extends BaseTool

const ColorReplaceShader := preload("res://src/Shaders/ColorReplace.shader")

var _prev_mode := 0
var _pattern: Patterns.Pattern
var _similarity := 100
var _fill_area := 0
var _fill_with := 0
var _offset_x := 0
var _offset_y := 0
# working array used as buffer for segments while flooding
var _allegro_flood_segments: Array
# results array per image while flooding
var _allegro_image_segments: Array


func _ready() -> void:
	update_pattern()


func _input(event: InputEvent) -> void:
	var options: OptionButton = $FillAreaOptions

	if event.is_action_pressed("ctrl"):
		_prev_mode = options.selected
	if event.is_action("ctrl"):
		options.selected = _prev_mode ^ 1
		_fill_area = options.selected
		$Similarity.visible = (_fill_area == 1)
	if event.is_action_released("ctrl"):
		options.selected = _prev_mode
		_fill_area = options.selected
		$Similarity.visible = (_fill_area == 1)


func _on_FillAreaOptions_item_selected(index: int) -> void:
	_fill_area = index
	update_config()
	save_config()


func _on_FillWithOptions_item_selected(index: int) -> void:
	_fill_with = index
	$Similarity/Value.value = _similarity
	update_config()
	save_config()


func _on_Value_value_changed(value: float) -> void:
	_similarity = value
	$Similarity/Slider.value = _similarity
	update_config()
	save_config()


func _on_Slider_value_changed(value: float) -> void:
	_similarity = value
	update_config()
	save_config()


func _on_PatternType_pressed() -> void:
	var popup: Popup = Global.patterns_popup
	if !popup.is_connected("pattern_selected", self, "_on_Pattern_selected"):
		popup.connect("pattern_selected", self, "_on_Pattern_selected", [], CONNECT_ONESHOT)
	popup.popup(Rect2($FillPattern/Type.rect_global_position, Vector2(226, 72)))


func _on_Pattern_selected(pattern: Patterns.Pattern) -> void:
	_pattern = pattern
	update_pattern()
	save_config()


func _on_PatternOffsetX_value_changed(value: float) -> void:
	_offset_x = int(value)
	update_config()
	save_config()


func _on_PatternOffsetY_value_changed(value: float) -> void:
	_offset_y = int(value)
	update_config()
	save_config()


func get_config() -> Dictionary:
	if !_pattern:
		return {"fill_area": _fill_area, "fill_with": _fill_with, "similarity": _similarity}
	return {
		"pattern_index": _pattern.index,
		"fill_area": _fill_area,
		"fill_with": _fill_with,
		"similarity": _similarity,
		"offset_x": _offset_x,
		"offset_y": _offset_y,
	}


func set_config(config: Dictionary) -> void:
	if _pattern:
		var index = config.get("pattern_index", _pattern.index)
		_pattern = Global.patterns_popup.get_pattern(index)
	_fill_area = config.get("fill_area", _fill_area)
	_fill_with = config.get("fill_with", _fill_with)
	_similarity = config.get("similarity", _similarity)
	_offset_x = config.get("offset_x", _offset_x)
	_offset_y = config.get("offset_y", _offset_y)
	update_pattern()


func update_config() -> void:
	$FillAreaOptions.selected = _fill_area
	$FillWithOptions.selected = _fill_with
	$Similarity.visible = (_fill_area == 1)
	$Similarity/Value.value = _similarity
	$Similarity/Slider.value = _similarity
	$FillPattern.visible = _fill_with == 1
	$FillPattern/XOffset/OffsetX.value = _offset_x
	$FillPattern/YOffset/OffsetY.value = _offset_y


func update_pattern() -> void:
	if _pattern == null:
		if Global.patterns_popup.default_pattern == null:
			return
		else:
			_pattern = Global.patterns_popup.default_pattern
	var tex := ImageTexture.new()
	if !_pattern.image.is_empty():
		tex.create_from_image(_pattern.image, 0)
	$FillPattern/Type/Texture.texture = tex
	var size := _pattern.image.get_size()
	$FillPattern/XOffset/OffsetX.max_value = size.x - 1
	$FillPattern/YOffset/OffsetY.max_value = size.y - 1


func draw_start(position: Vector2) -> void:
	.draw_start(position)
	if Input.is_action_pressed("alt"):
		_pick_color(position)
		return

