open Syntax

type t = {
  lock: Miou.Mutex.t;
  sm_key: Signkey.t;
  denom_ht: (Bin_type.DenominationHash.t, Denomination.t) Hashtbl.t;
}

let get_sm_key t = t.sm_key

let get_denoms t =
  Miou.Mutex.protect t.lock @@ fun () ->
  Hashtbl.to_seq_values t.denom_ht |> List.of_seq

let add_master_signatures conn t l =
  Miou.Mutex.protect t.lock @@ fun () ->
  list_iter
    (fun (h_denom_pub, master_sig) ->
      match Hashtbl.find_opt t.denom_ht h_denom_pub with
      | None -> Error "secmod_denom failure: denomination hash not found."
      | Some denom ->
          let denom = { denom with master_sig= Some master_sig } in
          let* () = Pg.add_denomination_key conn denom |> unwrap_err_caqti in
          Hashtbl.replace t.denom_ht h_denom_pub denom;
          Ok ())
    l

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
  get_denoms t
  |> List.mapi (fun i key ->
      let fname = Fpath.(dir / string_of_int i) in
      (fname, key.Denomination.priv))
  |> list_iter (fun (fname, key) -> Data_file.write_rsa fname key)

let load conn =
  let error_invalid_state =
    Fmt.error_msg "secmod_denom load error: invalid store state."
  in
  let* sm_key = Data_file.load_signkey conn Fpath.(dir / "sm_key") in
  let* denoms =
    let* l =
      let open Config.Coin in
      Syntax.list_map
        (fun coin ->
          let section_name = coin.section_name in
          let fname = Fpath.(dir / section_name) in
          (* todo: could check that coin config match db values *)
          Data_file.load_denom conn ~section_name fname)
        all_coins
    in
    match Syntax.opt_list l with
    | Error () -> error_invalid_state
    | Ok opt -> Ok opt
  in
  match (sm_key, denoms) with
  | None, None -> Ok None
  | Some sm_key, Some denoms ->
      let lock = Miou.Mutex.create () in
      let denom_ht =
        denoms
        |> List.map (fun v -> (v.Denomination.h_pub, v))
        |> List.to_seq
        |> Hashtbl.of_seq
      in
      Ok (Some { lock; sm_key; denom_ht })
  | _, _ -> error_invalid_state

let make_new () =
  let lock = Miou.Mutex.create () in
  let sm_key = Signkey.make () in
  let denoms = List.map Denomination.make Config.Coin.all_coins in
  let denom_ht =
    denoms
    |> List.map (fun v -> (v.Denomination.h_pub, v))
    |> List.to_seq
    |> Hashtbl.of_seq
  in
  { lock; sm_key; denom_ht }

let init conn =
  match load conn with
  | Ok None ->
      let t = make_new () in
      Logs.info (fun m -> m "secmod_denom initialized with fresh keys");
      t
  | Ok (Some v) ->
      Logs.info (fun m -> m "secmod_denom initialized from storage");
      v
  | Error _ -> Fmt.failwith "secmod_denom init failure."