# UiManager (P1) —— 窗口栈：打开 / 关闭 / 置顶 / ESC 关顶层 / modal 变暗 / 标题栏拖动。
#
#   var ui := preload("res://ui/ui_manager.gd").new()
#   add_child(ui)
#   ui.locale = func(k): return Locale.t(k)
#   var w := ui.open_script("res://../assets/uiscript/uiscript/systemdialog.py", assets_root)
#   w.nodes["close_button"].pressed.connect(func(): ui.close(w.root))
#
# open_script 返回 { root: Control, nodes: {name: Control} }（同 UiBuild.build）。
extends CanvasLayer

const UiScript = preload("res://ui/uiscript.gd")
const UiBuild = preload("res://ui/ui_build.gd")

signal window_opened(root: Control)
signal window_closed(root: Control)

var locale: Callable
var screen := Vector2i(1920, 1080)

var _root: Control          # 全屏容器
var _dim: ColorRect         # modal 变暗层
var _stack: Array[Control] = []
var _drag_win: Control = null
var _drag_from := Vector2.ZERO

func _ready() -> void:
	layer = 10
	_root = Control.new()
	_root.set_anchors_preset(Control.PRESET_FULL_RECT)
	_root.mouse_filter = Control.MOUSE_FILTER_IGNORE
	add_child(_root)
	_dim = ColorRect.new()
	_dim.color = Color(0, 0, 0, 0.45)
	_dim.set_anchors_preset(Control.PRESET_FULL_RECT)
	_dim.visible = false
	_root.add_child(_dim)
	set_process_unhandled_input(true)

# --- open / close --------------------------------------------------------

func build_script(path: String, assets_root: String) -> Dictionary:
	var us := UiScript.new()
	us.screen = screen
	if locale.is_valid():
		us.locale = locale
	var spec := us.parse_file(path)
	if spec.is_empty():
		push_warning("UiManager: parse failed (%s): %s" % [path, us.last_error])
		return {"root": Control.new(), "nodes": {}}
	return UiBuild.build(spec, assets_root)

# 解析 + 构建 + 打开，返回 { root, nodes }
func open_script(path: String, assets_root: String, modal := false) -> Dictionary:
	var r := build_script(path, assets_root)
	open(r.root, modal)
	return r

func open(win: Control, modal := false) -> void:
	if win.get_parent() == null:
		_root.add_child(win)
	win.set_meta("modal", modal)
	_wire_drag(win)
	_stack.erase(win)
	_stack.append(win)
	_restack()
	window_opened.emit(win)

func close(win: Control) -> void:
	if win == null:
		return
	_stack.erase(win)
	if win.get_parent():
		win.get_parent().remove_child(win)
	win.queue_free()
	_restack()
	window_closed.emit(win)

func close_top() -> bool:
	if _stack.is_empty():
		return false
	close(_stack[-1])
	return true

func top() -> Control:
	return _stack[-1] if not _stack.is_empty() else null

func _restack() -> void:
	var any_modal := false
	for i in _stack.size():
		var w := _stack[i]
		w.move_to_front()
		if bool(w.get_meta("modal", false)):
			any_modal = true
	_dim.visible = any_modal
	if any_modal:
		# 变暗层紧贴在最顶层 modal 之下
		_dim.move_to_front()
		_stack[-1].move_to_front()

# --- ESC ---------------------------------------------------------------

func _unhandled_input(e: InputEvent) -> void:
	if e is InputEventKey and e.pressed and e.keycode == KEY_ESCAPE:
		if close_top():
			get_viewport().set_input_as_handled()

# --- 标题栏拖动 --------------------------------------------------------

func _wire_drag(win: Control) -> void:
	var handle := _find_drag_handle(win)
	if handle == null or handle.has_meta("_drag_wired"):
		return
	handle.set_meta("_drag_wired", true)
	handle.mouse_filter = Control.MOUSE_FILTER_STOP
	handle.gui_input.connect(func(ev: InputEvent): _on_handle_input(win, ev))

func _find_drag_handle(win: Control) -> Control:
	# 优先 titlebar；否则 board_with_titlebar 的顶部条；否则整个 window 根
	for n in win.find_children("*", "", true, false):
		if n is Control and (n.get_meta("is_titlebar", false) or n.get_meta("titlebar_h", 0) > 0):
			return n
	return win

func _on_handle_input(win: Control, ev: InputEvent) -> void:
	if ev is InputEventMouseButton and ev.button_index == MOUSE_BUTTON_LEFT:
		if ev.pressed:
			_drag_win = win
			_drag_from = win.get_global_mouse_position() - win.position
			open(win)   # 置顶
		else:
			_drag_win = null
	elif ev is InputEventMouseMotion and _drag_win == win:
		win.position = win.get_global_mouse_position() - _drag_from