1 files changed, 23 insertions, 68 deletions
diff --git a/internal/game/cmd_room_insert.go b/internal/game/cmd_room_insert.go
index 988cd08..b72591f 100644
--- a/internal/game/cmd_room_insert.go
+++ b/internal/game/cmd_room_insert.go
@@ -65,53 +65,42 @@ func (g *Game) roomInsert(sess *net.Session, args []string) {
 
 	oppositeDir := world.OppositeExit[dir]
 
-	if delta3D, ok := world.DirectionDeltas3D[dir]; ok {
-		coord, roomAt := g.buildGridFrom(p.RoomID)
-
-		sSet := g.bfsReachable(targetID, func(_ int, _ world.ExitDir, target int) bool {
-			return target == p.RoomID
-		})
+	newID, err := findNextRoomID(curPath)
+	if err != nil {
+		sess.WriteLine("Error scanning room directory.")
+		return
+	}
 
-		withoutEdge := g.bfsReachable(p.RoomID, func(rid int, d world.ExitDir, target int) bool {
-			return rid == p.RoomID && d == dir && target == targetID
-		})
-		for rid := range sSet {
-			if withoutEdge[rid] {
-				room, _ := g.World.LoadRoom(rid)
-				conflictName := fmt.Sprintf("#%d", rid)
+	conflicts := world.InsertGridConflicts(p.RoomID, dir, targetID, newID, func(id int) (*world.Room, bool) {
+		r, err := g.World.LoadRoom(id)
+		if err != nil {
+			return nil, false
+		}
+		return r, true
+	})
+	if len(conflicts) > 0 {
+		for _, c := range conflicts {
+			switch c.Kind {
+			case "twist":
+				room, _ := g.World.LoadRoom(c.Target)
+				conflictName := fmt.Sprintf("#%d", c.Target)
 				if room != nil {
-					conflictName = fmt.Sprintf("#%d (%s)", rid, room.Name)
+					conflictName = fmt.Sprintf("#%d (%s)", c.Target, room.Name)
 				}
 				sess.WriteLine(fmt.Sprintf(
 					"Cannot insert: room %s would have an ambiguous grid position after insertion (reachable via an alternate path from here).",
 					conflictName))
-				return
-			}
-		}
-
-		for rid := range sSet {
-			if _, inGrid := coord[rid]; !inGrid {
-				continue
-			}
-			oldPos := coord[rid]
-			newPos := [3]int{oldPos[0] + delta3D[0], oldPos[1] + delta3D[1], oldPos[2] + delta3D[2]}
-			if occupier, ok := roomAt[newPos]; ok && !sSet[occupier] {
-				occRoom, _ := g.World.LoadRoom(occupier)
-				occName := fmt.Sprintf("#%d", occupier)
+			case "overlap":
+				occRoom, _ := g.World.LoadRoom(c.Occupier)
+				occName := fmt.Sprintf("#%d", c.Occupier)
 				if occRoom != nil {
-					occName = fmt.Sprintf("#%d (%s)", occupier, occRoom.Name)
+					occName = fmt.Sprintf("#%d (%s)", c.Occupier, occRoom.Name)
 				}
 				sess.WriteLine(fmt.Sprintf(
 					"Cannot insert: pushing %s would cause grid collision with %s.",
 					targetName, occName))
-				return
 			}
 		}
-	}
-
-	newID, err := findNextRoomID(curPath)
-	if err != nil {
-		sess.WriteLine("Error scanning room directory.")
 		return
 	}
 
@@ -228,37 +217,3 @@ func (g *Game) roomInsert(sess *net.Session, args []string) {
 	g.runEnterSteps(sess, newID)
 	g.checkAggro(sess)
 }
-
-// bfsReachable returns the set of rooms reachable from startID over the room
-// exit graph, restricted to known rooms. skipEdge, when non-nil, prunes an
-// individual directed exit (the edge from rid via dir to target) from the walk.
-func (g *Game) bfsReachable(startID int, skipEdge func(rid int, dir world.ExitDir, target int) bool) map[int]bool {
-	roomIndex := g.World.RoomIndex()
-	visited := map[int]bool{startID: true}
-	queue := []int{startID}
-
-	for len(queue) > 0 {
-		rid := queue[0]
-		queue = queue[1:]
-		room, err := g.World.LoadRoom(rid)
-		if err != nil {
-			continue
-		}
-		for _, ed := range world.ExitOrder {
-			exit, ok := room.Exits[ed]
-			if !ok || exit.Room <= 0 || !roomIndex[exit.Room] {
-				continue
-			}
-			target := exit.Room
-			if skipEdge != nil && skipEdge(rid, ed, target) {
-				continue
-			}
-			if visited[target] {
-				continue
-			}
-			visited[target] = true
-			queue = append(queue, target)
-		}
-	}
-	return visited
-}