extends Line2D

var epsilon = 2

@onready var leftBorder = $LeftBorder
@onready var rightBorder = $RightBorder

# Called when the node enters the scene tree for the first time.
func _ready():
	pass # Replace with function body.

# Called every frame. 'delta' is the elapsed time since the previous frame.
func _process(delta):
	pass

func simplify():
	points = simplify_rec(points, epsilon)

func simplify_rec(pointArray: PackedVector2Array, epsilon: float):
	var dmax = 0
	var index = -1
	if pointArray.size() < 3:
		return pointArray
	var end = pointArray.size() - 1
	for i in range(1, end-1):
		var d = find_perpendicular_distance(pointArray[i], pointArray[0], pointArray[end])
		if d > dmax:
			index = i
			dmax = d
	
	if dmax > epsilon:
		var recResults1 = simplify_rec(pointArray.slice(0, index), epsilon)
		var recResults2 = simplify_rec(pointArray.slice(index, end), epsilon)
		recResults1.append_array(recResults2)
		return recResults1
	else:
		return [pointArray[0], pointArray[end]]

func find_perpendicular_distance(p: Vector2, p1: Vector2, p2: Vector2):
	var result
	var slope
	var intercept
	if p1.x == p2.x:
		result = p.x - p1.x
	else:
		slope = (p2.y - p1.y) / (p2.x - p1.x)
		intercept = p1.y - (slope * p1.x)
		result = abs(slope * p.x - p.y + intercept) / sqrt(pow(slope, 2) + 1)
	
	return result

func get_bisector(left_side: bool, p2: Vector2, p1: Vector2 = p2, p3: Vector2 = p2):
	var v1 = (p2 - p1).normalized()
	var v2 = (p2 - p3).normalized()
	var normal
	if v1 == -v2:
		normal = v2.rotated(-PI/2)
	else:
		normal = (v1 + v2).normalized()
		if v2.rotated(-PI/2).dot(v1) < 0:
			normal = -normal
	
	if left_side:
		normal = -normal
	return normal


func draw_borders():
	for pointIndex in range(0, points.size() - 1):
		var normal
		if pointIndex == 0:
			continue
		elif pointIndex == points.size() -1:
			continue
			#normal = Vector2.ZERO
		else:
			normal = get_bisector(true, points[pointIndex], points[pointIndex-1], points[pointIndex+1])
		
		var point = points[pointIndex] + (normal*50)
		leftBorder.add_point(point)
		point = points[pointIndex] - (normal*50)
		rightBorder.add_point(point)

func clear_borders():
	leftBorder.clear_points()
	rightBorder.clear_points()