WP - Private Page Redirect to Login with Custom Message

functions.php

/** Redirect private pages/posts to login */
require_once( 'library/private-redirect.php' );

private-login-redirect.php

<?php
add_action('wp', 'my_private_page_404');
function my_private_page_404()
{
    $queried_object = get_queried_object();
    if (isset($queried_object->post_status) && 'private' == $queried_object->post_status && !is_user_logged_in()) {
        wp_safe_redirect(add_query_arg('private', '1', wp_login_url($_SERVER['REQUEST_URI'])));
        exit;
    }
}
add_filter('login_message', 'my_private_page_login_message');
function my_private_page_login_message($message)
{
    if (isset($_REQUEST['private']) && $_REQUEST['private'] == 1) {
        $message .= sprintf('<p class="message">%s</p>', __('The page you tried to visit is restricted. Please log in or register to continue.'));
    }
    return $message;
}