open Crypto
open Api

let verify_future_keys_response =
  let verify_future_denom ~sm_denom_pub
      FutureDenom.
        {
          section_name;
          value= _;
          stamp_start;
          stamp_expire_withdraw;
          stamp_expire_deposit= _;
          stamp_expire_legal= _;
          denom_pub;
          fee_withdraw= _;
          fee_deposit= _;
          fee_refresh= _;
          fee_refund= _;
          denom_secmod_sig;
        } =
    let h_denom_pub =
      DenominationHash.hash (DenominationKey.to_octets denom_pub)
    in
    let h_section_name = Hash.Cstring.H64.hash section_name in
    let anchor_time = stamp_start in
    let duration_withdraw = Timestamp.diff stamp_start stamp_expire_withdraw in
    let open Bin_sig.DenominationKeyAnnouncement in
    verify_f
      ~f:(EddsaSignature.verify ~key:sm_denom_pub)
      denom_secmod_sig
      { h_denom_pub; h_section_name; anchor_time; duration_withdraw }
  in
  let verify_future_signkey ~sm_signkey_pub
      FutureSignKey.
        { key; stamp_start; stamp_expire; stamp_end= _; signkey_secmod_sig } =
    let exchange_pub = key in
    let anchor_time = stamp_start in
    let duration = Timestamp.diff stamp_start stamp_expire in
    let open Bin_sig.SigningKeyAnnouncement in
    verify_f
      ~f:(EddsaSignature.verify ~key:sm_signkey_pub)
      signkey_secmod_sig
      { exchange_pub; anchor_time; duration }
  in

  fun our_master_public_key
    FutureKeysResponse.
      {
        future_denoms;
        future_signkeys;
        master_pub;
        denom_secmod_public_key;
        signkey_secmod_public_key;
      }
  ->
    let open Syntax in
    let* () =
      match master_pub = our_master_public_key with
      | false ->
          Fmt.error
            "master public key of the future key response does not match ours"
      | true -> Ok ()
    in
    let* () =
      list_iter
        (verify_future_denom ~sm_denom_pub:denom_secmod_public_key)
        future_denoms
    in
    let* () =
      list_iter
        (verify_future_signkey ~sm_signkey_pub:signkey_secmod_public_key)
        future_signkeys
    in
    Ok ()

let mk_future_keys =
  let denom_signature ~master_key
      FutureDenom.
        {
          section_name= _;
          value;
          stamp_start;
          stamp_expire_withdraw;
          stamp_expire_deposit;
          stamp_expire_legal;
          denom_pub;
          fee_withdraw;
          fee_deposit;
          fee_refresh;
          fee_refund= _;
          denom_secmod_sig= _;
        } =
    let octets = DenominationKey.to_octets denom_pub in
    let h_denom_pub = DenominationHash.hash octets in
    let master_sig =
      let open Bin_sig.DenominationKeyValidity in
      let master = EddsaPrivateKey.(pub_of_priv master_key) in
      sign_f
        ~f:(EddsaSignature.sign ~key:master_key)
        {
          master;
          start= stamp_start;
          expire_withdraw= stamp_expire_withdraw;
          expire_spend= stamp_expire_deposit;
          expire_legal= stamp_expire_legal;
          value;
          fee_withdraw;
          fee_deposit;
          fee_refresh;
          denom_hash= h_denom_pub;
        }
    in
    DenomSignature.{ h_denom_pub; master_sig }
  in
  let signkey_signature ~master_key
      FutureSignKey.
        { key; stamp_start; stamp_expire; stamp_end; signkey_secmod_sig= _ } =
    let master_sig =
      let open Bin_sig.ExchangeSigningKeyValidity in
      sign_f
        ~f:(EddsaSignature.sign ~key:master_key)
        {
          start= stamp_start;
          expire= stamp_expire;
          end_= stamp_end;
          signkey_pub= key;
        }
    in
    SignKeySignature.{ key; master_sig }
  in

  fun ~master_key
    FutureKeysResponse.
      {
        future_denoms;
        future_signkeys;
        master_pub= _;
        denom_secmod_public_key= _;
        signkey_secmod_public_key= _;
      }
  ->
    let denom_sigs = List.map (denom_signature ~master_key) future_denoms in
    let signkey_sigs =
      List.map (signkey_signature ~master_key) future_signkeys
    in
    MasterSignatures.{ denom_sigs; signkey_sigs }