/*

Copyright (c) 2016, Alden Torres

Copyright (c) 2017, 2019-2020, Arvid Norberg

All rights reserved.

Redistribution and use in source and binary forms, with or without

modification, are permitted provided that the following conditions

are met:

    * Redistributions of source code must retain the above copyright

      notice, this list of conditions and the following disclaimer.

    * Redistributions in binary form must reproduce the above copyright

      notice, this list of conditions and the following disclaimer in

      the documentation and/or other materials provided with the distribution.

    * Neither the name of the author nor the names of its

      contributors may be used to endorse or promote products derived

      from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

POSSIBILITY OF SUCH DAMAGE.

*/

#include <libtorrent/kademlia/ed25519.hpp>

#include <libtorrent/random.hpp>

#include <libtorrent/aux_/ed25519.hpp>

namespace libtorrent { namespace dht {

  std::array<char, 32> ed25519_create_seed()

  {

    std::array<char, 32> seed;

    aux::crypto_random_bytes(seed);

    return seed;

  }

  std::tuple<public_key, secret_key> ed25519_create_keypair(

    std::array<char, 32> const& seed)

  {

    public_key pk;

    secret_key sk;

    auto const pk_ptr = reinterpret_cast<unsigned char*>(pk.bytes.data());

    auto const sk_ptr = reinterpret_cast<unsigned char*>(sk.bytes.data());

    auto const seed_ptr = reinterpret_cast<unsigned char const*>(seed.data());

    lt::aux::ed25519_create_keypair(pk_ptr, sk_ptr, seed_ptr);

    return std::make_tuple(pk, sk);

  }

  signature ed25519_sign(span<char const> msg

    , public_key const& pk, secret_key const& sk)

  {

    signature sig;

    auto const sig_ptr = reinterpret_cast<unsigned char*>(sig.bytes.data());

    auto const msg_ptr = reinterpret_cast<unsigned char const*>(msg.data());

    auto const pk_ptr = reinterpret_cast<unsigned char const*>(pk.bytes.data());

    auto const sk_ptr = reinterpret_cast<unsigned char const*>(sk.bytes.data());

    lt::aux::ed25519_sign(sig_ptr, msg_ptr, msg.size(), pk_ptr, sk_ptr);

    return sig;

  }

  bool ed25519_verify(signature const& sig

    , span<char const> msg, public_key const& pk)

  {

    auto const sig_ptr = reinterpret_cast<unsigned char const*>(sig.bytes.data());

    auto const msg_ptr = reinterpret_cast<unsigned char const*>(msg.data());

    auto const pk_ptr = reinterpret_cast<unsigned char const*>(pk.bytes.data());

    return lt::aux::ed25519_verify(sig_ptr, msg_ptr, msg.size(), pk_ptr) == 1;

  }

  public_key ed25519_add_scalar(public_key const& pk

    , std::array<char, 32> const& scalar)

  {

    public_key ret(pk.bytes.data());

    auto const ret_ptr = reinterpret_cast<unsigned char*>(ret.bytes.data());

    auto const scalar_ptr = reinterpret_cast<unsigned char const*>(scalar.data());

    lt::aux::ed25519_add_scalar(ret_ptr, nullptr, scalar_ptr);

    return ret;

  }

  secret_key ed25519_add_scalar(secret_key const& sk

    , std::array<char, 32> const& scalar)

  {

    secret_key ret(sk.bytes.data());

    auto const ret_ptr = reinterpret_cast<unsigned char*>(ret.bytes.data());

    auto const scalar_ptr = reinterpret_cast<unsigned char const*>(scalar.data());

    lt::aux::ed25519_add_scalar(nullptr, ret_ptr, scalar_ptr);

    return ret;

  }

  std::array<char, 32> ed25519_key_exchange(

    public_key const& pk, secret_key const& sk)

  {

    std::array<char, 32> secret;

    auto const secret_ptr = reinterpret_cast<unsigned char*>(secret.data());

    auto const pk_ptr = reinterpret_cast<unsigned char const*>(pk.bytes.data());

    auto const sk_ptr = reinterpret_cast<unsigned char const*>(sk.bytes.data());

    lt::aux::ed25519_key_exchange(secret_ptr, pk_ptr, sk_ptr);

    return secret;

  }

}}