/***************************************************************************
 *   Copyright (C) 2010 by Joris Guisson                                   *
 *   joris.guisson@gmail.com                                               *
 *                                                                         *
 *   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.          *
 ***************************************************************************/

#ifndef BT_SUPERSEEDER_H
#define BT_SUPERSEEDER_H

#include <ktorrent_export.h>
#include <util/constants.h>
#include <QMap>
#include <QSet>

namespace bt
{
class ChunkCounter;
class PeerInterface;
class BitSet;


/**
    Class which manages superseeding. Superseeding is a way to achieve much higher seeding
    efficiences, thereby allowing a peer to use much less bandwidth to get a torrent seeded.
    @see http://bittorrent.org/beps/bep_0016.html
*/
class KTORRENT_EXPORT SuperSeeder
{
public:
    /**
        Constructor.
        @param num_chunks The number of chunks
    */
    SuperSeeder(Uint32 num_chunks);
    virtual ~SuperSeeder();

    /**
        A HAVE message was sent by a Peer
        @param peer The Peer
        @param chunk The chunk
    */
    void have(PeerInterface* peer, bt::Uint32 chunk);

    /**
        A HAVE_ALL message was sent by a Peer
        @param peer The Peer
    */
    void haveAll(PeerInterface* peer);

    /**
        A BITSET message was sent by a Peer
        @param peer The Peer
    */
    void bitset(PeerInterface* peer, const BitSet & bs);

    /**
        A Peer has been added
        @param peer The Peer
    */
    void peerAdded(PeerInterface* peer);

    /**
        A Peer has been removed
        @param peer The Peer
    */
    void peerRemoved(PeerInterface* peer);

    /**
        Dump the status of the SuperSeeder for debugging purposes.
    */
    void dump();

private:
    void sendChunk(PeerInterface* peer);

private:
    ChunkCounter* chunk_counter;
    QMultiMap<bt::Uint32, bt::PeerInterface*> active_chunks;
    QMap<bt::PeerInterface*, bt::Uint32> active_peers;
    Uint32 num_seeders;

    typedef QMultiMap<bt::Uint32, bt::PeerInterface*>::iterator ActiveChunkItr;
    typedef QMap<bt::PeerInterface*, bt::Uint32>::iterator ActivePeerItr;
};

}

#endif // BT_SUPERSEEDER_H
