stairs3x3

local args = { ... }

numArgs = table.getn(args)

TORCH_INTERVAL = 5

function fuel ()
  if turtle.getFuelLevel() == 0 then
    turtle.select(1)
    turtle.refuel(1)
  end
end

function plantTunnelTorch ()
  turtle.select(2)
  turtle.placeDown()
end

function goodDig ()
  while turtle.detect() do
    fuel()
    turtle.dig()
    sleep(0.5)
  end
  fuel()
end

function goodDigUp ()
  while turtle.detectUp() do
    fuel()
    turtle.digUp()
    sleep(0.5)
  end
  fuel()
end

function threeByThree ()
  goodDigUp()
  turtle.digDown()
  fuel()
  turtle.turnLeft()
  goodDig()
  turtle.forward()
  goodDigUp()
  turtle.digDown()
  fuel()
  turtle.back()
  fuel()
  turtle.turnRight()
  fuel()
  turtle.turnRight()
  goodDig()
  turtle.forward()
  fuel()
  goodDigUp()
  turtle.digDown()
  fuel()
  turtle.back()
  fuel()
  turtle.turnLeft()
end

function twoByTwo()
  goodDigUp()
  turtle.digDown()
  fuel()
  turtle.turnRight()
  goodDig()
  turtle.forward()
  fuel()
  goodDigUp()
  turtle.digDown()
  fuel()
  turtle.back()
  fuel()
  turtle.turnLeft()
end

function tunnel (len)
  count = 0
  torch = TORCH_INTERVAL
  while count < len do
    threeByThree()

    --Stairs
    fuel()
    turtle.up()
    threeByThree()
    turtle.up()
    threeByThree()
    turtle.down()
    --EndStairs

    if torch == TORCH_INTERVAL then
      plantTunnelTorch()
      torch = 0
    end
    goodDig()
    turtle.forward()
    fuel()
    count = count+1
    torch = torch+1
  end
end

function leftOrRight (dire)
  threeByThree()
  goodDig()
  turtle.forward()
  threeByThree()
  turtle.back()
  fuel()
  if dire == 'l' then
    turtle.turnLeft()
  elseif dire == 'r' then
    turtle.turnRight()
  else
    term.write("Error, bad direction.")
  end
end

--================Main===============--

if numArgs == 1.0 then
  digNum = tonumber(args[1])
  tunnel(digNum)
elseif numArgs == 2.0 or numArgs == 3.0 then

  if numArgs == 3.0 then
    intervalWidth = tonumber(args[3])
  else
    intervalWidth = TORCH_INTERVAL
  end

  digNum = tonumber(args[1])
  direction = args[2]
  if direction ~= 'r' and direction ~= 'l' then
    error("Second argument must be 'r' or 'l'")
  end
  tunnel(digNum)
  leftOrRight(direction)
  tunnel(intervalWidth)
  leftOrRight(direction)
  tunnel(digNum)
else
  error("Usage: dig [int] opt[l | r]")
end