/*
   orxonox - the future of 3D-vertical-scrollers

   Copyright (C) 2004 orx

   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, or (at your option)
   any later version.

### File Specific:
   main-programmer: Christoph Renner
   co-programmer:
*/

#include "udp_server_socket.h"
#include "debug.h"


ObjectListDefinition(UdpServerSocket);
/**
 * constructor
 * @param port port to listen on
 */
UdpServerSocket::UdpServerSocket( int port ) : ServerSocket( port )
{
  packet = SDLNet_AllocPacket( UDP_PACKET_SIZE );

  if ( !packet )
  {
    PRINTF(1)("SDLNet_AllocPacket: %s\n", SDLNet_GetError());

    assert( false );
    bOk = false;
  }

  memset( packet->data, 0, UDP_PACKET_SIZE );

  listen( port );
}

/**
 * default destructor
 */
UdpServerSocket::~UdpServerSocket( )
{
  for ( int i = 0; i < (int)packetBuffer.size(); i++ )
    removeUserPackets( i );

  if ( packet )
    SDLNet_FreePacket( packet );

  if ( socket )
    SDLNet_UDP_Close( socket );
}

/**
 * tell udpServerSocket to recieve packets on port
 * @param port port
 * @return true on success
 */
bool UdpServerSocket::listen( unsigned int port )
{
  socket = SDLNet_UDP_Open( port );

  PRINTF(0)("listening on port: %d\n", port);

  if ( !socket )
  {

    bOk = false;
    return false;
  }

  return true;
}

/**
 * get newly connected socket. note
 * @return new socket or NULL if no new socket exists
 */
NetworkSocket * UdpServerSocket::getNewSocket( void )
{
  NetworkSocket * result = NULL;

  if ( newSocketList.size() > 0 )
  {
    result = newSocketList.front();

    newSocketList.pop_front();
  }

  return result;
}


/**
 * stop listening on server
 */
void UdpServerSocket::close( )
{

  for ( int i = 0; i < (int)packetBuffer.size(); i++ )
    removeUserPackets( i );

  packetBuffer.clear();
  userList.clear();

  SDLNet_UDP_Close( socket );
  socket = NULL;
}

/**
 * clean up users buffer
 * @param userId users userid
 */
void UdpServerSocket::removeUserPackets( int userId )
{
  if ( userId >= (int)packetBuffer.size() )
    return;

  for ( NetworkPacketList::iterator it = packetBuffer[userId].begin(); it!=packetBuffer[userId].end(); it++ )
  {
    if ( it->data )
    {
      free( it->data );
      it->data = NULL;
    }
  }

  packetBuffer[userId].clear();
}

/**
 * get next packet for user
 * @param userId user id
 * @return recieved packet or packet with length 0 if no packet available
 */
NetworkPacket UdpServerSocket::getPacket( int userId )
{
  NetworkPacket res;
  res.data = NULL;
  res.length = 0;

  if ( (int)packetBuffer.size() > userId && (int)packetBuffer[userId].size() > 0 )
  {
    res.data = packetBuffer[userId].front().data;
    res.length = packetBuffer[userId].front().length;
    packetBuffer[userId].pop_front();
  }

  return res;
}

/**
 * get number of packets recieved for user
 * @param userId user id
 * @return number of packets in buffer
 */
int UdpServerSocket::getPacketCount( int userId )
{
  if ( userId >= (int)packetBuffer.size() )
    return -1;

  return packetBuffer[userId].size();
}

/**
 * will set user state
 * @param userId users id
 * @param ip users host / port
 */
void UdpServerSocket::initUser( int userId, IPaddress ip, byte randomByte )
{
  int channel = SDLNet_UDP_Bind( socket, userId, &ip );
  if( channel != userId )
  {
    PRINTF(1)("SDLNet_UDP_Bind: %s\n", SDLNet_GetError());
    assert(false);
    return;
  }

  if ( userId < (int)packetBuffer.size() )
    removeUserPackets( userId );

  if ( (int)packetBuffer.size() <= userId )
    packetBuffer.resize( userId + 1 );

  if ( (int)userList.size() <= userId )
    userList.resize( userId + 1 );

  userList[ userId ].addr = ip;
  userList[ userId ].randomByte = randomByte;
}

/**
 * remove user from list
 * @param userId user id
 */
void UdpServerSocket::removeUser( int userId )
{
  removeUserPackets( userId );

  if ( userId >= (int)userList.size() )
    return;

  userList[userId].addr.host = 0;
  userList[userId].addr.port = 0;

  SDLNet_UDP_Unbind( socket, userId );
}

/**
 * send one packet to client associated to userId
 * @param networkPacket packet to send
 * @param userId users id
 * @return true on success
 */
bool UdpServerSocket::sendPacket( NetworkPacket networkPacket , int userId )
{
  if ( !socket )
    return false;

  assert( networkPacket.length <= UDP_PACKET_SIZE );

  memcpy( packet->data, networkPacket.data, networkPacket.length );
  packet->len = networkPacket.length;
  packet->channel = -1;

  if ( SDLNet_UDP_Send( socket, userId, packet ) == 0 )
  {
    PRINTF(1)("SDLNet_UDP_Send: %s\n", SDLNet_GetError());
    return false;
  }

  return true;
}

/**
 * do periodically things
 */
void UdpServerSocket::update( )
{
  int res;
  int newConn = 0;

  // iterate through all newly received packets and assign them to the users packet buffer
  for ( res = SDLNet_UDP_Recv( socket, packet ); res == 1; res = SDLNet_UDP_Recv( socket, packet ) )
  {
    int userId;
    bool isNewConnection = false;

    if ( packet->len <= 0 )
      continue;

    // search the user id this backet belongs to
    for ( userId = 0; userId < (int)userList.size(); userId++ )
    {
      if ( userList[userId].addr.host == packet->address.host &&
           userList[userId].addr.port == packet->address.port &&
           userList[userId].randomByte == ( packet->data[0] & 0xFC ) )
        break;
    }

    // is it a new packet initializing a new connecion?
    if ( userId >= (int)userList.size() )
    {
      newConn++;
      isNewConnection = true;

      if ( newConn > MAX_NEW_CONNECTIONS )
      {
        PRINTF(2)("Too many new connections. Dropping packet\n");
        continue;
      }

      for ( userId =0; userId < (int)userList.size(); userId++ )
        if ( userList[userId].addr.host == 0 && userList[userId].addr.port == 0 )
          break;

      this->initUser( userId, packet->address, packet->data[0] & 0xFC );
      UdpSocket * sock = new UdpSocket( this, packet->address, userId, packet->data[0] & 0xFC );
      newSocketList.push_back( sock );
      PRINTF(0)("NEW CONNECTION %x\n", packet->address.host );
    }


    // add new packet to packetbuffer
    NetworkPacket networkPacket;
    networkPacket.length = packet->len;
    if ( packet->len != 0 )
    {
      networkPacket.data = (byte*)malloc( packet->len );
      assert( networkPacket.data );
    }
    else
    {
      networkPacket.data = NULL;
    }
    memcpy( networkPacket.data, packet->data, packet->len );
    packetBuffer[userId].push_back( networkPacket );
  }

  assert( res == 0 );
}