1 files changed, 35 insertions, 4 deletions
diff --git a/internal/game/flagstore.go b/internal/game/flagstore.go
index 2790d89..bc72c60 100644
--- a/internal/game/flagstore.go
+++ b/internal/game/flagstore.go
@@ -2,18 +2,29 @@ package game
 
 import "sync"
 
+// FlagChangeCallback is invoked when a world flag value actually changes
+// (old value differs from new, or new flag is created with a truthy value).
+type FlagChangeCallback func(name string, value any)
+
 // FlagStore holds world flags — shared mutable state visible to all players
 // (e.g. opened doors, quest state). Player-specific flags live on
 // *player.Player.Flags instead. FlagStore is safe for concurrent use.
 type FlagStore struct {
-	mu    sync.Mutex
-	flags map[string]any
+	mu        sync.Mutex
+	flags     map[string]any
+	callbacks []FlagChangeCallback
 }
 
 func NewFlagStore() *FlagStore {
 	return &FlagStore{flags: make(map[string]any)}
 }
 
+func (f *FlagStore) OnChange(cb FlagChangeCallback) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	f.callbacks = append(f.callbacks, cb)
+}
+
 func (f *FlagStore) Get(name string) (any, bool) {
 	f.mu.Lock()
 	defer f.mu.Unlock()
@@ -23,15 +34,35 @@ func (f *FlagStore) Get(name string) (any, bool) {
 
 func (f *FlagStore) Set(name string, value any) {
 	f.mu.Lock()
-	defer f.mu.Unlock()
+	old, existed := f.flags[name]
 	f.flags[name] = value
+	cbs := f.callbacks
+	f.mu.Unlock()
+
+	if !existed || !valuesEqual(old, value) {
+		for _, cb := range cbs {
+			cb(name, value)
+		}
+	}
 }
 
 func (f *FlagStore) SetAll(m map[string]any) {
 	f.mu.Lock()
-	defer f.mu.Unlock()
+	changed := make(map[string]any)
 	for k, v := range m {
+		old, existed := f.flags[k]
 		f.flags[k] = v
+		if !existed || !valuesEqual(old, v) {
+			changed[k] = v
+		}
+	}
+	cbs := f.callbacks
+	f.mu.Unlock()
+
+	for k, v := range changed {
+		for _, cb := range cbs {
+			cb(k, v)
+		}
 	}
 }