Adopt shared charge helpers in till and gift-card flows; redact card tokens

Till sales and gift-card purchases now use uniqueChargeKey and resolveChargeSource/chargeFailureStatus instead of duplicated inline logic. The saved-card delete path logs the square_card_id through square.TokenPrefix so full ccof references never reach logs.

backend/handlers/payments/giftcards.go

@@ -1,7 +1,6 @@
 package payments
 
 import (
-	"context"
 	"database/sql"
 	"encoding/json"
 	"errors"
@@ -896,7 +895,7 @@ func BuyGiftCard(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	if req.IdempotencyKey == "" {
-		req.IdempotencyKey = uniqueTillKey()
+		req.IdempotencyKey = uniqueChargeKey("till-")
 	}
 
 	allowedAmounts := map[int64]bool{1000: true, 2000: true, 5000: true}
@@ -935,31 +934,11 @@ func BuyGiftCard(w http.ResponseWriter, r *http.Request) {
 	if lockKey == "" {
 		lockKey = userID
 	}
-	pinConn, err := db.Conn.Acquire(ctx)
-	if err != nil {
-		log.Printf("Failed to acquire connection for gift-card lock: %v", err)
-		http.Error(w, "internal server error", http.StatusInternalServerError)
-		return
-	}
-	defer pinConn.Release()
-	lockOK, err := acquireAdvisoryLock(ctx, pinConn, "crussell:giftcard:"+lockKey)
-	if err != nil {
-		log.Printf("Failed to acquire gift-card serialization lock for %s: %v", lockKey, err)
-		http.Error(w, "internal server error", http.StatusInternalServerError)
-		return
-	}
+	pinConn, lockOK := acquireBookingPaymentLock(ctx, w, "crussell:giftcard:"+lockKey, "Purchase in progress, try again")
 	if !lockOK {
-		log.Printf("Gift-card serialization lock for %s not acquired within bound — a purchase is already in progress", lockKey)
-		http.Error(w, "Purchase in progress, try again", http.StatusConflict)
 		return
 	}
-	defer func() {
-		if _, err := pinConn.Exec(context.Background(), `
-			SELECT pg_advisory_unlock(hashtext('crussell:giftcard:' || $1))
-		`, lockKey); err != nil {
-			log.Printf("Failed to release gift-card serialization lock for %s: %v", lockKey, err)
-		}
-	}()
+	defer releaseBookingPaymentLock(pinConn, "crussell:giftcard:"+lockKey)
 
 	// Idempotency: only short-circuit when the existing record is 'completed'.
 	// A 'pending' record means the previous Square call failed — returning it
@@ -1003,71 +982,12 @@ func BuyGiftCard(w http.ResponseWriter, r *http.Request) {
 	var sourceID string
 	var savedCardID *string
 	var savedCardCustomerID string
-
-	if req.NewCardToken != nil && *req.NewCardToken != "" {
-		// A cnon: nonce charge needs NO card-on-file and NO customer (R6). The
-		// old code tokenized every new card via CreateCardOnFile even for
-		// one-off non-save purchases, creating an orphan card at Square for a
-		// payment that only ever uses the nonce once.
-		if req.SaveCard {
-			// Save path: provision (or reuse) the user's Square customer BEFORE
-			// tokenizing so the new card is created against that customer, and
-			// forward the customer id on the charge. A ccof: source MUST carry
-			// its customer (R6).
-			squareCustomerID, custErr := paymentService.EnsureSquareCustomer(ctx, userID)
-			if custErr != nil {
-				log.Printf("Failed to provision Square customer for user %s: %v", userID, custErr)
-				http.Error(w, "Failed to process card", http.StatusInternalServerError)
-				return
-			}
-			cardOnFile, err := SquareClient.CreateCardOnFile(ctx, userID, *req.NewCardToken, squareCustomerID)
-			if err != nil {
-				log.Printf("Failed to create card on file: %v", err)
-				http.Error(w, "Failed to process card", http.StatusInternalServerError)
-				return
-			}
-			sourceID = cardOnFile.CardID
-			savedCardCustomerID = squareCustomerID
-
-			cardID, err := paymentService.SaveCardForUser(ctx, userID, squareCustomerID, cardOnFile.CardID, cardOnFile.Brand, cardOnFile.Last4, cardOnFile.ExpMonth, cardOnFile.ExpYear, cardOnFile.Fingerprint)
-			if err != nil {
-				log.Printf("Failed to save card: %v", err)
-			} else {
-				savedCardID = &cardID
-			}
-		} else {
-			// One-off new-card purchase: use the cnon: nonce DIRECTLY as the
-			// source. No card-on-file is created (nothing to orphan, no
-			// customer needed).
-			sourceID = *req.NewCardToken
-		}
-	} else if req.CardID != nil {
-		card, err := paymentService.GetCardByID(ctx, *req.CardID, userID)
-		if err != nil {
-			if errors.Is(err, pgx.ErrNoRows) {
-				http.Error(w, "Card not found", http.StatusNotFound)
-				return
-			}
-			log.Printf("Failed to get card: %v", err)
-			http.Error(w, "internal server error", http.StatusInternalServerError)
-			return
-		}
-		// A ccof: source can NEVER be charged without a CustomerID — Square
-		// rejects the payment. A saved-card row created before P14 has an empty
-		// square_customer_id; lazily provision the user's Square customer and
-		// persist it on the row BEFORE charging (R6).
-		if card.SquareCustomerID == "" {
-			provisioned, provErr := paymentService.EnsureSquareCustomerForSavedCard(ctx, *req.CardID, userID)
-			if provErr != nil {
-				log.Printf("Failed to provision Square customer for saved card %s (user %s): %v", *req.CardID, userID, provErr)
-				http.Error(w, "Failed to process card", http.StatusInternalServerError)
-				return
-			}
-			card.SquareCustomerID = provisioned
-		}
-		sourceID = card.SquareCardID
-		savedCardID = req.CardID
-		savedCardCustomerID = card.SquareCustomerID
+	// Resolve the new-card-vs-saved-card Square source — shared with
+	// CreateBookingPayment/CreateTipPayment (see resolveChargeSource for the
+	// R6 rationale).
+	sourceID, savedCardID, savedCardCustomerID, sourceOK := resolveChargeSource(ctx, w, paymentService, userID, req.NewCardToken, req.CardID, req.SaveCard, "Card not found")
+	if !sourceOK {
+		return
 	}
 
