Compose D&D enemy event production family

internal/modules/dnd/register/merge.go

@@ -70,6 +70,27 @@ func appendCombatTurnLists(values []dnd.CombatTurnList) (dnd.CombatTurnList, err
 	return combined, nil
 }
 
+func appendEnemyEventLists(values []dnd.EnemyEventList) (dnd.EnemyEventList, error) {
+	count := 0
+	present := false
+	for _, value := range values {
+		if value.Events != nil {
+			present = true
+		}
+		count += len(value.Events)
+	}
+	if !present {
+		return dnd.EnemyEventList{}, nil
+	}
+	combined := dnd.EnemyEventList{Events: make([]dnd.EnemyEvent, 0, count)}
+	for _, value := range values {
+		for _, event := range value.Events {
+			combined.Events = append(combined.Events, cloneEnemyEvent(event))
+		}
+	}
+	return combined, nil
+}
+
 func appendItemEventLists(values []dnd.ItemEventList) (dnd.ItemEventList, error) {
 	count := 0
 	present := false
@@ -137,6 +158,12 @@ func cloneCombatTurn(value dnd.CombatTurn) dnd.CombatTurn {
 	return clone
 }
 
+func cloneEnemyEvent(value dnd.EnemyEvent) dnd.EnemyEvent {
+	clone := value
+	clone.SourceRefs = cloneSourceRefs(value.SourceRefs)
+	return clone
+}
+
 func cloneItemEvent(value dnd.ItemEvent) dnd.ItemEvent {
 	clone := value
 	if value.Quantity != nil {