Godot Movement with Grid

extends Node2D

var speed = 256
var tile_size = 32

var last_position = Vector2()
var target_position = Vector2()
var movedir = Vector2()

onready var ray = $Sprite/RayCast2D

func _ready():
    position = position.snapped(Vector2(tile_size, tile_size))
    last_position = position
    target_position = position

func _process(delta):
    #MOVEMENT
    #collision
    if ray.is_colliding():
        position = last_position
        target_position = last_position

    else:
        #Movement
        position += speed * movedir * delta

        if position.distance_to(last_position) >= tile_size - speed * delta:
            position = target_position

    #IDLE
    if position == target_position:
        get_movedir()
        last_position = position
        target_position += movedir * tile_size


func get_movedir():
    var Left = Input.is_action_just_pressed("left")
    var Right = Input.is_action_just_pressed("right")
    var Down = Input.is_action_just_pressed("down")
    var Up = Input.is_action_just_pressed("up")

    movedir.x = -int(Left) + int(Right)
    movedir.y = - int(Up) + int(Down)

    if movedir.x != 0 && movedir.y != 0:
        movedir = Vector2.ZERO
    #collsion
    if movedir != Vector2.ZERO:
        ray.cast_to = movedir * tile_size