/*

* 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: VideoThumbnailDataPrivate class definition

*

*/

#ifndef __VIDEOTHUMBNAILDATAPRIVATE_H__

#define __VIDEOTHUMBNAILDATAPRIVATE_H__

// INCLUDES

#include <QObject>

#include <QPointer>

#include <QCache>

#include <QIcon>

#include <QSet>

#include <QList>

#include <e32const.h>

#include <mpxitemid.h>

// FORWARD DECLARATIONS

class ThumbnailManager;

class VideoCollectionWrapper;

class VideoSortFilterProxyModel;

class QModelIndex;

class QTimer;

class VideoThumbnailDataPrivate : public QObject

{

    /**

     * defined to be able to use signals and slots

     */

    Q_OBJECT

public:

    /**

     * Default constructor

     */

    VideoThumbnailDataPrivate();

    /**

     * Destructor

     */

    virtual ~VideoThumbnailDataPrivate();

    /**

     * Starts fetching thumbnails for medias in the model defined by the indexes 

     * parameter. Priority for the thumbnails is ascending starting from the 

     * defined priority. Uses method startFetchingThumbnail for the actual 

     * fetching.

     *

     * param @indexes indexes of the medias in the model

     * param @priority starting priority for the thumbnails

     *

     * @return int count of fetches started or -1 in case of error.

     */

    int startFetchingThumbnails(const QList<QModelIndex> &indexes, int priority);

    /**

     * 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(TMPXItemId mediaId, int priority);

    /**

     * 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 ocpied

     *

     * @return QIcon* thumbnail pointer

     *

     */

    const QIcon* getThumbnail(TMPXItemId mediaId);

    /**

     * 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);

    /**

     * Starts background thumbnail fetching from the given fetch index.

     *

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

     */

    void startBackgroundFetching(int fetchIndex);

    /**

     * Enables or disables thumbnail background fetching.

     * 

     * @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();

protected:    

    /**

     * Method creates member objects and connects signals.

     *

     * @return int 0 initialization ok, -1 initialization failed

     *

     */

    int initialize();

    /**

     * Cleanup internal data. This must be called before UI environment is destroyed.

     */

    void cleanup();

    /**

     * Connects the signals.

     *

     * @return int 0 connecting ok, -1 connecting failed.

     */

    int connectSignals();

    /**

     * Disconnects the signals.

     *

     */

    void disconnectSignals();

    /**

     * Appends indexes in the source model to the list between start and end.

     *

     * @param indexes list of indexes

     * @param startIndex start index

     * @param endIndex end index

     */

    void getModelIndexes(QList<QModelIndex> &indexes, int startIndex, int endIndex);

    /**

     * Method returns default thumbnail data.

     *

     * @param mediaId media id for which to get thumbnail

     * 

     * @return QIcon: reference to default thumbnail data

     *

     */

    const QIcon* defaultThumbnail(TMPXItemId mediaId);

    /**

     * Removes given id from the fetch list. Fetch list is an internal id list containing

     * thumbnail ids currently under fetching.

     *

     * When list is emptied the background thumbnail fetching is continued.

     *

     * @param tnId thumbnail id to be removed from the list

     *

     * @return true if id was found from fetch list, otherwise false.

     */

    bool removeFromFetchList(int tnId);

    /**

     * Starts timer that continues the background thumbnail fetching at timeout.

     */

    void continueBackgroundFetch();

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 slots:

    /**

     * Thumbnail manager signals this slot when thumbnail is ready

     * for some item.

     *

     * @param tnData: thumbnail

     * @param internal: internal data contains pointer to the media id used in emitted signal

     * @param id: thumbnail id

     * @param error: possible error code from thumbnail manager ( 0 == ok )

     *

     */

    void thumbnailReadySlot(QPixmap tnData, void *internal , int id , int error);

    /**

     * VideoSortFilterProxyModel signals this slot when the layout of items in the model have

     * changed.

     *

     */

    void layoutChangedSlot();

    /**

     * VideoSortFilterProxyModel signals this slot when the rows have been inserted to the model.

     *

     */

    void rowsInsertedSlot(const QModelIndex & parent, int start, int end);

    /**

     * Fetches thumbnails around of mCurrentFetchIndex in batches of THUMBNAIL_BACKGROUND_FETCH_AMOUNT.

     * The fetch index is set by startFetchingThumbnails which also resets

     * mCurrentBackgroundFetchCount. Maximum of THUMBNAIL_MAX_BACKGROUND_FETCH thumbnails are

     * fetched between the count resets.

     *

     */

    void doBackgroundFetching();

    /**

     * Signaled when UI environment is about to be destroyed. Thumbnails must be cleaned before that.

     * 

     */

    void aboutToQuitSlot();

    /**

     * Emits thumbnailReady signals for list of thumbnails. 

     * 

     */

    void reportThumbnailsReadySlot();

private: // Data

    /**

     * Thumbnail manager object.

     */

    ThumbnailManager                *mThumbnailManager;

    /**

     * list containing thumbnails ids which data is

     * currently being fetched from the tn wrapper.

     * empty if there are no thumbnail fetching

     * ongoing

     */

    QSet<int>                       mFetchList;

    /**

     * Local data map for thumbnail data:

     * - key is the video's media id

     * - data is the actual thumbnail data.

     * If thumbnail data is not yet fetched, QIcon is default thumbnail.

     */

    QCache<TMPXItemId, QIcon>       mThumbnailData;

    /**

     * Default thumbnail for a video.

     */

    QIcon                           *mDefaultTnVideo;

    /**

     * Default thumbnail for a category.

     */

    QIcon                           *mDefaultTnCategory;

    /**

     * Wrapper to collection.

     */

    VideoCollectionWrapper          *mCollectionWrapper;

    /**

     * Model containing the media, not owned.

     */

    QPointer<VideoSortFilterProxyModel>     mModel;

    /**

     * Current index for background thumbnail fetching.

     */

    int                             mCurrentFetchIndex;

    /**

     * Current count of background thumbnails fetched around the fetch index.

     */

    int                             mCurrentBackgroundFetchCount;

    /**

     * Timer for background fetching.

     */

    QTimer                          *mBgFetchTimer;

    /**

     * Timer for thumbnail ready signaling.

     */

    QTimer                          *mTbnReportTimer;

    /**

     * List of media ids for thumbnails that are ready.

     */

    QList<TMPXItemId>               mReadyThumbnailMediaIds;

    /**

     * Flag for signal connections.

     */

    bool                            mSignalsConnected;

    /**

     * Indicates if background thumbnail fetching is enabled.

     */

    bool                            mBackgroundFetchingEnabled;

};

#endif  // __VIDEOTHUMBNAILDATAPRIVATE_H__

// End of file