Staircase Builder

local xPos, yPos, zPos = 0, 0, 0 --location zPos (bigger then zero is below startpoint and smaller then zero is above startpoint)
local xSave, ySave, zSave, dirSave = 0, 0, 0, 0
local direction = 0 --direction in for ways 0 is start position
local al = true --alternate

local firsttime = true
local length, width, height = 0, 0, 0

local args={...}

function main()
	if #args ~= 3 then
		print("ClearOut<height><width><length>")
	else
		length = tonumber(args[1])
		width = tonumber(args[2])
		height = tonumber(args[3])

		for z = 0, height - 1 do
			for x = 0, width - 1 do
				for y = 0, length - 2 do
					if firsttime then
						y = y + 1
						firsttime = false
					end
					Forward()
				end
				if x < length - 1 then
					if al then
						RightUTurn(true)
						al = false
					else
						LeftUTurn(true)
						al = true
					end
				end
			end
			if height > 0 then
				Down()
			else
				Up()
			end
			RightUTurn(false)

			if direction == 0 then
				al = false
			else
				al = true
			end
			al2 = false
		end
	end
end

function CheckFuel()
	local fuel = turtle.getFuelLevel()
	local level = xPos + yPos + math.abs(zPos) + 2

	if fuel > level then
		return true;
	else
		print("Taking new fuel from slot 1")
		if turtle.getItemCount(1) > 0 then
			turtle.select(1)
			if turtle.refuel(5) == false then
				print("No fuel in slot")
				SaveLocation()
				print("Going back to chest")
				Goto(0,0,0)
				if CheckChestFuel() == false then
					print("no fuel in chest")
					shell.exit()
				end
				CheckFuel()
				RestoreLocation()
			end
		end
	end
end

function Forward()
	CheckFuel()
	while turtle.forward() == false do
		CheckInventory(0)
		turtle.dig()
	end

	if direction == 0 then
		yPos = yPos + 1
	elseif direction == 2 then
		yPos = yPos - 1
	elseif direction == 1 then
		xPos = xPos + 1
	else
		xPos = xPos - 1
	end
end

function Down()
	CheckFuel()
	while turtle.down() == false do
		CheckInventory(2)
		turtle.digDown()
	end
	zPos = zPos + 1
end

function Up()
	CheckFuel()
	while turtle.up() == false do
		CheckInventory(1)
		turtle.digUp()
	end
	zPos = zPos - 1
end

function Left(forward)
	turtle.turnLeft()

	SubstractDirection()

	if forward then
		Forward()
	end
end

function Right(forward)
	turtle.turnRight()

	AddDirection()

	if forward then
		Forward()
	end
end

function AddDirection()
	direction = direction + 1

	if direction > 3 then
		direction = 0
	end
end

function SubstractDirection()
	direction = direction - 1

	if direction < 0 then
		direction = 3
	end
end

function RightUTurn(forward)
	Right(forward)
	Right(false)
end

function LeftUTurn(forward)
	Left(forward)
	Left(false)
end

function Goto(xLoc, yLoc, zLoc)
	while zPos ~= zLoc do
		if zPos > 0 then
			Up()
		else
			Down()
		end
	end

	while direction ~= 3 do
		if direction == 0 then
			Left(false)
		else
			Right(false)
		end
	end

	while xPos > xLoc do
		Forward()
	end

	Left()

	while yPos > yLoc do
		Forward()
	end
end

function ChangeDirection(dir)
	while direction ~= dir do
		Right(false)
	end
end

function SaveLocation()
	xSave, ySave, zSave, dirSave = xPos, yPos, zPos, direction
end

function RestoreLocation()
	Goto(xSave, ySave, zSave)
	ChangeDirection(dirSave)
end

function CheckInventory(check)
	if turtle.getItemCount(9) > 0 then
		if BlockFit() == false then
			print("Inventory is full")
			SaveLocation()
			print("Returning to chest...")
			Goto(0, 0, 0)

			print("Empty inventory")
			EmptyInventory()

			print("Restore location")
			RestoreLocation()
		end
	end
end

function BlockFit()
	for i = 1, 16 do
		if turtle.getItemSpace(i) > 0 then
			turtle.select(i)
			if check == 0 then
				if turtle.compare() then
					return true
				end
			elseif check == 1 then
				if turtle.compareUp() then
					return true
				end
			else
				if turtle.compareDown() then
					return true
				end
			end
		end
	end
	return false
end

function EmptyInventory()
	for i = 2, 16 do
		select(i)
		if turtle.drop() == false then
			print("Chest if full")
			shell.exit()
		end
	end
end

function GetEmptySlot()
	for i = 2, 16 do
		if turtle.getItemCount(i) == 0 then
			return i
		end
	end
	return 0
end

function CheckChestFuel()
	local slot = GetEmptySlot()
	if slot == 0 then
		EmptyInventory()
	else
		turtle.select(slot)
		for i = 0, 10 do
			if turtle.suck() == false then
				print("No fuel found")
				shell.exit()
			end
			if turtle.drop() == false then
				print("Chest if full")
				shell.exit()
			end
		end
		CheckFuel()
	end
end

main()