Programmatically add a Navigation menu and menu items

Through API functions, I want to define a new Navigation menu, select it in the current theme, and then insert a few Pages as menu items. This is to be done for instance on a theme activation.

Through a (moderately painful) process of reverse engineering the database inserts and updates after manually setting up the Navigation menu and items, I’ve pieced together the following steps, where ‘footer-nav’ is the slug ID of the Navigation menu I’m creating:

if (!term_exists('footer-nav', 'nav_menu')) {

    $menu = wp_insert_term('Footer nav', 'nav_menu', array('slug' => 'footer-nav'));

    // Select this menu in the current theme
    update_option('theme_mods_'.get_current_theme(), array("nav_menu_locations" => array("primary" => $menu['term_id'])));

    // Insert new page
    $page = wp_insert_post(array('post_title' => 'Blog',
                                 'post_content' => '',
                                 'post_status' => 'publish',
                                 'post_type' => 'page'));

    // Insert new nav_menu_item
    $nav_item = wp_insert_post(array('post_title' => 'News',
                                     'post_content' => '',
                                     'post_status' => 'publish',
                                     'post_type' => 'nav_menu_item'));


    add_post_meta($nav_item, '_menu_item_type', 'post_type');
    add_post_meta($nav_item, '_menu_item_menu_item_parent', '0');
    add_post_meta($nav_item, '_menu_item_object_id', $page);
    add_post_meta($nav_item, '_menu_item_object', 'page');
    add_post_meta($nav_item, '_menu_item_target', '');
    add_post_meta($nav_item, '_menu_item_classes', 'a:1:{i:0;s:0:"";}');
    add_post_meta($nav_item, '_menu_item_xfn', '');
    add_post_meta($nav_item, '_menu_item_url', '');

    wp_set_object_terms($nav_item, 'footer-nav', 'nav_menu');
}

This seems to work, but:

• is it a robust and elegant way of doing it?
• am I missing something totally obvious that would do all this in one line of code?

I might be misunderstanding you, but why not use wp_create_nav_menu()?

E.g., this is what I do to create a custom BuddyPress menu when I detect BP as active:

    $menuname = $lblg_themename . ' BuddyPress Menu';
$bpmenulocation = 'lblgbpmenu';
// Does the menu exist already?
$menu_exists = wp_get_nav_menu_object( $menuname );

// If it doesn't exist, let's create it.
if( !$menu_exists){
    $menu_id = wp_create_nav_menu($menuname);

    // Set up default BuddyPress links and add them to the menu.
    wp_update_nav_menu_item($menu_id, 0, array(
        'menu-item-title' =>  __('Home'),
        'menu-item-classes' => 'home',
        'menu-item-url' => home_url( "https://wordpress.stackexchange.com/" ), 
        'menu-item-status' => 'publish'));

    wp_update_nav_menu_item($menu_id, 0, array(
        'menu-item-title' =>  __('Activity'),
        'menu-item-classes' => 'activity',
        'menu-item-url' => home_url( '/activity/' ), 
        'menu-item-status' => 'publish'));

    wp_update_nav_menu_item($menu_id, 0, array(
        'menu-item-title' =>  __('Members'),
        'menu-item-classes' => 'members',
        'menu-item-url' => home_url( '/members/' ), 
        'menu-item-status' => 'publish'));

    wp_update_nav_menu_item($menu_id, 0, array(
        'menu-item-title' =>  __('Groups'),
        'menu-item-classes' => 'groups',
        'menu-item-url' => home_url( '/groups/' ), 
        'menu-item-status' => 'publish'));

    wp_update_nav_menu_item($menu_id, 0, array(
        'menu-item-title' =>  __('Forums'),
        'menu-item-classes' => 'forums',
        'menu-item-url' => home_url( '/forums/' ), 
        'menu-item-status' => 'publish'));

    // Grab the theme locations and assign our newly-created menu
    // to the BuddyPress menu location.
    if( !has_nav_menu( $bpmenulocation ) ){
        $locations = get_theme_mod('nav_menu_locations');
        $locations[$bpmenulocation] = $menu_id;
        set_theme_mod( 'nav_menu_locations', $locations );
    }