extends BaseTool

var _start_pos: Vector2i
var _offset: Vector2i

## Used to check if the state of content transformation has been changed
## while draw_move() is being called. For example, pressing Enter while still moving content
var _content_transformation_check := false
var _snap_to_grid := false  ## Mouse Click + Ctrl

@onready var selection_node: Node2D = Global.canvas.selection


func _input(event: InputEvent) -> void:
	if _start_pos == Vector2i(Vector2.INF):
		return
	if event.is_action_pressed("transform_snap_grid"):
		_snap_to_grid = true
		_offset = _offset.snapped(Global.grid_size)
		if Global.current_project.has_selection and selection_node.is_moving_content:
			var prev_pos: Vector2 = selection_node.big_bounding_rectangle.position
			selection_node.big_bounding_rectangle.position = prev_pos.snapped(Global.grid_size)
			# The first time transform_snap_grid is enabled then _snap_position() is not called
			# and the selection had wrong offset, so do selection offsetting here
			var grid_offset := Global.grid_offset
			grid_offset = Vector2(
				fmod(grid_offset.x, Global.grid_size.x), fmod(grid_offset.y, Global.grid_size.y)
			)
			selection_node.big_bounding_rectangle.position += grid_offset
			selection_node.marching_ants_outline.offset += (
				selection_node.big_bounding_rectangle.position - prev_pos
			)
	elif event.is_action_released("transform_snap_grid"):
		_snap_to_grid = false


func draw_start(pos: Vector2i) -> void:
	super.draw_start(pos)
	if !Global.current_project.layers[Global.current_project.current_layer].can_layer_get_drawn():
		return
	_start_pos = pos
	_offset = pos
	if Global.current_project.has_selection:
		selection_node.transform_content_start()
	_content_transformation_check = selection_node.is_moving_content
	Global.canvas.sprite_changed_this_frame = true
	Global.canvas.measurements.update_measurement(Global.MeasurementMode.MOVE)


func draw_move(pos: Vector2i) -> void:
	super.draw_move(pos)
	if !Global.current_project.layers[Global.current_project.current_layer].can_layer_get_drawn():
		return
	# This is true if content transformation has been confirmed (pressed Enter for example)
	# while the content is being moved
	if _content_transformation_check != selection_node.is_moving_content:
		return
	pos = _snap_position(pos)

	if Global.current_project.has_selection:
		selection_node.move_content(pos - _offset)
	else:
		Global.canvas.move_preview_location = pos - _start_pos
	_offset = pos
	Global.canvas.sprite_changed_this_frame = true
	Global.canvas.measurements.update_measurement(Global.MeasurementMode.MOVE)


func draw_end(pos: Vector2i) -> void:
	super.draw_end(pos)
	if !Global.current_project.layers[Global.current_project.current_layer].can_layer_get_drawn():
		return
	if (
		_start_pos != Vector2i(Vector2.INF)
		and _content_transformation_check == selection_node.is_moving_content
	):
		pos = _snap_position(pos)
		var project := Global.current_project

		if project.has_selection:
			selection_node.move_borders_end()
		else:
			var pixel_diff := pos - _start_pos
			Global.canvas.move_preview_location = Vector2i.ZERO

			_commit_undo("Draw", pixel_diff)

	_start_pos = Vector2.INF
	_snap_to_grid = false
	Global.canvas.sprite_changed_this_frame = true
	Global.canvas.measurements.update_measurement(Global.MeasurementMode.NONE)


func _snap_position(pos: Vector2) -> Vector2:
	if Input.is_action_pressed("transform_snap_axis"):
		var angle := pos.angle_to_point(_start_pos)
		if absf(angle) <= PI / 4 or absf(angle) >= 3 * PI / 4:
			pos.y = _start_pos.y
		else:
			pos.x = _start_pos.x
	if _snap_to_grid:  # Snap to grid
		pos = pos.snapped(Global.grid_size)
		# The part below only corrects the offset for situations when there is no selection
		# Offsets when there is selection is controlled in _input() function
		if !Global.current_project.has_selection:
			var move_offset := Vector2.ZERO
			move_offset.x = (
				_start_pos.x - (_start_pos.x / Global.grid_size.x) * Global.grid_size.x
			)
			move_offset.y = (
				_start_pos.y - (_start_pos.y / Global.grid_size.y) * Global.grid_size.y
			)
			pos += move_offset

	return pos


func _commit_undo(action: String, diff: Vector2i) -> void:
	var project := Global.current_project
	var frame := -1
	var layer := -1
	if Global.animation_timer.is_stopped() and project.selected_cels.size() == 1:
		frame = project.current_frame
		layer = project.current_layer

	var images := _get_selected_draw_images()
	project.undos += 1
	project.undo_redo.create_action(action)
	project.undo_redo.add_do_method(Global.undo_redo_move.bind(diff, images))
	project.undo_redo.add_do_method(Global.undo_or_redo.bind(false, frame, layer))
	project.undo_redo.add_undo_method(Global.undo_redo_move.bind(-diff, images))
	project.undo_redo.add_undo_method(Global.undo_or_redo.bind(true, frame, layer))
	project.undo_redo.commit_action()