class_name MotionPack extends RefCounted

static var tick:int = 0
var direction := Vector2.ZERO
var mask:Array[bool]

func _init() -> void:
	mask.resize(256)
	mask.fill(false)

func pack() -> PackedByteArray:
	var buffer := StreamPeerBuffer.new()
	buffer.put_32(tick)
	buffer.put_float(direction.x)
	buffer.put_float(direction.y)
	# bitpack mask array into single byte
	var packed:int = 0
	for i in mask.size():
		if mask[i]: packed |= (1 << i)
	buffer.put_u8(packed)
	return buffer.data_array

static func unpack(data:PackedByteArray) -> MotionPack:
	var buffer := StreamPeerBuffer.new()
	buffer.data_array = data
	var move := MotionPack.new()
	move.tick = buffer.get_32()
	move.direction = Vector2(buffer.get_float(), buffer.get_float())
	# unpack mask array
	var packed:int = buffer.get_u8()
	for i in range(256): # 0 to 255
		move.mask[i] = bool(packed & (1 << i))
	return move