digtunnel

args = {...}
distance = args[1]

if not tonumber(distance) then
  print("digtunnel <distance>")
  return
end

for i = 1, distance, 1 do
  fuelLevel = turtle.getFuelLevel()

  if fuelLevel == 0 then
    print "Refueling..."
    turtle.refuel(4)
  end

  if turtle.detect() then
    turtle.dig()
  end
  turtle.forward()
  if turtle.detectUp() then
    turtle.digUp()
  end
  if turtle.detectDown() then
    turtle.digDown()
  end
end

turtle.turnLeft()
turtle.turnLeft()

for i = 1, distance, 1 do
  turtle.forward()
end

turtle.turnLeft()
turtle.turnLeft()