/*

* Copyright (c) 2007-2008 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:  Page by Page Data Window Implemenation

*

*/

#ifndef MULPAGEDATAWINDOW_H_

#define MULPAGEDATAWINDOW_H_

#include "mulmodeldef.h"

namespace Alf

	{

//Forward Declaration

class MulModelImpl;

/**

 * Implametation of Data Window Class

 * This class maintain offset for buffer item that are required by widget,

 * so only that much item remain present in alf model instance.It update buffer items

 * when highlight changed and notify model to update alf model if items are not present

 * in Alf model.

 * 

 */

class MulPageDataWindow

	{

public: //Constructor and Destructor

	/**

	 * C++ constructor

	 * 

	 * @param aMulModel refrece of model implementation

	 */

	MulPageDataWindow( MulModelImpl& aMulModel );

	/**

	 * Descturctor

	 */

	~MulPageDataWindow();

public: //New Method

	/**

	 * Set window size

	 * 

	 * @param aWindowSize No of items that are visible on screen

	 */

	void SetWindowSize( int aWindowSize, int aPageTopIndex = KNotInitialized );

	/**

	 * Set Buffer size

	 * Here buffser size mean number of items that will be above and below window

	 * By default buffer size is equal to window size if following api is not called.

	 *

	 * @param aBufferSize Size of buffer

	 */

	void SetBufferSize( int aBufferSize );

	/**

	 * Change highlighted index. 

	 * Changing highlight will check that data window needs to be updated or not 

	 * and if required it update data window

	 *

	 * @aHighlightIndex New highlighted item in Data window

	 * @throws invaid_argument exception

	 */

	void SetHighlight( int aHighlightIndex );

	/**

	 * Scroll Window to mention item index 

	 * it will check that data window needs to be updated or not 

	 * and if required it update data window

	 *

	 * @aItemIndex item index

	 * @throws invaid_argument exception

	 */

	void ScrollWindow( int aPageTopIndex );

	/**

	 * Return Highlighted item's index

	 * 

	 * @return Highlighted item's index

	 */

	int Highlight() const

		{

		return mHighlight;

		}

	/**

	 * Return previous top offset

	 * 

	 * @return Previos top offset

	 */

	int OldTopOffset() const

		{

		return mOldBufferTop;

		}

	/**

	 * Return previous bottom offset

	 * 

	 * @return Previos bottom offset

	 */

	int OldBottomOffset() const

		{

		return mOldBufferBottom;

		}

	/**

	 * Return current top offset

	 * 

	 * @return Current top offset

	 */

	int TopOffset() const

		{

		return mBufferTop;

		}

	/**

	 * Return current bottom offset

	 * 

	 * @return Current bottom offset

	 */

	int BottomOffset() const

		{

		return mBufferBottom;

		}

	/**

	 * Return visible window top offset

	 * 

	 * @return Current window top offset

	 */

	int TopWindowOffset() const

		{

		return mWindowTop;

		}

	/**

	 * Return visible window bottom offset

	 * 

	 *  @return Current window bottom offset

	 */

	int BottomWindowOffset() const

		{

		return mWindowBottom;

		}

	/**

	 * Return the Old Rear Top offset

	 * 

	 * @return Old Rear Top offset

	 */

	int OldRearTopOffset() const

		{

		return mOldRearBufferTop;

		}

	/**

	 * Return the Old Rear Bottom offset

	 * 

	 * @return Old Rear Bottom offset

	 */

	int OldRearBottomOffset() const

		{

		return mOldRearBufferBottom;

		}		

	/**

	 * Return the Rear Top offset

	 * 

	 * @return Rear Top offset

	 */

	int RearTopOffset() const

		{

		return mRearBufferTop;

		}

	/**

	 * Return the Rear Bottom offset

	 * 

	 * @return Rear Bottom offset

	 */

	int RearBottomOffset() const

		{

		return mRearBufferBottom;

		}

	/**

	 * Return buffer size

	 * 

	 * @return Current buffer size

	 */

	int BufferSize() const

		{

		return mBufferSize;

		}

	/**

	 * Return window size

	 * 

	 * @return Current window size

	 */

	int WindowSize() const

		{

		return mWindowSize;

		}		

	/**

	 * Check that items falls in data window or not

	 * 

	 * @param aItemIndex index of item

	 * @return true if item is in data window otherwise false

	 */

	bool IsItemInDataWindow(int aItemIndex ) const;

	/**

     * Check that items falls in visible window or not

     * 

     * @param aItemIndex index of item

     * @return true if item is in visible window otherwise false

     */

	bool IsItemInVisibleWindow(int aItemIndex ) const;

	/**

	 * Returns Relative index in datawindow from Absolute index

	 *

	 * @param aAbsoluteIndex Absolute index

	 * @return Relative index

	 */

	int RelativeIndex( int aAbsoluteIndex ) const;

	/**

	 * Returns Absoulte index from relative index

	 *

	 * @param aRelativeIndex Relative index

	 * @return Absolute index

	 */

	int AbsoluteIndex( int aRelativeIndex ) const;

	/**

	 * Check that valid window size it set or not.

	 * 

	 * @return true - valid window size is set 

	 * 		   false - otherwisze

	 */

	bool IsWindowEnabled() const

		{

		return ( mWindowSize != KNotInitialized );

		}

	/**

	 * Adjust buffer offset according to window offset

	 */

	void AdjustBuffer();

	/**

	 * Return the complete buffer size, i.e. both top, bottom buffer and the window

	 */	

	int ActualBufferSize() const

		{

		return (2 * mBufferSize) + mWindowSize;	

		}

	/**

	 * Change highlighted index. 

	 * This change will not check that data window needs to be updated or not 

	 *

	 * @aHighlightIndex New highlighted item in Data window

	 */

	void UpdateHighlight( int aHighlightIndex );

	/**

	 * Adjust Window and buffer offset after insert or remove

	 * 

	 */

	void AdjustOffset();

	/**

	 * Save old values

	 */

	void SaveOldValues()

		{

		mOldBufferTop = mBufferTop;

		mOldBufferBottom = mBufferBottom;

		mOldRearBufferTop = mRearBufferTop;

		mOldRearBufferBottom = mRearBufferBottom;

		}

	/**

	 * Compares the current and old buffer values and returns true if teh values are cahnged

	 */

	bool IsBufferOffsetChanged();					

private://New Method

	/**

	 * Check that visible window need to be updated or not.

	 * If required it update visible window.

	 */

	void UpdateDataWindow();

	/**

	 * Data window is updated and window need to sifted down

	 */

	//void ShiftWindowDown();

	/**

	 * Data window is updated and window need to sifted up

	 */

	//void ShiftWindowUp();

private: // Data

	MulModelImpl& mMulModel; //not own

	int mHighlight;	

	int mPageTopIndex;

	int mOldPageTopIndex;

	int mBufferSize;

	int mWindowSize;

	int mWindowTop;

	int mWindowBottom;

	int mBufferTop;

	int mBufferBottom;

	int mOldBufferTop;

	int mOldBufferBottom;

	int mRearBufferTop;

	int mRearBufferBottom;

	int mOldRearBufferTop;

	int mOldRearBufferBottom;

	};

	} //namespace Alf

#endif //MULPAGEDATAWINDOW_H_

//End of file