startup

function tryRefuel()
  if turtle.getFuelLevel()<50 then
    turtle.select(1);
    turtle.refuel(32);
  end
end

function spawnWither()
  turtle.dig();
  turtle.forward();
  turtle.forward();
  turtle.select(2);
  turtle.placeDown();
  turtle.forward();
  turtle.down();
  turtle.placeDown();
  turtle.place();
  turtle.up();
  turtle.placeDown();
  turtle.select(3);
  turtle.place();
  turtle.back();
  turtle.place();
  turtle.back();
  turtle.place();
  turtle.back();
  turtle.select(4);
  turtle.place();
end

function killWither()
  for x=0,13
    rs.setAnalogOutput("back",15);
    sleep(.2)
    rs.setAnalogOutput("back",0);
    sleep(1.3)
  end
  sleep(10)
end

function collectStar()
  turtle.dig();
  turtle.forward();
  turtle.forward();
  turtle.forward();
  turtle.down();
  turtle.suckDown();
  turtle.up();
  turtle.back();
  turtle.back();
  turtle.back();
  turtle.select(4);
  turtle.place();
  if turtle.getItemCount(5)>1 then
    turtle.select(5);
    turtle.turnRight();
    turtle.drop(1);
    turtle.turnLeft();
  end
end

while rs.getAnalogInput("top")==15 do
  spawnWither();
  sleep(10);
  killWither();
  collectStar();
  sleep(60);
end