/* Copyright 2009 Klarälvdalens Datakonsult AB

   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) version 3 or any later version
   accepted by the membership of KDE e.V. (or its successor approved
   by the membership of KDE e.V.), which shall act as a proxy
   defined in Section 14 of version 3 of the license.

   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, see <http://www.gnu.org/licenses/>.
*/
#include "backupjob.h"

#include <Akonadi/CollectionDeleteJob>
#include <Akonadi/CollectionFetchJob>
#include <Akonadi/CollectionFetchScope>
#include <Akonadi/ItemFetchJob>
#include <Akonadi/ItemFetchScope>
#include <KMime/Message>

#include <klocale.h>
#include <kzip.h>
#include <ktar.h>
#include <kmessagebox.h>
#include <kio/global.h>

#include <QFileInfo>
#include <QTimer>

using namespace KMail;

BackupJob::BackupJob( QWidget *parent )
  : QObject( parent ),
    mArchiveType( Zip ),
    mRootFolder( 0 ),
    mArchive( 0 ),
    mParentWidget( parent ),
    mArchivedMessages( 0 ),
    mArchivedSize( 0 ),
    mProgressItem( 0 ),
    mAborted( false ),
    mDeleteFoldersAfterCompletion( false ),
    mCurrentFolder( Akonadi::Collection() ),
    mCurrentJob( 0 )
{
}

BackupJob::~BackupJob()
{
  mPendingFolders.clear();
  delete mArchive;
  mArchive = 0;
}

void BackupJob::setRootFolder( const Akonadi::Collection &rootFolder )
{
  mRootFolder = rootFolder;
}

void BackupJob::setSaveLocation( const KUrl& savePath )
{
  mMailArchivePath = savePath;
}

void BackupJob::setArchiveType( ArchiveType type )
{
  mArchiveType = type;
}

void BackupJob::setDeleteFoldersAfterCompletion( bool deleteThem )
{
  mDeleteFoldersAfterCompletion = deleteThem;
}

bool BackupJob::queueFolders( const Akonadi::Collection &root )
{
  mPendingFolders.append( root );
  // FIXME: Get rid of the exec()
  // We could do a recursive CollectionFetchJob, but we only fetch the first level
  // and then recurse manually. This is needed because a recursive fetch doesn't
  // sort the collections the way we want. We need all first level children to be
  // in the mPendingFolders list before all second level children, so that the
  // directories for the first level are written before the directories in the
  // second level, in the archive file.
  Akonadi::CollectionFetchJob *job = new Akonadi::CollectionFetchJob( root,
      Akonadi::CollectionFetchJob::FirstLevel );
  job->fetchScope().setAncestorRetrieval( Akonadi::CollectionFetchScope::All );
  job->exec();
  if ( job->error() ) {
    kWarning() << job->errorString();
    abort( i18n( "Unable to retrieve folder list." ) );
    return false;
  }

  foreach ( const Akonadi::Collection &collection, job->collections() ) {
    if ( !queueFolders( collection ) )
      return false;
  }

  mAllFolders = mPendingFolders;
  return true;
}

bool BackupJob::hasChildren( const Akonadi::Collection &collection ) const
{
  foreach( const Akonadi::Collection &curCol, mAllFolders ) {
    if ( collection == curCol.parentCollection() )
      return true;
  }
  return false;
}

void BackupJob::cancelJob()
{
  abort( i18n( "The operation was canceled by the user." ) );
}

void BackupJob::abort( const QString &errorMessage )
{
  // We could be called this twice, since killing the current job below will cause the job to fail,
  // and that will call abort()
  if ( mAborted )
    return;

  mAborted = true;
  if ( mCurrentFolder.isValid() ) {
    mCurrentFolder = Akonadi::Collection();
  }
  if ( mArchive && mArchive->isOpen() ) {
    mArchive->close();
  }
  if ( mCurrentJob ) {
    mCurrentJob->kill();
    mCurrentJob = 0;
  }
  if ( mProgressItem ) {
    mProgressItem->setComplete();
    mProgressItem = 0;
    // The progressmanager will delete it
  }

  QString text = i18n( "Failed to archive the folder '%1'.", mRootFolder.name() );
  text += '\n' + errorMessage;
  KMessageBox::sorry( mParentWidget, text, i18n( "Archiving failed" ) );
  deleteLater();
  // Clean up archive file here?
}

void BackupJob::finish()
{
  if ( mArchive->isOpen() ) {
    if ( !mArchive->close() ) {
      abort( i18n( "Unable to finalize the archive file." ) );
      return;
    }
  }

  mProgressItem->setStatus( i18n( "Archiving finished" ) );
  mProgressItem->setComplete();
  mProgressItem = 0;

