From e88b95f2295e0ea4e3235eceddd66d6f6b675baf Mon Sep 17 00:00:00 2001
From: James Banton <james@alt-design.net>
Date: Mon, 13 Oct 2025 10:49:48 +0100
Subject: [PATCH] Adjust discount calculation in
 `CalculateProductCouponsDiscounts` to account for item-to-basket subtotal
 ratio.

---
 .../RecalculateBasket/CalculateProductCouponsDiscounts.php      | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Commerce/Pipeline/RecalculateBasket/CalculateProductCouponsDiscounts.php b/src/Commerce/Pipeline/RecalculateBasket/CalculateProductCouponsDiscounts.php
index d668703..08e8ebf 100644
--- a/src/Commerce/Pipeline/RecalculateBasket/CalculateProductCouponsDiscounts.php
+++ b/src/Commerce/Pipeline/RecalculateBasket/CalculateProductCouponsDiscounts.php
@@ -54,7 +54,7 @@ protected function processCoupon(ProductCoupon $coupon, Basket $basket): void
                 id: Uuid::uuid4()->toString(),
                 discountItemId: $discountItem->id,
                 name: $coupon->name(),
-                amount: $discountTotal,
+                amount: $discountTotal * ($item->subTotal / $basket->subTotal),
             );
 
             $item->discountTotal += array_sum(array_column($item->discounts, 'amount'));