Strip mine

Args = {...}
x,y = 0,0
dir = { [1]="+X", [2]="+Y", [3]="-X", [4]="-Y" }
nDir = 1

function printUsage()
	print("Usage:")
	print("strip <BLOCKS> <WIDE> <left/right>")
	print("Strip mines <BLOCKS> blocks infront and <WIDE> blocks to the side.")
end

function printFail()
	print("Failed at a task.")
end

function hasSpace()
	local space = false
	for i=1,16 do
		if turtle.getItemCount(i) == 0 then
			space = true
		end
	end
	return space
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.digDown()
	turtle.select(1)
	if turtle.placeDown() then
		for i=2,16 do
			turtle.select(i)
			turtle.dropDown()
		end
		turtle.select(1)
		turtle.digDown()
	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
	if not hasSpace() then dropOff() end
	return true
end

function mineUp()
	while detectUp() do
		turtle.digUp()
		os.sleep(0.5)
	end
	if not hasSpace() then dropOff() end
	return true
end

function mineDown()
	turtle.digDown()
	if not hasSpace() then dropOff() end
	return true
end

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

function goBack()
	if turtle.back() then
		goDirFor(false)
	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 detectFor()
	return turtle.detect()
end

function detectUp()
	return turtle.detectUp()
end

function detectDown()
	return turtle.detectDown()
end

function mine()
	mineFor()
	mineUp()
	mineDown()
	goFor()
end

function stripFor()
	if dirFor then
		while x < blocksfor do
			mineFor()
			mineUp()
			mineDown()
			goFor()
		end
	else
		while x > 0 do
			mineFor()
			mineUp()
			mineDown()
			goFor()
		end
	end
end

function resetPos()
	while dir[nDir] ~= "-X" do
		turnRight()
	end
	while x ~= 0 do
		goFor()
	end
	if y < 0 then
		while dir[nDir] ~= "+Y" do
			turnLeft()
		end
	else
		while dir[nDir] ~= "-Y" do
			turnLeft()
		end
	end
	while y ~= 0 do
		goFor()
	end
	if dir[nDir] == "+Y" then
		turnRight()
	elseif dir[nDir] == "-Y" then
		turnLeft()
	end
end

function stripMine(num)
	for i=1,num do
		stripFor()
		if i < num then
			print("Turning around, fuel: "..getFuel())
			if boolTurnRight then
				turnRight()
				mine()
				turnRight()
			else
				turnLeft()
				mine()
				turnLeft()
			end
			boolTurnRight = not boolTurnRight
			dirFor = not dirFor
		end
	end
	mineUp()
	mineDown()
	print("Going back to start, fuel: "..getFuel())
	resetPos()
	dropOff()
	print("Job done, fuel: "..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
				boolTurnRight = true
			else
				boolTurnRight = false
			end
			blocksfor = tonumber(Args[1]) - 1
			dirFor = true
			stripMine(tonumber(Args[2]))
		end
	end
end