/*

* Copyright (c) 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:

*

*/

// System includes

#include <QGraphicsSceneEvent>

// User includes

#include "radiostripbase.h"

// Constants

/*!

 *

 */

RadioStripBase::RadioStripBase( QGraphicsItem* parent ) :

    HbScrollArea( parent ),

    mAutoScrollTime( 0 ),

    mStripContainer( new HbWidget( this ) ),

    mModel( 0 ),

    mIsCyclic( true ),

    mAutoCenter( false ),

    mOverlap( 0 ),

    mItemPoolParent( new QGraphicsWidget( NULL ) ),

    mCurrentIndex( 0 ),

    mPressedIndex( 0 ),

    mStripLength( 0 ),

    mContentsLength( 0 )

{

    setClampingStyle( HbScrollArea::NoClamping );

    setScrollDirections( Qt::Horizontal );

    setFlag( QGraphicsItem::ItemClipsChildrenToShape, true );

    setContentWidget( mStripContainer );

    setFrictionEnabled( true );

    setLongPressEnabled( false );

    setHorizontalScrollBarPolicy( HbScrollArea::ScrollBarAlwaysOff );

    setVerticalScrollBarPolicy( HbScrollArea::ScrollBarAlwaysOff );

    // mItemParent is used to hold the unused QGraphicsItem's in the pool.  It's visibility is set to false

    // so the visibility of the items doesn't need to be modified.

    mItemPoolParent->setVisible( false );

}

/*!

 *

 */

RadioStripBase::~RadioStripBase()

{

}

/*!

 *

 */

void RadioStripBase::setAutoScrollTime( const int time )

{

    mAutoScrollTime = time;

}

/*!

 *

 */

int RadioStripBase::autoScrollTime() const

{

    return mAutoScrollTime;

}

/*!

 *

 */

void RadioStripBase::setModel( QAbstractItemModel* model )

{

    if ( mModel != model )

    {

    //    if ( mModel )

    //    {

    //        disconnectDataModel();

    //    }

        mModel = model;

        if ( mModel )

        {

    //        connectDataModel();

            mCurrentIndex = 0;

            populateAndLayout();

        }

    }

}

/*!

 *

 */

QAbstractItemModel* RadioStripBase::model() const

{

    return mModel;

}

/*!

 *

 */

void RadioStripBase::setCyclic( bool isCyclic )

{

    mIsCyclic = isCyclic;

}

/*!

 *

 */

void RadioStripBase::setOverlap( qreal overlap )

{

    mOverlap = overlap;

}

/*!

 *

 */

void RadioStripBase::setAutoCenter( bool autoCenter )

{

    mAutoCenter = autoCenter;

}

/*!

 *

 */

void RadioStripBase::setItemSize( const QSizeF& size )

{

    if ( mItemSize != size ) {

        mItemSize = size;

        prepareGeometryChange();

        populateAndLayout();

        update();

        updateGeometry();

    }

}

/*!

 *

 */

void RadioStripBase::setIndex( int index, bool animateToCenter )

{

    Q_UNUSED( animateToCenter )

    // Sanity checks

    if ( !mModel || ( !mIsCyclic && ( index < 0 || index >= mModel->rowCount() ) ) ) {

        return;

    }

    const int oldIndex = mCurrentIndex;

    if ( mIsCyclic )

    {

        int numRows = mModel->rowCount();

        index = (index + numRows) % numRows;

    }

    Q_ASSERT( index >= 0 );

    mCurrentIndex = index;

    updateItemWithIndex( mCurrentIndex );

    updateItemWithIndex( oldIndex );

}

/*!

 * \reimp

 */

void RadioStripBase::resizeEvent( QGraphicsSceneResizeEvent* event )

{

    HbScrollArea::resizeEvent( event );

    populateAndLayout();

}

/*!

