Tunnel

local length = 200

local function refuel()
    if turtle.getFuelLevel() < 50 then
        local prev = turtle.getSelectedSlot()
        turtle.select(1)
        if not turtle.refuel(4) then
            print('Need more fuel')
            while not turtle.refuel(4) do
                sleep(1)
            end
        end
        turtle.select(prev)
    end
end

local function tryForwards()
	refuel()
	while not turtle.forward() do
		if turtle.detect() then
			turtle.dig()
			sleep(.5)
			while turtle.detect() do
				turtle.dig()
				sleep(.5)
			end
		elseif turtle.attack() then
		else
			sleep(1)
		end
	end
end

local function tryUp()
	refuel()
	while not turtle.up() do
		if turtle.detectUp() then
			turtle.digUp()
			sleep(.5)
			while turtle.detectUp() do
				turtle.digUp()
				sleep(.5)
			end
		elseif turtle.attackUp() then
		else
			sleep(1)
		end
	end
end

local function tryDown()
	refuel()
	while not turtle.down() do
		if turtle.detectDown() then
			turtle.digDown()
		elseif turtle.attackDown() then
		else
			sleep(1)
		end
	end
end

local function turnAround()
	turtle.turnLeft()
	turtle.turnLeft()
end

local function level()
	tryForwards()
	turtle.turnLeft()

	tryForwards()
	tryUp()
	turtle.digUp()

	tryForwards()
	tryUp()

	tryForwards()
	tryUp()

	turnAround()
	turtle.digUp()
	tryForwards()
	turtle.dig()
	tryUp()

	turtle.dig()
	tryUp()
	tryForwards()

	tryUp()
	tryForwards()
	turtle.dig()
	tryDown()
	turtle.digDown()
	tryForwards()
	turtle.dig()
	tryDown()
	tryForwards()
	turtle.dig()
	tryDown()
	turtle.dig()
	turnAround()
	tryForwards()
	turtle.dig()
	tryDown()
	turtle.dig()
	turnAround()
	tryForwards()
	turtle.dig()
	tryDown()
	turnAround()
	tryForwards()
	turtle.dig()
	tryDown()
	tryForwards()
	turtle.turnRight()


end

for i=1, length, 1 do
	level()
end