stairs

--
-- Constructs stairs down that are 4 high and some given length (by default 5)
--
-- The intention is to build one-wide platforms after every 5 steps down.
--

--------------------
-- Digging Down
--------------------
function dig_step()
  turtle.dig()
	turtle.forward()
	turtle.digUp()
	turtle.digDown()
	turtle.down()
	turtle.digDown()
end

function dig_steps( remaining )
  if remaining == 0 then return 0 end

	local count
	if remaining > 5 then
		count = 5
	else
	  count = 5 - remaining
	end

	for i = 1, count, 1 do
		dig_step()
	end

	return remaining - count
end

function dig_platform( remaining )
  if remaining == 0 then return 0 end

	turtle.dig()
	turtle.forward()
	turtle.digUp()
	turtle.digDown()

	return remaining - 1
end

function descend( steps )
	while steps > 0 do
		steps = dig_steps( steps )
		steps = dig_platform( steps )
	end
end

--------------------
-- Turtle Ascension
--------------------

function ascend( steps )
	for i = 1, steps, 1 do
	  if (i % 6) ~= 0 then
	  	turtle.up()
		end
		turtle.back()
	end
end

--------------------
-- Driver
--------------------
local argv = {...}
local count = argv[1] or 10

local steps = tonumber(count)
descend( steps )
ascend( steps )

-- TODO: get argument parsing done
function help()
  print("stairs [length=10]")
end