parent item mutations

pkg/cart/mutation_change_quantity.go

@@ -4,9 +4,8 @@ import (
 	"context"
 	"fmt"
 	"log"
-	"time"
 
-	messages "git.k6n.net/mats/go-cart-actor/proto/cart"
+	cart_messages "git.k6n.net/mats/go-cart-actor/proto/cart"
 )
 
 // mutation_change_quantity.go
@@ -15,8 +14,11 @@ import (
 //
 // Behavior:
 //   - Locates an item by its cart-local line item Id (not source item_id).
-//   - If requested quantity <= 0 the line is removed.
-//   - Otherwise the line's Quantity field is updated.
+//   - If requested quantity <= 0 the line AND any descendants are
+//     removed via the shared RemoveItem cascade (transitive parent→child).
+//   - Otherwise the line's Quantity is updated and direct children are
+//     rescaled proportionally so a "2 of this + 2 of each accessory"
+//     bundle stays internally consistent when the parent becomes 3.
 //   - Totals are recalculated (WithTotals).
 //
 // Error handling:
@@ -29,7 +31,7 @@ import (
 //     (If strict locking is required around every mutation, wrap logic in
 //     an explicit g.mu.Lock()/Unlock(), but current model mirrors prior code.)
 
-func (c *CartMutationContext) ChangeQuantity(g *CartGrain, m *messages.ChangeQuantity) error {
+func (c *CartMutationContext) ChangeQuantity(g *CartGrain, m *cart_messages.ChangeQuantity) error {
 	if m == nil {
 		return fmt.Errorf("ChangeQuantity: nil payload")
 	}
@@ -48,23 +50,18 @@ func (c *CartMutationContext) ChangeQuantity(g *CartGrain, m *messages.ChangeQua
 	}
 
 	if m.Quantity <= 0 {
-		// Remove the item
-		itemToRemove := g.Items[foundIndex]
-		if itemToRemove.ReservationEndTime != nil && itemToRemove.ReservationEndTime.After(time.Now()) {
-			err := c.ReleaseItem(ctx, g.Id, itemToRemove.Sku, itemToRemove.StoreId)
-			if err != nil {
-				log.Printf("unable to release reservation for %s in location: %v", itemToRemove.Sku, itemToRemove.StoreId)
-			}
-		}
-		g.Items = append(g.Items[:foundIndex], g.Items[foundIndex+1:]...)
-		g.UpdateTotals()
-		return nil
+		// Setting a parent line to 0 means "remove it AND its accessories".
+		// Delegate to RemoveItem so the cascade logic in one place stays
+		// the source of truth for descendant cleanup + reservation
+		// release — otherwise we'd duplicate the transitive cascade here.
+		return c.RemoveItem(g, &cart_messages.RemoveItem{Id: m.Id})
 	}
 	item := g.Items[foundIndex]
 	if item == nil {
 		return fmt.Errorf("ChangeQuantity: item id %d not found", m.Id)
 	}
-	if g.Type == messages.CartType_REGULAR && c.UseReservations(item) {
+	oldQty := item.Quantity
+	if g.Type == cart_messages.CartType_REGULAR && c.UseReservations(item) {
 		if item.ReservationEndTime != nil {
 			err := c.ReleaseItem(ctx, g.Id, item.Sku, item.StoreId)
 			if err != nil {
@@ -79,6 +76,14 @@ func (c *CartMutationContext) ChangeQuantity(g *CartGrain, m *messages.ChangeQua
 		item.ReservationEndTime = endTime
 	}
 	item.Quantity = uint16(m.Quantity)
+	// Rescale any direct child lines proportionally so accessories stay
+	// in sync with their parent. Descends recursively into grandchildren
+	// via CascadeChildQuantities itself. Skipped when the target itself
+	// is a child line — direct qty edits on a child are treated as
+	// explicit user intent and don't propagate further.
+	if item.ParentId == nil {
+		c.CascadeChildQuantities(ctx, g, item.Id, oldQty, item.Quantity)
+	}
 	g.UpdateTotals()
 
 	return nil