type fancyobj = <
  to_string : unit -> string;
  to_html : unit -> string
>;;

let sepx = "\xe2\xbf\x96";;
let endx = "\xe2\xbf\x97";;

let socket_name = "/tmp/fancy.log";;

let html_enabled = Sys.file_exists socket_name;;

let socket = let open Unix in
  if html_enabled
  then socket PF_UNIX SOCK_STREAM 0
  else socket PF_INET SOCK_STREAM 0;;

let html_enabled = if html_enabled then
  try
    let _ = Unix.connect socket (Unix.ADDR_UNIX socket_name) in true
  with Unix.Unix_error _ -> false
  else false
;;

let cols =
  let process_output_to_list2 = fun command ->
    let chan = Unix.open_process_in command in
    let res = ref ([] : string list) in
    let rec process_otl_aux () =
      let e = input_line chan in
      res := e::!res;
      process_otl_aux() in
    try process_otl_aux ()
    with End_of_file ->
      let stat = Unix.close_process_in chan in (List.rev !res,stat)
  in let cmd_to_list command =
    let (l,_) = process_output_to_list2 command in l
  in try let lines = cmd_to_list "tput cols" in int_of_string (List.hd (lines))
  with _ -> 100 (* default value *)
;;

let writeall s =
  let _ = Unix.send socket s 0 (String.length s) [] in ()
;;

let concat ls = (String.concat sepx ls) ^ endx;;

(* HELO message *)
if html_enabled then
  writeall(concat["helo"; String.concat " " (Array.to_list Sys.argv)])
;;


(* let logs objs =
  if html_enabled then (
    let strs = (List.map (fun x -> x#to_html()) objs) in
    writeall (concat ("log" :: strs))
  ); prerr_endline (String.concat " " (List.map (fun x -> x#to_string()) objs))
;; *)

let html_escape s =
  let m = [("&", "&amp;"); (">", "&gt;"); ("<", "&lt;"); ("&quot;", "\""); ("&#39;", "'")]
  in let m = List.map (fun (x,y) -> Str.regexp x, y) m
  in List.fold_right (fun (x,y) z -> Str.global_replace x y z) m s;; (* FIXME TODO *)

let fancy_of_string s : fancyobj = object
  method to_string () = s
  method to_html () = html_escape s
end;;

let empty = fancy_of_string "";;

let line = ref empty;;

let (/) a b = object
  method to_string () = a
  method to_html () = b
end;;

let (^^) a b = object
  method to_string () = (a#to_string () ^ "" ^ b#to_string ())
  method to_html () = a#to_html () ^ " " ^ b#to_html ()
end;;

(* Output functions on standard output *)

let print_string s =
  line := !line ^^ fancy_of_string s
;;

let print_char c =
  print_string (String.make 1 c)
;;

(* let print_bytes : bytes -> unit *)

let print_int n =
  print_string (string_of_int n)
;;

(* val print_float : float -> unit *)

let print_newline () =
  if !line <> empty then (
  Pervasives.print_endline (!line#to_string());
  if html_enabled then (writeall (concat ["log"; !line#to_html()]));
  line := empty
  )
;;

let print f =
  line := !line ^^ f
;;

let print_string_endline f =
  print (fancy_of_string f); print_newline ()
;;

let print_endline f =
  print f; print_newline ()
;;

let print_hline () =
  print_newline ();
  print_endline ( String.make cols '-' / "<hr>")
;;

let print_heading s =
  print_newline ();
  print_endline (("# " ^ s) / ("<h2>" ^ html_escape s ^ "</h2>"))
;;

let print_bullet f =
  print_newline ();
  print_endline (("- " / "<ul><li>") ^^ f ^^ ("" / "</ul>"))
;;

let print_math s =
  print_endline ( s / "" );
  if html_enabled then (writeall (concat ["math"; s]))
;;