let h = ref []

let history prefix =
  if prefix <> "" then List.filter (fun s -> String.starts_with ~prefix s) !h
  else !h

let complete s =
  match String.get s 0 with
  | 'h' -> [ "hello"; "hello there"; "heya" ]
  | _ | (exception Invalid_argument _) -> []

let hint s =
  if s = "" then None
  else if String.starts_with ~prefix:s "hello" then
    let len = String.length s in
    Some (String.sub "hello" len (5 - len), `Fg `Cyan)
  else None

let () =
  Fmt_tty.setup_std_outputs ();
  let ctx = Bruit_unix.stdctx ~hint () in
  let rec loop sys_break =
    let prompt =
      if sys_break then "[\x1b[31m130\x1b[0m] \x1b[33m>>\x1b[0m "
      else "\x1b[33m>>\x1b[0m "
    in
    match Bruit.run ~history ~hint ~complete ctx prompt with
    | String (Some s) ->
        let _ : int = Unix.write_substring Unix.stdout s 0 (String.length s) in
        let _ : int = Unix.write_substring Unix.stdout "\n" 0 1 in
        h := s :: !h;
        loop false
    | String None -> ()
    | Ctrl_c -> loop true
  in
  loop false