//////////////////////////////////////////////////////////////////////

//

// This file is part of BeeBEEP.

//

// BeeBEEP 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 3 of the License,

// or (at your option) any later version.

//

// BeeBEEP 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 BeeBEEP.  If not, see <http://www.gnu.org/licenses/>.

//

// Author: Marco Mastroddi <marco.mastroddi(AT)gmail.com>

//

// $Id$

//

//////////////////////////////////////////////////////////////////////



#include "FileShare.h"

#include "FileTransfer.h"

#include "FileTransferPeer.h"

#include "Random.h"

#include "Settings.h"

#include "Protocol.h"





FileTransfer::FileTransfer( QObject *parent )

  : QTcpServer( parent ), m_files(), m_peers()

{

}



bool FileTransfer::startListener()

{

  qDebug() << "Starting File Transfer server";



  if( !listen( Settings::instance().hostAddressToListen(), Settings::instance().defaultFileTransferPort() ) )

  {

    qWarning() << "Unable to bind default file transfer port" << Settings::instance().defaultFileTransferPort();

    if( !listen( Settings::instance().hostAddressToListen() ) )

    {

      qWarning() << "Unable to bind a valid file transfer port";

      return false;

    }

  }



  qDebug() << "File Transfer server listen" << serverAddress().toString() << serverPort();

  resetServerFiles();

  emit listening();



  if( downloadsInQueue() > 0  )

    qDebug() << "File Transfer has" << downloadsInQueue() << "files in queue";



  return true;

}



void FileTransfer::stopListener()

{

  if( isListening() )

  {

    foreach( FileTransferPeer* transfer_peer, m_peers )

      transfer_peer->cancelTransfer();



    m_files.clear();



    qDebug() << "File Transfer server closed";

    close();

  }

  else

    qDebug() << "File Transfer server is not active";

}



void FileTransfer::resetServerFiles()

{

  qDebug() << "File Transfer reset files to" << Settings::instance().localUser().hostAddress().toString() << serverPort();

  QList<FileInfo>::iterator it = m_files.begin();

  while( it != m_files.end() )

  {

    (*it).setHostAddress( Settings::instance().localUser().hostAddress() );

    (*it).setHostPort( serverPort() );

    ++it;

  }

}



FileInfo FileTransfer::fileInfo( VNumber file_id ) const

{

  QList<FileInfo>::const_iterator it = m_files.begin();

  while( it != m_files.end() )

  {

    if( (*it).id() == file_id )

      return *it;

    ++it;

  }

  return FileInfo();

}



FileInfo FileTransfer::fileInfoFromPath( const QString& file_absolute_path ) const

{

  QList<FileInfo>::const_iterator it = m_files.begin();

  while( it != m_files.end() )

  {

    if( (*it).path() == file_absolute_path )

      return *it;

    ++it;

  }

  return FileInfo();

}



void FileTransfer::removeFile( const QFileInfo& fi )

{

  QString file_path = fi.absoluteFilePath();

  QList<FileInfo>::iterator it = m_files.begin();

  while( it != m_files.end() )

  {

    if( (*it).path() == file_path )

      it = m_files.erase( it );

    else

      ++it;

  }

}



FileInfo FileTransfer::addFile( const QFileInfo& fi, const QString& share_folder )

{

  FileInfo file_info = fileInfoFromPath( fi.absoluteFilePath() );

  if( file_info.isValid() )

  {

    QString file_hash = Protocol::instance().fileInfoHash( fi );

    if( file_info.fileHash() == file_hash )

      return file_info;

    else

      removeFile( fi );

  }



  file_info = Protocol::instance().fileInfo( fi, share_folder );

  file_info.setHostAddress( Settings::instance().localUser().hostAddress() );

  file_info.setHostPort( serverPort() );

  m_files.append( file_info );

  return file_info;

}



void FileTransfer::addFileInfoList( const QList<FileInfo>& file_info_list )

