type privmsg = {
  pm_from : string;
  pm_text : string;
}

type user = {
  mutable nick : string option;
  inbox : notif Lwt_stream.t;
  push_inbox : (notif option -> unit);
}

and notif = privmsg

let make_user () =
  let inbox, push_inbox = Lwt_stream.create () in
  { nick = None; inbox; push_inbox }

let notify u no = u.push_inbox (Some no)

type t = {
  users : (string, user) Hashtbl.t
  (* TODO: channels *)
}

let make () =
  { users = Hashtbl.create 4096 }

let register t ~nick ~user =
  if Hashtbl.mem t.users nick then
    `inuse
  else begin
    Option.iter (Hashtbl.remove t.users) user.nick;
    Hashtbl.add t.users nick user;
    user.nick <- Some nick;
    `ok
  end

let leave t user =
  Option.iter (Hashtbl.remove t.users) user.nick