import turtle
import time
import random

wn=turtle.Screen()
wn.setup(width=600, height=600)
wn.tracer(0)


head=turtle.Turtle()
head.speed(0)
head.shape("square")
head.penup()
head.goto(0,0)
head.direction="stop"


food=turtle.Turtle()
food.speed(0)
food.color("red")
food.penup()
food.goto(0,100)
food.shape("circle")


def go_up():
  head.direction="up"

def go_down():
  head.direction="down"

def go_left():
  head.direction="left"

def go_right():
  head.direction="right"

def move():
  if head.direction=="up":
    y=head.ycor()
    head.sety(y+20)
  if head.direction=="down":
    y=head.ycor()
    head.sety(y-20)
  if head.direction=="left":
    x=head.xcor()
    head.setx(x-20)
  if head.direction=="right":
    x=head.xcor()
    head.setx(x+20)


wn.listen()
wn.onkey(go_up, "up")
wn.onkey(go_down, "down")
wn.onkey(go_left, "left")
wn.onkey(go_right, "right")

segments=[]

while True:
  wn.update()

  if head.distance(food)<20:
    x=random.randint(-290, 290)
    y=random.randint(-290, 290)
    food.goto(x,y)

    new_segment=turtle.Turtle()
    new_segment.speed(0)
    new_segment.shape("square")
    new_segment.color("grey")
    new_segment.penup()
    segments.append(new_segment)
  for index in range(len(segments)-1, 0, -1):
    x = segments[index-1].xcor()
    y = segments[index-1].ycor()
    segments[index].goto(x, y)
  move()

  time.sleep(0.1)