/*

* Copyright (c) 2006 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:  State manager for session and audio routing states.

*

*/

#ifndef CVTENGSTATEMANAGER_H

#define CVTENGSTATEMANAGER_H

//  INCLUDES

#include <e32base.h>

#include "vtengcommands.h"

#include "MVtEngSessionInfo.h"

// FORWARD DECLARATIONS

class CVtEngStateBase;

class CVtEngHandlerContainer;

class CVtEngEventManager;

class CVtEngOperation;

// CLASS DECLARATION

/**

*  Owner of engine states. Delegates update request

*  to active state when requested. Provides method

*  to enquire command availability in current state.

*

*  @lib videoteleng

*  @since 2.6

*/

NONSHARABLE_CLASS( CVtEngStateManager ): public CBase

    {

    public:  // Constructors and destructor

        /**

        * Two-phased constructor.

        */

        static CVtEngStateManager* NewL(

            CVtEngHandlerContainer& aHandlers,

            CVtEngEventManager& aEventManager );

        /**

        * Destructor.

        */

        virtual ~CVtEngStateManager();

    public: // New functions

        /**

        * Requests updates for current state.        

        */

        void Update( );

        /**

        * Checks if a command is possible in current state

        * @param aCommandId command to check

        * @return ETrue if command can be performed

        */

        TBool IsCommandPossible( 

            const TVtEngCommandId aCommandId ) const;

        /**

        * Sets new session state.

        * @param aNewState new session state

        */

        void SetState( CVtEngStateBase& aNewState );

        /**

        * Passes an operation to current state for

        * handling.

        * @param aOp operation to be handled

        * @return ETrue if operation handled

        */

        TBool HandleOperationL( CVtEngOperation& aOp );

        /**

        * Previous session state.

        */

        MVtEngSessionInfo::TSessionState PreviousSessionState() const;

        /**

        * Current session state.

        */

        MVtEngSessionInfo::TSessionState SessionState() const;

        /**

        * Returns handler container.

        * @return handler container

        */

        inline CVtEngHandlerContainer& Handlers();

        /**

        * Returns event manager.

        * @return event manager

        */

        inline CVtEngEventManager& EventManager();

    private:

        /**

        * C++ constructor.

        */

        CVtEngStateManager( 

            CVtEngHandlerContainer& aHandlers,

            CVtEngEventManager& aEventManager );

        /**

        * By default Symbian 2nd phase constructor is private.

        */

        void ConstructL();

    private:    // Data

        // Previous session state

        MVtEngSessionInfo::TSessionState iPreviousSessionState;

        // Current session state

        CVtEngStateBase*        iSessionState;

        // Handler container

        CVtEngHandlerContainer& iHandlers;

        // Event manager

        CVtEngEventManager&     iEventManager;

    };

#include    "CVtEngStateManager.inl"

#endif      // CVTENGSTATEMANAGER_H   

// End of File