Turtle Miner

programs = {"stairs", "strip", "exit"}

function contains(table, element)
  for _, value in pairs(table) do
    if value == element then
      return true
    end
  end
  return false
end

function threeRound(num)
  if num > 0 then
    return math.ceil(num/3.0) * 3;
  elseif num < 0 then
    return math.floor(num/3.0) * 3;
  else
    return 3;
  end
end

function stairs()
  print("stairs - test")
end

function strip()
  print("Enter length of tunnel: ")
  len = threeRound(tonumber(read()))
  print(len)
  if len > 0 then
    turtle.digUp()
    turtle.up()
    for i = 1, len do
      if i % 3 == 0 then
        turtle.turnLeft()
        for j = 1, 5 do
          turtle.dig()
          turtle.forward()
          if j == 5 then
            turtle.turnRight()
            turtle.turnRight()
            for k = 0, j-1 do
              turtle.forward()
            end
          end
        end
        for j = 1, 5 do
          turtle.dig()
          turtle.forward()
          if j == 5 then
            turtle.turnRight()
            turtle.turnRight()
            for k = 0, j-1 do
              turtle.forward()
            end
          end
        end
        turtle.turnRight()
      end
      if i % 6 == 0 then
        turtle.placeDown()
      end
      turtle.dig()
      turtle.forward()
      turtle.digDown()
    end
  else
    print("Length of tunnel must be bigger than 0")
    strip()
  end
end

function getProg()
  input = read()
  if contains(programs, input) then
    if input == "stairs" then
        stairs()
    elseif input == "strip" then
        strip()
    elseif input == "exit" then
        print("Goodbye")
    end
  else
    print("Invalid program!")
    getProg()
  end
end

function start()
  print("Enter password: ")
    pass = read()
    if pass == "dw20" then
        print("Correct password!")
        print("Type the name of a program to start:")
        for program in pairs(programs) do
            print(program .. ". - " .. programs[program])
        end
        getProg()
    else
        print("Wrong password!")
        start()
    end
end

start()