# UiScript (P1) —— 解析原始客户端的 `assets/uiscript/*.py` 布局脚本为嵌套 Dictionary。
#
# 这些文件是 Python **dict 字面量**，用到的子集很小：
#   语句：  import X（忽略）· NAME = <expr>（文件常量）· window = {...}
#   表达式：str/int/float · NAME · NAME.ATTR · (e) · 元组 (e,e) · 列表 [e,e] ·
#           dict {k:v} · 一元 - · 二元 + - * /
#   注释：  # 和 ## 到行尾
#
# 名字解析顺序：文件常量 → {SCREEN_WIDTH, SCREEN_HEIGHT} → uiScriptLocale.<X>
# （交给 locale 回调）→ 未知则 0 / ""。除法按浮点算（调用方按需取整）。
#
# 用法：
#   var us := preload("res://ui/uiscript.gd").new()
#   us.screen = Vector2i(1920, 1080)
#   us.locale = func(key): return Locale.t(key)          # 可选
#   var tree: Dictionary = us.parse_file("res://../assets/uiscript/uiscript/popupdialog.py")
#   # tree = { name, type?, x, y, width, height, children:[...], ... }
extends RefCounted

var screen := Vector2i(1920, 1080)
var locale: Callable                 # func(key: String) -> String
var last_error := ""

var _consts := {}                    # 文件顶层 NAME = expr
var _s := ""                         # 源文本
var _p := 0                          # 游标

# --- public ---------------------------------------------------------------

func parse_file(path: String) -> Dictionary:
	if not FileAccess.file_exists(path):
		last_error = "no such file: " + path
		return {}
	return parse_text(FileAccess.get_file_as_string(path))

func parse_text(src: String) -> Dictionary:
	last_error = ""
	_consts = {"SCREEN_WIDTH": screen.x, "SCREEN_HEIGHT": screen.y}
	_s = _strip_comments(src)
	_p = 0
	var window := {}
	while true:
		_skip_ws()
		if _p >= _s.length():
			break
		if _match_kw("import"):
			_skip_to_newline()
			continue
		var name := _read_ident()
		if name == "":
			# 可能是散落的括号/逗号；跳一个字符防死循环
			_p += 1
			continue
		_skip_ws()
		if _p < _s.length() and _s[_p] == "=":
			_p += 1
			var val = _parse_expr()
			if name == "window":
				window = val if val is Dictionary else {}
			else:
				_consts[name] = val
		else:
			_skip_to_newline()
	if window.is_empty() and last_error == "":
		last_error = "no `window = {...}` found"
	return window

# --- lexing helpers -----------------------------------------------------

func _strip_comments(src: String) -> String:
	var out := ""
	var in_str := false
	var q := ""
	var i := 0
	while i < src.length():
		var c := src[i]
		if in_str:
			out += c
			if c == "\\" and i + 1 < src.length():
				out += src[i + 1]
				i += 2
				continue
			if c == q:
				in_str = false
			i += 1
			continue
		if c == '"' or c == "'":
			in_str = true
			q = c
			out += c
		elif c == "#":
			while i < src.length() and src[i] != "\n":
				i += 1
			continue
		else:
			out += c
		i += 1
	return out

func _skip_ws() -> void:
	while _p < _s.length() and _s[_p] in [" ", "\t", "\r", "\n", ","]:
		_p += 1

func _skip_to_newline() -> void:
	while _p < _s.length() and _s[_p] != "\n":
		_p += 1

func _match_kw(kw: String) -> bool:
	_skip_ws()
	if _s.substr(_p, kw.length()) == kw:
		var after := _p + kw.length()
		if after >= _s.length() or not _is_ident_char(_s[after]):
			_p = after
			return true
	return false

func _is_ident_char(c: String) -> bool:
	return c == "_" or (c >= "a" and c <= "z") or (c >= "A" and c <= "Z") or (c >= "0" and c <= "9")

func _read_ident() -> String:
	_skip_ws()
	var start := _p
	while _p < _s.length() and _is_ident_char(_s[_p]):
		_p += 1
	return _s.substr(start, _p - start)

# --- expression parser (precedence: + - then * /) ----------------------

func _parse_expr():
	var lhs = _parse_term()
	while _p < _s.length():
		_skip_ws_no_comma()
		if _p >= _s.length():
			break
		var c := _s[_p]
		if c == "+" or c == "-":
			_p += 1
			var rhs = _parse_term()
			if c == "+" and (lhs is String or rhs is String):
				lhs = _str_or(lhs) + _str_or(rhs)
			elif c == "+":
				lhs = _num(lhs) + _num(rhs)
			else:
				lhs = _num(lhs) - _num(rhs)
		elif c == "%":
			# Python 字符串格式化 "fmt" % (args)：取 fmt，丢掉格式参数
			_p += 1
			_parse_term()
		elif c == '"' or c == "'":
			# Python 相邻字符串字面量隐式拼接： "a" "b"
			lhs = _str_or(lhs) + _str_or(_parse_atom())
		else:
			break
	return lhs

