/* This file is part of the KDE Project
   Copyright (c) 2009-2011 Sebastian Trueg <trueg@kde.org>

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License version 2 as published by the Free Software Foundation.

   This library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with this library; see the file COPYING.LIB.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.
*/

#ifndef _NEPOMUK_METADATA_MOVER_H_
#define _NEPOMUK_METADATA_MOVER_H_

#include <QtCore/QMutex>
#include <QtCore/QQueue>
#include <QtCore/QSet>
#include <QtCore/QDateTime>

#include <KUrl>

#include "updaterequest.h"

class QTimer;

namespace Soprano {
    class Model;
}

namespace Nepomuk {
    class MetadataMover : public QObject
    {
        Q_OBJECT

    public:
        MetadataMover( Soprano::Model* model, QObject* parent = 0 );
        ~MetadataMover();

    public Q_SLOTS:
        void moveFileMetadata( const KUrl& from, const KUrl& to );
        void removeFileMetadata( const KUrl& file );
        void removeFileMetadata( const KUrl::List& files );

    Q_SIGNALS:
        /**
         * Emitted for files (and folders) that have been moved but
         * do not have metadata to be moved. This allows the file indexer
         * service to pick them up in case they are of interest. The
         * typical example would be moving a file from a non-indexed into
         * an indexed folder.
         */
        void movedWithoutData( const QString& path );

    private Q_SLOTS:
        void slotClearRecentlyFinishedRequests();
        void slotWorkUpdateQueue();

        /**
         * Start the update queue from the main thread.
         */
        void slotStartUpdateTimer();

    private:
        /**
         * Remove the metadata for file \p url
         */
        void removeMetadata( const KUrl& url );

        /**
         * Recursively update the nie:url and nie:isPartOf properties
         * of the resource describing \p from.
         */
        void updateMetadata( const KUrl& from, const KUrl& to );

        // if the second url is empty, just delete the metadata
        QQueue<UpdateRequest> m_updateQueue;

        // we use several systems to watch for file operations.
        // Thus, we can get the same request more than once. We then
        // need a way to determine if we have already handled it.
        // (otherwise we would remove the previously moved data.)
        // The only way to do that is to keep a list of all requests
        // that have been handled in the last N seconds.
        QSet<UpdateRequest> m_recentlyFinishedRequests;

        QMutex m_queueMutex;

        QTimer* m_queueTimer;
        QTimer* m_recentlyFinishedRequestsTimer;

        Soprano::Model* m_model;
    };
}

#endif
