根据在WooCommerce中的总支出，每位用户仅自动应用一次优惠券

Question

我想根据客户的总消费金额自动应用优惠券。此优惠券仅需由客户使用一次。到目前为止，这是我尝试过的操作，但是出现黑屏：add_action( 'woocommerce_before_calculate_totals', 'loyalty_order_discount', 10, 1 );function loyalty_order_discount( $order_id ) {    global $woocommerce;    $coupon = 'loyaltydiscount';    $customer = new WC_Customer(get_current_user_id());    $total_spent = 30;    $order = wc_get_order( $order_id );    foreach( $order->get_used_coupons( $customer ) as $coupon_name ){        // Retrieving the coupon ID        $coupon_post_obj = get_page_by_title($coupon_name, OBJECT, 'shop_coupon');        $coupon_id = $coupon_post_obj->ID;        $coupons_obj = new WC_Coupon($coupon_id);        if( $coupons_obj == $coupon && $customer->get_total_spent() < $total_spent ){            $woocommerce->cart->remove_coupon( $coupon );        }        elseif ( ! $coupons_obj == $coupon && $customer->get_total_spent() >= $total_spent){            $woocommerce->cart->add_discount( $coupon );        }    }}任何帮助表示赞赏。