Register item registry normalization

internal/modules/dnd/register/merge.go

@@ -112,6 +112,27 @@ func appendItemEventLists(values []dnd.ItemEventList) (dnd.ItemEventList, error)
 	return combined, nil
 }
 
+func appendItemRegistries(values []dnd.ItemRegistry) (dnd.ItemRegistry, error) {
+	count := 0
+	present := false
+	for _, value := range values {
+		if value.Items != nil {
+			present = true
+		}
+		count += len(value.Items)
+	}
+	if !present {
+		return dnd.ItemRegistry{}, nil
+	}
+	combined := dnd.ItemRegistry{Items: make([]dnd.Item, 0, count)}
+	for _, value := range values {
+		for _, item := range value.Items {
+			combined.Items = append(combined.Items, cloneItem(item))
+		}
+	}
+	return combined, nil
+}
+
 func appendNPCOccurrenceLists(values []dnd.NPCOccurrenceList) (dnd.NPCOccurrenceList, error) {
 	count := 0
 	present := false
@@ -216,6 +237,12 @@ func cloneItemEvent(value dnd.ItemEvent) dnd.ItemEvent {
 	return clone
 }
 
+func cloneItem(value dnd.Item) dnd.Item {
+	clone := value
+	clone.SourceRefs = cloneSourceRefs(value.SourceRefs)
+	return clone
+}
+
 func cloneSpellCast(value dnd.SpellCast) dnd.SpellCast {
 	clone := value
 	clone.SourceRefs = cloneSourceRefs(value.SourceRefs)