/* <!-- copyright */
/*
 * aria2 - The high speed download utility
 *
 * Copyright (C) 2006 Tatsuhiro Tsujikawa
 *
 * 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
 *
 * In addition, as a special exception, the copyright holders give
 * permission to link the code of portions of this program with the
 * OpenSSL library under certain conditions as described in each
 * individual source file, and distribute linked combinations
 * including the two.
 * You must obey the GNU General Public License in all respects
 * for all of the code used other than OpenSSL.  If you modify
 * file(s) with this exception, you may extend this exception to your
 * version of the file(s), but you are not obligated to do so.  If you
 * do not wish to do so, delete this exception statement from your
 * version.  If you delete this exception statement from all source
 * files in the program, then also delete it here.
 */
/* copyright --> */
#include "DefaultPeerStorage.h"

#include <algorithm>

#include "LogFactory.h"
#include "Logger.h"
#include "message.h"
#include "Peer.h"
#include "BtRuntime.h"
#include "BtSeederStateChoke.h"
#include "BtLeecherStateChoke.h"
#include "PieceStorage.h"
#include "wallclock.h"

namespace aria2 {

static const int MAX_PEER_LIST_SIZE = 1024;

DefaultPeerStorage::DefaultPeerStorage():
  _logger(LogFactory::getInstance()),
  _removedPeerSessionDownloadLength(0),
  _removedPeerSessionUploadLength(0),
  _seederStateChoke(new BtSeederStateChoke()),
  _leecherStateChoke(new BtLeecherStateChoke()),
  _lastTransferStatMapUpdated(0)
{}

DefaultPeerStorage::~DefaultPeerStorage()
{
  delete _seederStateChoke;
  delete _leecherStateChoke;
}

class FindIdenticalPeer {
private:
  SharedHandle<Peer> _peer;
public:
  FindIdenticalPeer(const SharedHandle<Peer>& peer):_peer(peer) {}

  bool operator()(const SharedHandle<Peer>& peer) const {
    return (_peer == peer) ||
      ((_peer->getIPAddress() == peer->getIPAddress()) &&
       (_peer->getPort() == peer->getPort()));
  }
};

bool DefaultPeerStorage::isPeerAlreadyAdded(const SharedHandle<Peer>& peer)
{
  return std::find_if(_peers.begin(), _peers.end(),
                      FindIdenticalPeer(peer)) != _peers.end();
}

static size_t calculateMaxPeerListSize(const SharedHandle<BtRuntime>& btRuntime)
{
  if(btRuntime.isNull()) {
    return MAX_PEER_LIST_SIZE;
  }
  return btRuntime->getMaxPeers() == 0 ?
    MAX_PEER_LIST_SIZE :
    btRuntime->getMaxPeers()+(btRuntime->getMaxPeers() >> 2);
}

bool DefaultPeerStorage::addPeer(const SharedHandle<Peer>& peer) {
  if(isPeerAlreadyAdded(peer)) {
    if(_logger->debug()) {
      _logger->debug("Adding %s:%u is rejected because it has been already"
                    " added.", peer->getIPAddress().c_str(), peer->getPort());
    }
    return false;
  }
  size_t maxPeerListSize = calculateMaxPeerListSize(_btRuntime);
  if(_peers.size() >= maxPeerListSize) {
    deleteUnusedPeer(_peers.size()-maxPeerListSize+1);
  }
  _peers.push_front(peer);
  return true;
}

void DefaultPeerStorage::addPeer(const std::vector<SharedHandle<Peer> >& peers)
{
  for(std::vector<SharedHandle<Peer> >::const_iterator itr = peers.begin(),
        eoi = peers.end(); itr != eoi; ++itr) {
    const SharedHandle<Peer>& peer = *itr;
    if(addPeer(peer)) {
      if(_logger->debug()) {
        _logger->debug(MSG_ADDING_PEER,
                       peer->getIPAddress().c_str(), peer->getPort());
      }
    }
  }  
}

const std::deque<SharedHandle<Peer> >& DefaultPeerStorage::getPeers()
{
  return _peers;
}

class FindFinePeer {
public:
  bool operator()(const SharedHandle<Peer>& peer) const {
    return peer->unused() && peer->isGood();
  }
};

