/*
	This file is part of cpp-ethereum.

	cpp-ethereum 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 3 of the License, or
	(at your option) any later version.

	cpp-ethereum 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 cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
*/
/** @file SHA3.cpp
 * @author Gav Wood <i@gavwood.com>
 * @date 2014
 */

#include "SHA3.h"

#include <libdevcore/RLP.h>
#include "CryptoPP.h"
using namespace std;
using namespace dev;

namespace dev
{

h256 EmptySHA3 = sha3(bytesConstRef());
h256 EmptyListSHA3 = sha3(rlpList());

std::string sha3(std::string const& _input, bool _hex)
{
	if (!_hex)
	{
		string ret(32, '\0');
		sha3(bytesConstRef((byte const*)_input.data(), _input.size()), bytesRef((byte*)ret.data(), 32));
		return ret;
	}

	uint8_t buf[32];
	sha3(bytesConstRef((byte const*)_input.data(), _input.size()), bytesRef((byte*)&(buf[0]), 32));
	std::string ret(64, '\0');
	for (unsigned int i = 0; i < 32; i++)
		sprintf((char*)(ret.data())+i*2, "%02x", buf[i]);
	return ret;
}

void sha3(bytesConstRef _input, bytesRef _output)
{
	CryptoPP::SHA3_256 ctx;
	ctx.Update((byte*)_input.data(), _input.size());
	assert(_output.size() >= 32);
	ctx.Final(_output.data());
}

void ripemd160(bytesConstRef _input, bytesRef _output)
{
	CryptoPP::RIPEMD160 ctx;
	ctx.Update((byte*)_input.data(), _input.size());
	assert(_output.size() >= 32);
	ctx.Final(_output.data());
}

void sha256(bytesConstRef _input, bytesRef _output)
{
	CryptoPP::SHA256 ctx;
	ctx.Update((byte*)_input.data(), _input.size());
	assert(_output.size() >= 32);
	ctx.Final(_output.data());
}

bytes sha3Bytes(bytesConstRef _input)
{
	bytes ret(32);
	sha3(_input, &ret);
	return ret;
}

h256 sha3(bytesConstRef _input)
{
	h256 ret;
	sha3(_input, bytesRef(&ret[0], 32));
	return ret;
}
	
void sha3mac(bytesConstRef _secret, bytesConstRef _plain, bytesRef _output)
{
	CryptoPP::SHA3_256 ctx;
	assert(_secret.size() > 0);
	ctx.Update((byte*)_secret.data(), _secret.size());
	ctx.Update((byte*)_plain.data(), _plain.size());
	assert(_output.size() >= 32);
	ctx.Final(_output.data());
}

bytes aesDecrypt(bytesConstRef _ivCipher, std::string const& _password, unsigned _rounds, bytesConstRef _salt)
{
	bytes pw = asBytes(_password);

	if (!_salt.size())
		_salt = &pw;

	bytes target(64);
	CryptoPP::PKCS5_PBKDF2_HMAC<CryptoPP::SHA256>().DeriveKey(target.data(), target.size(), 0, pw.data(), pw.size(), _salt.data(), _salt.size(), _rounds);

	try
	{
		CryptoPP::AES::Decryption aesDecryption(target.data(), 16);
		auto cipher = _ivCipher.cropped(16);
		auto iv = _ivCipher.cropped(0, 16);
		CryptoPP::CBC_Mode_ExternalCipher::Decryption cbcDecryption(aesDecryption, iv.data());
		std::string decrypted;
		CryptoPP::StreamTransformationFilter stfDecryptor(cbcDecryption, new CryptoPP::StringSink(decrypted));
		stfDecryptor.Put(cipher.data(), cipher.size());
		stfDecryptor.MessageEnd();
		return asBytes(decrypted);
	}
	catch (exception const& e)
	{
		cerr << e.what() << endl;
		return bytes();
	}
}

}