/*
 *   ORXONOX - the hottest 3D action shooter ever to exist
 *
 *
 *   License notice:
 *
 *   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.
 *
 *   Author:
 *      Oliver Scheuss, (C) 2007
 *   Co-authors:
 *      ...
 *
 */

//
// C++ Implementation: GameStateManager
//
// Description:
//
//
// Author:  Oliver Scheuss, (C) 2007
//
// Copyright: See COPYING file that comes with this distribution
//
//
#include "GameStateManager.h"

namespace network {

GameStateManager::GameStateManager(ClientInformation *head)
{
  id=0;
  head_=head;
}

GameStateManager::~GameStateManager()
{
}

void GameStateManager::update(){
  reference = getSnapshot(id);
  gameStateMap.insert(std::pair<int, GameState*>(id, reference));
  gameStateUsed[id]=0;
  ++id;
  return;
}

GameStateCompressed GameStateManager::popGameState(int clientID){
  int gID = head_->findClient(clientID)->getGamestateID();
  if(gID!=GAMESTATEID_INITIAL){
    GameState *client = gameStateMap[gID];
    GameState *server = reference;
    return encode(client, server);
  }
  GameState *server = reference;
  return encode(server);
  // return an undiffed gamestate and set appropriate flags
}



/**
 * This function goes through the whole list of synchronisables and
 * saves all the synchronisables to a flat "list".
 * @return struct of type gamestate containing the size of the whole gamestate and a pointer linking to the flat list
 */
GameState *GameStateManager::getSnapshot(int id)
{
  //the size of the gamestate
  int totalsize=0;
  //the size of one specific synchronisable
  int tempsize=0;
  // get the start of the Synchronisable list
  orxonox::Iterator<Synchronisable> it;
  // struct for return value of Synchronisable::getData()
  syncData sync;

  GameState *retval=new GameState; //return value
  retval->id=id;
  // reserve a little memory and increase it later on
  retval->data = (unsigned char*)malloc(1);

  // offset of memory functions
  int offset=0;
  // go through all Synchronisables
  for(it = orxonox::ObjectList<Synchronisable>::start(); it != 0; ++it){
    //get size of the synchronisable
    tempsize=it->getSize();
    // add place for data and 3 ints (length,classid,objectid)
    totalsize+=tempsize+3*sizeof(int);
    // allocate additional space
    retval->data = (unsigned char *)realloc((void *)retval->data, totalsize);

    // run Synchronisable::getData with offset and additional place for 3 ints in between (for ids and length)
    sync=it->getData(retval->data+offset+3*sizeof(int));
    *(retval->data+offset)=sync.length;
    *(retval->data+offset+sizeof(int))=sync.objectID;
    *(retval->data+offset+2*sizeof(int))=sync.classID;
    // increase data pointer
    offset+=tempsize+3*sizeof(int);
  }
  retval->size=totalsize;
  return retval;
}



GameStateCompressed GameStateManager::encode(GameState *a, GameState *b){
    GameState r = diff(a,b);
  r.diffed = true;
  return compress_(&r);
}

GameStateCompressed GameStateManager::encode(GameState *a){
  a->diffed=false;
  return compress_(a);
}

GameState GameStateManager::diff(GameState *a, GameState *b){
  unsigned char *ap = a->data, *bp = b->data;
  int of=0; // pointers offset
  int dest_length=0;
  if(a->size>=b->size)
    dest_length=a->size;
  else
    dest_length=b->size;
  unsigned char *dp = (unsigned char *)malloc(dest_length*sizeof(unsigned char));
  while(of<a->size && of<b->size){
    *(dp+of)=*(ap+of)^*(bp+of); // do the xor
    ++of;
  }
  if(a->size!=b->size){ // do we have to fill up ?
    unsigned char n=0;
    if(a->size<b->size){
      while(of<dest_length){
        *(dp+of)=n^*(bp+of);
        of++;
      }
    } else{
      while(of<dest_length){
        *(dp+of)=*(ap+of)^n;
        of++;
      }
    }
  }
  // should be finished now
  GameState r = {b->id, dest_length, dp};
  return r;
}

GameStateCompressed GameStateManager::compress_(GameState *a) {
  int size = a->size;
  uLongf buffer = (uLongf)((a->size + 12)*1.01)+1;
  unsigned char* dest = (unsigned char*)malloc( buffer );
  int retval;
  retval = compress( dest, &buffer, a->data, (uLong)size );

  switch ( retval ) {
  case Z_OK: std::cout << "successfully compressed" << std::endl; break;
  case Z_MEM_ERROR: std::cout << "not enough memory available" << std::endl; break;
  case Z_BUF_ERROR: std::cout << "not enough memory available in the buffer" << std::endl; break;
  case Z_DATA_ERROR: std::cout << "data corrupted" << std::endl; break;
  }

  GameStateCompressed compressedGamestate;
  compressedGamestate.compsize = buffer;
  compressedGamestate.normsize = size;
  compressedGamestate.id = GAMESTATE;
  compressedGamestate.data = dest;
  compressedGamestate.diffed = a->diffed;

  return compressedGamestate;
}

void GameStateManager::ackGameState(int clientID, int gamestateID){
  ClientInformation *temp = head_->findClient(clientID);
  int curid = temp->getID();
  // decrease usage of gamestate and save it
  deleteUnusedGameState(curid);
  //increase gamestateused
  ++gameStateUsed.find(gamestateID)->second;
  temp->setGamestateID(gamestateID);
  /*
  GameState *old = clientGameState[clientID];
  deleteUnusedGameState(old);
  clientGameState[clientID]=idGameState[gamestateID];*/
}

bool GameStateManager::deleteUnusedGameState(int gamestateID){
  int used = --(gameStateUsed.find(gamestateID)->second);
  if(id-gamestateID>KEEP_GAMESTATES && used==0){
    // delete gamestate
    delete gameStateMap.find(gamestateID)->second;
    gameStateMap.erase(gamestateID);
    return true;
  }
  return false;
}

}