Menu subitem doesn't keep its position

Question

I try to hide some menu items (from an unique menu) dynamically in functions.php. I have some subdomains. I add CSS classes to menu items and then I hide them according to the current subdomain. Here is my code :

add_filter( 'wp_get_nav_menu_items', 'hide_menu_item', 10, 3 );
function hide_menu_item ( $items, $menu, $args ) {
    $sub = array_shift((explode(".",$_SERVER['HTTP_HOST'])));

    if(!is_admin()){
        foreach ( $items as $key => $item ) {
            if ( $item->classes[0] == 'subdomain1' && $sub != 'part1' || $item->classes[0] == 'main' && $sub != 'domain') {
                unset( $items[$key] );
            }
        }
    }
    return $items;
}

subdomain1 and main are classes, part1 is a subdomain and domain is the main domain. I.e. main is the class for the item Products, and subdomain1 is the class for the subitem Smartphone. Both of them are shown on domain.com, and Products is hidden on part1.domain.com. It works, but the problem is that Smartphone on subdomain part1 is ejected to the end of the menu while it was originally at the middle of the menu.

How can I do to 'keep' the position of the subitem, or the position of the hidden parent ?

Answer 1

I found the answer in nav-menu.php, it wasn't too complicated. I just changed the foreach loop content like this :

if($item->classes[0] == 'subdomain1' && !empty( $item->menu_item_parent )){
    $item->menu_item_parent = '';
}elseif($item->classes[0] == 'main' && $sub != 'domain'){
    unset($items[$key]);
}

Hope it can help !