// === Helper: Check if MPHB already logged "Zimmercode" sent (DE/EN) ===
if (!function_exists('elbe6_mphb_already_sent_zimmercode')){
function elbe6_mphb_already_sent_zimmercode($booking_id){
    $bid = (int)$booking_id;
    if ($bid <= 0) return false;
    if (!function_exists('get_comments')) return false;
    $comments = get_comments(array('post_id'=>$bid,'number'=>25,'orderby'=>'comment_date_gmt','order'=>'DESC','status'=>'approve'));
    if (!is_array($comments) || empty($comments)) return false;
    foreach ($comments as $c){
        $msg = is_object($c) ? (string)$c->comment_content : (string)$c;
        $m = strtolower(wp_strip_all_tags($msg));
        if ($m === '') continue;
        if ((strpos($m,'notification') !== false && strpos($m,'zimmercode') !== false && (strpos($m,'was sent') !== false || strpos($m,'gesendet') !== false))
            || preg_match('/notification\s*[\"\\\']?zimmercode[\"\\\']?\s+was\s+sent/i', $m)){
            return true;
        }
    }
    return false;
}}