# UiAssets (P1) —— 解析 uiscript 里的图片路径（`.sub` / `.tga` / `.png` / `.jpg` / `.dds`）。
#
# 路径形如 `d:/ymir work/ui/public/middle_button_01.sub`。解析：
#   1) 优先从 40250 Client/pack（Metin2Pack）取（保持 d:/ 盘符或规范相对路径）
#   2) 支持 pack 内 .sub 子图切片（AtlasTexture），支持 version 1.0 / 2.0 及公用 Public.dds / IntroEmpire.dds 母图寻址
#   3) 若 pack 找不到且指定了 assets_root，回退到散文件目录
#   4) .dds 走 Metin2World.load_dds（C++ dxt 解码）运行时解成 Image。
extends RefCounted

static var _cache := {}

static func clear_cache() -> void:
	_cache.clear()

# 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
	var helper: Object = ClassDB.instantiate("Metin2World")
	var img = helper.call("load_dds", path)
	helper.free()
	return img if img is Image else null

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

# 只从 40250 Client/pack（Metin2Pack）取，不看 assets/ 散文件：移植的客户端从包里读模型，
# 贴图也必须是同一份（assets/ 里同名的 fork 贴图 UV 布局可能不同）。
static func load_pack_tex(vpath: String) -> Texture2D:
	if vpath == "":
		return null
	var key := "pack|" + vpath
	if _cache.has(key):
		return _cache[key]
	var tex: Texture2D = _load_pack_any(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 _find_pack_path(vpath: String) -> String:
	if not ClassDB.class_exists("Metin2Pack") or not Metin2Pack.is_ready():
		return ""
	var norm := vpath.replace("\\", "/").strip_edges()
	var stripped := _strip_drive(norm)
	var candidates: Array[String] = [
		norm,
		stripped,
		"d:/" + stripped,
		norm.to_lower(),
		stripped.to_lower(),
		("d:/" + stripped).to_lower(),
	]
	for c in candidates:
		if Metin2Pack.exists(c):
			return c
	return ""

static func _load_pack_any(vpath: String) -> Texture2D:
	var pack_path := _find_pack_path(vpath)
	if pack_path == "":
		return null
	var ext := pack_path.get_extension().to_lower()
	if ext == "sub":
		return _load_pack_sub(pack_path)
	return _load_pack_image(pack_path)

static func _load_pack_sub(pack_path: String) -> Texture2D:
	if not ClassDB.class_exists("Metin2Pack") or not Metin2Pack.is_ready():
		return null
	if not Metin2Pack.exists(pack_path):
		return null
	var bytes: PackedByteArray = Metin2Pack.get_bytes(pack_path)
	if bytes.is_empty():
		return null
	var txt := bytes.get_string_from_ascii()
	var image_name := ""
	var version := ""
	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].to_lower():
			"version": version = parts[1].strip_edges().trim_prefix('"').trim_suffix('"')
			"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

	var sub_dir := pack_path.get_base_dir()
	var candidates: Array[String] = []
	if version == "2.0":
		candidates.append(sub_dir.path_join(image_name))
		candidates.append("d:/ymir work/ui/".path_join(image_name))
	else:
		candidates.append("d:/ymir work/ui/".path_join(image_name))
		candidates.append(sub_dir.path_join(image_name))

	var search_dir := sub_dir
	for _i in 4:
		var parent := search_dir.get_base_dir()
		if parent == search_dir or parent.is_empty():
			break
		candidates.append(parent.path_join(image_name))
		search_dir = parent

	var base_tex: Texture2D = null
	for cand in candidates:
		base_tex = _load_pack_any(cand)
		if base_tex != null:
			break
	if base_tex == null:
		return null
	if r <= l or b <= t:
		return base_tex
	var at := AtlasTexture.new()
	at.atlas = base_tex
	at.region = Rect2(l, t, r - l, b - t)
	return at

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
	return ""

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

static func _load_pack_image(rel: String) -> Texture2D:
	if not ClassDB.class_exists("Metin2Pack") or not Metin2Pack.is_ready():
		return null
	if not Metin2Pack.exists(rel):
		return null
	var ext := rel.get_extension().to_lower()
	var image: Image
	if ext == "dds":
		if not ClassDB.class_exists("Metin2World"):
			return null
		var helper: Object = ClassDB.instantiate("Metin2World")
		image = helper.call("load_dds", "pack://" + rel)
		helper.free()
	else:
		var bytes: PackedByteArray = Metin2Pack.get_bytes(rel)
		image = Image.new()
		var err := ERR_FILE_UNRECOGNIZED
		match ext:
			"tga": err = image.load_tga_from_buffer(bytes)
			"png": err = image.load_png_from_buffer(bytes)
			"jpg", "jpeg": err = image.load_jpg_from_buffer(bytes)
			"bmp": err = image.load_bmp_from_buffer(bytes)
		if err != OK:
			return null
	return ImageTexture.create_from_image(image) if image != null and not image.is_empty() else null

static func _load_image_file(path: String) -> Texture2D:
	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
	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
	var region_top := t
	at.region = Rect2(l, region_top, r - l, b - t)
	return at