same stuff?

pkg/cart/mutation_markings.go

@@ -0,0 +1,32 @@
+package cart
+
+import (
+	"fmt"
+
+	messages "git.k6n.net/mats/go-cart-actor/proto/cart"
+)
+
+// LineItemMarking sets a marking on the line item with the given ID.
+func LineItemMarking(grain *CartGrain, req *messages.LineItemMarking) error {
+	for i, item := range grain.Items {
+		if item.Id == req.Id {
+			grain.Items[i].Marking = &Marking{
+				Type: req.Type,
+				Text: req.Marking,
+			}
+			return nil
+		}
+	}
+	return fmt.Errorf("item with ID %d not found", req.Id)
+}
+
+// RemoveLineItemMarking clears the marking on the line item with the given ID.
+func RemoveLineItemMarking(grain *CartGrain, req *messages.RemoveLineItemMarking) error {
+	for i, item := range grain.Items {
+		if item.Id == req.Id {
+			grain.Items[i].Marking = nil
+			return nil
+		}
+	}
+	return fmt.Errorf("item with ID %d not found", req.Id)
+}