{

  foreach( FileInfo fi, file_info_list )

  {

    if( !fileInfo( fi.id() ).isValid() )

      m_files.append( fi );

  }

}



void FileTransfer::incomingConnection( qintptr socket_descriptor )

{

  FileTransferPeer *upload_peer = new FileTransferPeer( this );

  upload_peer->setTransferType( FileTransferPeer::Upload );

  upload_peer->setId( Protocol::instance().newId() );

  m_peers.append( upload_peer );

  setupPeer( upload_peer, socket_descriptor );

}



void FileTransfer::setupPeer( FileTransferPeer* transfer_peer, int socket_descriptor )

{

  if( transfer_peer->isInQueue() )

  {

#ifdef BEEBEEP_DEBUG

    qDebug() << transfer_peer->name() << "is removed from queue";

#endif

    transfer_peer->removeFromQueue();

  }



#ifdef BEEBEEP_DEBUG

  qDebug() << transfer_peer->name() << "starts its connection. Active downloads:" << activeDownloads();

#endif

  if( !transfer_peer->isDownload() )

  {

    connect( transfer_peer, SIGNAL( fileUploadRequest( VNumber, const QByteArray& ) ), this, SLOT( checkUploadRequest( VNumber, const QByteArray& ) ) );

  }



  connect( transfer_peer, SIGNAL( authenticationRequested() ), this, SLOT( checkAuthentication() ) );

  connect( transfer_peer, SIGNAL( progress( VNumber, VNumber, const FileInfo&, FileSizeType ) ), this, SIGNAL( progress( VNumber, VNumber, const FileInfo&, FileSizeType ) ) );

  connect( transfer_peer, SIGNAL( message( VNumber, VNumber, const FileInfo&, const QString& ) ), this, SIGNAL( message( VNumber, VNumber, const FileInfo&, const QString& ) ) );

  connect( transfer_peer, SIGNAL( destroyed() ), this, SLOT( peerDestroyed() ) );



  transfer_peer->setConnectionDescriptor( socket_descriptor );

  int delay = Random::number( 1, 9 ) * 100;

#ifdef BEEBEEP_DEBUG

  qDebug() << transfer_peer->name() << "starts in" << delay << "ms";

#endif

  QTimer::singleShot( delay, transfer_peer, SLOT( startConnection() ) );

}



void FileTransfer::checkAuthentication()

{

  FileTransferPeer* mp_peer = (FileTransferPeer*)sender();

  if( !mp_peer )

  {

    qWarning() << "Sender Peer not found in check authentication";

    return;

  }



  qDebug() << mp_peer->name() << "checks authentication message";

  emit userConnected( mp_peer->id(), mp_peer->peerAddress(), mp_peer->messageAuth() );

}



void FileTransfer::validateUser( VNumber FileTransferPeer_id, VNumber user_id )

{

  qDebug() << "File Transfer server validate user" << user_id << "for peer" << FileTransferPeer_id;

  QList<FileTransferPeer*>::iterator it = m_peers.begin();

  while( it != m_peers.end() )

  {

    if( (*it)->id() == FileTransferPeer_id )

    {

      if( user_id == ID_INVALID )

      {

        qWarning() << (*it)->name() << "has not authorized the user";

        (*it)->cancelTransfer();

      }

      else

      {

        qDebug() << (*it)->name() << "has authorized user" << user_id;

        (*it)->setUserAuthorized( user_id );

      }

      return;

    }

    ++it;

  }

}



void FileTransfer::checkUploadRequest( VNumber file_id, const QByteArray& file_password )

{

#ifdef BEEBEEP_DEBUG

  qDebug() << "Checking upload request:" << file_id << file_password;

#endif

  FileTransferPeer *upload_peer = qobject_cast<FileTransferPeer*>( sender() );

  if( !upload_peer )

  {

    qWarning() << "File Transfer server received a signal from invalid upload peer";

    return;

  }



  if( !Settings::instance().fileTransferIsEnabled() )