 	amountPounds := float64(req.Amount) / 100.0
@@ -1177,7 +1097,7 @@ func BuyGiftCard(w http.ResponseWriter, r *http.Request) {
 	if err != nil {
 		log.Printf("Failed to process gift card purchase payment: %v", err)
 		// Payment record intentionally left as 'pending' for manual retry.
-		http.Error(w, "Payment failed", http.StatusPaymentRequired)
+		http.Error(w, "Payment failed", chargeFailureStatus(err))
 		return
 	}
 

backend/handlers/payments/service.go

@@ -548,7 +548,9 @@ func (s *PaymentService) DeletePaymentMethod(ctx context.Context, cardID, userID
 			if square.ErrorCode(err) == "NOT_FOUND" || strings.Contains(msg, "NOT_FOUND") || strings.Contains(msg, "NOT FOUND") {
 				// Square already removed/disabled the card — nothing to do.
 			} else {
-				slog.Warn("failed to disable Square card on local delete — card may remain enabled at Square", "square_card_id", sqCardID.String, "err", err)
+				// TokenPrefix redacts the ccof: card token — the full ID must
+				// never reach logs.
+				slog.Warn("failed to disable Square card on local delete — card may remain enabled at Square", "square_card_id", square.TokenPrefix(sqCardID.String), "err", err)
 			}
 		}
 	}

backend/handlers/payments/till.go

@@ -46,15 +46,9 @@ type TillSaleResponse struct {
 	CheckoutID    *string `json:"checkout_id,omitempty"`
 }
 
-// uniqueTillKey generates a unique idempotency key for till sales where the
-// client did not supply one. Dedup of retries is handled by the client-supplied
-// key (the frontend sends a UUID); this fallback only needs to be unique so it
-// never collides with the till_sales idempotency_key UNIQUE constraint.
-// Deliberately NOT derived from request fields — two legitimate identical
-// sales (e.g. two £50 cash gift-card creations) would hash to the same key.
-func uniqueTillKey() string {
-	return "till-" + rand.Text()
-}
+// uniqueChargeKey is defined in handlers.go (the till fallback key was
+// byte-identical to the tip fallback except the prefix — see the consolidated
+// helper).
 
 // definitivePaymentDeclineCodes are Square payment error codes meaning the
 // card charge can never succeed (declined / expired / not supported). They are
@@ -520,7 +514,7 @@ func CreateTillSale(w http.ResponseWriter, r *http.Request) {
 		saleStatus = "completed"
 		dbPaymentMethod = "cash"
 		if req.IdempotencyKey == "" {
-			req.IdempotencyKey = uniqueTillKey()
+			req.IdempotencyKey = uniqueChargeKey("till-")
 		}
 	case "saved_card":
 		dbPaymentMethod = "online_square"
@@ -577,7 +571,7 @@ func CreateTillSale(w http.ResponseWriter, r *http.Request) {
 		}
 
 		if req.IdempotencyKey == "" {
-			req.IdempotencyKey = uniqueTillKey()
+			req.IdempotencyKey = uniqueChargeKey("till-")
 		}
 
 		saleStatus = "pending"
@@ -585,7 +579,7 @@ func CreateTillSale(w http.ResponseWriter, r *http.Request) {
 	case "card_machine":
 		dbPaymentMethod = "in_person_card"
 		if req.IdempotencyKey == "" {
-			req.IdempotencyKey = uniqueTillKey()
+			req.IdempotencyKey = uniqueChargeKey("till-")
 		}
 
 		if existingPendingCheckoutID != "" {
@@ -617,7 +611,7 @@ func CreateTillSale(w http.ResponseWriter, r *http.Request) {
 	case "online_square":
 		dbPaymentMethod = "online_square"
 		if req.IdempotencyKey == "" {
-			req.IdempotencyKey = uniqueTillKey()
+			req.IdempotencyKey = uniqueChargeKey("till-")
 		}
 
 		saleStatus = "pending"
@@ -626,7 +620,7 @@ func CreateTillSale(w http.ResponseWriter, r *http.Request) {
 		saleStatus = "completed"
 		dbPaymentMethod = "on_the_house"
 		if req.IdempotencyKey == "" {
-			req.IdempotencyKey = uniqueTillKey()
+			req.IdempotencyKey = uniqueChargeKey("till-")
 		}
 	}