  QFileInfo archiveFileInfo( mMailArchivePath.path() );
  QString text = i18n( "Archiving folder '%1' successfully completed. "
                       "The archive was written to the file '%2'.",
                       mRootFolder.name(), mMailArchivePath.path() );
  text += '\n' + i18np( "1 message of size %2 was archived.",
                        "%1 messages with the total size of %2 were archived.",
                        mArchivedMessages, KIO::convertSize( mArchivedSize ) );
  text += '\n' + i18n( "The archive file has a size of %1.",
                       KIO::convertSize( archiveFileInfo.size() ) );
  KMessageBox::information( mParentWidget, text, i18n( "Archiving finished" ) );

  if ( mDeleteFoldersAfterCompletion ) {
    // Some safety checks first...
    if ( archiveFileInfo.size() > 0 && ( mArchivedSize > 0 || mArchivedMessages == 0 ) ) {
      // Sorry for any data loss!
      new Akonadi::CollectionDeleteJob( mRootFolder );
    }
  }

  deleteLater();
}

void BackupJob::archiveNextMessage()
{
  if ( mAborted )
    return;

  if ( mPendingMessages.isEmpty() ) {
    kDebug() << "===> All messages done in folder " << mCurrentFolder.name();
    archiveNextFolder();
    return;
  }

  Akonadi::Item item = mPendingMessages.front();
  mPendingMessages.pop_front();
  kDebug() << "Fetching item with ID" << item.id() << "for folder" << mCurrentFolder.name();

  mCurrentJob = new Akonadi::ItemFetchJob( item );
  mCurrentJob->fetchScope().fetchFullPayload( true );
  connect( mCurrentJob, SIGNAL(result(KJob*)),
           this, SLOT(itemFetchJobResult(KJob*)) );
}

void BackupJob::processMessage( const Akonadi::Item &item )
{
  if ( mAborted )
    return;

  const KMime::Message::Ptr message = item.payload<KMime::Message::Ptr>();
  kDebug() << "Processing message with subject " << message->subject( false );
  const QByteArray messageData = message->encodedContent();
  const qint64 messageSize = messageData.size();
  const QString messageName = QString::number( item.id() );
  const QString fileName = pathForCollection( mCurrentFolder ) + "/cur/" + messageName;

  // PORT ME: user and group!
  kDebug() << "AKONDI PORT: disabled code here!";
  if ( !mArchive->writeFile( fileName, "user", "group", messageData, messageSize ) ) {
    abort( i18n( "Failed to write a message into the archive folder '%1'.", mCurrentFolder.name() ) );
    return;
  }

  mArchivedMessages++;
  mArchivedSize += messageSize;

  // Use a singleshot timer, otherwise the job started in archiveNextMessage()
  // will hang
  QTimer::singleShot( 0, this, SLOT(archiveNextMessage()) );
}

void BackupJob::itemFetchJobResult( KJob *job )
{
  if ( mAborted )
    return;

  Q_ASSERT( job == mCurrentJob );
  mCurrentJob = 0;

  if ( job->error() ) {
    Q_ASSERT( mCurrentFolder.isValid() );
    kWarning() << job->errorString();
    abort( i18n( "Downloading a message in folder '%1' failed.", mCurrentFolder.name() ) );
  }
  else {
    Akonadi::ItemFetchJob *fetchJob = dynamic_cast<Akonadi::ItemFetchJob*>( job );
    Q_ASSERT( fetchJob );
    Q_ASSERT( fetchJob->items().size() == 1 );
    processMessage( fetchJob->items().first() );
  }
}

bool BackupJob::writeDirHelper( const QString &directoryPath )
{
  // PORT ME: Correct user/group
  kDebug() << "AKONDI PORT: Disabled code here!";
  return mArchive->writeDir( directoryPath, "user", "group" );
}

QString BackupJob::collectionName( const Akonadi::Collection &collection ) const
{
  foreach ( const Akonadi::Collection &curCol, mAllFolders ) {
    if ( curCol == collection )
      return curCol.name();
  }
  Q_ASSERT( false );
  return QString();
}

