mine adv

function fuel()
    fuelLevel = turtle.getFuelLevel()
        if fuelLevel == "unlimited" or fuelLevel > 10 then
            return
        end

    function tryRefuel()
        for n=4,16 do
            if turtle.getItemCount(n) > 0 then
                turtle.select(n)
                if turtle.refuel(1) then
                    print("Fuel: "..turtle.getFuelLevel().."")
                    turtle.select(2)
                    return true
                end
            end
        end
        turtle.select(2)
        return false
    end

    if not tryRefuel() then
        print( "Add more fuel to continue." )
            while not tryRefuel() do
                sleep(1)
            end
        print( "Resuming Tunnel." )
    end
end

function turn()
    turtle.turnRight()
    turtle.turnRight()
end

function dig()
    turtle.dig()
    sleep(1)
end

function tunnel()
    turtle.digUp()
    turtle.select(2)
    turtle.placeDown()
    turtle.turnLeft()
    turtle.detect()
    turtle.place()
    turtle.turnLeft()
    turtle.turnLeft()
    turtle.detect()
    turtle.place()
    turtle.turnLeft()
end

function torch()
    if distance == 10 then
        turtle.select(2)
            while turtle.up() == false do
                turtle.digUp()
                sleep(1)
            end
        turtle.turnLeft()
        turtle.dig()
        sleep(1)
            while turtle.forward() == false do
                turtle.dig()
                sleep(1)
            end
        turtle.place()
        turtle.placeUp()
        turtle.back()
        turtle.select(3)
        turtle.place()
        turtle.turnRight()
        turtle.down()
        distance = 0
    end
end

function chest()
    for n = 5, 16 do
        turtle.getItemCount()
    end
        if not turtle.getItemCount(n) == 0 then
            turn()
            turtle.select(1)
            turtle.place()
                for n = 5, 16 do
                    turtle.drop()
                    sleep(1)
                end
            turtle.dig()
            turn()
        end
end

function back()
    turtle.up()
    turn()
        while  j > 1 do
            if turtle.forward() == true then
                fuel()
                j = j - 1
            else
                dig()
            end
        end
    turtle.down()
    turn()
end

    -- Main-Script --
print("Slot 1: Enderchest")
print("Slot 2: Cobblestone")
print("Slot 3: Torch")
print("Slot 4: Coal")
print("Fuel: "..turtle.getFuelLevel().."")
write("Tunnel length: ")
length = tonumber(read())
print("Starting...")
i = 1
j = 1
distance = 1
    while i <= length do
        if turtle.forward() == true then
            fuel()
            chest()
            tunnel()
            torch()
            i = i + 1
            j = j + 1
            distance = distance +1
        else
            dig()
        end
    end
back()
print("Done...")