1 files changed, 24 insertions, 0 deletions
diff --git a/internal/world/mob.go b/internal/world/mob.go
index f33b2f9..a794bdd 100644
--- a/internal/world/mob.go
+++ b/internal/world/mob.go
@@ -722,3 +722,27 @@ func (s *MobStore) SeedMobs(roomID int, entries []RoomMob) {
 		s.instances[instID] = inst
 	}
 }
+
+// RekeyRooms remaps every live mob instance's RoomID and HomeRoomID per
+// idMap (oldID -> newID), including wander rooms. Uses delete-all-then-
+// set-all so a swap cannot clobber an entry mid-rekey.
+func (s *MobStore) RekeyRooms(idMap map[int]int) {
+	if len(idMap) == 0 {
+		return
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	for _, inst := range s.instances {
+		if newID, ok := idMap[inst.RoomID]; ok && newID != inst.RoomID {
+			inst.RoomID = newID
+		}
+		if newID, ok := idMap[inst.HomeRoomID]; ok && newID != inst.HomeRoomID {
+			inst.HomeRoomID = newID
+		}
+		for i, room := range inst.WanderRooms {
+			if newID, ok := idMap[room]; ok && newID != room {
+				inst.WanderRooms[i] = newID
+			}
+		}
+	}
+}