t = turtle
function moveForward()
    if t.detect() then
        t.dig()
        t.forward()
    else
        t.forward()
    end
end
function moveUpward()
    if t.detectUp() then
        t.digUp()
        t.up()
    else
        t.up()
    end
end
function moveDownward()
    if t.detectDown() then
        t.digDown()
        t.down()
    else
        t.down()
    end
end
function fuelTurtle(distance)
    t.refuel((distance/80)+1)
end
function moveDistanceForward(distance)
    while distance > 0 do
        moveForward()
        distance = distance - 1
    end
end
function moveDistanceUpward(distance)
    while distance > 0 do
        moveUpward()
        distance = distance - 1
    end
end
function moveDistanceDownward(distance)
    while distance > 0 do
        moveDownward()
        distance = distance - 1
    end
end
function distanceInput()
  print("Input distance: ")
  num = io.read()
  num = tonumber(num)
  return num
end
function turnAround()
    t.turnLeft()
    t.turnLeft()
end
function moveUp()
    if t.detectUp() then
        t.digUp()
        t.up()
    else
        t.up()
    end
end
---------------
function shaft()
    distance = distanceInput()
    fuelTurtle(distance*2)
    moveDistanceForward(distance)
    moveUp()
    turnAround()
    moveDistanceForward(distance)
end

function hole()
    distance = distanceInput()
    print("Return? 0 = no, 1 = yes")
    yon = tonumber(io.read())
    fuelTurtle(distance)
    moveDistanceDownward(distance)
    fuelTurtle(distance)
    if not yon == 0 then
        moveDistanceUpward(distance)
    end
end
--------------
function main()
    print("1 = Shaft, 2 = Hole")
    func = io.read()
    func = tonumber(func)
    if func == 1 then
        shaft()
    elif func == 2 then
        hole()
    else
        print("Please input a valid function")
    end
end

main()