# id (int) -> WeakRef(ReedScene)
var _by_id: Dictionary = {}

signal registered(id: int, node: ReedScene)
signal unregistered(id: int)
signal conflict(id: int, existing: ReedScene, incoming: ReedScene)

# -------------------------
# 注册
# -------------------------
func register(id: int, node: ReedScene) -> bool:
	if id < 0:
		push_error("[SceneRegistry] register(): invalid id (<0): %d" % id)
		return false

	if node == null:
		push_error("[SceneRegistry] register(): node is null for id=%d" % id)
		return false

	_cleanup_dead(id)

	if _by_id.has(id):
		var existing: ReedScene = _by_id[id].get_ref()
		if existing == node:
			return true # 重复注册同一个实例，忽略

		emit_signal("conflict", id, existing, node)
		push_error(
			"[SceneRegistry] Duplicate id=%d existing=%s incoming=%s"
			% [id, existing, node]
		)
		return false

	_by_id[id] = weakref(node)
	emit_signal("registered", id, node)
	return true

# -------------------------
# 注销
# -------------------------
func unregister(id: int, node: ReedScene = null) -> void:
	if not _by_id.has(id):
		return

	var existing: ReedScene = _by_id[id].get_ref()
	if node != null and existing != node:
		# 防止误删
		return

	_by_id.erase(id)
	emit_signal("unregistered", id)

# -------------------------
# 查询
# -------------------------
func get_scene(id: int) -> ReedScene:
	_cleanup_dead(id)
	var ref: WeakRef = _by_id.get(id)
	return ref.get_ref() if ref else null

func has(id: int) -> bool:
	return get_scene(id) != null

# -------------------------
# 调用
# -------------------------
func call_scene(id: int, method: String, args: Array = []) -> Variant:
	var n := get_scene(id)
	if n == null:
		push_warning("[SceneRegistry] call_scene(): id not found: %d" % id)
		return null

	if not n.has_method(method):
		push_warning(
			"[SceneRegistry] call_scene(): id=%d has no method '%s'"
			% [id, method]
		)
		return null

	return n.callv(method, args)

# -------------------------
# 列表
# -------------------------
func list_ids() -> PackedInt32Array:
	for id in _by_id.keys():
		_cleanup_dead(id)

	var result := PackedInt32Array()
	for id in _by_id.keys():
		result.append(id)
	return result

# -------------------------
# 内部：清理死引用
# -------------------------
func _cleanup_dead(id: int) -> void:
	if not _by_id.has(id):
		return

	var ref: WeakRef = _by_id[id]
	if ref == null or ref.get_ref() == null:
		_by_id.erase(id)