/*

* Copyright (c) 2007-2009 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:  Implementation for calendar database accessor

*

*/

#ifndef CESMRCALDBBASE_H

#define CESMRCALDBBASE_H

#include <e32base.h>

#include <calprogresscallback.h>

#include <calcommon.h>

class CESMRCalDbBase;

class CCalEntryView;

class CCalInstanceView;

class CCalEntry;

class CCalInstance;

class CCalSession;

/**

* Observer interface for handling calendar database status.

*

* @lib esmrdb.lib

*/

class MESMRCalDbObserver

    {

public: // Data types

    /**

     * Enumeration for database status.

     */

    enum TDbStatus

        {

        EUninitialized       = 0x0000, // nothing done yet

        EReseting            = 0x0002, // db reset ongoing

        EInitEntryView       = 0x0004, // init entry view

        EInitInstanceView    = 0x0008, // init instance view

        EFinishedOk          = 0x0010, // init succeeded

        EFinishedError       = 0x0020  // init failed

        };

public: // Interface

    /**

     * Callback method for handling database status.

     * @param aNotifier for identifying the notifying database

     * @param aStatus new current status of the database

     */

    virtual void HandleCalDbStatus(

            const CESMRCalDbBase* aNotifier,

            TDbStatus aStatus ) = 0;

    };

/**

* Base class representing a calendar database.

*

* @lib esmrdb.lib

*/

class CESMRCalDbBase : public CBase,

                       public MCalProgressCallBack

    {

public: // Constructors and destructors

    /**

    * Destructor.

    */

    ~CESMRCalDbBase();

    /**

     * Entry view accessor. Ownership not transferred.

     * @return entry view, may be NULL

     */

    const CCalEntryView* EntryView() const;

    /**

     * Instance view accessor. Ownership not transferred.

     * @return instance view, may be NULL

     */

    const CCalInstanceView* InstanceView() const;

    /**

     * Session accessor. Ownership not transferred.

     * @return session, may be NULL

     */

    const CCalSession* Session() const;

    /**

     * Entry view accessor. Ownership not transferred.

     * @return entry view, may be NULL

     */

    CCalEntryView* EntryView();

    /**

     * Instance view accessor. Ownership not transferred.

     * @return instance view, may be NULL

     */

    CCalInstanceView* InstanceView();

    /**

     * Session accessor. Ownership not transferred.

     * @return session, may be NULL

     */

    CCalSession* Session();

    /**

     * Database status getter.

     * @return current database status

     */

    MESMRCalDbObserver::TDbStatus DbStatus();

    /**

     * CCalEntryView lacks fetch with time range. This method provides such

     * functionality. In case of repeating entries the entire sequence must

     * be within range (but modifying entries are considered separately).

     * If database doesn't have both instance and entry view then this

     * method leaves with KErrNotSupported.

     * @param aCalEntryArray fetched entries, caller owns array items

     * @param aCalTimeRange time range

     * @param aFetchFullCopy copy type of calendar entry

     */

    void FetchWithRangeL(

            RPointerArray<CCalEntry>& aCalEntryArray,

            const CalCommon::TCalTimeRange& aCalTimeRange,

            TBool aFetchFullCopy = ETrue );

    /**

     * Reset database, causes asynchronous db initialization

     * which is notified through MMRUtilsCalDbObserver interface.

     * Calling this method requires that there are no external

     * open references for the session.

     * The default implementation leaves with KErrNotSupported.

     */

    virtual void ResetDbL();

    /**

     * Tests whether given entry fits completely within given time range.

     * @param aEntry entry to test

     * @param aCalTimeRange criterion

     * @return ETrue if fits, EFalse if exceeds from either end

     */

    static TBool IsCompletelyWithinRangeL(

            const CCalEntry& aEntry,

            const CalCommon::TCalTimeRange& aCalTimeRange );

    /**

     * Wrapper which traps leaving CompareL(), and in leave situation

     * returns that objects are equal since that is a safer interpretation

     * and avoids duplicates in database.

     * In real life CompareL() is not expected to ever leave.

     * @param aFirst entry

     * @param aSecond entry

     * @return zero if the objects are equal, a negative value if aFirst is

     *         less than aSecond and a positive value otherwise

     */

    static TInt Compare(

            const CCalEntry& aFirst,

            const CCalEntry& aSecond );

    /**

     * Helper which allows ordering entries in an array. That is implemented

     * by evaluating GUID and RECURRENCE-ID of the two entries.

     * @param aFirst entry

     * @param aSecond entry

     * @return zero if the objects are equal, a negative value if aFirst is

     *         less than aSecond and a positive value otherwise

     */

    static TInt CompareL(

            const CCalEntry& aFirst,

            const CCalEntry& aSecond );

protected: // From MCalProgressCallBack

    void Progress(

            TInt aPercentageCompleted );

    TBool NotifyProgress();

protected: // Constructors and destructors

   /**

    * C++ default constructor.

    * @param aDbObserver database observer reference

    * @param aCmdObserver asynchronous command observer reference

    */

    CESMRCalDbBase(

            MESMRCalDbObserver& aDbObserver,

            MCalProgressCallBack& aCmdObserver );

protected: // data

    /**

    * Current database status

    * Own.

    */

    MESMRCalDbObserver::TDbStatus iDbStatus;

    /**

    * Used for notifying about database status

    * Not own.

    */

    MESMRCalDbObserver& iDbObserver;

    /**

    * This callback is used for notifying about asynchronous

    * command progress, Note: currently not used for anything!

    * Not own.

    */

    MCalProgressCallBack& iCmdObserver;

    /**

    * Calender DB view. Managed by the subclass

    * Own.

    */

    CCalEntryView* iCalEntryView;

    /**

    * Caledar DB instance view. Managed by the subclass

    * Own.

    */

    CCalInstanceView* iCalInstanceView;

    /**

    * Calendar DB session. Managed by the subclass

    * Own.

    */

    CCalSession* iCalSession;

    };

#endif // CESMRCALDBBASE_H