/*

* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:   VideoThumbnailData singleton class definition

*/

#ifndef __VIDEOTHUMBNAILDATA_H__

#define __VIDEOTHUMBNAILDATA_H__

// INCLUDES

#include <QObject>

#include <QHash>

#include <QPair>

#include <QIcon>

#include <QSet>

#include <QPointer>

#include <mpxitemid.h>

#include "videocollectionexport.h"

// FORWARD DECLARATIONS

class VideoThumbnailDataPrivate;

// CLASS DECLARATIONS

class VIDEOCOLLECTION_DLL_EXPORT VideoThumbnailData : public QObject

{

    /**

     * Defined to be able to use signals and slots.

     */

    Q_OBJECT

    /**

     * disable copy-constructor and assignment operator

     */

	Q_DISABLE_COPY(VideoThumbnailData)

public:

    /*

     * Thumbnail fetch priorities.

     */

    enum VideoThumbnailPriority

    {

        VideoThumbnailPriorityLow = 2000,

        VideoThumbnailPriorityMedium = 3000,

        VideoThumbnailPriorityHigh = 5000

    };    

    /**

     * Returns singleton instance for this class.

     *

     * @return The singleton instance.

     *

     */

    static VideoThumbnailData &instance();

    /**

     * Method starts fetching thumbnail for the video specified by given mediaId

     * Media IDs are used as a key identification in the thumbnail map where data is

     * collected. Id is passed to thumbnail manager as internal data and when

     * thumbnail is fetched and thumbnailReadySlot is signaled, id is used to notify

     * client about which item's thumbnail is ready.

     *

     * If thumbnail fetching is started succesfully, method saves thumbnail item

     * into local repository with default thumbnail data.

     *

     * @param mediaId media id for which to start fetching thumbnail

     * @param priority priority for the fetch

     *

     * @return int: thumbnail id or -1 if fetch starting fails.

     *

     */

    int startFetchingThumbnail(int mediaId, int priority);

    /**

     * Method removes thumbnail data from the local repository.

     *

     * @param mediaId id for media whose thumbnail is to be removed

     *

     * @return bool: true if item removed correctly, false if not.

     *

     */

    bool removeThumbnail(TMPXItemId mediaId);

    /**

     * Method returns a pointer to video's thumbnail.

     *

     * If thumbnail fetching is ongoing or not yet started, pointer to default 

     * thumbnail is returned.

     *

     * @param mediaId media id for which to get thumbnail

     * @param tnData reference to thumbnail data where data is occupied

     *

     * @return QIcon* thumbnail pointer

     *

     */

    const QIcon* getThumbnail(TMPXItemId mediaId);

    /**

     * Starts background thumbnail fetching.

     *

     * @param fetchIndex index where to start the background thumbnail fetching.

     *  

     */

    void startBackgroundFetching(int fetchIndex);

    /**

     * Enables or disables thumbnail background fetching. Default is enabled.

     * 

     * @param enable true enables and false disables thumbnail background fetching.

     */

    void enableBackgroundFetching(bool enable);

    /**

     * Frees allocated data for thumbnails and cancels ongoing fetches.

     * 

     */

    void freeThumbnailData();

signals:

    /**

     * This signal is emitted from thumbnailReadySlot, when

     *

     * @param mediaIds: media ids of the videos whose thumbnail is ready.

     *

     */

    void thumbnailsFetched(QList<TMPXItemId> mediaIds);

private:

    /**

     * Default constructor

     */

    VideoThumbnailData();

    /**

     * Destructor

     */

    ~VideoThumbnailData();

    /**

     * Private implementation.

     */

    QPointer<VideoThumbnailDataPrivate> const d_ptr;

};

#endif  // __VIDEOTHUMBNAILDATA_H__

// End of file