all the refactor

pkg/order/tax.go

@@ -1,30 +1,35 @@
 package order
 
-import "git.k6n.net/mats/go-cart-actor/pkg/cart"
+import (
+	"git.k6n.net/mats/platform/money"
+	"git.k6n.net/mats/platform/tax"
+)
 
 // TaxProvider computes taxes for orders and line items.
-// The canonical definition is in pkg/cart; this is a re-export for
-// backward compatibility.
-type TaxProvider = cart.TaxProvider
+// The canonical definition is in platform/tax; this is a type alias
+// for backward compatibility.
+type TaxProvider = tax.Provider
 
-// ComputeTax is the shared tax formula: tax = total x rate / (100 + rate).
-// Re-exported from pkg/cart for backward compatibility.
-func ComputeTax(total int64, taxRate int) int64 {
-	return cart.ComputeTax(total, taxRate)
+// ComputeTax is the shared ex-VAT-first tax formula. rateBp is basis points
+// (2500 = 25%). Re-exported from platform/tax for backward compatibility.
+func ComputeTax(total money.Cents, rateBp int) money.Cents {
+	return money.Cents(tax.Compute(total.Int64(), rateBp))
 }
 
 // NordicTaxProvider implements TaxProvider for the Nordic countries.
-// Re-exported from pkg/cart for backward compatibility.
-type NordicTaxProvider = cart.NordicTaxProvider
+// Re-exported from platform/tax for backward compatibility.
+type NordicTaxProvider = tax.Nordic
 
+// NewNordicTaxProvider returns a new NordicTaxProvider.
 func NewNordicTaxProvider(defaultCountry string) *NordicTaxProvider {
-	return cart.NewNordicTaxProvider(defaultCountry)
+	return tax.NewNordic(defaultCountry)
 }
 
 // StaticTaxProvider is a stateless TaxProvider with no country awareness.
-// Re-exported from pkg/cart for backward compatibility.
-type StaticTaxProvider = cart.StaticTaxProvider
+// Re-exported from platform/tax for backward compatibility.
+type StaticTaxProvider = tax.Static
 
+// NewStaticTaxProvider returns a new StaticTaxProvider.
 func NewStaticTaxProvider() *StaticTaxProvider {
-	return cart.NewStaticTaxProvider()
+	return tax.NewStatic()
 }