	Global.canvas.selection.transform_content_confirm()
	if (
		!Global.current_project.layers[Global.current_project.current_layer].can_layer_get_drawn()
		or !Global.current_project.tile_mode_rects[Global.TileMode.NONE].has_point(position)
	):
		return
	if (
		Global.current_project.has_selection
		and not Global.current_project.can_pixel_get_drawn(position)
	):
		return
	var undo_data = _get_undo_data()
	if _fill_area == 0:
		fill_in_area(position)
	else:
		fill_in_color(position)
	commit_undo("Draw", undo_data)


func draw_move(position: Vector2) -> void:
	.draw_move(position)


func draw_end(position: Vector2) -> void:
	.draw_end(position)


func fill_in_color(position: Vector2) -> void:
	var project: Project = Global.current_project
	var color: Color = _get_draw_image().get_pixelv(position)
	var images := _get_selected_draw_images()
	for image in images:
		if _fill_with == 0 or _pattern == null:
			if tool_slot.color.is_equal_approx(color):
				return

		var selection: Image
		var selection_tex := ImageTexture.new()
		if project.has_selection:
			selection = project.bitmap_to_image(project.selection_bitmap)
		else:
			selection = Image.new()
			selection.create(project.size.x, project.size.y, false, Image.FORMAT_RGBA8)
			selection.fill(Color(1, 1, 1, 1))

		selection_tex.create_from_image(selection)

		var pattern_tex := ImageTexture.new()
		if _pattern:
			pattern_tex.create_from_image(_pattern.image)

		var params := {
			"size": project.size,
			"old_color": color,
			"new_color": tool_slot.color,
			"similarity_percent": _similarity,
			"selection": selection_tex,
			"pattern": pattern_tex,
			"pattern_size": pattern_tex.get_size(),
			# pixel offset converted to pattern uv offset
			"pattern_uv_offset":
			Vector2.ONE / pattern_tex.get_size() * Vector2(_offset_x, _offset_y),
			"has_pattern": true if _fill_with == 1 else false
		}
		var gen := ShaderImageEffect.new()
		gen.generate_image(image, ColorReplaceShader, params, project.size)
		yield(gen, "done")


func fill_in_area(position: Vector2) -> void:
	var project: Project = Global.current_project
	_flood_fill(position)

	# Handle Mirroring
	var mirror_x = project.x_symmetry_point - position.x
	var mirror_y = project.y_symmetry_point - position.y
	var mirror_x_inside: bool
	var mirror_y_inside: bool

	mirror_x_inside = project.can_pixel_get_drawn(Vector2(mirror_x, position.y))
	mirror_y_inside = project.can_pixel_get_drawn(Vector2(position.x, mirror_y))

	if Tools.horizontal_mirror and mirror_x_inside:
		_flood_fill(Vector2(mirror_x, position.y))
		if Tools.vertical_mirror and mirror_y_inside:
			_flood_fill(Vector2(mirror_x, mirror_y))
	if Tools.vertical_mirror and mirror_y_inside:
		_flood_fill(Vector2(position.x, mirror_y))


# Add a new segment to the array
func _add_new_segment(y: int = 0) -> void:
	var segment = {}
	segment.flooding = false
	segment.todo_above = false
	segment.todo_below = false
	segment.left_position = -5  # anything less than -1 is ok
	segment.right_position = -5
	segment.y = y
	segment.next = 0
	_allegro_flood_segments.append(segment)


# fill an horizontal segment around the specifid position, and adds it to the
# list of segments filled. Returns the first x coordinate after the part of the
# line that has been filled.
# gdlint: ignore=max-line-length
func _flood_line_around_point(position: Vector2, project: Project, image: Image, src_color: Color) -> int:
	# this method is called by `_my_flood_fill` after the required data structures
	# have been initialized
	if not image.get_pixelv(position).is_equal_approx(src_color):
		return int(position.x) + 1
	var west: Vector2 = position
	var east: Vector2 = position
	while project.can_pixel_get_drawn(west) && image.get_pixelv(west).is_equal_approx(src_color):
		west += Vector2.LEFT
	while project.can_pixel_get_drawn(east) && image.get_pixelv(east).is_equal_approx(src_color):
		east += Vector2.RIGHT
	# Make a note of the stuff we processed
	var c = int(position.y)
	var segment = _allegro_flood_segments[c]
	# we may have already processed some segments on this y coordinate
	if segment.flooding:
		while segment.next > 0:
			c = segment.next  # index of next segment in this line of image
			segment = _allegro_flood_segments[c]
		# found last current segment on this line
		c = _allegro_flood_segments.size()
		segment.next = c
		_add_new_segment(position.y)
		segment = _allegro_flood_segments[c]
	# set the values for the current segment
	segment.flooding = true
	segment.left_position = west.x + 1
	segment.right_position = east.x - 1
	segment.y = position.y
	segment.next = 0
	# Should we process segments above or below this one?
	if project.has_selection:
		# when there is a selected area, the pixels above and below the one we started creating this
		# segment from may be outside it. It's easier to assume we should be checking for segments
		# above and below this one than to specifically check every single pixel in it, because that
		# test will be performed later anyway.
		segment.todo_above = position.y > 0
		segment.todo_below = position.y < project.size.y - 1
	else:
		segment.todo_above = project.can_pixel_get_drawn(position + Vector2.UP)
		segment.todo_below = project.can_pixel_get_drawn(position + Vector2.DOWN)
	# this is an actual segment we should be coloring, so we add it to the results for the
	# current image
	_allegro_image_segments.append(segment)
	# we know the point just east of the segment is not part of a segment that should be
	# processed, else it would be part of this segment
	return int(east.x) + 1


