function woocommerce_category_id() {
    global $post;
    $prod_terms = get_the_terms( $post->ID, 'product_cat' );

    if ($prod_terms != null) {
    foreach ($prod_terms as $prod_term) {
        // gets product cat id
        $product_cat_name = $prod_term->term_id;

        // gets an array of all parent category levels
        $product_parent_categories_all_hierachy = get_ancestors( $product_cat_name, 'product_cat' );

        // This cuts the array and extracts the last set in the array
        $last_parent_cat = array_slice($product_parent_categories_all_hierachy, -1, 1, true);
        foreach($last_parent_cat as $last_parent_cat_value){

        // $last_parent_cat_value is the id of the most top level category, can be use whichever one like
        $product_id = $last_parent_cat_value;

        $args = array('hierarchical' => 1, 'show_option_none' => '', 'hide_empty' => 0, 'parent' => $product_id, 'taxonomy' => 'product_cat' );

        $subcats = get_categories($args);

        if ( is_product_category() ) {

        foreach ($subcats as $sc) {

            if(get_queried_object()->slug == $sc->slug) { $class = ' class="current"'; }
            else { $class = ''; }

            $link = get_term_link( $sc->slug, $sc->taxonomy );

            echo '<li'.$class.'><a href="'. $link .'">'.$sc->name.'</a></li>';

            }

        } elseif ( is_product() ){


        foreach ($subcats as $sc) {

            if(get_queried_object()->slug == $sc->slug) { $class = ' class="current"'; }
            else { $class = ''; }

            $link = get_term_link( $sc->slug, $sc->taxonomy );

            echo '<li'.$class.'><a href="'. $link .'">'.$sc->name.'</a></li>';

            }

        } else {


         $args2 = array('hierarchical' => 1, 'show_option_none' => '', 'hide_empty' => 0, 'parent' => 0, 'taxonomy' => 'product_cat' );

        $subproducts = get_terms( 'product_cat', $args2);

        foreach ($subproducts as $subproduct) {
        $link2 = get_term_link( $subproduct->slug, $subproduct->taxonomy );
        echo '<li><a href="'.$link2.'">'.$subproduct->name.'</a></li>';
        }

         }

        }
    }
    else {
        echo '<p>No items found.</p>';
    }
}