  {

    qWarning() << "File Transfer is disabled";

    upload_peer->cancelTransfer();

    return;

  }



  FileInfo file_info = fileInfo( file_id );

  if( !file_info.isValid() )

  {

    // Now check file sharing

    file_info = FileShare::instance().localFileInfo( file_id );



    if( !file_info.isValid() )

    {

      qWarning() << "File Transfer server received a request of a file not in list";

      upload_peer->cancelTransfer();

      return;

    }

  }



  if( file_info.password() != file_password )

  {

    qWarning() << "File Transfer server received a request for the file" << file_info.name() << "but with the wrong password";

    upload_peer->cancelTransfer();

    return;

  }



  upload_peer->startUpload( file_info );

}



void FileTransfer::downloadFile( const FileInfo& fi )

{

  FileTransferPeer *download_peer = new FileTransferPeer( this );

  download_peer->setTransferType( FileTransferPeer::Download );

  download_peer->setId( Protocol::instance().newId() );

  download_peer->setFileInfo( fi );

  download_peer->setInQueue();

  m_peers.append( download_peer );

#ifdef BEEBEEP_DEBUG

  qDebug() << download_peer->name() << "is scheduled for download";

#endif



  if( activeDownloads() < Settings::instance().maxSimultaneousDownloads() )

    setupPeer( download_peer, 0 );

}



FileTransferPeer* FileTransfer::peer( VNumber peer_id ) const

{

  QList<FileTransferPeer*>::const_iterator it = m_peers.begin();

  while( it != m_peers.end() )

  {

    if( (*it)->id() == peer_id )

      return *it;

    ++it;

  }

  qWarning() << "File Transfer server has not found the peer" << peer_id;

  return 0;

}



void FileTransfer::peerDestroyed()

{

  if( !sender() )

  {

    qWarning() << "File Transfer is unable to find peer sender of signal destroyed(). List become invalid";

    return;

  }



  if( m_peers.removeOne( (FileTransferPeer*)sender() ) )

    qDebug() << "Removing peer from list." << m_peers.size() << "peers remained";



  if( isListening() && downloadsInQueue() > 0 )

    startNewDownload();

}



bool FileTransfer::cancelTransfer( VNumber peer_id )

{

  FileTransferPeer* transfer_peer = peer( peer_id );

  if( transfer_peer )

  {

    qDebug() << "File Transfer server requests to cancel transfer in progress of" << transfer_peer->name();

    transfer_peer->cancelTransfer();

    return true;

  }

  qWarning() << "File Transfer server cannot cancel the file transfer because it has not found the peer" << peer_id;

  return false;

}



int FileTransfer::activeDownloads() const

{

  int active_downloads = 0;

  foreach( FileTransferPeer* transfer_peer, m_peers )

  {

    if( transfer_peer->isDownload() && transfer_peer->isActive() )

      active_downloads++;

  }

  return active_downloads;

}



int FileTransfer::downloadsInQueue() const

{

  int downloads_in_queue = 0;

  foreach( FileTransferPeer* transfer_peer, m_peers )

  {

    if( transfer_peer->isDownload() && transfer_peer->isInQueue() )

      downloads_in_queue++;

  }

  return downloads_in_queue;

}



FileTransferPeer* FileTransfer::nextDownloadInQueue() const

{

  foreach( FileTransferPeer* transfer_peer, m_peers )

  {

    if( transfer_peer->isDownload() && transfer_peer->isInQueue() )

      return transfer_peer;

  }

  return 0;

}



void FileTransfer::startNewDownload()

{

  if( activeDownloads() >= Settings::instance().maxSimultaneousDownloads() )

    return;



  FileTransferPeer* download_peer = nextDownloadInQueue();

  if( !download_peer )

    return;



#ifdef BEEBEEP_DEBUG

  qDebug() << download_peer->name() << "is removed from queue and started";

#endif



  setupPeer( download_peer, 0 );

}