cart and checkout

cmd/checkout/order_create.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 
 	"git.k6n.net/mats/go-cart-actor/pkg/checkout"
@@ -27,6 +28,16 @@ type settledPayment struct {
 // selections into from-checkout order lines. Shared by every provider so the
 // order payload is built the same way no matter who settled the payment.
 func buildOrderLinesFromGrain(grain *checkout.CheckoutGrain) []OrderLine {
+	hasFreeShipping := false
+	if grain.CartState != nil {
+		for _, ap := range grain.CartState.AppliedPromotions {
+			if ap.Type == "free_shipping" && !ap.Pending {
+				hasFreeShipping = true
+				break
+			}
+		}
+	}
+
 	lines := make([]OrderLine, 0, len(grain.CartState.Items)+len(grain.Deliveries))
 	for _, it := range grain.CartState.Items {
 		if it == nil {
@@ -38,11 +49,19 @@ func buildOrderLinesFromGrain(grain *checkout.CheckoutGrain) []OrderLine {
 			Name:      it.Meta.Name,
 			Quantity:  int32(it.Quantity),
 			UnitPrice: it.Price.IncVat,
-			TaxRate:   int32(it.Tax),
+			// CartItem.Tax is percentage x 100 (e.g. 2500 = 25.00%). Convert to raw percent (25).
+			TaxRate:   int32(it.Tax / 100),
 		})
 	}
 	for _, d := range grain.Deliveries {
-		if d == nil || d.Price.IncVat <= 0 {
+		if d == nil {
+			continue
+		}
+		unitPrice := d.Price.IncVat
+		if hasFreeShipping {
+			unitPrice = 0
+		}
+		if unitPrice <= 0 && !hasFreeShipping {
 			continue
 		}
 		lines = append(lines, OrderLine{
@@ -50,10 +69,35 @@ func buildOrderLinesFromGrain(grain *checkout.CheckoutGrain) []OrderLine {
 			Sku:       d.Provider,
 			Name:      "Delivery",
 			Quantity:  1,
-			UnitPrice: d.Price.IncVat,
-			TaxRate:   2500,
+			UnitPrice: unitPrice,
+			TaxRate:   25,
 		})
 	}
+
+	// Reflected applied promotions as negative discount lines
+	if grain.CartState != nil {
+		for _, ap := range grain.CartState.AppliedPromotions {
+			if ap.Pending {
+				continue
+			}
+			discountVal := int64(0)
+			if ap.Discount != nil {
+				discountVal = ap.Discount.IncVat
+			}
+			if discountVal <= 0 {
+				continue
+			}
+			lines = append(lines, OrderLine{
+				Reference: "promo-" + ap.PromotionId,
+				Sku:       "promo-" + ap.PromotionId,
+				Name:      "Promotion: " + ap.Name,
+				Quantity:  1,
+				UnitPrice: -discountVal,
+				TaxRate:   25, // default standard tax rate for promotion discount
+			})
+		}
+	}
+
 	return lines
 }
 
@@ -64,8 +108,10 @@ func buildOrderLinesFromGrain(grain *checkout.CheckoutGrain) []OrderLine {
 //
 // It is idempotent: the order service dedupes on "checkout-{checkoutId}", so
 // repeated provider callbacks (Klarna re-push, retried Adyen CAPTURE) return the
-// existing order rather than creating a duplicate. Callers should treat a
-// non-nil error as non-fatal and retry on the next callback.
+// existing order rather than creating a duplicate.
+//
+// If the HTTP call fails or is not configured, it falls back to publishing the
+// exact same payload to RabbitMQ via s.orderHandler.OrderCompleted(body).
 func createOrderFromSettledCheckout(ctx context.Context, s *CheckoutPoolServer, grain *checkout.CheckoutGrain, pay settledPayment) (*CreateOrderResult, error) {
 	if grain.CartState == nil {
 		return nil, fmt.Errorf("from-checkout: checkout %s has no cart state", grain.Id)
@@ -96,15 +142,41 @@ func createOrderFromSettledCheckout(ctx context.Context, s *CheckoutPoolServer,
 	req.Payment.Reference = pay.Reference
 	req.Payment.Amount = pay.Amount
 
-	result, err := s.orderClient.CreateOrder(ctx, req, "")
-	if err != nil {
-		return nil, err
+	var createErr error
+	if s.orderClient != nil {
+		result, err := s.orderClient.CreateOrder(ctx, req, "")
+		if err == nil {
+			_ = s.ApplyAnywhere(ctx, grain.Id, &messages.OrderCreated{
+				OrderId:   result.OrderId,
+				Status:    "completed",
+				CreatedAt: timestamppb.Now(),
+			})
+			return result, nil
+		}
+		createErr = err
+		logger.WarnContext(ctx, "from-checkout HTTP call failed; falling back to AMQP", "err", err, "checkoutId", grain.Id.String())
 	}
 
-	_ = s.ApplyAnywhere(ctx, grain.Id, &messages.OrderCreated{
-		OrderId:   result.OrderId,
-		Status:    "completed",
-		CreatedAt: timestamppb.Now(),
-	})
-	return result, nil
+	// Fallback to AMQP
+	if s.orderHandler != nil {
+		body, err := json.Marshal(req)
+		if err != nil {
+			return nil, fmt.Errorf("failed to marshal order fallback: %w", err)
+		}
+		if pubErr := s.orderHandler.OrderCompleted(body); pubErr != nil {
+			if createErr != nil {
+				return nil, fmt.Errorf("AMQP fallback failed: %w (HTTP error: %v)", pubErr, createErr)
+			}
+			return nil, fmt.Errorf("AMQP fallback failed: %w", pubErr)
+		}
+		logger.InfoContext(ctx, "order request published to AMQP successfully as fallback", "checkoutId", grain.Id.String())
+		return &CreateOrderResult{
+			OrderId: "queued-" + grain.Id.String(),
+		}, nil
+	}
+
+	if createErr != nil {
+		return nil, createErr
+	}
+	return nil, fmt.Errorf("neither order client nor AMQP order handler configured")
 }