(* https://docs.taler.net/core/api-common.html#binary-formats

   - numeric values are in network byte order (big endian) *)

(* TODO
   use Bin.seq instead of Bin.bytes?
   less boilerplate (just make type t abstract)?
   padding issues?
   how to encode union?
   test *)

(* -- Time -- *)

module Time = struct
  module Absolute = struct
    type t = { timestamp_us: int64 }
    type t_nbo = { abs_value_us__: int64 }

    let bin =
      let open Bin in
      record (fun timestamp_us -> { timestamp_us })
      |+ field neint64 (fun t -> t.timestamp_us) (* not BE here? *)
      |> sealr

    let nbo_bin =
      let open Bin in
      record (fun abs_value_us__ -> { abs_value_us__ })
      |+ field beint64 (fun t -> t.abs_value_us__)
      |> sealr
  end

  module Relative = struct
    type t = { timestamp_us: int64 }
    type t_nbo = { rel_value_us__: int64 }

    let bin =
      let open Bin in
      record (fun timestamp_us -> { timestamp_us })
      |+ field neint64 (fun t -> t.timestamp_us)
      |> sealr

    let nbo_bin =
      let open Bin in
      record (fun rel_value_us__ -> { rel_value_us__ })
      |+ field beint64 (fun t -> t.rel_value_us__)
      |> sealr
  end
end

(* -- Cryptographic primitives -- *)

module Hash_code = struct
  (* usually SHA-512 *)
  type t = { hash: string (* = uint8_t hash[64] *) }

  let bin =
    let open Bin in
    record (fun hash -> { hash }) |+ field (bytes 64) (fun t -> t.hash) |> sealr
end

module Short_hash_code = struct
  type t = { hash: string }

  let bin =
    let open Bin in
    record (fun hash -> { hash }) |+ field (bytes 32) (fun t -> t.hash) |> sealr
end

module MAKE_H (H : sig
  type t

  val bin : t Bin.t
end) =
struct
  type t = { hash: H.t }

  let bin =
    let open Bin in
    record (fun hash -> { hash }) |+ field H.bin (fun t -> t.hash) |> sealr
end

module Denomination_hash = MAKE_H (Hash_code)
module Private_contract_hash = MAKE_H (Hash_code)
module Extensions_policy_hash = MAKE_H (Hash_code)
module Merchant_wire_hash = MAKE_H (Hash_code)

(* Hash over a full payto://-URI, including receiver-name
   (and possibly BIC and other optional fields). *)
module Full_payto_hash = MAKE_H (Short_hash_code)

(* Hash over a normalized payto://-URI, including all optional
   fields and also with account-part canonicalized (so no BIC). *)
module Normalized_payto_hash = MAKE_H (Short_hash_code)

(* Hash over:
     a) the hash of the denomination's public key,
     b) an enum value identifying the cipher, and
     c) cipher-dependant blinded information.
   See implementation of `TALER_coin_ev_hash`
   in libtalerexchange for details. *)
module Blinded_coin_hash = MAKE_H (Hash_code)
module Coin_pub_hash = MAKE_H (Hash_code)
module Output_commitment_hash = MAKE_H (Hash_code)

module MAKE_EDDSA_PUB () = struct
  type t = { eddsa_pub: string }

  let bin =
    let open Bin in
    record (fun eddsa_pub -> { eddsa_pub })
    |+ field (bytes 32) (fun t -> t.eddsa_pub)
    |> sealr
end

module MAKE_EDDSA_PRIV () = struct
  type t = { eddsa_priv: string }

  let bin =
    let open Bin in
    record (fun eddsa_priv -> { eddsa_priv })
    |+ field (bytes 32) (fun t -> t.eddsa_priv)
    |> sealr
end

module MAKE_EDDSA_SIG () = struct
  (* 64 bytes *)
  type t = { eddsa_signature: string }

  let bin =
    let open Bin in
    record (fun eddsa_signature -> { eddsa_signature })
    |+ field (bytes 64) (fun t -> t.eddsa_signature)
    |> sealr
end

module MAKE_ECDHE_PUB () = struct
  type t = { ecdhe_pub: string }

  let bin =
    let open Bin in
    record (fun ecdhe_pub -> { ecdhe_pub })
    |+ field (bytes 32) (fun t -> t.ecdhe_pub)
    |> sealr
end

