open Brr

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" ]
  | _ | (exception Invalid_argument _) -> []

let stdin = Document.find_el_by_id G.document (Jstr.v "stdin") |> Option.get
let stdout = Document.find_el_by_id G.document (Jstr.v "stdout") |> Option.get
let prompt = Document.find_el_by_id G.document (Jstr.v "prompt") |> Option.get

let () =
  Eio_js_backend.start @@ fun () ->
  El.append_children (Document.head G.document)
    [ El.style [ El.txt' Ansi.css ] ];
  let ctx = Bruit_brr.stdctx ~redirect:true stdin prompt stdout 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 ~complete ctx prompt with
    | String (Some s) ->
        El.append_children stdout [ El.txt' s ];
        h := s :: !h;
        loop false
    | String None -> ()
    | Ctrl_c -> loop true
  in
  loop false