 * \reimp

 */

void RadioStripBase::mousePressEvent( QGraphicsSceneMouseEvent* event )

{

    if ( event->button() != Qt::LeftButton || !mModel || !mModel->rowCount() )

    {

        event->ignore();

        return;

    }

    HbScrollArea::mousePressEvent( event );

}

/*!

 * \reimp

 */

void RadioStripBase::mouseReleaseEvent( QGraphicsSceneMouseEvent* event )

{

    if ( event->button() != Qt::LeftButton )

    {

        event->ignore();

        return;

    }

    HbScrollArea::mouseReleaseEvent( event );

}

/*!

 *

 */

void RadioStripBase::moveAllItemsToPool()

{

    // set parent of all items to pool

    foreach( QGraphicsItem* item, mItemAtSlot )

    {

        item->setParentItem( mItemPoolParent );

    }

    // move all items to pool

    mItemPool += mItemAtSlot;

    mItemAtSlot.clear();

    mIndexAtSlot.clear();

}

/*!

 *

 */

void RadioStripBase::populateAndLayout()

{

    moveAllItemsToPool();

    if ( !mModel || mModel->rowCount() == 0 )

    {

        return;

    }

    mStripLength = boundingRect().width();

    qreal itemSize = mItemSize.width();

    mContentsLength = mModel->rowCount() * (itemSize - mOverlap);

    if ( mIsCyclic )

    {

        // if treating the items cyclically, double the content area so it can

        // be shifted back and forth as you scroll

        mContentsLength *= 2;

    }

    qreal currPos = -mOverlap;

    for ( int i = 0; i < mModel->rowCount(); ++i ) {

        if ( currPos > mStripLength )

        {

            break;

        }

        QGraphicsItem* item = constructItem( i, true );

        if ( item )

        {

            item->setPos( QPointF( currPos, 0 ) );

            currPos += itemSize - mOverlap;

        }

    }

    mStripContainer->setPreferredSize( mContentsLength, mItemSize.height() );

    if ( mCurrentIndex >= 0 )

    {

        setIndex( mCurrentIndex, false );

    }

}

/*!

 *

 */

QGraphicsItem* RadioStripBase::constructItem( int index, bool append )

{

    QGraphicsItem* item = getFromPool();

    if ( mIsCyclic )

    {

        Q_ASSERT( index >= 0 && index < 2 * mModel->rowCount() );

        updateItemPrimitive( item, index % mModel->rowCount() );

    }

    else

    {

        Q_ASSERT( index >= 0 && index < mModel->rowCount() );

        updateItemPrimitive( item, index );

    }

    item->setParentItem( mStripContainer );

    if ( append )

    {

        mItemAtSlot.append( item );

        mIndexAtSlot.append( index );

    }

    else

    {

        mItemAtSlot.prepend( item );

        mIndexAtSlot.prepend( index );

    }

    return item;

}

/*!

 *

 */

QGraphicsItem* RadioStripBase::getFromPool()

{

    QGraphicsItem* item = 0;

    if ( mItemPool.isEmpty() )

    {

        item = createItemPrimitive( this );

    }

    else

    {

        item = mItemPool.takeFirst();

    }

    return item;

}

/*!

 *

 */

void RadioStripBase::returnToPool( QGraphicsItem* item )

{

    // Unparent the item so it doesn't get deleted

    item->setParentItem( mItemPoolParent );

    mItemPool.append( item );

}

/*!

 * Returns starting coordinate of the item with the specified index

 */

qreal RadioStripBase::indexToOffset( int index )

{

    return index * ( mItemSize.width() - mOverlap ) - mOverlap;

}

/*!

 * Returns item index for specified offset amount into the content

 */

int RadioStripBase::offsetToIndex( qreal offset )

{

    const int rows = mModel->rowCount();

    int index = (int)( offset / ( mItemSize.width() - mOverlap ) );

    if ( mIsCyclic )

    {

       return qBound( 0, index, 2 * rows - 1 );

    }

    return qBound( 0, index, rows - 1 );

}

/*!

