(* TODO
     - key rotation
     - how many signkey to use?
       we just use 1 for now *)
open Syntax

type t = {
  sm_key: Signkey.t;
  keys: Signkey.t list;
}

let dir = Fpath.(v "data" / "secmod_signkey")

let store_secmod_data t =
  let* () = Data_file.write_eddsa Fpath.(dir / "sm_key") t.sm_key.priv in
  t.keys
  |> List.mapi (fun i key ->
      let fname = Fpath.(dir / string_of_int i) in
      (fname, key.Signkey.priv))
  |> list_iter (fun (fname, key) -> Data_file.write_eddsa fname key)

let load conn =
  let error_invalid_state =
    Fmt.error_msg "secmod_signkey load error: invalid store state."
  in
  let* sm_key = Data_file.load_signkey conn Fpath.(dir / "sm_key") in
  let* keys =
    let l = List.init 1 (fun i -> Fpath.(dir / string_of_int i)) in
    let* l =
      Syntax.list_map (fun fname -> Data_file.load_signkey conn fname) l
    in
    match Syntax.opt_list l with
    | Error () -> error_invalid_state
    | Ok opt -> Ok opt
  in
  match (sm_key, keys) with
  | None, None -> Ok None
  | Some sm_key, Some keys -> Ok (Some { sm_key; keys })
  | _, _ -> error_invalid_state

let make_new () =
  let sm_key = Signkey.make () in
  let keys = [ Signkey.make () ] in
  { sm_key; keys }