(*---------------------------------------------------------------------------
   Copyright (c) 2024 Anil Madhavapeddy. All rights reserved.
   SPDX-License-Identifier: ISC
  ---------------------------------------------------------------------------*)

module Unknown = struct
  type t = (string * Jsont.json) list

  let empty = []
  let is_empty = function [] -> true | _ -> false
end

type t = { type_ : string; url : string; unknown : Unknown.t }

let create ~type_ ~url ?(unknown = Unknown.empty) () = { type_; url; unknown }
let type_ t = t.type_
let url t = t.url
let unknown t = t.unknown
let equal a b = a.type_ = b.type_ && a.url = b.url
let pp ppf t = Format.fprintf ppf "%s: %s" t.type_ t.url

let jsont =
  let kind = "Hub" in
  let doc = "A hub endpoint" in
  let unknown_mems :
      (Unknown.t, Jsont.json, Jsont.mem list) Jsont.Object.Mems.map =
    let open Jsont.Object.Mems in
    let dec_empty () = [] in
    let dec_add _meta (name : string) value acc =
      ((name, Jsont.Meta.none), value) :: acc
    in
    let dec_finish _meta mems =
      List.rev_map (fun ((name, _meta), value) -> (name, value)) mems
    in
    let enc =
      {
        enc =
          (fun (type acc)
            (f : Jsont.Meta.t -> string -> Jsont.json -> acc -> acc)
            unknown
            (acc : acc)
          ->
            List.fold_left
              (fun acc (name, value) -> f Jsont.Meta.none name value acc)
              acc unknown);
      }
    in
    map ~kind:"Unknown members" Jsont.json ~dec_empty ~dec_add ~dec_finish ~enc
  in
  let create_obj type_ url unknown = create ~type_ ~url ~unknown () in
  Jsont.Object.map ~kind ~doc create_obj
  |> Jsont.Object.mem "type" Jsont.string ~enc:type_
  |> Jsont.Object.mem "url" Jsont.string ~enc:url
  |> Jsont.Object.keep_unknown unknown_mems ~enc:unknown
  |> Jsont.Object.finish