adlerka.space/templates/navpages.php

<?php
ob_start();

$navsite_template = '<li><a href="__LOCATION__" __CLASS__>__NAME__</a><ul class="navpage_list">__NAVPAGES__</ul></li>';
$navpage_template = '<li><a class="navpage_link" href="__LOCATION__" __CLASS__>__NAME__</a></li>';


$site_dirs = array_diff(scandir($page_dir), array('.', '..'));

foreach($site_dirs as $site_dir){
    $pages_dir = array_diff(scandir("$page_dir/$site_dir"), array('.', '..'));
    
    $navsite = $navpage_template;
    $site_location = "$site_dir.$domain.$tld/$default_page";
    $site_class = "class=\"navsite_link\"";
    $site_name = str_replace("_", " ", $site_location);
    $navsite = str_replace("__CLASS__", $site_class, $navsite);
    $navsite = str_replace("__LOCATION__", $site_location, $navsite);
    $navsite = str_replace("__NAME__", $site_name, $navsite);
    
    if($subdomain == $site_dir){
        //this is the current page
        $site_class = "class=\"navsite_link active\"";
    }
    
    $navpages = "";
    foreach($pages_dir as $page_dir){
        $navpage = $navpage_template;
        $page_class = "class=\"navpage_link\"";
        if($subdomain == $site_dir && $page_name == $page_dir){
            $page_class = "class=\"navpage_link active\"";
        }

        $page_location = "$site_dir.$domain.$tld/$page_dir";

        $page_name = str_replace("_", " ", $page_location);

        $navpage = str_replace("__CLASS__", $page_class, $navpage);
        $navpage = str_replace("__LOCATION__", $page_location, $navpage);
        $navpage = str_replace("__NAME__", $page_name, $navpage);
        $navpages .= $navpage;
    }
    $navsite = str_replace("__NAVPAGES__", $navpages, $navsite);
}

return ob_get_clean();

?>