/*
    Copyright (c) 2007 Tobias Koenig <tokoe@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 as published by
    the Free Software Foundation; either version 2 of the License, or (at your
    option) any later version.

    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 AKONADI_MONITOR_P_H
#define AKONADI_MONITOR_P_H

#include "monitor.h"
#include "collection.h"
#include "collectionstatisticsjob.h"
#include "collectionfetchscope.h"
#include "item.h"
#include "itemfetchscope.h"
#include "job.h"
#include <akonadi/private/notificationmessage_p.h>
#include "notificationmanagerinterface.h"
#include "entitycache_p.h"

#include <kmimetype.h>

#include <QtCore/QObject>
#include <QtCore/QTimer>

namespace Akonadi {

class Monitor;

/**
 * @internal
 */
class MonitorPrivate
{
  public:
    MonitorPrivate( Monitor *parent );
    virtual ~MonitorPrivate() {}
    void init();

    Monitor *q_ptr;
    Q_DECLARE_PUBLIC( Monitor )
    org::freedesktop::Akonadi::NotificationManager *nm;
    Collection::List collections;
    QSet<QByteArray> resources;
    QSet<Item::Id> items;
    QSet<QString> mimetypes;
    bool monitorAll;
    QList<QByteArray> sessions;
    ItemFetchScope mItemFetchScope;
    CollectionFetchScope mCollectionFetchScope;
    Session *session;
    CollectionCache collectionCache;
    ItemCache itemCache;
    QQueue<NotificationMessage> pendingNotifications;
    QQueue<NotificationMessage> pipeline;
    bool fetchCollection;
    bool fetchCollectionStatistics;

    bool isCollectionMonitored( Collection::Id collection, const QByteArray &resource ) const
    {
      if ( monitorAll || isCollectionMonitored( collection ) || resources.contains( resource ) )
        return true;
      return false;
    }

    bool isItemMonitored( Item::Id item, Collection::Id collection, Collection::Id collectionDest,
                          const QString &mimetype, const QByteArray &resource ) const
    {
      if ( monitorAll || isCollectionMonitored( collection ) ||
           isCollectionMonitored( collectionDest ) ||items.contains( item ) ||
           resources.contains( resource ) || isMimeTypeMonitored( mimetype ) )
        return true;
      return false;
    }

    bool isSessionIgnored( const QByteArray &sessionId ) const
    {
      return sessions.contains( sessionId );
    }

    bool connectToNotificationManager();
    bool acceptNotification( const NotificationMessage &msg );
    void dispatchNotifications();
    bool ensureDataAvailable( const NotificationMessage &msg );
    void emitNotification( const NotificationMessage &msg );
    void updatePendingStatistics( const NotificationMessage &msg );
    void invalidateCaches( const NotificationMessage &msg );

    /** Used by ResourceBase to inform us about collection changes before the notifications are emitted,
        needed to avoid the missing RID race on change replay.
    */
    void invalidateCache( const Collection &col );

    virtual int pipelineSize() const;

    // private slots
    void dataAvailable();
    void slotSessionDestroyed( QObject* );
    void slotStatisticsChangedFinished( KJob* );
    void slotFlushRecentlyChangedCollections();

    void appendAndCompress( const NotificationMessage &msg  );

    virtual void slotNotify( const NotificationMessage::List &msgs );

    void emitItemNotification( const NotificationMessage &msg, const Item &item = Item(),
                               const Collection &collection = Collection(), const Collection &collectionDest = Collection() );
    void emitCollectionNotification( const NotificationMessage &msg, const Collection &col = Collection(),
                                     const Collection &par = Collection(), const Collection &dest = Collection() );


    /**
      @brief Class used to determine when to purge items in a Collection

      The buffer method can be used to buffer a Collection. This may cause another Collection
      to be purged if it is removed from the buffer.

      The purge method is used to purge a Collection from the buffer, but not the model.
      This is used for example, to not buffer Collections anymore if they get referenced,
      and to ensure that one Collection does not appear twice in the buffer.

      Check whether a Collection is buffered using the isBuffered method.
    */
    class PurgeBuffer
    {
      // Buffer the most recent 10 unreferenced Collections
      static const int MAXBUFFERSIZE = 10;
    public:
      explicit PurgeBuffer()
        : m_index( 0 ),
          m_bufferSize( MAXBUFFERSIZE )
      {
      }

      /**
        Adds @p id to the Collections to be buffered

        @returns The collection id which was removed form the buffer or -1 if none.
      */
      Collection::Id buffer( Collection::Id id );

      /**
      Removes @p id from the Collections being buffered
      */
      void purge( Collection::Id id );

      bool isBuffered( Collection::Id id ) const
      {
        return m_buffer.contains( id );
      }

    private:
      QList<Collection::Id> m_buffer;
      int m_index;
      int m_bufferSize;
    } m_buffer;


    QHash<Collection::Id, int> refCountMap;
    bool useRefCounting;
    void ref( Collection::Id id );
    Collection::Id deref( Collection::Id id );

  private:
    // collections that need a statistics update
    QSet<Collection::Id> recentlyChangedCollections;

    /**
      @returns True if @p msg should be ignored. Otherwise appropriate signals are emitted for it.
    */
    bool isLazilyIgnored( const NotificationMessage & msg ) const;

    bool isCollectionMonitored( Collection::Id collection ) const
    {
      if ( collections.contains( Collection( collection ) ) )
        return true;
      if ( collections.contains( Collection::root() ) )
        return true;
      return false;
    }

    bool isMimeTypeMonitored( const QString& mimetype ) const
    {
      if ( mimetypes.contains( mimetype ) )
        return true;

      KMimeType::Ptr mimeType = KMimeType::mimeType( mimetype, KMimeType::ResolveAliases );
      if ( mimeType.isNull() )
        return false;

      foreach ( const QString &mt, mimetypes ) {
        if ( mimeType->is( mt ) )
          return true;
      }

      return false;
    }

    void fetchStatistics( Collection::Id colId )
    {
      CollectionStatisticsJob *job = new CollectionStatisticsJob( Collection( colId ), session );
      QObject::connect( job, SIGNAL(result(KJob*)), q_ptr, SLOT(slotStatisticsChangedFinished(KJob*)) );
    }

    void notifyCollectionStatisticsWatchers( Collection::Id collection, const QByteArray &resource )
    {
      if ( isCollectionMonitored( collection, resource ) ) {
        if (recentlyChangedCollections.empty() )
          QTimer::singleShot( 500, q_ptr, SLOT(slotFlushRecentlyChangedCollections()) );
        recentlyChangedCollections.insert( collection );
      }
    }
};

}

#endif
