/*

* 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:    Back command handler

*

*/

#ifndef C_GLXCOMMANDHANDLERBACK_H

#define C_GLXCOMMANDHANDLERBACK_H

// INCLUDES

#include <e32base.h>

#include <glxcommandhandler.h>

// FORWARD DECLARATION

class MGlxMediaListProvider;

class MMPXCollectionUtility;

class MMPXViewUtility;

class CGlxNavigationalState;

class CAknAppUi;

/**

 * @class CGlxCommandHandlerBack

 *

 * Command handler that either takes you back to the previously

 * active view or one step back in the UI hierarchy

 *

 */

NONSHARABLE_CLASS (CGlxCommandHandlerBack)

    : public CGlxCommandHandler

	{

private:

	enum TGlxBackCommandId	

    {

    EGlxCmdBack,

    EGlxCmdPreviousView,

    EGlxCmdContainerPreviousView,

    };

public:

	/**

	 * Create Command handler for going back one step within the

	 * UI Hierarchy

	 * 

	 * @param aMediaListProvider media list owner

	 */

	IMPORT_C static CGlxCommandHandlerBack* NewBackCommandHandlerL();

	/**

	 * Create Command handler for going back one view when the

	 * current view is outside UI Hierarchy

	 * 

	 * @param aMediaListProvider media list owner

	 */							

	IMPORT_C static CGlxCommandHandlerBack* NewPreviousViewCommandHandlerL( 	

								MGlxMediaListProvider* aMediaListProvider = NULL);

	/**

	 * Create Command handler for checkig whether to go back one view or two view

	 * when the current view is outside UI Hierarchy 

	 * 

	 * @param aMediaListProvider media list owner

	 * @param aPrevViewId previous view id

	 */							

	IMPORT_C static CGlxCommandHandlerBack* NewContainerPreviousViewCommandHandlerL( 	

								MGlxMediaListProvider* aMediaListProvider = NULL, 

								TInt aPrevViewId = 0 );

	/** Destructor */

	IMPORT_C ~CGlxCommandHandlerBack();

private:

    /**

     * Two-phase constructor

	 *

	 * @param aCommandId Command id for command handler

	 * @param aMediaListProvider media list owner

	 * @param aPrevViewId previous view id

	 */

	static CGlxCommandHandlerBack* NewL(

							TInt aCommandId, 

							MGlxMediaListProvider* aMediaListProvider,

							TInt aPrevViewId );

    /** Second phase constructor */

	void ConstructL(TBool aIsContainerList);

    /** Constructor */

	CGlxCommandHandlerBack(MGlxMediaListProvider* aMediaListProvider,

							TInt aPrevViewId );

public: // From MGlxCommandHandler

	/**

	 * Execute the command, if applicable

	 * @param aCommand The command to handle

	 * @return ETrue iff command was handled

	 */

	TBool ExecuteL( TInt aCommandId);

	/**

	 * Modify a menu before it is displayed.

	 * @param aResourceId The resource ID of the menu

	 * @param aMenuPane The in-memory representation of the menu pane

	 */

	/**

	 * Called when the owning view is activated

	 * @param aViewId The ID of the view

	 */

	void DoActivateL(TInt aViewId);

	/**

	 * Called when the owning view is deactivated

	 */

	void Deactivate();

	/**

	 * Offers key events to the command handler

	 * @param aKeyEvent The key event. 

	 * @param aType The type of key event: EEventKey, EEventKeyUp or EEventKeyDown

	 * @return Indicates whether or not the key event was used by this control. EKeyWasNotConsumed or EKeyWasConsumed

	 */

	TKeyResponse OfferKeyEventL(const TKeyEvent& aKeyEvent, TEventCode aType);

	/**

	 * Perform any actions needed before the options menu is displayed.

	 * The view calling this must first arrange a wait dialog to be displayed, as this operation may take

	 * a long time to complete

	 */

	void PreDynInitMenuPaneL( TInt aResourceId );

    /**

     * See @ref MGlxCommandHandler::GetRequiredAttributesL

     * No implementation required

     */

    void GetRequiredAttributesL(RArray< TMPXAttribute >& /*aAttributes*/,

                                TBool /*aFilterUsingSelection*/,

                                TBool /*aFilterUsingCommandId*/, 

                                TInt /*aCommandId*/) const {}

private: // data

    /** Provider of media list */

    MGlxMediaListProvider* iMediaListProvider;

    /** Back functionality that command handler need to execute */

    TInt iCurrentCommandId;

    //Previous view id to be checked 

    TInt iPrevViewId;

    // Navigational state is stored here

    CGlxNavigationalState* iNavigationalState;

    /**

     * Check for the view activation and avoid previous view activation

     * till the view activation is called on back

     */

    TBool iIsViewActivated;

    /// The AppUI. Not owned

    CAknAppUi* iAppUi;

	};

#endif // C_GLXCOMMANDHANDLERBACK_H