(* Toplevel printers for JMAP types

   Usage in toplevel:
     #require "jmap.top";;

   Printers are automatically installed when the library is loaded.
*)

(* JSON printers *)

let json_printer ppf (json : Jsont.json) =
  match Jsont_bytesrw.encode_string Jsont.json json with
  | Ok s -> Format.pp_print_string ppf s
  | Error e -> Format.fprintf ppf "<json encoding error: %s>" e

let jsont_error_printer ppf (e : Jsont.Error.t) =
  Format.pp_print_string ppf (Jsont.Error.to_string e)

(* JSON encoding helpers *)

let encode (type a) (codec : a Jsont.t) (value : a) : Jsont.json =
  match Jsont.Json.encode codec value with
  | Ok json -> json
  | Error e -> invalid_arg e

let encode_string (type a) (codec : a Jsont.t) (value : a) : string =
  match Jsont_bytesrw.encode_string codec value with
  | Ok s -> s
  | Error e -> invalid_arg e

let pp_as_json (type a) (codec : a Jsont.t) ppf (value : a) =
  json_printer ppf (encode codec value)

(* Automatic printer installation *)

let printers =
  [ "Jmap.Id.pp";
    "Jmap.Keyword.pp";
    "Jmap.Role.pp";
    "Jmap.Capability.pp";
    "Jmap.Error.pp";
    "Jmap_top.json_printer";
    "Jmap_top.jsont_error_printer" ]

(* Suppress stderr during printer installation to avoid noise in MDX tests *)
let null_formatter = Format.make_formatter (fun _ _ _ -> ()) (fun () -> ())

let eval_string_quiet str =
  try
    let lexbuf = Lexing.from_string str in
    let phrase = !Toploop.parse_toplevel_phrase lexbuf in
    Toploop.execute_phrase false null_formatter phrase
  with _ -> false

let rec do_install_printers = function
  | [] -> true
  | printer :: rest ->
      let cmd = Printf.sprintf "#install_printer %s;;" printer in
      eval_string_quiet cmd && do_install_printers rest

let install () =
  (* Silently ignore failures - this handles non-toplevel contexts like MDX *)
  ignore (do_install_printers printers)

(* Only auto-install when OCAML_TOPLEVEL_NAME is set, indicating a real toplevel *)
let () =
  if Sys.getenv_opt "OCAML_TOPLEVEL_NAME" <> None then
    install ()