/*
Minetest-c55
Copyright (C) 2010 celeron55, Perttu Ahola 

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.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "connection.h"
#include "main.h"
#include "serialization.h"
#include "log.h"
#include "porting.h"

namespace con
{

BufferedPacket makePacket(Address &address, u8 *data, u32 datasize,
		u32 protocol_id, u16 sender_peer_id, u8 channel)
{
	u32 packet_size = datasize + BASE_HEADER_SIZE;
	BufferedPacket p(packet_size);
	p.address = address;

	writeU32(&p.data[0], protocol_id);
	writeU16(&p.data[4], sender_peer_id);
	writeU8(&p.data[6], channel);

	memcpy(&p.data[BASE_HEADER_SIZE], data, datasize);

	return p;
}

BufferedPacket makePacket(Address &address, SharedBuffer &data,
		u32 protocol_id, u16 sender_peer_id, u8 channel)
{
	return makePacket(address, *data, data.getSize(),
			protocol_id, sender_peer_id, channel);
}

SharedBuffer makeOriginalPacket(
		SharedBuffer data)
{
	u32 header_size = 1;
	u32 packet_size = data.getSize() + header_size;
	SharedBuffer b(packet_size);

	writeU8(&b[0], TYPE_ORIGINAL);

	memcpy(&b[header_size], *data, data.getSize());

	return b;
}

core::list makeSplitPacket(
		SharedBuffer data,
		u32 chunksize_max,
		u16 seqnum)
{
	// Chunk packets, containing the TYPE_SPLIT header
	core::list chunks;
	
	u32 chunk_header_size = 7;
	u32 maximum_data_size = chunksize_max - chunk_header_size;
	u32 start = 0;
	u32 end = 0;
	u32 chunk_num = 0;
	do{
		end = start + maximum_data_size - 1;
		if(end > data.getSize() - 1)
			end = data.getSize() - 1;
		
		u32 payload_size = end - start + 1;
		u32 packet_size = chunk_header_size + payload_size;

		SharedBuffer chunk(packet_size);
		
		writeU8(&chunk[0], TYPE_SPLIT);
		writeU16(&chunk[1], seqnum);
		// [3] u16 chunk_count is written at next stage
		writeU16(&chunk[5], chunk_num);
		memcpy(&chunk[chunk_header_size], &data[start], payload_size);

		chunks.push_back(chunk);
		
		start = end + 1;
		chunk_num++;
	}
	while(end != data.getSize() - 1);

	u16 chunk_count = chunks.getSize();

	core::list::Iterator i = chunks.begin();
	for(; i != chunks.end(); i++)
	{
		// Write chunk_count
		writeU16(&((*i)[3]), chunk_count);
	}

	return chunks;
}

core::list makeAutoSplitPacket(
		SharedBuffer data,
		u32 chunksize_max,
		u16 &split_seqnum)
{
	u32 original_header_size = 1;
	core::list list;
	if(data.getSize() + original_header_size > chunksize_max)
	{
		list = makeSplitPacket(data, chunksize_max, split_seqnum);
		split_seqnum++;
		return list;
	}
	else
	{
		list.push_back(makeOriginalPacket(data));
	}
	return list;
}

SharedBuffer makeReliablePacket(
		SharedBuffer data,
		u16 seqnum)
{
	/*dstream