/*

* Copyright (c) 2007 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:  Engine for BS Engine

 *

*/

#ifndef C_CBSENGINE_H

#define C_CBSENGINE_H

#include <e32base.h>

class CBSConfiguration;

class CBSApplicationInfo;

class CEikonEnv;

/**

 * Engine for BS solution

 * It is the place when whole BS logic is implemented.

 *

 *  @since S60 v3.2

 */

class CBSEngine : public CBase

    {

public:

    static CBSEngine* NewL();

    static CBSEngine* NewLC();

    /**

     * Destructor

     */

    virtual ~CBSEngine();

    /*

     * This method is notified when new application gain focus

     * 

     * @since S60 3.2

     * @param aApp application UID

     */

    void HandleFocusChangeL( const TUid& aApp );

    /**

     * Invoked when activation event appeared

     * appliction state changed or focus state changed

     *

     * @since S60 3.2

     * @param aApp application UID

     * @param aState state of application (like view ids)

     * @param aFocused indicate if it was item/exit state

     * @return EBSEngineCommandWasConsumed if event was consumed,

     *  else EBSEngineCommandWasNotConsumed

     */

    TInt HandleActivationEventL( const TUid& aApp, const TDesC8& aState,

        TBool aFocused );

    /**

     * Invoked when back event appeared

     *

     * @since S60 3.2

     * @param aApp application UID

     * @param aState state of application (like view ids)

     * @param aCheckOnly indicates if only checking should be done (no actual action)

     * @return EBSEngineCommandWasConsumed if event was consumed,

     *  else EBSEngineCommandWasNotConsumed

     */

    TInt HandleBackEventL( const TUid& aApp, const TDesC8& aState,

        TBool aCheckOnly );

    /**

     * Remove information about given application from BS stack

     */

    void RemoveAppRecord( const TUid& aApp );

private:

    CBSEngine();

    void ConstructL();

    /**

     * Returns previous application in focus stack for given application.

     *

     * @since S60 3.2

     * @param aApp application UID

     * @return UID of previous application, 

     * if information is missing returns TUid::Null

     */

    TUid FindPreviousApp( const TUid& aApp );

    /**

     * Sends given appliction to background

     * @since S60 3.2

     * @param aApp application UID

     */

    void SendToBackground( const TUid& aApp );

    /**

     * Resets BS history

     */

    void ResetHistory();

private:

    // data

    /**

     * list of application in BS stact

     */

    RPointerArray<CBSApplicationInfo> iAppsStack;

    /**

     * focus stack

     */

    RArray<TInt> iFocusHistory;

    /**

     * flag for handling fast swap events

    /**

     * Configuration of BS

     * Own.  

     */

    CBSConfiguration* iConfiguration;

    /**

     * Eikon environment

     * Not own.  

     */

    CEikonEnv* iEnv;

    };

#endif // C_CBSENGINE_H