SharedHandle<Peer> DefaultPeerStorage::getUnusedPeer() {
  std::deque<SharedHandle<Peer> >::const_iterator itr =
    std::find_if(_peers.begin(), _peers.end(), FindFinePeer());
  if(itr == _peers.end()) {
    return SharedHandle<Peer>();
  } else {
    return *itr;
  }
}

class FindPeer {
private:
  std::string ipaddr;
  uint16_t port;
public:
  FindPeer(const std::string& ipaddr, uint16_t port):
    ipaddr(ipaddr), port(port) {}

  bool operator()(const SharedHandle<Peer>& peer) const {
    return ipaddr == peer->getIPAddress() && port == peer->getPort();
  }
};

SharedHandle<Peer> DefaultPeerStorage::getPeer(const std::string& ipaddr,
                                               uint16_t port) const {
  std::deque<SharedHandle<Peer> >::const_iterator itr =
    std::find_if(_peers.begin(), _peers.end(), FindPeer(ipaddr, port));
  if(itr == _peers.end()) {
    return SharedHandle<Peer>();
  } else {
    return *itr;
  }
}

size_t DefaultPeerStorage::countPeer() const {
  return _peers.size();
}

bool DefaultPeerStorage::isPeerAvailable() {
  return !getUnusedPeer().isNull();
}

class CollectActivePeer {
private:
  std::vector<SharedHandle<Peer> >& _activePeers;
public:
  CollectActivePeer(std::vector<SharedHandle<Peer> >& activePeers):
    _activePeers(activePeers) {}

  void operator()(const SharedHandle<Peer>& peer)
  {
    if(peer->isActive()) {
      _activePeers.push_back(peer);
    }
  }
};

void DefaultPeerStorage::getActivePeers
(std::vector<SharedHandle<Peer> >& activePeers)
{
  std::for_each(_peers.begin(), _peers.end(), CollectActivePeer(activePeers));
}

static TransferStat calculateStatFor(const SharedHandle<Peer>& peer)
{
  TransferStat s;
  s.downloadSpeed = peer->calculateDownloadSpeed();
  s.uploadSpeed = peer->calculateUploadSpeed();
  s.sessionDownloadLength = peer->getSessionDownloadLength();
  s.sessionUploadLength = peer->getSessionUploadLength();
  return s;
}

TransferStat DefaultPeerStorage::calculateStat()
{
  TransferStat stat;
  if(_lastTransferStatMapUpdated.differenceInMillis(global::wallclock) >= 250) {
    if(_logger->debug()) {
      _logger->debug("Updating TransferStat of PeerStorage");
    }
    _lastTransferStatMapUpdated = global::wallclock;
    _peerTransferStatMap.clear();
    std::vector<SharedHandle<Peer> > activePeers;
    getActivePeers(activePeers);
    for(std::vector<SharedHandle<Peer> >::const_iterator i =
          activePeers.begin(), eoi = activePeers.end(); i != eoi; ++i) {
      TransferStat s;
      s.downloadSpeed = (*i)->calculateDownloadSpeed();
      s.uploadSpeed = (*i)->calculateUploadSpeed();
      s.sessionDownloadLength = (*i)->getSessionDownloadLength();
      s.sessionUploadLength = (*i)->getSessionUploadLength();

