open Syntax
open Crypto

let read fname = Bos.OS.File.read fname |> unwrap_err_msg
let write fname s = Bos.OS.File.write fname s |> unwrap_err_msg

let read_eddsa fname =
  let* data = read fname in
  EddsaPrivateKey.of_octets data

let write_eddsa fname priv = write fname (EddsaPrivateKey.to_octets priv)

module Config = struct
  (* TODO config *)
  open Config.Exchange_secmod_eddsa

  let dir = Config.secmod_eddsa_dir
  let lookahead_sign = lookahead_sign
  let overlap_duration = overlap_duration
  let duration = duration
end

open Mirage_crypto_ec

type priv = Ed25519.priv
type pub = Ed25519.pub

type t = {
  priv: priv;
  pub: pub;
  start: Timestamp.t;
  end_: Timestamp.t;
}

(*
  create dir if not exists
  read dir contents
  init sm_key
  check filename
  build sorted list
  check overlaps
  just fail if not good
  add keys until lookahead



  - sign
  - verify
  - expose future_sk list
  - purge
  - schedule tasks
  - !lock

  todo taler doc/config is confusing
  how is computed stamp_expire stamp_end
  what to do of 'Exchange.signkey_legal_duration'
  => (??)
    stamp_expire = stamp_start + duration
    stamp_end = stamp_start + signkey_legal_duration
*)