use std::stream::const
use std::stream::head
use gui::widget::*

let on_5_seconds = {
  let aux = fn prev -> {
    let second = gui::time::timestamp_millis () / 5000;
    if !(second == prev) then 
      true << @(aux second)
    else 
      false << @(aux prev)
  };
  aux 0
}

use data::usernames

let ui = gui::frame (100,50)

let (up_id, up_stream) = button ui (100, 50) (const "UP")
let (down_id, down_stream) = button ui (100, 50) (const "DOWN")

let index = {
  let aux = fn curr -> {
    let delta = if head on_5_seconds || head up_stream then 
      1
    else if head down_stream then
      -1
    else 
      0
   ;
   curr << @(aux ((curr + delta) % 10))
  };
  aux 0
}

let (lab_id, lab_stream) = label ui (100, 100) (std::stream::map #(fn n -> data::get_nth (usernames, n)) index)
let (grp_id, grp_stream) = hgroup 
  ui 
  (300,150) 
  (const [lab_id, up_id, down_id]) 
  (Alignment::Top)

let _ = gui::attach_root (ui, grp_id)