MystPortal

books = {"First Age", "Second Age", "Third Age"}
tArgs = {...}
if #tArgs ~= 1 then
  print("Syntax: "..shell.getRunningProgram().." <side of monitor>")
  error()
end

monitor = peripheral.wrap(tArgs[1])
monitor.setTextScale(0.5)

chosenBook = 1

function ifthenelse(one,two,three)
   if one then return two else return three end
end

for i=1,#books do
   if turtle.getItemCount(i) == 0 then
      chosenBook = i
   end
end

function drawButtons()
  local offsetX = 2
  local offsetY = 2
  for i=1,#books do
    monitor.setBackgroundColor(ifthenelse(i == chosenBook, colors.green, colors.red))
    for y=0,2 do
      monitor.setCursorPos(offsetX, offsetY + y)
      for x=0,12 do
        monitor.write(" ")
      end
    end
    local textOffset = math.floor((13 - #books[i]) / 2)
    monitor.setCursorPos(offsetX + textOffset, offsetY + 1)
    monitor.write(books[i])
    offsetY = offsetY + 4
  end
end

function checkButtons(x, y)
  local offsetX = 2
  local offsetY = 2
  for i=1,#books do
    if x >= offsetX and x <= offsetX + 12 then
      if y >= offsetY and y <= offsetY + 2 then
        turtle.suck()
        turtle.select(i)
        turtle.drop()
        chosenBook = i
      end
    end
    offsetY = offsetY + 4
  end
end

monitor.setBackgroundColor(colors.black)
monitor.clear()
drawButtons()

while true do
  local event, side, xPos, yPos = os.pullEvent("monitor_touch")
  monitor.setBackgroundColor(colors.black)
  monitor.clear()
  checkButtons(xPos, yPos)
  drawButtons()
end