children or ancestors if yes, output pages menu.
if(!empty($children) or !empty($ancestors)){
    if( is_page() ) { 
        global $post;
        $parents = get_post_ancestors( $post->ID );
        $id = ($parents) ? $parents[count($parents)-1]: $post->ID;
        $parent = get_page( $id );
        //Variables for adding ancestor page to the menu
        $currentUrl = "http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";
        $parentUrl = get_permalink($id);
        $parentTitle = get_the_title($id);
    }
    
    $args = array('child_of' => $id, 'title_li'=> ''); 
?>
<ul class="product-list">
    
    <li <?php /*Check if is current page*/ if($parentUrl == $currentUrl){echo 'class="active"';} ?> >
        <a href="<?php echo $parentUrl; ?>"><?php echo $parentTitle; ?></a>
    </li>
    
    <?php /*List subpages*/ wp_list_pages( $args ); ?>
    
</ul>
<?php } ?>