# MobileWindowHost —— touch-safe presentation for existing feature windows.
#
# Feature controllers keep ownership of data, packets and permissions.  This
# helper only gives their Control roots a landscape-safe frame, a predictable
# back/close affordance and a screen-touch bridge for legacy Button nodes.
extends RefCounted

const NAV_HEIGHT := 40.0
const EDGE_MARGIN := 12.0
const MIN_SCALE := 0.42

static func safe_rect(viewport: Viewport) -> Rect2:
	if viewport == null:
		return Rect2(Vector2.ZERO, Vector2(844, 390))
	var viewport_size := viewport.get_visible_rect().size
	return safe_rect_for(viewport_size, DisplayServer.get_display_safe_area())

## Resolve a platform-reported safe area against the current logical viewport.
## Keeping this pure makes the edge cases testable without an Android/iOS
## device and avoids trusting desktop backends that return physical-screen
## coordinates unrelated to the current viewport.
static func safe_rect_for(viewport_size: Vector2, reported: Rect2) -> Rect2:
	if viewport_size.x <= 0.0 or viewport_size.y <= 0.0:
		return Rect2(Vector2.ZERO, viewport_size)
	if reported.size.x <= 0.0 or reported.size.y <= 0.0:
		return Rect2(Vector2.ZERO, viewport_size)
	var result := reported
	# Some desktop backends report a screen-space safe area larger than the
	# current viewport.  Treat that as unavailable rather than moving windows
	# outside the viewport.
	if result.size.x < 1.0 or result.size.y < 1.0:
		return Rect2(Vector2.ZERO, viewport_size)
	if result.position.x < 0.0 or result.position.y < 0.0 \
			or result.end.x > viewport_size.x + 1.0 \
			or result.end.y > viewport_size.y + 1.0:
		return Rect2(Vector2.ZERO, viewport_size)
	return result

static func content_size(root: Control) -> Vector2:
	if root == null:
		return Vector2(320, 240)
	var result := root.size
	if result.x <= 1.0 or result.y <= 1.0:
		result = root.get_combined_minimum_size()
	if result.x <= 1.0 or result.y <= 1.0:
		result = Vector2(320, 240)
	return result

static func install(root: Control, area: Rect2, title: String,
		close_cb: Callable, back_cb: Callable = Callable()) -> Dictionary:
	if root == null:
		return {}
	var base_size := content_size(root)
	var available := area.size - Vector2(EDGE_MARGIN * 2.0, EDGE_MARGIN * 2.0)
	var scale_value := minf(available.x / base_size.x, available.y / base_size.y)
	scale_value = maxf(MIN_SCALE, minf(1.0, scale_value))
	root.set_anchors_preset(Control.PRESET_TOP_LEFT)
	root.size = base_size
	root.pivot_offset = Vector2.ZERO
	root.scale = Vector2.ONE * scale_value
	root.position = area.position + (area.size - base_size * scale_value) * 0.5
	root.set_meta("mobile_hosted", true)
	root.set_meta("mobile_base_size", base_size)
	root.set_meta("mobile_scale", scale_value)

	var nav := root.get_node_or_null("__mobile_nav") as Control
	if nav == null:
		nav = Panel.new()
		nav.name = "__mobile_nav"
		nav.mouse_filter = Control.MOUSE_FILTER_STOP
		nav.z_index = 100
		var nav_style := StyleBoxFlat.new()
		nav_style.bg_color = Color(0.025, 0.045, 0.08, 0.96)
		nav_style.border_color = Color(0.36, 0.6, 0.92, 0.82)
		nav_style.border_width_bottom = 1
		nav.add_theme_stylebox_override("panel", nav_style)
		root.add_child(nav)
	nav.position = Vector2.ZERO
	nav.size = Vector2(base_size.x, NAV_HEIGHT)
	nav.visible = true

	var title_label := nav.get_node_or_null("Title") as Label
	if title_label == null:
		title_label = Label.new()
		title_label.name = "Title"
		title_label.position = Vector2(88, 0)
		title_label.size = Vector2(maxf(80.0, base_size.x - 176.0), NAV_HEIGHT)
		title_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
		title_label.vertical_alignment = VERTICAL_ALIGNMENT_CENTER
		title_label.add_theme_font_size_override("font_size", 15)
		title_label.add_theme_color_override("font_color", Color(0.95, 0.84, 0.58))
		title_label.mouse_filter = Control.MOUSE_FILTER_IGNORE
		nav.add_child(title_label)
	title_label.text = title if title != "" else String(root.name)

	var back := nav.get_node_or_null("Back") as Button
	if back == null:
		back = Button.new()
		back.name = "Back"
		back.text = "返回"
		back.position = Vector2(8, 4)
		back.size = Vector2(70, 32)
		back.add_theme_font_size_override("font_size", 12)
		nav.add_child(back)
	if not back.has_meta("mobile_host_wired"):
		back.set_meta("mobile_host_wired", true)
		back.pressed.connect(func():
			if back_cb.is_valid():
				back_cb.call()
			elif close_cb.is_valid():
				close_cb.call())

	var close := nav.get_node_or_null("Close") as Button
	if close == null:
		close = Button.new()
		close.name = "Close"
		close.text = "×"
		close.add_theme_font_size_override("font_size", 18)
		nav.add_child(close)
	if not close.has_meta("mobile_host_wired"):
		close.set_meta("mobile_host_wired", true)
		close.pressed.connect(func(): if close_cb.is_valid(): close_cb.call())
	close.position = Vector2(maxf(78.0, base_size.x - 78.0), 4)
	close.size = Vector2(70, 32)

	_wire_buttons(root)
	return {"size": base_size, "scale": scale_value, "area": area}

static func uninstall(root: Control) -> void:
	if root == null:
		return
	var nav := root.get_node_or_null("__mobile_nav") as Control
	if nav:
		nav.visible = false
	root.set_meta("mobile_hosted", false)

static func wire_buttons(root: Node) -> void:
	if root:
		_wire_buttons(root)

static func _wire_buttons(root: Node) -> void:
	for node in root.find_children("*", "BaseButton", true, false):
		var button := node as BaseButton
		if button == null or button.has_meta("mobile_touch_wired"):
			continue
		button.set_meta("mobile_touch_wired", true)
		button.gui_input.connect(func(event: InputEvent):
			_handle_button_touch(button, event))

static func _handle_button_touch(button: BaseButton, event: InputEvent) -> void:
	if button == null or not is_instance_valid(button):
		return
	if event is InputEventScreenTouch:
		var touch := event as InputEventScreenTouch
		if touch.pressed:
			if int(button.get_meta("mobile_touch_index", -1)) < 0:
				button.set_meta("mobile_touch_index", touch.index)
		else:
			if int(button.get_meta("mobile_touch_index", -1)) == touch.index:
				button.set_meta("mobile_touch_index", -1)
				if not button.disabled:
					button.pressed.emit()
		button.accept_event()