QString BackupJob::pathForCollection( const Akonadi::Collection &collection ) const
{
  QString fullPath = collectionName( collection );
  Akonadi::Collection curCol = collection.parentCollection();
  if ( collection != mRootFolder ) {
    Q_ASSERT( curCol.isValid() );
    while( curCol != mRootFolder ) {
      fullPath.prepend( '.' + collectionName( curCol ) + ".directory" + '/' );
      curCol = curCol.parentCollection();
    }
    Q_ASSERT( curCol == mRootFolder );
    fullPath.prepend( '.' + collectionName( curCol ) + ".directory" + '/' );
  }
  return fullPath;
}

QString BackupJob::subdirPathForCollection( const Akonadi::Collection &collection ) const
{
  QString path = pathForCollection( collection );
  const int parentDirEndIndex = path.lastIndexOf( collection.name() );
  Q_ASSERT( parentDirEndIndex != -1 );
  path = path.left( parentDirEndIndex );
  path.append( '.' + collection.name() + ".directory" );
  return path;
}

void BackupJob::archiveNextFolder()
{
  if ( mAborted )
    return;

  if ( mPendingFolders.isEmpty() ) {
    finish();
    return;
  }

  mCurrentFolder = mPendingFolders.takeAt( 0 );
  kDebug() << "===> Archiving next folder: " << mCurrentFolder.name();
  mProgressItem->setStatus( i18n( "Archiving folder %1", mCurrentFolder.name() ) );

  const QString folderName = mCurrentFolder.name();
  bool success = true;
  if ( hasChildren( mCurrentFolder ) ) {
    if ( !writeDirHelper( subdirPathForCollection( mCurrentFolder ) ) )
      success = false;
  }
  if ( !writeDirHelper( pathForCollection( mCurrentFolder ) ) )
    success = false;
  if ( !writeDirHelper( pathForCollection( mCurrentFolder ) + "/cur" ) )
    success = false;
  if ( !writeDirHelper( pathForCollection( mCurrentFolder ) + "/new" ) )
    success = false;
  if ( !writeDirHelper( pathForCollection( mCurrentFolder ) + "/tmp" ) )
    success = false;
  if ( !success ) {
    abort( i18n( "Unable to create folder structure for folder '%1' within archive file.",
                 mCurrentFolder.name() ) );
    return;
  }

  Akonadi::ItemFetchJob *job = new Akonadi::ItemFetchJob( mCurrentFolder );
  job->setProperty( "folderName", folderName );
  connect( job, SIGNAL( result( KJob* ) ), SLOT( onArchiveNextFolderDone( KJob* ) ) );
}

void BackupJob::onArchiveNextFolderDone( KJob *job )
{
  if ( job->error() ) {
    kWarning() << job->errorString();
    abort( i18n( "Unable to get message list for folder %1.", job->property( "folderName" ).toString() ) );
    return;
  }

  Akonadi::ItemFetchJob *fetchJob = qobject_cast<Akonadi::ItemFetchJob*>( job );
  mPendingMessages += fetchJob->items();
  archiveNextMessage();
}

void BackupJob::start()
{
  Q_ASSERT( !mMailArchivePath.isEmpty() );
  Q_ASSERT( mRootFolder.isValid() );

  if ( !queueFolders( mRootFolder ) )
    return;

  switch ( mArchiveType ) {
    case Zip: {
      KZip *zip = new KZip( mMailArchivePath.path() );
      zip->setCompression( KZip::DeflateCompression );
      mArchive = zip;
      break;
    }
    case Tar: {
      mArchive = new KTar( mMailArchivePath.path(), "application/x-tar" );
      break;
    }
    case TarGz: {
      mArchive = new KTar( mMailArchivePath.path(), "application/x-gzip" );
      break;
    }
    case TarBz2: {
      mArchive = new KTar( mMailArchivePath.path(), "application/x-bzip2" );
      break;
    }
  }

  kDebug() << "Starting backup.";
  if ( !mArchive->open( QIODevice::WriteOnly ) ) {
    abort( i18n( "Unable to open archive for writing." ) );
    return;
  }

  mProgressItem = KPIM::ProgressManager::createProgressItem(
      "BackupJob",
      i18n( "Archiving" ),
      QString(),
      true );
  mProgressItem->setUsesBusyIndicator( true );
  connect( mProgressItem, SIGNAL(progressItemCanceled(KPIM::ProgressItem*)),
           this, SLOT(cancelJob()) );

  archiveNextFolder();
}

#include "backupjob.moc"