## GiftBox — tap while closed to open: lid rises and fades out, gift inside fades in.
class_name GiftBox extends Node2D

enum State { CLOSED, OPENING, OPEN }

const LID_OPEN_Y: float = -120.0
const OPEN_DURATION: float = 0.5
const GIFT_FADE_DURATION: float = 0.4
const BUTTON_HALF_WIDTH: float = 40.0
const BUTTON_HALF_HEIGHT: float = 50.0

var _state: State = State.CLOSED


func _ready() -> void:
	var gift: Node2D = get_node_or_null("Gift") as Node2D
	if gift != null:
		gift.modulate.a = 0.0


func _input(event: InputEvent) -> void:
	if _state != State.CLOSED:
		return
	if not event is InputEventScreenTouch:
		return
	var touch: InputEventScreenTouch = event as InputEventScreenTouch
	if not touch.pressed:
		return
	var local: Vector2 = to_local(touch.position)
	if abs(local.x) > BUTTON_HALF_WIDTH or abs(local.y) > BUTTON_HALF_HEIGHT:
		return
	_start_opening()


func _start_opening() -> void:
	_state = State.OPENING
	var lid: Node2D = get_node_or_null("Lid") as Node2D
	if lid == null:
		_state = State.OPEN
		return
	var tween: Tween = create_tween()
	tween.set_ease(Tween.EASE_OUT)
	tween.set_trans(Tween.TRANS_BACK)
	tween.tween_property(lid, "position:y", LID_OPEN_Y, OPEN_DURATION)
	tween.parallel().tween_property(lid, "modulate:a", 0.0, OPEN_DURATION)
	tween.finished.connect(_on_lid_opened)


func _on_lid_opened() -> void:
	_state = State.OPEN
	var gift: Node2D = get_node_or_null("Gift") as Node2D
	if gift == null:
		return
	var tween: Tween = create_tween()
	tween.tween_property(gift, "modulate:a", 1.0, GIFT_FADE_DURATION)