1 files changed, 83 insertions, 0 deletions
diff --git a/internal/game/core_flagstore.go b/internal/game/core_flagstore.go
new file mode 100644
index 0000000..ecefccf
--- /dev/null
+++ b/internal/game/core_flagstore.go
@@ -0,0 +1,83 @@
+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
+	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()
+	v, ok := f.flags[name]
+	return v, ok
+}
+
+func (f *FlagStore) Set(name string, value any) {
+	f.mu.Lock()
+	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()
+	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)
+		}
+	}
+}
+
+func (f *FlagStore) Delete(name string) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	delete(f.flags, name)
+}
+
+func (f *FlagStore) All() map[string]any {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	out := make(map[string]any, len(f.flags))
+	for k, v := range f.flags {
+		out[k] = v
+	}
+	return out
+}