try new vouchers

cmd/cart/mutation_add_voucher.go

@@ -7,6 +7,32 @@ import (
 	"git.tornberg.me/go-cart-actor/pkg/messages"
 )
 
+func RemoveVoucher(g *CartGrain, m *messages.RemoveVoucher) error {
+	if m == nil {
+		return &actor.MutationError{
+			Message:    "RemoveVoucher: nil payload",
+			Code:       1003,
+			StatusCode: 400,
+		}
+	}
+
+	if !slices.ContainsFunc(g.Vouchers, func(v *Voucher) bool {
+		return v.Id == m.Id
+	}) {
+		return &actor.MutationError{
+			Message:    "voucher not applied",
+			Code:       1004,
+			StatusCode: 400,
+		}
+	}
+
+	g.Vouchers = slices.DeleteFunc(g.Vouchers, func(v *Voucher) bool {
+		return v.Id == m.Id
+	})
+	g.UpdateTotals()
+	return nil
+}
+
 func AddVoucher(g *CartGrain, m *messages.AddVoucher) error {
 	if m == nil {
 		return &actor.MutationError{
@@ -31,7 +57,7 @@ func AddVoucher(g *CartGrain, m *messages.AddVoucher) error {
 		Id:    g.lastVoucherId,
 		Code:  m.Code,
 		Rules: m.VoucherRules,
-		Value: *NewPriceFromIncVat(m.Value, 25.0),
+		Value: m.Value,
 	})
 	g.UpdateTotals()
 	return nil