/*

* Copyright (c) 2008-2009 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:    Navigational state of the app

*

*/

#ifndef __C_GLXNAVIGATIONALSTATE_H__

#define __C_GLXNAVIGATIONALSTATE_H__

#include <e32std.h>

#include <glxmediaid.h>

#include <vwsdef.h>

#include <glxnavigationalstatedefs.h>

class CGlxNavigationalStateImp;

class CMPXCollectionPath;

class MGlxNavigationalStateObserver;

/**

 * CGlxNavigationalState

 *

 * Class that stores the navigational state of the application.

 * Navigational state means the currently viewed node in UI hierarchy

 *

 * Design: CGlxNavigationalState delegates all operations to 

 * CGlxNavigationalStateImp, to avoid client having to include mpx dependencies.

 * CGlxNavigationalStateImp stores the navigational state in MPX collection 

 * server by owning an MMPXCollectionUtility. 

 * 

 * @author Aki Vanhatalo

 */

class CGlxNavigationalState : public CBase

    {

private:

public:

    /**

     * Return a (singleton) instance of the class

     * Close the instance by calling Close() when done with the instance

     */

    IMPORT_C static CGlxNavigationalState* InstanceL(); 

    /**

     * Close the instance and remove observer if any

     * See @ref MGlxActiveMediaListResolver::Close

     * @param aObserver Observer to remove

     */

    IMPORT_C void Close();

    /**

     * Add an observer

     * @param aObserver Observer of changes to the state

     */

    IMPORT_C void AddObserverL( MGlxNavigationalStateObserver& aObserver );

    /**

     * Remove an observer

     * @param aObserver Observer to remove. 

     */

    IMPORT_C void RemoveObserver( MGlxNavigationalStateObserver& aObserver );

    /**

     * @return the current navigational state. Caller gets ownership.

     */

    IMPORT_C CMPXCollectionPath* StateLC() const;

    /**

     * Navigate back in the UI hierarchy

     * Does nothing, if currently at root.

     */

    IMPORT_C void NavigateToParentL();

    /**

     * Navigate forward to provided item

     * @param aItemToOpen Id of item to navigate to

     */

    IMPORT_C void NavigateToChildL( const TGlxMediaId& aItemIdToOpen );

    /**

     * Navigate to provided position in hierarchy

     * @param aNewState Path object which describes the new position in hierarchy

     */

    IMPORT_C void NavigateToL( const CMPXCollectionPath& aNewState );

     /**

     * Activate previous view

     */

    IMPORT_C void ActivatePreviousViewL();

     /**

     * returns the current viewing mode of the application

     */

     IMPORT_C NGlxNavigationalState::TViewingMode ViewingMode();

     /**

     * Sets the mode to "view"

     */

     IMPORT_C void SetToViewMode();

     /**

     * Sets the BackExitStatus

     * @param aStatus ETrue photos navigates to parent on Back EFalse photos exits on back.

     */

     IMPORT_C void SetBackExitStatus(TBool aStatus);

     /**

     * Gets the BackExitStatus

     * @return BackExitStatus

     */          

     IMPORT_C TBool BackExitStatus();

     /**

     * Sets the starting navigation level

     * @param aLevel starting level

     */

     IMPORT_C void SetStartingLevel(TInt aLevel);

     /**

     * Gets the starting navigation level

     * @return starting navigation level

     */     

     IMPORT_C TInt StartingLevel();

private:

    /** Constructor for singleton store */

    static CGlxNavigationalState* NewL();

    /** Destructor */

    ~CGlxNavigationalState();

private:

    /// Implementation 

    CGlxNavigationalStateImp* iImp;

    TBool iBackExitStatus;

    TInt iStartingLevel ;

    };

#endif // __C_GLXNAVIGATIONALSTATE_H__