/*
 * Copyright (C) 2013 Emeric Poupon
 *
 * This file is part of LMS.
 *
 * LMS 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.
 *
 * LMS 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 LMS.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef REMOTE_HEADER_HPP
#define REMOTE_HEADER_HPP

#include "logger/Logger.hpp"

#include <iomanip>

namespace Remote
{


class Header
{
	public:
		static const std::size_t size = 8;	// HeaderSize
		static const std::size_t max_data_size = 65536*64 - size;

		Header() : _dataSize(0) {}

		void setDataSize(std::size_t size)	{ _dataSize = size; }
		std::size_t getDataSize(void) const	{return _dataSize;}

		bool from_istream(std::istream &is)
		{
			std::array<unsigned char, size>	buffer;

			bool res = is.read(reinterpret_cast<char*>(buffer.data()), buffer.size());

			if (res && is.gcount() == buffer.size())
				return from_buffer(buffer);
			else
				return false;
		}

		bool from_buffer(const std::array<unsigned char, size>& buffer)
		{
			if (decode32(&buffer[0]) != _magic) {
				LMS_LOG(MOD_REMOTE, SEV_ERROR) << "Header: bad magic ('" << std::hex << std::setfill('0') << std::setw(8) << decode32(&buffer[0]) << "' instead of '" << std::hex << std::setfill('0') << std::setw(8) << _magic << "')";
				return false;
			}
			else
			{
				_dataSize = decode32(&buffer[4]);

				if (_dataSize > max_data_size)
					LMS_LOG(MOD_REMOTE, SEV_ERROR) << "Header: msg too big (" << _dataSize << ")!";

				return _dataSize <= max_data_size;
			}
		}

/*		void to_ostream(std::ostream& os)
		{


		}*/

		void to_buffer(std::array<unsigned char, size>& buffer) const
		{
			encode32(_magic, &buffer[0]);
			encode32(_dataSize, &buffer[4]);
		}

	private:
		static uint32_t	decode32(const unsigned char* data)
		{
			return (static_cast<uint32_t>(data[0]) << 24)
				+ (static_cast<uint32_t>(data[1]) << 16)
				+ (static_cast<uint32_t>(data[2]) << 8)
				+ (static_cast<uint32_t>(data[3]));
		}

		static void		encode32(uint32_t value, unsigned char* data)
		{
			data[0] = (value >> 24) & 0xFF;
			data[1] = (value >> 16) & 0xFF;
			data[2] = (value >> 8) & 0xFF;
			data[3] = (value) & 0xFF;
		}

		static const uint32_t _magic = 0xdeadbeef;

		uint32_t	_dataSize;
};



} // namespace Remote


#endif