#!/usr/bin/lua5.3

function main(arg)
	validateInput(arg)
	startMining(math.floor(arg[1]))
end

function validateInput(arg)
	if #arg < 1
	then
		print("Too few arguments!")
		showUsage()
	elseif #arg > 1
	then
		print("Too many arguments!")
		showUsage()
	elseif not tonumber(arg[1])
	then
		print("The parameter you provided was not numeric!")
		showUsage()
        elseif (tonumber(arg[1]) ~= math.floor(arg[1]))
        then
                print("Only whole numbers are allowed!")
		showUsage()
	elseif tonumber(arg[1]) < 1
	then
		print("No work to do! Enter a number greater than 0!")
		showUsage()
	end
end

function showUsage()
	print("Usage: spiral " .. "<int number of complete cycles>")
	os.exit()
end

function checkFuel()
	if turtle.getFuelLevel() == 0
	then
		burnFuel()
	end
end

function burnFuel()
	for i = 1, 16, 1
	do
		turtle.select(i)
		if turtle.refuel(1)
		then
			break
		end
	end
	if turtle.getFuelLevel() == 0
	then
		print("Fatal Error: Out of fuel")
		os.exit()
	end
end

function digOut()
	turtle.turnLeft()
	while turtle.detect()
	do
		turtle.dig()
	end
	turtle.turnRight()
	turtle.turnRight()
	while turtle.detect()
	do
		turtle.dig()
	end
	turtle.turnLeft()
	while turtle.detectDown()
	do
		turtle.digDown()
	end
	while turtle.detectUp()
	do
		turtle.digUp()
	end
	while turtle.detect()
	do
		turtle.dig()
	end
	checkFuel()
	while not turtle.forward()
	do
		turtle.dig()
	end
end

function startMining(cycles)
	local n = 0
	local c = 3
	while n < cycles
	do
		for i = 1, 4, 1
		do
			for j = 1, c, 1
			do
				digOut()
			end
			c = c + 3
			turtle.turnRight()
		end
		n = n + 1
	end
end


args = {...}
main(args)