menu

---------------
-- Variables --
---------------

local termWidth, termHeight = term.getSize ()
local selectedItem = 1
local inMainMenu = true
local inLightsMenu = false

---------------
-- Functions --
---------------

function Choice1 ()

  term.clear ()
  term.setCursorPos (1, 1)
  term.write ("Hello, my name is "..os.getComputerLabel ())

  sleep (3)

end

function Choice2 ()

  inLightsMenu = true
  selectedItem = 1

  while inLightsMenu do

    term.clear ()
    term.setCursorPos (1, 1)

    printMenu (lightsMenu)

    event, key = os.pullEvent ("key")

    onKeyPressed (key, lightsMenu)

  end

end

function LightsOn ()

  inLightsMenu = false

end

function LightsOff ()

  inLightsMenu = false

end

function Exit ()

  inMainMenu = false

end

---------------
-- Main Menu --
---------------

local mainMenu = {

  [1] = {text = "Choice 1", handler = Choice1},
  [2] = {text = "Choice 2", handler = Choice2},
  [3] = {text = "Exit"    , handler = Exit},

}

local lightsMenu = {

  [1] = {text = "Lights On" , handler = LightsOn},
  [2] = {text = "Lights Off", handler = LightsOff},

}

--DebugLine, says lightsMenu is not nil, but error thinks it's nil???
if (lightsMenu == nil) then print ("True") else print ("Not nil")end

sleep (3)

--------------------
-- Screen Refresh --
--------------------

function printMenu (menu)

  for i = 1, #menu do

    if (i == selectedItem) then

      print ("> "..menu[i].text)

    else

      print ("  "..menu[i].text)

    end

  end

end

--------------
-- Handlers --
--------------

function onKeyPressed (key, menu)

  if (key == keys.enter) then

    onItemSelected (menu)

  elseif (key == keys.up and selectedItem > 1) then

    selectedItem = selectedItem - 1

  elseif (key == keys.down and selectedItem < #menu) then

    selectedItem = selectedItem + 1

  end

end

function onItemSelected (menu)

  menu[selectedItem].handler ()

end

-----------------
-- Main Method --
-----------------

function main ()

  while inMainMenu do

    term.clear ()
    term.setCursorPos (1, 1)

    printMenu (mainMenu)

    event, key = os.pullEvent ("key")

    onKeyPressed (key, mainMenu)

  end

end

main ()