/*
 * Copyright (c) 2023, [MTG AG](https://www.mtg.de).
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1.  Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *
 * 2.  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.
 *
 * 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.
 */

#ifndef KYBER_H_
#define KYBER_H_

#include "config.h"
#include <rnp/rnp_def.h>
#include <vector>
#include <repgp/repgp_def.h>
#include "crypto/rng.h"
#include <botan/kyber.h>
#include <botan/pubkey.h>

enum kyber_parameter_e { kyber_768, kyber_1024 };

struct kyber_encap_result_t {
    std::vector<uint8_t> ciphertext;
    std::vector<uint8_t> symmetric_key;
};

class pgp_kyber_private_key_t {
  public:
    pgp_kyber_private_key_t(const uint8_t *   key_encoded,
                            size_t            key_encoded_len,
                            kyber_parameter_e mode);
    pgp_kyber_private_key_t(std::vector<uint8_t> const &key_encoded, kyber_parameter_e mode);
    pgp_kyber_private_key_t() = default;

    bool is_valid(rnp::RNG *rng) const;

    std::vector<uint8_t> decapsulate(rnp::RNG *     rng,
                                     const uint8_t *ciphertext,
                                     size_t         ciphertext_len);
    std::vector<uint8_t>
    get_encoded() const
    {
        return Botan::unlock(key_encoded_);
    };

    kyber_parameter_e
    param() const
    {
        return kyber_mode_;
    }

  private:
    Botan::Kyber_PrivateKey botan_key() const;

    Botan::secure_vector<uint8_t> key_encoded_;
    kyber_parameter_e             kyber_mode_;
    bool                          is_initialized_ = false;
};

class pgp_kyber_public_key_t {
  public:
    pgp_kyber_public_key_t(const uint8_t *   key_encoded,
                           size_t            key_encoded_len,
                           kyber_parameter_e mode);
    pgp_kyber_public_key_t(std::vector<uint8_t> const &key_encoded, kyber_parameter_e mode);
    pgp_kyber_public_key_t() = default;
    kyber_encap_result_t encapsulate(rnp::RNG *rng) const;

    bool
    operator==(const pgp_kyber_public_key_t &rhs) const
    {
        return (kyber_mode_ == rhs.kyber_mode_) && (key_encoded_ == rhs.key_encoded_);
    }

    bool is_valid(rnp::RNG *rng) const;

    std::vector<uint8_t>
    get_encoded() const
    {
        return key_encoded_;
    };

  private:
    Botan::Kyber_PublicKey botan_key() const;

    std::vector<uint8_t> key_encoded_;
    kyber_parameter_e    kyber_mode_;
    bool                 is_initialized_ = false;
};

std::pair<pgp_kyber_public_key_t, pgp_kyber_private_key_t> kyber_generate_keypair(
  rnp::RNG *rng, kyber_parameter_e kyber_param);

#endif