Update nav menu not selecting parent

Question

I am building a nav menu programmatically like so:

$menu_exists = wp_get_nav_menu_object( 'test_menu' );
if( !$menu_exists){
    $menu_id = wp_create_nav_menu('test_menu');
    buildMenu($menuArray,$menu_id);
}

function buildMenu($array,$menu_id) {

    foreach ($array as $menu) {

        var_dump( wp_update_nav_menu_item($menu_id, 0, array(
            'menu-item-title' => $menu[0]->post_title,
            'menu-item-object' => 'page',
            'menu-item-object-id' => $menu[0]->ID,
            'menu-item-type' => 'post_type',
            'menu-item-status' => 'publish',
            'menu-item-parent-id' => $menu[0]->post_parent)));


        if(!empty($menu[1])) {
            buildMenu($menu[1],$menu_id);
        }
    }

}

Where $menuArray is collection of post objects. This is working, however all the menus items get added to the top level and the menu-item-parent-id is ignored. Does WordPress expect the menu-item-parent-id to be the nav menu id or the post id?

Answer 1

As I originally suspected, menu-item-parent-id takes the id of the menu item and not the id of the parent page.

So I referenced the menu item ID and passed it into the recursive function :

function buildMenu( $array, $menu_id, $parent_id = false ) {

    foreach ($array as $menu) {

        $menuItemId = wp_update_nav_menu_item(
            $menu_id,
            0,
            array(
                'menu-item-title'     => $menu[0]->post_title,
                'menu-item-object'    => 'page',
                'menu-item-object-id' => $menu[0]->ID,
                'menu-item-type'      => 'post_type',
                'menu-item-status'    => 'publish',
                'menu-item-parent-id' => $parent_id
            )
        );


        if(!empty($menu[1])) {
            buildMenu( $menu[1], $menu_id, $menuItemId );
        }

    }

}