params = {...}

tunnelDistance = tonumber(params[1] or 10)
turtlePos = vector.new(0,0,0)

function checkSlot()
    currSlot = turtle.getSelectedSlot()
    if turtle.getItemCount(currSlot) == 0 then
        for i = 1,16 do
            if turtle.getItemCount(i) > 0 then
                turtle.select(i)
                return true
            end
        end
        return false
    end
    return true
end

turtle.select(1)

while turtlePos.y ~= tunnelDistance do
    turtle.dig()
    turtle.forward()

    turtle.placeDown()
    checkSlot()

    turtle.turnLeft()
    turtle.place()
    checkSlot()

    turtle.turnRight()
    turtle.turnRight()
    turtle.place()
    checkSlot()

    turtle.turnLeft()

    turtlePos.y = turtlePos.y + 1
end

turtle.placeDown()
checkSlot()

turtle.turnLeft()
turtle.place()
checkSlot()

turtle.turnRight()
turtle.turnRight()
turtle.place()
checkSlot()

turtle.up()
turtle.turnRight()

while turtlePos.y ~= 0 do
    turtle.dig()
    turtle.forward()

    turtle.placeUp()
    checkSlot()

    turtle.turnLeft()
    turtle.place()
    checkSlot()

    turtle.turnRight()
    turtle.turnRight()
    turtle.place()
    checkSlot()

    turtle.turnLeft()

    turtlePos.y = turtlePos.y - 1
end