cart and checkout

cmd/checkout/checkout_builder.go

@@ -64,7 +64,9 @@ type CheckoutMeta struct {
 //
 // If you later need to support different tax rates per line, you can extend
 // CartItem / Delivery to expose that data and propagate it here.
-func BuildCheckoutOrderPayload(grain *checkout.CheckoutGrain, meta *CheckoutMeta) ([]byte, *CheckoutOrder, error) {
+// tp is an optional TaxProvider; when non-nil, its DefaultTaxRate is used for
+// delivery lines instead of the hardcoded 2500 (25 % as CartItem format).
+func BuildCheckoutOrderPayload(grain *checkout.CheckoutGrain, meta *CheckoutMeta, tp cart.TaxProvider) ([]byte, *CheckoutOrder, error) {
 	if grain == nil {
 		return nil, nil, fmt.Errorf("nil grain")
 	}
@@ -106,12 +108,32 @@ func BuildCheckoutOrderPayload(grain *checkout.CheckoutGrain, meta *CheckoutMeta
 		})
 	}
 
+	hasFreeShipping := false
+	if grain.CartState != nil {
+		for _, ap := range grain.CartState.AppliedPromotions {
+			if ap.Type == "free_shipping" && !ap.Pending {
+				hasFreeShipping = true
+				break
+			}
+		}
+	}
+
 	total := cart.NewPrice()
 	total.Add(*grain.CartState.TotalPrice)
 
-	// Delivery lines
+	// Delivery lines — use the configured default tax rate for the purchase country.
+	defaultKlarnaRate := defaultKlarnaTaxRate(tp, country)
 	for _, d := range grain.Deliveries {
-		if d == nil || d.Price.IncVat <= 0 {
+		if d == nil {
+			continue
+		}
+		unitPrice := d.Price.IncVat
+		taxAmount := d.Price.TotalVat()
+		if hasFreeShipping {
+			unitPrice = 0
+			taxAmount = 0
+		}
+		if unitPrice <= 0 && !hasFreeShipping {
 			continue
 		}
 		//total.Add(d.Price)
@@ -120,11 +142,11 @@ func BuildCheckoutOrderPayload(grain *checkout.CheckoutGrain, meta *CheckoutMeta
 			Reference:      d.Provider,
 			Name:           "Delivery",
 			Quantity:       1,
-			UnitPrice:      int(d.Price.IncVat),
-			TaxRate:        2500,
+			UnitPrice:      int(unitPrice),
+			TaxRate:        defaultKlarnaRate,
 			QuantityUnit:   "st",
-			TotalAmount:    int(d.Price.IncVat),
-			TotalTaxAmount: int(d.Price.TotalVat()),
+			TotalAmount:    int(unitPrice),
+			TotalTaxAmount: int(taxAmount),
 		})
 	}
 
@@ -154,6 +176,24 @@ func BuildCheckoutOrderPayload(grain *checkout.CheckoutGrain, meta *CheckoutMeta
 	return payload, order, nil
 }
 
+// defaultKlarnaTaxRate returns the default tax rate for the purchase country, in Klarna
+// format (percent x 100, e.g. 2500 = 25.00 %). When tp is nil, falls back to 2500 (25 %).
+func defaultKlarnaTaxRate(tp cart.TaxProvider, country string) int {
+	if tp == nil {
+		return 2500
+	}
+	return tp.DefaultTaxRate(country) * 100
+}
+
+// defaultAdyenTaxRate returns the default tax rate for the purchase country, in Adyen
+// format (raw percent, e.g. 25 = 25 %). When tp is nil, falls back to 25.
+func defaultAdyenTaxRate(tp cart.TaxProvider, country string) int64 {
+	if tp == nil {
+		return 25
+	}
+	return int64(tp.DefaultTaxRate(country))
+}
+
 func GetCheckoutMetaFromRequest(r *http.Request) *CheckoutMeta {
 	host := getOriginalHost(r)
 	country := getCountryFromHost(host)
@@ -171,7 +211,7 @@ func GetCheckoutMetaFromRequest(r *http.Request) *CheckoutMeta {
 	}
 }
 
-func BuildAdyenCheckoutSession(grain *checkout.CheckoutGrain, meta *CheckoutMeta) (*adyenCheckout.CreateCheckoutSessionRequest, error) {
+func BuildAdyenCheckoutSession(grain *checkout.CheckoutGrain, meta *CheckoutMeta, tp cart.TaxProvider) (*adyenCheckout.CreateCheckoutSessionRequest, error) {
 	if grain == nil {
 		return nil, fmt.Errorf("nil grain")
 	}
@@ -204,20 +244,40 @@ func BuildAdyenCheckoutSession(grain *checkout.CheckoutGrain, meta *CheckoutMeta
 			TaxPercentage:      common.PtrInt64(int64(it.Tax)),
 		})
 	}
+	hasFreeShipping := false
+	if grain.CartState != nil {
+		for _, ap := range grain.CartState.AppliedPromotions {
+			if ap.Type == "free_shipping" && !ap.Pending {
+				hasFreeShipping = true
+				break
+			}
+		}
+	}
+
 	total := cart.NewPrice()
 	total.Add(*grain.CartState.TotalPrice)
 
-	// Delivery lines
+	// Delivery lines — use the configured default tax rate for the purchase country.
+	defaultAdyenRate := defaultAdyenTaxRate(tp, country)
 	for _, d := range grain.Deliveries {
-		if d == nil || d.Price.IncVat <= 0 {
+		if d == nil {
+			continue
+		}
+		amountIncTax := d.Price.IncVat
+		amountExTax := d.Price.ValueExVat()
+		if hasFreeShipping {
+			amountIncTax = 0
+			amountExTax = 0
+		}
+		if amountIncTax <= 0 && !hasFreeShipping {
 			continue
 		}
 		lineItems = append(lineItems, adyenCheckout.LineItem{
 			Quantity:           common.PtrInt64(1),
-			AmountIncludingTax: common.PtrInt64(d.Price.IncVat),
+			AmountIncludingTax: common.PtrInt64(amountIncTax),
 			Description:        common.PtrString("Delivery"),
-			AmountExcludingTax: common.PtrInt64(d.Price.ValueExVat()),
-			TaxPercentage:      common.PtrInt64(25),
+			AmountExcludingTax: common.PtrInt64(amountExTax),
+			TaxPercentage:      common.PtrInt64(defaultAdyenRate),
 		})
 	}