(** Parser for validator/tests/messages.json *)

type t = (string, string) Hashtbl.t
(** Maps test file path to expected error message *)

let json_string = function
  | Jsont.String (s, _) -> s
  | _ -> failwith "Expected string"

let json_object = function
  | Jsont.Object (obj, _) -> obj
  | _ -> failwith "Expected object"

let load path =
  let messages = Hashtbl.create 4096 in
  let ic = open_in path in
  let content = really_input_string ic (in_channel_length ic) in
  close_in ic;

  (* Parse JSON *)
  let json = match Jsont_bytesrw.decode_string Jsont.json content with
    | Ok j -> j
    | Error e -> failwith (Printf.sprintf "JSON parse error: %s" e)
  in
  let obj = json_object json in
  List.iter (fun ((key, _), value) ->
    let msg = json_string value in
    Hashtbl.replace messages key msg
  ) obj;
  messages

let get messages path =
  Hashtbl.find_opt messages path

let count messages =
  Hashtbl.length messages