// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
// Mobius Forensic Toolkit
// Copyright (C)
// 2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018,2019,2020,2021,2022,2023,2024,2025
// Eduardo Aguiar
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2, or (at your option) any later
// version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
// Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
#include <mobius/core/crypt/cipher_impl_ige.hpp>
#include <mobius/core/exception.inc>

namespace mobius::core::crypt
{
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
// @brief Constructor
// @param cipher_id Cipher ID
// @param key Cipher key
// @param iv Initialization vector
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
cipher_impl_ige::cipher_impl_ige (const std::string &cipher_id,
                                  const mobius::core::bytearray &key,
                                  const mobius::core::bytearray &iv)
    : cipher_ (cipher_id, "ecb"),
      iv_ (iv),
      v1_ (iv.slice (0, iv.size () / 2 - 1)),
      v2_ (iv.slice (iv.size () / 2, iv.size () - 1))
{
    if (cipher_.is_stream ())
        throw std::invalid_argument (
            MOBIUS_EXCEPTION_MSG ("cannot use cipher mode with stream cipher"));

    cipher_.set_key (key);
}

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
// @brief Encrypt data
// @param data Plaintext data
// @return Encrypted data
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
mobius::core::bytearray
cipher_impl_ige::encrypt (const mobius::core::bytearray &data)
{
    mobius::core::bytearray out;
    const auto block_size = cipher_.get_block_size ();

    for (std::size_t i = 0; i < data.size (); i += block_size)
    {
        const auto block_data = data.slice (i, i + block_size - 1);
        v1_ = cipher_.encrypt (block_data ^ v1_) ^ v2_;
        v2_ = block_data;
        out += v1_;
    }

    return out;
}

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
// @brief Decrypt data
// @param data Ciphertext data
// @return Decrypted data
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
mobius::core::bytearray
cipher_impl_ige::decrypt (const mobius::core::bytearray &data)
{
    mobius::core::bytearray out;
    const auto block_size = cipher_.get_block_size ();

    for (std::size_t i = 0; i < data.size (); i += block_size)
    {
        const auto block_data = data.slice (i, i + block_size - 1);
        v2_ = cipher_.decrypt (block_data ^ v2_) ^ v1_;
        v1_ = block_data;
        out += v2_;
    }

    return out;
}

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
// @brief Reset cipher mode
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
void
cipher_impl_ige::reset ()
{
    v1_ = iv_.slice (0, iv_.size () / 2 - 1);
    v2_ = iv_.slice (iv_.size () / 2, iv_.size () - 1);
    cipher_.reset ();
}

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
// @brief Set final flag
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
void
cipher_impl_ige::final ()
{
    cipher_.final ();
}

} // namespace mobius::core::crypt