      _peerTransferStatMap[(*i)->getID()] = calculateStatFor(*i);
      stat += s;
    }
    _cachedTransferStat = stat;
  } else {
    stat = _cachedTransferStat;
  }
  stat.sessionDownloadLength += _removedPeerSessionDownloadLength;
  stat.sessionUploadLength += _removedPeerSessionUploadLength;
  stat.setAllTimeUploadLength(_btRuntime->getUploadLengthAtStartup()+
                              stat.getSessionUploadLength());
  return stat;
}

void DefaultPeerStorage::updateTransferStatFor(const SharedHandle<Peer>& peer)
{
  if(_logger->debug()) {
    _logger->debug("Updating TransferStat for peer %s", peer->getID().c_str());
  }
  std::map<std::string, TransferStat>::iterator itr =
    _peerTransferStatMap.find(peer->getID());
  if(itr == _peerTransferStatMap.end()) {
    return;
  }
  _cachedTransferStat -= (*itr).second;
  TransferStat s = calculateStatFor(peer);
  _cachedTransferStat += s;
  (*itr).second = s;
}

TransferStat DefaultPeerStorage::getTransferStatFor
(const SharedHandle<Peer>& peer)
{
  std::map<std::string, TransferStat>::const_iterator itr =
    _peerTransferStatMap.find(peer->getID());
  if(itr == _peerTransferStatMap.end()) {
    return TransferStat();
  } else {
    return (*itr).second;
  }
}

void DefaultPeerStorage::deleteUnusedPeer(size_t delSize) {
  std::deque<SharedHandle<Peer> > temp;
  for(std::deque<SharedHandle<Peer> >::const_reverse_iterator itr =
        _peers.rbegin(), eoi = _peers.rend(); itr != eoi; ++itr) {
    const SharedHandle<Peer>& p = *itr;
    if(p->unused() && delSize > 0) {
      onErasingPeer(p);
      delSize--;
    } else {
      temp.push_front(p);
    }
  }
  _peers.swap(temp);
}

void DefaultPeerStorage::onErasingPeer(const SharedHandle<Peer>& peer) {}

void DefaultPeerStorage::onReturningPeer(const SharedHandle<Peer>& peer)
{
  if(peer->isActive()) {
    TransferStat removedStat(calculateStatFor(peer));
    _removedPeerSessionDownloadLength += removedStat.getSessionDownloadLength();
    _removedPeerSessionUploadLength += removedStat.getSessionUploadLength();
    _cachedTransferStat -= removedStat;

    // Execute choking algorithm if unchoked and interested peer is
    // disconnected.
    if(!peer->amChoking() && peer->peerInterested()) {
      executeChoke();
    }
  }
}

void DefaultPeerStorage::returnPeer(const SharedHandle<Peer>& peer)
{
  std::deque<SharedHandle<Peer> >::iterator itr =
    std::find(_peers.begin(), _peers.end(), peer);
  if(itr == _peers.end()) {
    if(_logger->debug()) {
      _logger->debug("Cannot find peer %s:%u in PeerStorage.",
                    peer->getIPAddress().c_str(), peer->getPort());
    }
  } else {
    _peers.erase(itr);

    onReturningPeer(peer);
    onErasingPeer(peer);
  }
}

bool DefaultPeerStorage::chokeRoundIntervalElapsed()
{
  const time_t CHOKE_ROUND_INTERVAL = 10;
  if(_pieceStorage->downloadFinished()) {
    return _seederStateChoke->getLastRound().
      difference(global::wallclock) >= CHOKE_ROUND_INTERVAL;
  } else {
    return _leecherStateChoke->getLastRound().
      difference(global::wallclock) >= CHOKE_ROUND_INTERVAL;
  }
}

void DefaultPeerStorage::executeChoke()
{
  std::vector<SharedHandle<Peer> > activePeers;
  getActivePeers(activePeers);
  if(_pieceStorage->downloadFinished()) {
    return _seederStateChoke->executeChoke(activePeers);
  } else {
    return _leecherStateChoke->executeChoke(activePeers);
  }
}

void DefaultPeerStorage::setPieceStorage(const SharedHandle<PieceStorage>& ps)
{
  _pieceStorage = ps;
}

void DefaultPeerStorage::setBtRuntime(const SharedHandle<BtRuntime>& btRuntime)
{
  _btRuntime = btRuntime;
}

} // namespace aria2