module MAKE_ECDHE_PRIV () = struct
  type t = { ecdhe_priv: string }

  let bin =
    let open Bin in
    record (fun ecdhe_priv -> { ecdhe_priv })
    |+ field (bytes 32) (fun t -> t.ecdhe_priv)
    |> sealr
end

module Ecdh_ephemeral_public_key_p = struct
  type t = { ecdh_pub: string (* = uint8_t ecdh_pub[32] *) }

  let bin =
    let open Bin in
    record (fun ecdh_pub -> { ecdh_pub })
    |+ field (bytes 32) (fun t -> t.ecdh_pub)
    |> sealr
end

module Reserve_public_key_p = MAKE_EDDSA_PUB ()
module Reserve_private_key_p = MAKE_EDDSA_PRIV ()
module Reserve_signature_p = MAKE_EDDSA_SIG ()
module Merchant_public_key_p = MAKE_EDDSA_PUB ()
module Merchant_private_key_p = MAKE_EDDSA_PRIV ()
(*module Merchant_signature_p = MAKE_EDDSA_SIG ()*)

module Transfert_public_key_p = MAKE_ECDHE_PUB ()
module Transfert_private_key_p = MAKE_ECDHE_PRIV ()

(*
enum TALER_AmlDecisionState {
  NORMAL, PENDING, FROZEN
};
*)

module Aml_officer_public_key_p = MAKE_EDDSA_PUB ()
module Aml_officer_private_key_p = MAKE_EDDSA_PRIV ()
module Exchange_public_key_p = MAKE_EDDSA_PUB ()
module Exchange_private_key_p = MAKE_EDDSA_PRIV ()
module Exchange_signature_p = MAKE_EDDSA_SIG ()
module Master_public_key_p = MAKE_EDDSA_PUB ()
module Master_private_key_p = MAKE_EDDSA_PRIV ()
module Master_signature_p = MAKE_EDDSA_SIG ()

module Wire_transfert_identifier_raw_p = struct
  (* uint8_t raw[32]; *)
  type t = { raw: string }

  let bin =
    let open Bin in
    record (fun raw -> { raw }) |+ field (bytes 32) (fun t -> t.raw) |> sealr
end

module UUID = struct
  (* uint32_t value[4]; *)
  type t = { value: string }

  let bin =
    let open Bin in
    record (fun value -> { value })
    |+ field (bytes (4 * 4)) (fun t -> t.value)
    |> sealr
end

module Wad_id = struct
  (* uint32_t value[6]; *)
  type t = { raw: string }

  let bin =
    let open Bin in
    record (fun raw -> { raw })
    |+ field (bytes (4 * 6)) (fun t -> t.raw)
    |> sealr
end

(* TODO not sure what to do of unions *)
(*
union TALER_CoinSpendPublicKeyP {
  uint8_t eddsa_pub[32];
  uint8_t ecdhe_pub[32];
};
union TALER_CoinSpendPrivateKeyP {
  uint8_t eddsa_priv[32];
  uint8_t ecdhe_priv[32];
};
*)

module Coin_spend_signature_p = MAKE_EDDSA_SIG ()

(* TODO padding: sizeof used here (assume no padding for now) *)
(*
struct TALER_TransferSecretP {
  uint8_t key[sizeof (struct GNUNET_HashCode)];
};
  uint8_t key[sizeof (struct GNUNET_HashCode)];
};
struct TALER_EncryptedLinkSecretP {
  uint8_t enc[sizeof (struct TALER_LinkSecretP)];
};
*)
module Transfert_secret_p = MAKE_H (Hash_code)
module Link_secret_p = MAKE_H (Hash_code)
module Encrypted_link_secret_p = MAKE_H (Hash_code)

(*
union TALER_TokenPublicKeyP {
  uint8_t eddsa_pub[32];
  uint8_t ecdhe_pub[32];
};
*)

(* -- Signatures -- *)

module Ecc_signature_purpose = struct
  type t = {
    (* This field equals the number of bytes being signed,
       namely 'sizeof (struct Data)'. *)
    size: int32;
    (* This field is used to express the context in
       which the signature is made, ensuring that a
       signature cannot be lifted from one part of the protocol
       to another. *)
    purpose: int32;
  }

  let bin =
    let open Bin in
    record (fun size purpose -> { size; purpose })
    |+ field beint32 (fun t -> t.size)
    |+ field beint32 (fun t -> t.purpose)
    |> sealr
end