Sorting Posts ASC and DESC Same Link

Hi there. Currently I have a table where I can order titles asc and desc but with individual links such as “A-Z” and “Z-A”.

I would like it if there was just a link called “Titles” and when the user clicks it, it’ll sort by ASC and then once clicked again it’ll sort by DESC.

The following is my code for what I currently have but I am not sure how to approach this to combine in one link.

<?php
    $type = 'shows';
    $args=array(
      'post_type' => $type,
      'post_status' => 'publish',
      'posts_per_page' => -1,
      'ignore_sticky_posts'=> 1
    );

    if( isset( $_GET['sort'] ) && "titleasc" == $_GET['sort'] ){
        $args['orderby'] = 'title';
        $args['order'] = 'ASC';
    }

    if( isset( $_GET['sort'] ) && "titledesc" == $_GET['sort'] ){
        $args['orderby'] = 'title';
        $args['order'] = 'DESC';
    }

The link I currently have is:
<th>Title <span><a href="?sort=titleasc">A-Z</a> <a href="?sort=titledesc">Z-A</a></span> </th>

Your help is greatly appreciated. Thanks!