godot-plateformer/addons/reedscene/scene/SceneIDDatabase.gd

''' 
	用來儲存所有的SceneID的數據集，通常，
	1. 你不應該通過面板修改這個DataBase。
	2. 每個項目通常只存在一個ID Database
'''

@tool
extends Resource
class_name SceneIDDatabase

var next_id: int =  10000

@export var entries: Array[SceneIDEntry] = []

## 請求一個ID
func request_new_id(prefix: int) -> int:
	##合理性檢測
	if prefix < 0: return -1
	
	##獲取到已經使用的所有的ID
	var used_ids : Array[int] = []
	var used_set := {}
	for i in entries:
		used_ids.append(i.scene_id)
	
	# 转成 Set（O(1) contains）
	for id in used_ids:
		used_set[id] = true

	var candidate := prefix + 1
	while used_set.has(candidate):
		candidate += 1

	return candidate

## 注冊SceneID
func register_scene_id(
	scene_path: String,
	uid: String,
	scene_id: int
) -> bool:
	for entry in entries:
		if entry.scene_id == scene_id:
			push_error("SceneIDDatabase: duplicated scene_id %d" % scene_id)
			return false

	var entry := SceneIDEntry.new()
	entry.scene_id = scene_id
	entry.scene_path = scene_path
	entry.scene_uid = uid

	entries.append(entry)

	emit_changed()
	return true

## 檢查SceneID 是否有效
func validate_scene_id(
	scene_id: int,
	scene_uid: String,
	scene_path: String
) -> SceneIDValidationResult:
	var result := SceneIDValidationResult.new()

	var matched_entry : SceneIDEntry = null
	for entry in entries:
		if entry.scene_id == scene_id:
			matched_entry = entry
			break

	if matched_entry == null:
		result.add_warning(
			"Scene ID %d is not registered in SceneIDDatabase."
			% scene_id
		)
		return result

	if matched_entry.scene_uid != scene_uid:
		result.add_warning(
			"Scene ID %d belongs to a different scene."
			% scene_id
		)

	if matched_entry.scene_path != scene_path:
		result.add_warning(
			"Scene ID %d path mismatch.\nDB: %s\nCurrent: %s"
			% [scene_id, matched_entry.scene_path, scene_path]
		)

	return result