add_action('init', 'start_ap_session', 1);

function start_ap_session() {

    if( !session_id() ) {

        session_start();

        if ( isset( $_SESSION['last_activity'] ) && ( time() - $_SESSION['last_activity'] > 1800) ) {

            session_unset();
            session_destroy();

        }

        $_SESSION['last_activity'] = time();

        if ( !isset( $_SESSION['records'] ) ) {

            require ABSPATH . '/FM/fmdb.php';

            $records = get_webflats();

            foreach ($records as $key => $value) {
                if ( $value->floor == 'ground floor' ) {
                    unset($records[$key]);
                }
            }

            $_SESSION['records'] = $records;

            $total_disp_nr = count($records);

            foreach ( $records as $r ) {
                if ( $r->reserved == 'yes' ) {
                    $total_disp_nr--;
                }
            }

            $_SESSION['disp'] = $total_disp_nr;

        }

    }

}