extends Node

const BACKDROP_SCENE := preload("res://addons/nebula_backdrop/backdrop.tscn")
var backdrop: NebulaBackdrop
var panel: PanelContainer
var status: Label
var camera_slider: HSlider
var mode_picker: OptionButton
var speed_slider: HSlider
var brightness_slider: HSlider
var pause_toggle: CheckBox
var reduced_motion_toggle: CheckBox
var capture_path := ""

func _ready() -> void:
	var background := CanvasLayer.new()
	background.layer = -10
	add_child(background)
	backdrop = BACKDROP_SCENE.instantiate() as NebulaBackdrop
	background.add_child(backdrop)
	backdrop.set_preset_resource(NebulaPlaceholderLayers.create_preset())
	_build_controls()
	for argument in OS.get_cmdline_user_args():
		if argument.begins_with("--capture="):
			capture_path = argument.trim_prefix("--capture=")
	if not capture_path.is_empty():
		pause_toggle.button_pressed = true
		await get_tree().process_frame
		await RenderingServer.frame_post_draw
		var output := get_viewport().get_texture().get_image()
		var result := output.save_png(capture_path)
		print("DEMO_CAPTURE result=", result, " size=", output.get_size())
		get_tree().quit(0 if result == OK else 1)

func _process(_delta: float) -> void:
	if status != null:
		var mode := "autoscroll" if backdrop.motion_mode == NebulaBackdrop.MotionMode.AUTOSCROLL else "camera input"
		var hold := " / held" if backdrop.paused or backdrop.reduced_motion else ""
		status.text = "%s%s\nLayer offsets: %.1f / %.1f / %.1f px" % [mode, hold, backdrop.layer_phase(0), backdrop.layer_phase(1), backdrop.layer_phase(2)]

func _label(value: String, size: int = 15) -> Label:
	var label := Label.new()
	label.text = value
	label.add_theme_font_size_override("font_size", size)
	label.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
	return label

func _slider(parent: VBoxContainer, title: String, low: float, high: float, value: float, step: float, callback: Callable) -> HSlider:
	var label := _label(title + ": " + String.num(value, 2))
	parent.add_child(label)
	var slider := HSlider.new()
	slider.min_value = low
	slider.max_value = high
	slider.step = step
	slider.value = value
	slider.value_changed.connect(func(number: float) -> void:
		label.text = title + ": " + String.num(number, 2)
		callback.call(number)
	)
	parent.add_child(slider)
	return slider

func _build_controls() -> void:
	var layer := CanvasLayer.new()
	add_child(layer)
	panel = PanelContainer.new()
	panel.position = Vector2(24, 24)
	panel.custom_minimum_size = Vector2(342, 0)
	var style := StyleBoxFlat.new()
	style.bg_color = Color(0.02, 0.025, 0.035, 0.96)
	style.border_color = Color(0.21, 0.26, 0.31)
	style.set_border_width_all(1)
	style.content_margin_left = 20
	style.content_margin_right = 20
	style.content_margin_top = 18
	style.content_margin_bottom = 18
	panel.add_theme_stylebox_override("panel", style)
	layer.add_child(panel)
	var column := VBoxContainer.new()
	column.add_theme_constant_override("separation", 12)
	panel.add_child(column)
	column.add_child(_label("NEBULA / FREE CONTROLLER", 12))
	column.add_child(_label("Horizontal parallax", 24))
	column.add_child(_label("Three original placeholder layers:\ngradient / checker grid / stars."))
	var mode := OptionButton.new()
	mode_picker = mode
	mode.add_item("Autoscroll")
	mode.add_item("Camera input")
	mode.item_selected.connect(func(index: int) -> void:
		backdrop.motion_mode = index as NebulaBackdrop.MotionMode
		camera_slider.editable = index == 1
		if index == 1:
			backdrop.set_camera_position(Vector2(camera_slider.value, 0.0))
	)
	column.add_child(mode)
	speed_slider = _slider(column, "Speed / source px per second", -240, 240, backdrop.speed, 1, func(value: float) -> void: backdrop.speed = value)
	camera_slider = _slider(column, "Camera X / source pixels", -1024, 1024, 0, 1, func(value: float) -> void: backdrop.set_camera_position(Vector2(value, 0.0)))
	camera_slider.editable = false
	brightness_slider = _slider(column, "Brightness", 0, 1, backdrop.brightness, 0.05, func(value: float) -> void: backdrop.brightness = value)
	var pause := CheckBox.new()
	pause_toggle = pause
	pause.text = "Pause current frame"
	pause.toggled.connect(func(value: bool) -> void: backdrop.paused = value)
	column.add_child(pause)
	var reduced := CheckBox.new()
	reduced_motion_toggle = reduced
	reduced.text = "Reduced motion / hold frame"
	reduced.toggled.connect(func(value: bool) -> void: backdrop.reduced_motion = value)
	column.add_child(reduced)
	status = _label("", 13)
	column.add_child(status)
	column.add_child(_label("Replace placeholders with your own licensed layers. This demo includes no Nebula pack artwork.\nMIT code · Godot 4.5 Compatibility · AI-assisted code", 12))