feat(medusa, admin-ui): Improve gift card application (#4944)

Fix for the problems identified in issue #4892 

Bugfix: admin-ui order summary no longer uses gift card total from order when displaying how much has been withdrawn from each giftcard.

Bugfix(?): no longer keep applying gift cards (at 0 value) when sufficient balance has been reached

Feature: multiple giftcards are now applied in ordered fashion. First by end_date (supports null), then by remaining balance. In order to ensure that customers ends up with as long lasting and few remaining gift cards as possible after the transaction.

packages/admin-ui/ui/src/domain/orders/details/detail-cards/summary.tsx

@@ -221,20 +221,20 @@ const SummaryCard: React.FC<SummaryCardProps> = ({ order, reservations }) => {
             }
           />
         ))}
-        {order?.gift_cards?.map((giftCard, index) => (
+        {order?.gift_card_transactions?.map((gcTransaction, index) => (
           <DisplayTotal
             key={index}
             currency={order.currency_code}
-            totalAmount={-1 * order.gift_card_total}
+            totalAmount={-1 * gcTransaction.amount}
             totalTitle={
               <div className="inter-small-regular text-grey-90 flex items-center">
                 Gift card:
                 <Badge className="ml-3" variant="default">
-                  {giftCard.code}
+                  {gcTransaction.gift_card.code}
                 </Badge>
                 <div className="ml-2">
                   <CopyToClipboard
-                    value={giftCard.code}
+                    value={gcTransaction.gift_card.code}
                     showValue={false}
                     iconSize={16}
                   />

packages/medusa/src/services/order.ts

@@ -733,7 +733,13 @@ class OrderService extends TransactionBaseService {
       let giftCardableAmountBalance = giftCardableAmount
       const giftCardService = this.giftCardService_.withTransaction(manager)
 
-      for (const giftCard of cart.gift_cards) {
+      //Order the gift cards by first ends_at date, then remaining amount. To ensure largest possible amount left, for longest possible time.
+      const orderedGiftCards = cart.gift_cards.sort((a, b) => {
+        let aEnd = a.ends_at ?? new Date(2100, 1, 1)
+        let bEnd = b.ends_at ?? new Date(2100, 1, 1)
+        return aEnd.getTime() - bEnd.getTime() || a.balance - b.balance
+      })
+      for (const giftCard of orderedGiftCards) {
         const newGiftCardBalance = Math.max(
           0,
           giftCard.balance - giftCardableAmountBalance
@@ -755,6 +761,9 @@ class OrderService extends TransactionBaseService {
 
         giftCardableAmountBalance =
           giftCardableAmountBalance - giftCardBalanceUsed
+
+        if (giftCardableAmountBalance == 0)
+          break;
       }
 
       const shippingOptionServiceTx =