# UiAssets (P1) —— 解析 uiscript 里的图片路径（`.sub` / `.tga` / `.png` / `.jpg`）。
#
# 路径形如 `d:/ymir work/ui/public/middle_button_01.sub`。解析：
#   1) 去掉盘符前缀
#   2) 依次试： <assets>/<rel>  ·  <assets>/<pack>/<rel>（散包目录）
#   3) `.sub` = 子图描述（title/image/left/top/right/bottom）→ 载入其 image + 裁剪成 AtlasTexture
#   `.dds` 走 Metin2World.load_dds（C++ dxt 解码）运行时解成 Image。
extends RefCounted

static var _cache := {}
static var _dds_helper: Object = null

# DDS 运行时解码：走 Metin2World.load_dds（C++ 里的 dxt.cpp，DXT1/3/5 + BGRA8）。
# Godot 无原生运行时 DDS 解码，UI 里的 select.dds / 职业名图都得走这条路。
static func load_dds_image(path: String) -> Image:
	if path == "" or not FileAccess.file_exists(path):
		return null
	if not ClassDB.class_exists("Metin2World"):
		return null
	if _dds_helper == null or not is_instance_valid(_dds_helper):
		_dds_helper = ClassDB.instantiate("Metin2World")
	var img = _dds_helper.call("load_dds", path)
	return img if img is Image else null

static func load_tex(assets_root: String, vpath: String) -> Texture2D:
	if vpath == "" or assets_root == "":
		return null
	var key := assets_root + "|" + vpath
	if _cache.has(key):
		return _cache[key]
	var tex: Texture2D = _load_uncached(assets_root, vpath)
	_cache[key] = tex
	return tex

static func _strip_drive(p: String) -> String:
	var s := p.replace("\\", "/")
	if s.length() >= 2 and s[1] == ":":
		s = s.substr(2)
	return s.lstrip("/")

static func _resolve(assets_root: String, rel: String) -> String:
	var direct := assets_root.path_join(rel)
	if FileAccess.file_exists(direct):
		return direct
	# 散包：<assets>/<sub>/<rel>
	var da := DirAccess.open(assets_root)
	if da:
		for sub in da.get_directories():
			var cand := assets_root.path_join(sub).path_join(rel)
			if FileAccess.file_exists(cand):
				return cand
	# 大小写不敏感兜底：<assets>/**/ymir work/ui/... —— 只按 basename 找
	return ""

static func _load_uncached(assets_root: String, vpath: String) -> Texture2D:
	var rel := _strip_drive(vpath)
	var real := _resolve(assets_root, rel)
	if real == "":
		# 试把 .sub 换成 .tga / .png
		for ext: String in [".tga", ".png", ".jpg"]:
			real = _resolve(assets_root, rel.get_basename() + ext)
			if real != "":
				break
	if real == "":
		return null
	if real.get_extension().to_lower() == "sub":
		return _load_sub(real)
	return _load_image_file(real)

static func _load_image_file(path: String) -> Texture2D:
	# .sub 文件可能引用了未随当前资源包发布的共享贴图（例如 Public.tga）。
	# 先做存在性检查，避免 headless/UI fallback 因缺失可选贴图刷错误日志。
	if not FileAccess.file_exists(path):
		return null
	var ext := path.get_extension().to_lower()
	if ext == "dds":
		var di := load_dds_image(path)
		return ImageTexture.create_from_image(di) if di != null else null
	var img := Image.new()
	if img.load(path) != OK:
		return null
	return ImageTexture.create_from_image(img)

static func _load_sub(path: String) -> Texture2D:
	var txt := FileAccess.get_file_as_string(path)
	var image_name := ""
	var l := 0
	var t := 0
	var r := -1
	var b := -1
	for line in txt.split("\n"):
		var parts := line.strip_edges().split(" ", false)
		if parts.size() < 2:
			continue
		match parts[0]:
			"image": image_name = parts[1].strip_edges().trim_prefix('"').trim_suffix('"')
			"left": l = int(parts[1])
			"top": t = int(parts[1])
			"right": r = int(parts[1])
			"bottom": b = int(parts[1])
	if image_name == "":
		return null
	# Skill .sub files live below ui/skill/<job>, while their shared DDS
	# lives in ui/. Search the containing directory and its parents.
	var img_path := ""
	var search_dir := path.get_base_dir()
	for _i in 6:
		for candidate in [image_name, image_name.get_basename() + ".tga",
				image_name.get_basename() + ".png", image_name.get_basename() + ".dds"]:
			var candidate_path := search_dir.path_join(candidate)
			if FileAccess.file_exists(candidate_path):
				img_path = candidate_path
				break
		if img_path != "":
			break
		var parent_dir := search_dir.get_base_dir()
		if parent_dir == search_dir:
			break
		search_dir = parent_dir
	if not FileAccess.file_exists(img_path):
		return null
	var base := _load_image_file(img_path)
	if base == null:
		return null
	if r <= l or b <= t:
		return base
	var at := AtlasTexture.new()
	at.atlas = base
	at.region = Rect2(l, t, r - l, b - t)
	return at