Создание скидки на общую сумму покупки в Битрикс корзине

<?if($arPrice["DISCOUNT_VALUE"] < $arPrice["VALUE"]):?>
        <s><?=$arPrice["PRINT_VALUE"]?></s> 
      <?=$arPrice["PRINT_DISCOUNT_VALUE"]?>
        <?else:?><?=$arPrice["PRINT_VALUE"]?><?endif;?>                  
     <?endif;?>
 

AddEventHandler("subscribe", "BeforePostingSendMail", Array("MyClass", "BeforePostingSendMailHandler"));
  
class MyClass
{
    // создаем обработчик события "BeforePostingSendMail"
    function BeforePostingSendMailHandler($arFields)
    {
        $sCoupon = CatalogGenerateCoupon();
        $iCatalogDiscount = 4;
        for( $iInd = 0; $iInd < $iQuantity; $iInd++ ) 
            {
               $sCoupon = CatalogGenerateCoupon();
               $aCouponFields = array(
               'DISCOUNT_ID'   => $iCatalogDiscount,
               'ACTIVE'        => 'Y',
               'ONE_TIME'      => 'Y',
               'COUPON'        => $sCoupon,
               'DATE_APPLY'    => false,
                     );
               $iCouponId  = CCatalogDiscountCoupon::Add( $aCouponFields );
             }
         $sCoupon = str_replace("#COUPON#");
    }
}