menu

local items = {}
local width, height = term.getSize()
local selected = 1
local padding = 1
local defaultTerm = term.current()

function addItem(name, callback, arg)
  local item = {}

  item["name"] = name
  item["callback"] = callback
  item["arg"] = arg

  local x = 1 + padding
  local y = nil

  if #items == 0 then
    y = 1 + padding
  else
    y = 2 + (#items) * (1 + padding)
  end

  local w = width - (2 * padding)
  local h = 1

  item["window"] = window.create(defaultTerm, x, y, w, h, true)

  items[#items + 1] = item
end

function createString(length)
  local output = ""

  for i=1,length,1 do
    output = output .. " "
  end

  return output
end

function draw()
  term.setBackgroundColor(colors.blue)
  term.setTextColor(colors.black)
  term.clear()

  for i, v in pairs(items) do
    if v["window"] ~= nil then
      if i == selected then
        v["window"].setBackgroundColor(colors.white)
      else
        v["window"].setBackgroundColor(colors.red)
      end

      v["window"].setTextColor(colors.black)

      local x, y = v["window"].getSize()

      local line = createString(x)

      local textStart = (x/2) - math.ceil(#v["name"]/2)
      local textStop = textStart + #v["name"]

      --v["window"].setCursorPos(1, 1)
      --v["window"].write(line)

      v["window"].setCursorPos(1, 1)
      v["window"].write(createString(textStart) .. v["name"] .. createString(x - textStop))

      --v["window"].setCursorPos(1, 3)
      --v["window"].write(line)

      v["window"].redraw()
    end
  end

  return true
end

function down()
  if selected < #items then
    selected = selected + 1
    draw()

    return true
  end

  return false
end

function up()
  if selected > 1 then
    selected = selected - 1
    draw()

    return true
  end

  return false
end

function getSelectedItem()
  return items[selected]
end