extends CanvasLayer

signal exiting
signal success

@onready var container = %PartsContainer
@onready var whole = %Whole
@onready var content_rect = %Content

# original: 152
var part_size = 110
var positions = []

# from part 0 to 3, rotated by 0, 90, 180, 270 degrees
var rotations = [0, 0, 0, 0]
var images = []
var game_finished = false

var selected := 0:
	set(value):
		selected = value
		_display_selected()


func _ready() -> void:
	layer = GlobalConfig.CANVAS_LAYER_LITTLE_GAME
	_setup()
	_shuffle()
	_display_selected()
	content_rect.modulate.a = 0.0
	content_rect.visible = true
	SceneManager.pop_center_notification(tr("input_拼凑信件"))


func _setup() -> void:
	# 保存 whole 中的 4 个 part 的位置，然后从 whole 中移除，添加到 container 中
	positions.clear()
	images.clear()
	for i in range(4):
		var part = whole.get_child(0) as TextureButton
		part.pressed.connect(_select_part.bind(part))
		images.append(part.texture_normal.get_image())
		positions.append(part.position)
		# 从 whole 中移除，添加到 container 中
		whole.remove_child(part)
		container.add_child(part)
		part.texture_click_mask = BitMap.new()
		part.texture_click_mask.create_from_image_alpha(images[i])
	_container_replace_children()


func _select_part(part) -> void:
	selected = part.get_index()
	_display_selected()


func _exchange_parts(a: int, b: int) -> void:
	var part_a = container.get_child(a)
	var part_b = container.get_child(b)
	container.move_child(part_a, b)
	container.move_child(part_b, a)
	# reassign answer
	container.move_child(part_a, b)
	_container_replace_children()


func _container_replace_children() -> void:
	container.get_child(0).position = Vector2(0, 0)
	container.get_child(1).position = Vector2(part_size, 0)
	container.get_child(2).position = Vector2(0, part_size)
	container.get_child(3).position = Vector2(part_size, part_size)


func _rotate_part(direction := 1) -> void:
	var part = container.get_child(selected) as TextureButton
	var id = int(str(part.name))
	rotations[id] = wrapi(rotations[id] + direction, 0, 4)
	images[id].rotate_90(direction)
	part.texture_normal = ImageTexture.create_from_image(images[id])
	part.texture_click_mask.create_from_image_alpha(images[id])


func _shuffle() -> void:
	# shuffle answer
	for i in range(30):
		var a = randi() % 4
		var b = randi() % 4
		_exchange_parts(a, b)
	# shuffle rotations
	for i in range(4):
		selected = i
		for j in range(randi() % 4):
			_rotate_part()
	selected = 0


func _display_selected() -> void:
	if game_finished:
		return
	for i in range(4):
		if i == selected:
			container.get_child(i).modulate = Color(1, 1, 1)
		else:
			container.get_child(i).modulate = Color(0.7, 0.7, 0.7)


func _check_answer() -> void:
	var _success = true
	for i in range(4):
		var part = container.get_child(i)
		var id = int(str(part.name))
		if rotations[id] != 0 or id != i:
			_success = false
			break
	game_finished = _success
	if _success:
		# 从 container 中移除，添加到 whole 中
		var tween = create_tween()
		tween.tween_property(whole, "scale", Vector2.ONE, 1.0)
		var diff = whole.position - container.position
		whole.position = container.position
		for i in range(4):
			var part = container.get_child(0)
			container.remove_child(part)
			whole.add_child(part)
			# 逐个恢复到原始 modulate
			part.modulate = Color(1, 1, 1)
			# 逐个移动到正确位置
			tween.parallel().tween_property(part, "position", diff + positions[i], 1.0)
		tween.tween_callback(_post_success)


func _post_success():
	# 不显示文本，让玩家在重要物品栏去看（提示）
	# var tween = create_tween()
	# tween.tween_property(content_rect, "modulate:a", 1.0, 1.0)
	var texture = preload("res://asset/art/prop/c01/院长的信.png")
	var inspector = SceneManager.get_inspector()
	inspector.pop_standard_inspection(texture, null, tr("prop_院长的信_说明"))
	SceneManager.enable_important_item("prop_院长的信")
	whole.visible = false
	# 1s 后退出
	await get_tree().create_timer(1.0).timeout
	if get_parent() != null:
		success.emit()
		get_parent().remove_child(self)


func _unhandled_input(event: InputEvent) -> void:
	# block all input
	get_viewport().set_input_as_handled()
	if event.is_action_pressed("cancel") or event.is_action_pressed("escape"):
		if game_finished:
			success.emit()
		else:
			exiting.emit()
		get_parent().remove_child(self)
		return
	if game_finished:
		return
	var handled = false
	if event.is_action_pressed("up"):
		if selected > 1:
			_exchange_parts(selected, selected - 2)
			selected -= 2
			handled = true
	elif event.is_action_pressed("down"):
		if selected < 2:
			_exchange_parts(selected, selected + 2)
			selected += 2
			handled = true
	elif event.is_action_pressed("left"):
		if selected % 2 == 1:
			_exchange_parts(selected, selected - 1)
			selected -= 1
			handled = true
	elif event.is_action_pressed("right"):
		if selected % 2 == 0:
			_exchange_parts(selected, selected + 1)
			selected += 1
			handled = true
	elif event.is_action_pressed("interact"):
		_rotate_part()
		handled = true
	if handled:
		$SfxMove.play()
		_display_selected()
		_check_answer()