phpDolphin admin-only module bootstrap

<?php
function PageMain() {
    global $TMPL, $LNG, $CONF, $db, $settings;

    if(isset($_POST['login'])) {
        $logInAdmin = new logInAdmin();
        $logInAdmin->db = $db;
        $logInAdmin->url = $CONF['url'];
        $logInAdmin->username = $_POST['username'];
        $logInAdmin->password = $_POST['password'];

        $TMPL['message'] = $logInAdmin->in();
    }
    if(isset($_SESSION['usernameAdmin']) && isset($_SESSION['passwordAdmin'])) {
        $loggedInAdmin = new loggedInAdmin();
        $loggedInAdmin->db = $db;
        $loggedInAdmin->url = $CONF['url'];
        $loggedInAdmin->username = $_SESSION['usernameAdmin'];
        $loggedInAdmin->password = $_SESSION['passwordAdmin'];
        $loggedIn = $loggedInAdmin->verify();

        if($loggedIn['username']) {
            $content = true;
            // ================= main page content ================

            // ================= end page content  ================
        } else {
            // Set the content to false, change the $skin to log-in.
            $content = false;
        }
    }

    /**
     * We must use a workaround here
     * as login.html appends
     * "/index.php?a=admin"
     * to the login form action URL.
     */
    $TMPL['url'] = $_SERVER['REQUEST_URI']."#";
    $TMPL['localurl'] = $CONF['url'];
    $TMPL['title'] = $LNG['title_admin'].' - '.($loggedIn['username'] ? $ttl : $LNG['login']).' - '.$settings['title'];
    $TMPL['rows'] = $tpl;
    if($content)
        $skin = new skin('SKIN_HERE');
    else
        $skin = new skin('admin/login');
    return $skin->make();
}