func _parse_term():
	var lhs = _parse_atom()
	while true:
		_skip_ws_no_comma()
		if _p < _s.length() and (_s[_p] == "*" or _s[_p] == "/"):
			var op := _s[_p]
			_p += 1
			var rhs = _parse_atom()
			if op == "*":
				lhs = _num(lhs) * _num(rhs)
			else:
				lhs = _num(lhs) / _num(rhs) if _num(rhs) != 0.0 else 0.0
		else:
			break
	return lhs

func _skip_ws_no_comma() -> void:
	while _p < _s.length() and _s[_p] in [" ", "\t", "\r", "\n"]:
		_p += 1

func _parse_atom():
	_skip_ws_no_comma()
	if _p >= _s.length():
		return 0
	var c := _s[_p]
	if c == "-":
		_p += 1
		return -_num(_parse_atom())
	if c == '"' or c == "'":
		return _parse_string()
	if c == "{":
		return _parse_dict()
	if c == "[":
		return _parse_seq("[", "]")
	if c == "(":
		return _parse_seq("(", ")")   # 元组或加括号的表达式，_parse_seq 统一处理
	if c == "_" or (c >= "A" and c <= "Z") or (c >= "a" and c <= "z"):
		return _parse_name()
	if (c >= "0" and c <= "9") or c == ".":
		return _parse_number()
	_p += 1
	return 0

func _parse_string():
	var q := _s[_p]
	_p += 1
	var out := ""
	while _p < _s.length() and _s[_p] != q:
		if _s[_p] == "\\" and _p + 1 < _s.length():
			var n := _s[_p + 1]
			out += "\n" if n == "n" else ("\t" if n == "t" else n)
			_p += 2
			continue
		out += _s[_p]
		_p += 1
	_p += 1  # closing quote
	return out

func _parse_number():
	var start := _p
	var is_float := false
	while _p < _s.length() and ((_s[_p] >= "0" and _s[_p] <= "9") or _s[_p] == "." or _s[_p] == "x" \
			or (_s[_p] >= "a" and _s[_p] <= "f") or (_s[_p] >= "A" and _s[_p] <= "F")):
		if _s[_p] == ".":
			is_float = true
		_p += 1
	var tok := _s.substr(start, _p - start)
	if tok.begins_with("0x") or tok.begins_with("0X"):
		return tok.hex_to_int()
	return float(tok) if is_float else int(tok)

func _parse_name():
	var name := _read_ident()
	# 属性链：uiScriptLocale.KEY / X.Y
	while _p < _s.length() and _s[_p] == ".":
		_p += 1
		var attr := _read_ident()
		if name == "uiScriptLocale":
			return _resolve_locale(attr)
		name += "." + attr
	if _consts.has(name):
		return _consts[name]
	if name == "True":
		return true
	if name == "False":
		return false
	if name == "None":
		return null
	# 未知名字：数值上下文当 0，字符串上下文当 ""；这里返回 0，_str_or 会兜
	return 0

func _resolve_locale(key: String):
	if locale.is_valid():
		var v = locale.call(key)
		if v != null and String(v) != "":
			return String(v)
	return "<" + key + ">"

func _parse_dict() -> Dictionary:
	var d := {}
	_p += 1  # {
	var guard := 0
	while _p < _s.length():
		guard += 1
		if guard > 4000:
			last_error = "dict parse runaway"
			break
		_skip_ws()
		if _p >= _s.length() or _s[_p] == "}":
			_p += 1
			break
		var before := _p
		var key = _parse_atom()
		_skip_ws()
		if _p < _s.length() and _s[_p] == ":":
			_p += 1
			var val = _parse_expr()
			d[_key(key)] = val
		elif _p == before:
			_p += 1   # 没进展也没 ':'，强制前进防死循环
		# 否则：孤立 token（相邻字符串续行残留等）——丢弃，继续
		_skip_ws()
	return d

func _key(k) -> String:
	if k is String:
		return k
	if k is int or k is float:
		return str(k)
	return "_"

# 统一处理 ( ) 和 [ ]：单元素且无尾逗号的 (x) 退化成 x，否则是数组。
func _parse_seq(open: String, close: String):
	_p += 1  # opening
	var items := []
	var had_comma := false
	var guard := 0
	while _p < _s.length():
		guard += 1
		if guard > 4000:
			break
		_skip_ws_no_comma()
		if _p >= _s.length() or _s[_p] == close:
			_p += 1
			break
		if _s[_p] == ",":
			had_comma = true
			_p += 1
			continue
		var before := _p
		items.append(_parse_expr())
		if _p == before:
			_p += 1
	if open == "(" and items.size() == 1 and not had_comma:
		return items[0]
	return items

# --- coercion ----------------------------------------------------------

func _num(v) -> float:
	if v is float:
		return v
	if v is int:
		return float(v)
	if v is bool:
		return 1.0 if v else 0.0
	return 0.0

func _str_or(v) -> String:
	if v is String:
		return v
	return str(v)