package world

// RewriteRoomIDs remaps every genuine room-ID reference in this room per idMap
// (oldID -> newID): exit targets, trigger Room/Teleport/DespawnRooms, on-enter
// Teleport/DespawnRooms, and mob WanderRooms. It does NOT touch author-chosen
// set_flags/set_player_flags values or condition `value:` fields — those are not
// structural room references (and historically the swapid regex rewrote them
// incorrectly as a side effect of matching any bare integer).
//
// idMap is assumed to be a bijection (each old ID maps to a distinct new ID);
// this holds for both swap (A<->B) and rename-to-unused (A->B). Returns whether
// any field was changed.
func (r *Room) RewriteRoomIDs(idMap map[int]int) bool {
	if r == nil || len(idMap) == 0 {
		return false
	}
	changed := false
	for dir, exit := range r.Exits {
		var exitChanged bool
		if remapInt(idMap, &exit.Room) {
			exitChanged = true
		}
		for i := range exit.OnTraverse {
			if exit.OnTraverse[i].Action != nil {
				if remapInt(idMap, &exit.OnTraverse[i].Action.Teleport) {
					exitChanged = true
				}
				if exit.OnTraverse[i].Action.SpawnMob != nil &&
					remapIntSlice(idMap, exit.OnTraverse[i].Action.SpawnMob.DespawnRooms) {
					exitChanged = true
				}
			}
		}
		if exitChanged {
			r.Exits[dir] = exit
			changed = true
		}
	}
	for i := range r.Triggers {
		if remapInt(idMap, &r.Triggers[i].Room) {
			changed = true
		}
		for j := range r.Triggers[i].Steps {
			s := &r.Triggers[i].Steps[j]
			if remapInt(idMap, &s.Teleport) {
				changed = true
			}
			if s.SpawnMob != nil && remapIntSlice(idMap, s.SpawnMob.DespawnRooms) {
				changed = true
			}
		}
	}
	for i := range r.OnEnter {
		s := &r.OnEnter[i]
		if remapInt(idMap, &s.Teleport) {
			changed = true
		}
		if s.SpawnMob != nil && remapIntSlice(idMap, s.SpawnMob.DespawnRooms) {
			changed = true
		}
	}
	for i := range r.Mobs {
		if remapIntSlice(idMap, r.Mobs[i].WanderRooms) {
			changed = true
		}
	}
	return changed
}

func remapInt(idMap map[int]int, n *int) bool {
	if newID, ok := idMap[*n]; ok && newID != *n {
		*n = newID
		return true
	}
	return false
}

func remapIntSlice(idMap map[int]int, slice []int) bool {
	changed := false
	for i := range slice {
		if remapInt(idMap, &slice[i]) {
			changed = true
		}
	}
	return changed
}