 * updates items with specified index value

 */

void RadioStripBase::updateItemWithIndex( int index )

{

    if( index >= 0 )

    {

        QList<QGraphicsItem *>::const_iterator item = mItemAtSlot.constBegin();

        QList<QGraphicsItem *>::const_iterator itemsEnd = mItemAtSlot.constEnd();

        QList<int>::const_iterator itemIndex = mIndexAtSlot.constBegin();

        const int rowCount = mModel->rowCount();

        // Find all items with this index (can be 2 in special cycling case)

        for( ; item != itemsEnd; ++item, ++itemIndex )

        {

            if( index == *itemIndex || index == *itemIndex - rowCount )

            {

                // update those items

                updateItemPrimitive( *item, index );

            }

        }

    }

}

/*!

 * Updates items during scrolling: removing invisible items and adding items that became visible

 */

void RadioStripBase::adjustItems()

{

    qreal contentPos = mStripContainer->pos().x();

    if ( mIsCyclic )

    {

        if ( -contentPos < 0 )

        {

            // trying  to display off the left end of the strip, so

            // shift the strip one length to the left

            contentPos -= mContentsLength * 0.5;

            mStripContainer->setPos( QPointF ( contentPos, mStripContainer->pos().y() ) );

        } else if (-contentPos > mContentsLength * 0.5) {

            // trying to display off the right end of the strip, so

            // shift the strip one length to the right

            contentPos += mContentsLength * 0.5;

            mStripContainer->setPos( QPointF ( contentPos, mStripContainer->pos().y() ) );

        }

    }

    // find the first and last indices of the visible items

    int firstVisibleIndex = offsetToIndex( -contentPos );

    int lastVisibleIndex = offsetToIndex( -contentPos + mStripLength );

    // remove items at the start that are no longer visible

    while ( !mIndexAtSlot.isEmpty() )

    {

        int firstSlotIndex = mIndexAtSlot.first();

        if ( firstVisibleIndex <= firstSlotIndex )

        {

            break;

        }

        returnToPool( mItemAtSlot.first() );

        mItemAtSlot.removeFirst();

        mIndexAtSlot.removeFirst();

    }

    // remove items at the end that are no longer visible

    while ( !mIndexAtSlot.isEmpty() )

    {

        int lastSlotIndex = mIndexAtSlot.last();

        if ( lastVisibleIndex >= lastSlotIndex )

        {

            break;

        }

        returnToPool( mItemAtSlot.last() );

        mItemAtSlot.removeLast();

        mIndexAtSlot.removeLast();

    }

    if ( mItemAtSlot.isEmpty() )

    {

        // fill area with all needed items

        for ( int i = firstVisibleIndex; i <= lastVisibleIndex; ++i )

        {

            QGraphicsItem* item = constructItem( i, true );

            if ( item )

            {

                item->setPos( QPointF( indexToOffset( i ), 0 ) );

            }

        }

    }

    else

    {

        // add missing items at the front

        int firstItemToCreate = mIndexAtSlot.first()-1;

        for ( int i = firstItemToCreate; i >= firstVisibleIndex; --i )

        {

            QGraphicsItem* item = constructItem( i, false );

            if ( item )

            {

                item->setPos( QPointF( indexToOffset( i ), 0 ) );

            }

        }

        // add missing items at the end

        firstItemToCreate = mIndexAtSlot.last()+1;

        for ( int i = firstItemToCreate; i <= lastVisibleIndex; ++i )

        {

            QGraphicsItem* item = constructItem( i, true );

            if ( item )

            {

                item->setPos( QPointF( indexToOffset( i ), 0 ) );

            }

        }

    }

}

/*!

 * \reimp

 */

bool RadioStripBase::scrollByAmount( const QPointF& delta )

{

    bool ret = HbScrollArea::scrollByAmount( delta );

    adjustItems();

    scrollPosChanged();

    return ret;

}