extends CanvasLayer
## In-game system menu, opened with Escape.
##
## Exists because without it there is no way out of a session short of killing
## the process -- and "kill the process" is exactly the behaviour the escape
## channel is designed to discourage, so leaving it as the only exit would work
## against the rest of the design.

signal resumed
signal return_to_hub_requested
signal disconnect_requested
signal characters_requested
signal settings_requested

var _panel: VBoxContainer
var _hub_button: Button
var _characters_button: Button
var _disconnect_button: Button
var _note: Label
var _in_dungeon: bool = false
var _open: bool = false


func _ready() -> void:
	layer = 20
	var root := UiTheme.themed_root()
	add_child(root)

	# Dim the game behind the menu so it is obvious the world is still running.
	var scrim := ColorRect.new()
	scrim.color = Color(0.0, 0.0, 0.0, 0.55)
	scrim.set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)
	scrim.mouse_filter = Control.MOUSE_FILTER_STOP
	root.add_child(scrim)

	var center := CenterContainer.new()
	center.set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)
	root.add_child(center)

	_panel = VBoxContainer.new()
	_panel.custom_minimum_size = Vector2(320.0, 0.0)
	_panel.add_theme_constant_override("separation", 10)
	center.add_child(_panel)

	var title := Label.new()
	title.text = "PAUSED"
	title.add_theme_font_size_override("font_size", 26)
	_panel.add_child(title)

	_note = Label.new()
	_note.add_theme_font_size_override("font_size", 12)
	_note.add_theme_color_override("font_color", Color(1.0, 0.7, 0.5))
	_note.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
	_note.custom_minimum_size = Vector2(320.0, 0.0)
	_panel.add_child(_note)

	_hub_button = _button("Return to hub", func() -> void:
		return_to_hub_requested.emit()
		close())
	_characters_button = _button("Change character", func() -> void:
		characters_requested.emit()
		close())
	_button("Settings", func() -> void:
		settings_requested.emit()
		close())
	_button("Resume", func() -> void: close())
	_disconnect_button = _button("Disconnect to menu", func() -> void:
		disconnect_requested.emit()
		close())
	_button("Quit game", func() -> void: get_tree().quit())

	visible = false


func _button(text: String, on_press: Callable) -> Button:
	var b := Button.new()
	b.text = text
	b.pressed.connect(on_press)
	_panel.add_child(b)
	return b


func _unhandled_input(event: InputEvent) -> void:
	if event.is_action_pressed("system_menu"):
		toggle()
		get_viewport().set_input_as_handled()


func toggle() -> void:
	if _open:
		close()
	else:
		open()


func open() -> void:
	_open = true
	visible = true
	# Nothing is paused -- the server does not stop for one client's menu, so
	# neither does the view. Only the mouse is freed.
	Input.mouse_mode = Input.MOUSE_MODE_VISIBLE


func close() -> void:
	_open = false
	visible = false


func is_open() -> bool:
	return _open


## The hub button is meaningless when you are already in the hub.
func set_in_dungeon(in_dungeon: bool) -> void:
	if in_dungeon == _in_dungeon and not _note.text.is_empty():
		return
	_in_dungeon = in_dungeon
	_hub_button.disabled = not in_dungeon
	# Swapping is hub-only, and the server enforces that regardless of what
	# this button does -- but a disabled button explains the rule, where a
	# refusal after the fact just looks broken.
	_characters_button.disabled = in_dungeon
	_characters_button.text = "Change character  (hub only)" if in_dungeon \
		else "Change character"
	if in_dungeon:
		# Disconnecting is not an escape: the server keeps the body in the
		# world, channelling out, for the same second the escape button costs.
		# Saying so is the difference between a considered choice and a nasty
		# surprise -- the mechanic only reads as fair if players know about it.
		_note.text = "The world keeps running while this is open. " \
			+ "Disconnecting does not save you: your ship stays in the dungeon " \
			+ "for one second and can still be killed."
		_disconnect_button.text = "Disconnect to menu  (ship stays 1s)"
	else:
		_note.text = "The world keeps running while this is open."
		_disconnect_button.text = "Disconnect to menu"