tArg = { ... }

fwd = function()
  refuel()

  while turtle.forward()==false do
    turtle.dig()
  end
end

down = function()
	refuel()

	while turtle.down()==false do
		turtle.digDown()
	end
end

chooseTurn = function(condition, condition2)
	if condition then
		turtle.turnRight()
		if condition2 then
			fwd()
		end
		turtle.turnRight()

	else
		turtle.turnLeft()
		if condition2 then
			fwd()
		end
		turtle.turnLeft()

	end
end

refuel = function()
  if turtle.getFuelLevel()<20 then
    if turtle.getItemCount(16)==1 then
      print("out of fuel!")
      exit()
    end

    turtle.select(16)

    if turtle.refuel(1)==false then
      print("problem fueling!")
      exit()
    end

    turtle.select(15)
  end

  if turtle.getItemCount(15) == 1 then
    print("Out of chests!")
    exit()
  end

  if isfull() then
    empty()
  end
end

isfull = function()
  local full = true

  for i=1,14 do
    if turtle.getItemCount(i)==0 then
      full = false
    end
  end

  return full
end

empty = function()
  turtle.digDown()
  turtle.select(15)
  turtle.placeUp()
  for i=1,14 do
    turtle.select(i)
    turtle.dropUp()
  end
  turtle.select(15)
end

dig = function(length, width, height)
	for i=1,height do
		down()

		for j=1,width-1 do
			for k=1,length-1 do
				fwd()
			end

			chooseTurn((((width+1)%2)*(i-1)+j)%2==1, true)
		end

		for k=1,length-1 do
			fwd()
		end

		turtle.turnRight()
		turtle.turnRight()
	end
end

dig(tArg[1], tArg[2], tArg[3])