From a51f7a53aa2c487ebf94ba0363038574ae8bb590 Mon Sep 17 00:00:00 2001
From: historia <[not public]>
Date: Tue, 7 Jul 2026 00:22:32 -0400
Subject: feat: hidden exits (and related flags) work with commands that change
 room ids. exit code simplified and unified between impassable and blocked
 exits.

---
 internal/world/room_migrate.go | 71 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 internal/world/room_migrate.go

(limited to 'internal/world/room_migrate.go')

diff --git a/internal/world/room_migrate.go b/internal/world/room_migrate.go
new file mode 100644
index 0000000..6d79499
--- /dev/null
+++ b/internal/world/room_migrate.go
@@ -0,0 +1,71 @@
+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 {
+		if remapInt(idMap, &exit.Room) {
+			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
+}
-- 
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