function getItemSlots()
  local slots = 15
  for i = 1, 15 do
    if turtle.getItemCount(i) > 0 then
      slots = slots - 1
    end
  end
  return slots
end

function autoRefuel()
  if turtle.getFuelLevel() <= 160 then
    turtle.refuel(2)
  end
end

function dropAllItems()
  for i = 1, 16 do
    turtle.select(i)
    turtle.drop()
  end
end

function dig()
  while turtle.inspect() do
  	turtle.dig()
  	turtle.suck()
  	os.sleep(0.5)
  end
end

function digUp()
  while turtle.inspectUp() do
  	turtle.digUp()
  	turtle.suck()
  	os.sleep(0.5)
  end
end

function digDown()
  while turtle.inspectDown() do
  	turtle.digDown()
  	turtle.suck()
  	os.sleep(0.5)
  end
end

while true do
  while getItemSlots() > 0 do
  	if turtle.inspect() then
      autoRefuel()
	  	dig()
	  	turtle.turnRight()
	  	dig()
	  	turtle.turnLeft()
	  	turtle.turnLeft()
	  	dig()
	  	turtle.turnRight()
	  	digUp()
	  	turtle.up()
	  	dig()
	  	turtle.turnRight()
	  	dig()
	  	turtle.turnLeft()
	  	turtle.turnLeft()
	  	dig()
	  	turtle.turnRight()
	  	turtle.down()
  	end
    turtle.forward()
  end
  --Turtle ran out of space
  turtle.turnRight()
  turtle.turnRight()
  --Turn Back
  while true do
    local _,data = turtle.inspect()
    if data.name == "IronChest:BlockIronChest" then break end
    autoRefuel()
    turtle.forward()
  end
  dropAllItems()
  turtle.turnRight()
  turtle.turnRight()
end