/**
 * MaNGOS is a full featured server for World of Warcraft, supporting
 * the following clients: 1.12.x, 2.4.3, 3.3.5a, 4.3.4a and 5.4.8
 *
 * Copyright (C) 2005-2014 MaNGOS project <http://getmangos.eu>
 *
 * 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 of the License, 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * World of Warcraft, and all World of Warcraft or Warcraft art, images,
 * and lore are copyrighted by Blizzard Entertainment, Inc.
 */

#include "AuthCrypt.h"
#include "Hmac.h"

AuthCrypt::AuthCrypt()
{
 _initialized = false;
}

void AuthCrypt::Init()
{
 _send_i = _send_j = _recv_i = _recv_j = 0;
 _initialized = true;
}

void AuthCrypt::DecryptRecv(uint8* data, size_t len)
{
 if (!_initialized) { return; }
 if (len < CRYPTED_RECV_LEN) { return; }

 for (size_t t = 0; t < CRYPTED_RECV_LEN; t++)
 {
 _recv_i %= _key.size();
 uint8 x = (data[t] - _recv_j) ^ _key[_recv_i];
 ++_recv_i;
 _recv_j = data[t];
 data[t] = x;
 }
}

void AuthCrypt::EncryptSend(uint8* data, size_t len)
{
 if (!_initialized) { return; }
 if (len < CRYPTED_SEND_LEN) { return; }

 for (size_t t = 0; t < CRYPTED_SEND_LEN; t++)
 {
 _send_i %= _key.size();
 uint8 x = (data[t] ^ _key[_send_i]) + _send_j;
 ++_send_i;
 data[t] = _send_j = x;
 }
}

void AuthCrypt::SetKey(const std::vector<uint8>& key)
{
 //MANGOS_ASSERT(key.size());
 _key = key;
 if (_key.empty())
 _key.resize(1); // temp
}

void AuthCrypt::SetKey(uint8* key, size_t len)
{
 //MANGOS_ASSERT(len);
 _key.resize(len);
 std::copy(key, key + len, _key.begin());

 if (_key.empty())
 _key.resize(1);
}


AuthCrypt::~AuthCrypt()
{
}

void AuthCrypt::GenerateKey(uint8* key, BigNumber* bn)
{
 HmacHash hash;
 hash.UpdateBigNumber(bn);
 hash.Finalize();
 memcpy(key, hash.GetDigest(), SHA_DIGEST_LENGTH);
}