/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set et sw=2 ts=2: */
/***************************************************************************
 *            hash.cc
 *
 *  Sun Jul  5 10:37:32 CEST 2020
 *  Copyright 2020 Bent Bisballe Nyeng
 *  deva@aasimon.org
 ****************************************************************************/

/*
 *  This file is part of Munia.
 *
 *  Munia 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.
 *
 *  Munia 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 Munia; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
 */
#include "hash.h"

#include <cstdint>
#include <vector>

#include <argon2.h>

std::string getEncoded(const Salt& salt, const std::string& password)
{
	constexpr std::size_t hashlen = 32u;
	constexpr std::uint32_t t_cost = 10;        // 10-pass computation
	constexpr std::uint32_t m_cost = (1 << 16); // 64 mebibytes memory usage
	constexpr std::uint32_t parallelism = 1;    // number of threads and lanes

	auto encodedlen = argon2_encodedlen(t_cost, m_cost, parallelism,
	                                    salt.size(), hashlen, Argon2_i);
	std::vector<char> encoded(encodedlen, '\0');
	auto ret = argon2i_hash_encoded(t_cost, m_cost, parallelism,
	                                password.data(), password.length(),
	                                salt.data(), salt.size(),
	                                hashlen,
	                                encoded.data(), encoded.size());
	if(ret != ARGON2_OK)
	{
		throw "Argon2 encoding error.";
	}

	// convert vector<char> to string
	std::string s;
	s.reserve(encoded.size());
	for(const auto& e : encoded)
	{
		s += e;
	}

	return s;
}

bool verifyEncoded(const std::string& encoded, const std::string& password)
{
	auto ret = argon2i_verify(encoded.data(), password.data(), password.length());
	return ret == ARGON2_OK;
}