2x2 Tunnel

local args = { ... }
-- Distance Variable
local distance = tonumber(args[1])
-- Fuel needed Variable
local fuelNeeded = (distance / 2) * 4
-- Torches needed variable
local torchNeeded = distance / 10

-- Check Amount of Fuel Function
local function checkFuel()
	while (turtle.getFuelLevel() < fuelNeeded) do
		turtle.select(1)
		if (turtle.getItemCount(1) == 0) then
			print("Not enough fuel to complete operation...")
			return false
		end
		turtle.refuel(1)
	end
	return true
end

-- Check Amount of Torches Function
local function checkTorches()
	if (turtle.getItemCount(2) < torchNeeded) then
		print ("Not enough torches to complete operation...")
		return false
	end
	return true
end

-- Detect & Dig Function
local function dig()
	while (turtle.detect()) do
		turtle.dig()
		sleep(0.5)
	end
end

-- Move Left & Dig Function
local function left()
	turtle.forward()
	turtle.digDown()
	turtle.turnLeft()
end

-- Move Right & Dig Function
local function right()
	turtle.forward()
	turtle.digDown()
	turtle.turnRight()
end

-- Main Function | Digs Tunnel
local function digTunnel()
	print("StartUp Complete. Commencing digging operations..")
	local t = 0
	local i = 0
	while (i < distance) do
		dig()
		right()
		dig()
		left()
		dig()
		left()
		dig()
		right()
		t = t + 2
		if (t == 10) then
			turtle.select(2)
			turtle.placeDown()
			t = 0
		end
		i = i + 2
	end
end

if checkFuel() and checkTorches() then
	digTunnel()
end