/**

   This file is part of CWRT package **

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

   This program is free software: you can redistribute it and/or modify

   it under the terms of the GNU (Lesser) General Public License as 

   published by the Free Software Foundation, version 2.1 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 

   (Lesser) General Public License for more details. You should have 

   received a copy of the GNU (Lesser) General Public License along 

   with this program. If not, see <http://www.gnu.org/licenses/>.

*/

#ifndef DOWNLOADBACKEND_H

#define DOWNLOADBACKEND_H

#include "dmpimpl.h"

#include "downloadinfo.h"

#include "downloadevent.h"

#include <QObject>

#include <QNetworkReply>

// forward declarations

class DownloadBackendPrivate;

class DownloadCore;

class Download;

class ClientDownload;

// class declaration

class DownloadBackend : public QObject

{

    Q_OBJECT

    DM_DECLARE_PRIVATE(DownloadBackend);

public:

    DownloadBackend(DownloadCore *dlCore, ClientDownload *dl);

    virtual ~DownloadBackend();

    // pauses the download

    virtual int pause() ;

    // resumes the download

    virtual int resume() ;

    // cancels the download

    virtual int cancel() ;

    // fetches the attributes

    virtual QVariant getAttribute(DownloadAttribute attr);

    // sets the attributes

    virtual int setAttribute(DownloadAttribute attr, const QVariant& value);

    // stores the data in storage

    // derived classes expected to have their own implementation

    virtual void store(QByteArray data, bool lastChunk=false) = 0;

    // deletes the storage

    // derived classes expected to have their own implementation

    virtual void deleteStore() = 0;

    // returns the size of stored data

    // derived classes expected to have their own implementation

    virtual qint64 storedDataSize()= 0;

    //returns the list of child downloads

    virtual void getChildren(QList<Download*>&) { }

    // initialises the download by reading from persistant storage

    virtual void init() { return; }

private: // copy constructor and assaignment operator

      DownloadBackend(const DownloadBackend &);

      DownloadBackend &operator=(const DownloadBackend &);

public:

    // functions which will store and retrieve the download persistant data

    int setValue(DownloadInfo::Key aKey, const QString& aStrValue);

    int setValue(DownloadInfo::Key aKey, long aIntValue);

    int setValue(DownloadInfo::Key aKey, const QList<QVariant>& aChildIds);

    int setValueForChild(DownloadInfo::Key aKey, const QString& aStrValue, int aChildId = INVALID_DL_ID);

    int setValueForChild(DownloadInfo::Key aKey, long aIntValue, int aChildId = INVALID_DL_ID);

    int getValue(DownloadInfo::Key aKey, QString& aStrValue);

    int getValue(DownloadInfo::Key aKey, long& aIntValue);

    int getValue(DownloadInfo::Key aKey, QList<QVariant>& aChildIds);

    int getValueForChild(DownloadInfo::Key aKey, QString& aStrValue, int aChildId = INVALID_DL_ID);

    int getValueForChild(DownloadInfo::Key aKey, long& aIntValue, int aChildId = INVALID_DL_ID);

    // deletes the persistant data of download

    int deleteInfo();

    // posts the event to recievers event loop

    void postEvent(DEventType type, DlEventAttributeMap* attrMap);

    // download state

    DownloadState downloadState(void);

    // sets the download state

    void setDownloadState(DownloadState state);

    // sets the current downloaded data size

    void setDownloadedDataSize(qint64 size);

    // set total download size

    void setTotalSize(qint64 size);

    // returns the download object

    ClientDownload* download(void);

    // sets the start time

    void setStartTime();

private:

    void postDownloadEvent(DEventType type, DlEventAttributeMap* attrMap);

public slots:

    virtual void bytesRecieved(qint64 bytesRecieved, qint64 bytesTotal);

    virtual void handleFinished();

    virtual void error(QNetworkReply::NetworkError);

    virtual void headerReceived(){}

    virtual void bytesUploaded(qint64, qint64){}

};    

#endif