Turtle Quarry Mk2

Args = {...}

x,y,z = 0,0,0
dir = { [1]="+X", [2]="+Y", [3]="-X", [4]="-Y" }
nDir = 1
atBedrock = false
dirDown = true
dirFor = true

function printUsage()
	print("Usage:")
	print("quarry <LENGTH> <WIDE> <left/right>")
	print("Quarries a <LENGTH> long and <WIDE> wide hole to bedrock.")
	print("Place enderchest in slot 1.")
end

function getFuel()
	return turtle.getFuelLevel()
end

function hasFuel()
	if getFuel() == 0 then
		return false
	else
		return true
	end
end

function dropOff()
	print("Dropping off items, fuel: "..getFuel())
	turtle.digUp()
	turtle.select(1)
	if turtle.placeUp() then
		for i=2,16 do
			turtle.select(i)
			turtle.dropUp()
		end
		turtle.select(1)
		turtle.digUp()
	else
		print("Failed to drop off.")
	end
end

function hasSpace()
	local space = false
	for i=1,16 do
		if turtle.getItemCount(i) == 0 then
			space = true
		end
	end
	if not space then dropOff() end
end

function goDirFor(bool)
	if bool then
		if dir[nDir] == "+X" then x = x + 1 elseif
		dir[nDir] == "-X" then x = x - 1 elseif
		dir[nDir] == "+Y" then y = y + 1 elseif
		dir[nDir] == "-Y" then y = y - 1 end
	else
		if dir[nDir] == "+X" then x = x - 1 elseif
		dir[nDir] == "-X" then x = x + 1 elseif
		dir[nDir] == "+Y" then y = y - 1 elseif
		dir[nDir] == "-Y" then y = y + 1 end
	end
end

function mineFor()
	while turtle.detect() do
		turtle.dig()
		os.sleep(0.5)
	end
	hasSpace()
	return true
end

function mineUp()
	while turtle.detectUp() do
		turtle.digUp()
		os.sleep(0.5)
	end
	hasSpace()
	return true
end

function mineDown()
	turtle.digDown()
	hasSpace()
	return true
end

function goFor()
	if turtle.forward() then
		goDirFor(true)
		return true
	else
		return false
	end
end

function goBack()
	if turtle.back() then
		goDirFor(false)
		return true
	else
		return false
	end
end

function goUp()
	if turtle.up() then
		z = z + 1
		return true
	else
		return false
	end
end

function goDown()
	if turtle.down() then
		z = z - 1
		return true
	else
		return false
	end
end

function turnRight()
	turtle.turnRight()
	if nDir < 4 then
		nDir = nDir + 1
	else
		nDir = 1
	end
end

function turnLeft()
	turtle.turnLeft()
	if nDir > 1 then
		nDir = nDir - 1
	else
		nDir = 4
	end
end

function stripFor()
	mineUp()
	if turtle.detectUp() then
		while turtle.detectUp() do
			goBack()
			mineUp()
		end
		goUp()
	end
	mineFor()
	while turtle.detect() do
		goUp()
		mineFor()
	end
	mineDown()
	if turtle.detectDown() and not atBedrock then
		atBedrock = true
		print("Hit bedrock.")
	end
	return goFor()
end

function turn()
	print("Turning around, fuel: "..getFuel())
	if tRight then
		turnRight()
		while not stripFor() do
			os.sleep(0.5)
		end
		turnRight()
	else
		turnLeft()
		while not stripFor() do
			os.sleep(0.5)
		end
		turnLeft()
	end
	tRight = not tRight
	dirFor = not dirFor
end

function stripDown()
	for i=1,3 do
		mineDown()
		mineUp()
		if turtle.detectDown() and not atBedrock then
			atBedrock = true
			print("Hit bedrock.")
			break
		end
		goDown()
	end
	turnRight()
	turnRight()
	dirFor = not dirFor
end

function turnTo(str)
	while dir[nDir] ~= str do
		turnRight()
	end
end

function resetPos()
	while z ~= 0 do
		goUp()
	end
	turnTo("-X")
	while x ~= 0 do
		goFor()
	end
	if y < 0 then
		turnTo("+Y")
	else
		turnTo("-Y")
	end
	while y ~= 0 do
		goFor()
	end
	turnTo("+X")
end

function quarry(dx,dy)
	while not atBedrock do
		for i=1,dy do
			if dirFor then
				while x < dx do
					stripFor()
				end
				if i < dy then
					turn()
				end
			else
				while x > 0 do
					stripFor()
				end
				if i < dy then
					turn()
				end
			end
		end
		if not atBedrock then
			stripDown()
		end
	end
	print("Going back to start, fuel: "..getFuel())
	mineDown()
	mineUp()
	resetPos()
	dropOff()
	print("Job done, fuel left: "..getFuel())
end

if #Args == 0 then
	printUsage()
else
	if tonumber(Args[1]) == 0 or tonumber(Args[2]) == 0 then
		printUsage()
	else
		if Args[3] == "right" or Args[3] == "left" then
			if Args[3] == "right" then
				tRight = true
			else
				tRight = false
			end
			quarry(tonumber(Args[1])-1,tonumber(Args[2]))
		else
			printUsage()
		end
	end
end