stairmine

-- Programmed:  17 May 2014
-- by Skyler James
--
-- Digs stairs <width> wide
-- and <length> long, placing
-- blocks underneath it as
-- needed (ensures you can
-- always get to your turtle)
--
-- The most important functions
-- are digstair and digxsides


local tArgs = { ... }
if #tArgs ~= 2 then
	print( "Usage: stairmine <width> <length>" )
	return
end

-- Set width of stairs with user input
local width = tonumber( tArgs[1] )
if width < 1 or width > 3 then
	print( "Stair width must be between 1 and 3, inclusive" )
	return
end

-- Set length of stairs with user input
local length = tonumber( tArgs[2] )
if length < 1 then
	print( "Stair length must be positive" )
	return
end

-- Dig, then wait in case
-- gravel / sand falls
function digfront()
	while turtle.detect() do
		turtle.dig()
		sleep(0.65)
	end
end

-- If width is 3 dig
-- both sides of turtle
function dig2sides()
	turtle.turnRight()
	digfront()
	turtle.turnLeft()
	turtle.turnLeft()
	digfront()
	turtle.turnRight()
end

-- If width is 2 dig
-- right side of turtle
function dig1side()
	turtle.turnRight()
	digfront()
	turtle.turnLeft()
end

-- Dig, then wait in case
-- sand / gravel falls
function digup()
	while turtle.detectUp() do
		turtle.digUp()
		sleep(0.65)
	end
end

-- Decide which digside
-- function to call based
-- on user input
function digxsides()
	if width == 3 then
		dig2sides()
	elseif width == 2 then
		dig1side()
	end
end

-- If there is nothing under the turtle,
-- it will place a block. Very prone
-- to bugs, but not needed often
-- Will only build bridge / stairs
-- 1 block wide, but it works
function putblockifneeded()
	-- first, of course, check
	-- if a block is needed
	if not (turtle.detectDown()) then
		local highestcount = 0
		local slotwithmost = 0
		local tempnum = 0

		-- iterate through 9 slots
		-- and find which one has
		-- the most blocks. That
		-- slot is most likely
		-- dirt or cobblestone.
		for i = 1,9,1 do
			tempnum = turtle.getItemCount(i)
			if tempnum > highestcount then
				slotwithmost = i
				highestcount = tempnum
			end
		end

		-- double check that there
		-- are any blocks to use.
		-- If yes, place one.
		turtle.select(slotwithmost)
		if highestcount > 0 then
			turtle.placeDown()
		else
			return
		end
	end
end

-- Move the turtle in a stair
-- mining pattern, digging a
-- ceiling 4 blocks high and
-- calling digxsides as needed
function digstair()
	digxsides()
	digup()
	turtle.digDown()
	turtle.up()
	digxsides()
	digup()
	turtle.up()
	digxsides()
	turtle.down()
	turtle.down()
	turtle.down()
	putblockifneeded()
	digxsides()
end


-- user input is not faulty,
-- so begin mining stairs
-- <length> blocks deep
print("Mining stairs . . .")
for i = 1,length,1 do
	digfront()
	turtle.forward()
	digstair()
	print("Mined "..i.." stairs")
end

-- That's all, folks!
return