func _check_flooded_segment(
	y: int, left: int, right: int, project: Project, image: Image, src_color: Color
) -> bool:
	var ret = false
	var c: int = 0
	while left <= right:
		c = y
		while true:
			var segment = _allegro_flood_segments[c]
			if left >= segment.left_position and left <= segment.right_position:
				left = segment.right_position + 2
				break
			c = segment.next
			if c == 0:  # couldn't find a valid segment, so we draw a new one
				left = _flood_line_around_point(Vector2(left, y), project, image, src_color)
				ret = true
				break
	return ret


func _flood_fill(position: Vector2) -> void:
	# implements the floodfill routine by Shawn Hargreaves
	# from https://www1.udel.edu/CIS/software/dist/allegro-4.2.1/src/flood.c
	var project: Project = Global.current_project
	var images := _get_selected_draw_images()
	for image in images:
		var color: Color = image.get_pixelv(position)
		if _fill_with == 0 or _pattern == null:
			if tool_slot.color.is_equal_approx(color):
				return
		# init flood data structures
		_allegro_flood_segments = []
		_allegro_image_segments = []
		# initially allocate at least 1 segment per line of image
		for j in image.get_height():
			_add_new_segment(j)
		# start flood algorithm
		_flood_line_around_point(position, project, image, color)
		# test all segments while also discovering more
		var done = false
		while not done:
			done = true
			for c in _allegro_flood_segments.size():
				var p = _allegro_flood_segments[c]
				if p.todo_below:  # check below the segment?
					p.todo_below = false
					if _check_flooded_segment(
						p.y + 1, p.left_position, p.right_position, project, image, color
					):
						done = false
				if p.todo_above:  # check above the segment?
					p.todo_above = false
					if _check_flooded_segment(
						p.y - 1, p.left_position, p.right_position, project, image, color
					):
						done = false
		# now actually color the image
		for c in _allegro_image_segments.size():
			var p = _allegro_image_segments[c]
			if p.flooding:  # sanity check: should always be true
				for px in range(p.left_position, p.right_position + 1):
					_set_pixel(image, px, p.y, tool_slot.color)


func _set_pixel(image: Image, x: int, y: int, color: Color) -> void:
	var project: Project = Global.current_project
	if !project.can_pixel_get_drawn(Vector2(x, y)):
		return

	if _fill_with == 0 or _pattern == null:
		image.set_pixel(x, y, color)
	else:
		var size := _pattern.image.get_size()
		if size.x == 0 or size.y == 0:
			return
		_pattern.image.lock()
		var px := int(x + _offset_x) % int(size.x)
		var py := int(y + _offset_y) % int(size.y)
		var pc := _pattern.image.get_pixel(px, py)
		_pattern.image.unlock()
		image.set_pixel(x, y, pc)


func commit_undo(action: String, undo_data: Dictionary) -> void:
	var redo_data := _get_undo_data()
	var project: 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

	project.undos += 1
	project.undo_redo.create_action(action)
	for image in redo_data:
		project.undo_redo.add_do_property(image, "data", redo_data[image])
		image.unlock()
	for image in undo_data:
		project.undo_redo.add_undo_property(image, "data", undo_data[image])
	project.undo_redo.add_do_method(Global, "undo_or_redo", false, frame, layer)
	project.undo_redo.add_undo_method(Global, "undo_or_redo", true, frame, layer)
	project.undo_redo.commit_action()


func _get_undo_data() -> Dictionary:
	var data := {}
	var images := _get_selected_draw_images()
	for image in images:
		image.unlock()
		data[image] = image.data
		image.lock()
	return data


func _pick_color(position: Vector2) -> void:
	var project: Project = Global.current_project
	if project.tile_mode and project.get_tile_mode_rect().has_point(position):
		position = position.posmodv(project.size)

	if position.x < 0 or position.y < 0:
		return

	var image := Image.new()
	image.copy_from(_get_draw_image())
	if position.x > image.get_width() - 1 or position.y > image.get_height() - 1:
		return

	image.lock()
	var color := image.get_pixelv(position)
	image.unlock()
	var button := BUTTON_LEFT if Tools._slots[BUTTON_LEFT].tool_node == self else BUTTON_RIGHT
	Tools.assign_color(color, button, false)