/*

* 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:   glxzoomwidget.cpp

*               description of the class GlxGlxZoomWidget which controls the Zoom behavior of coverflow.

*

*/

#include <QPinchGesture>

#include <hbiconitem.h>

#include <glxmediamodel.h>

#include "glximagedecoderwrapper.h"

#include "glxmodelparm.h"

#include "glxzoomwidget.h"

GlxZoomWidget::GlxZoomWidget(QGraphicsItem *parent):HbScrollArea(parent), mModel(NULL), mImageDecodeRequestSend(false), mPinchGestureOngoing(false), mDecodedImageAvailable(false)

{

    grabGesture(Qt::PinchGesture);

    setAcceptTouchEvents(true) ;

    setFrictionEnabled(false);

    setZValue(MINZVALUE);

    //create the child items and background

    mZoomWidget = new QGraphicsWidget(this);

    mZoomItem = new QGraphicsPixmapItem(mZoomWidget);

    mZoomItem->setTransformationMode(Qt::SmoothTransformation);

    //the black background

    //replace when a proper substitute for setting backgrounds is known

    mBlackBackgroundItem = new HbIconItem(this);

    mBlackBackgroundItem->setBrush(QBrush(Qt::black));

    mBlackBackgroundItem->hide();

    //does not work so is commented

    //setBackgroundItem(mBlackBackgroundItem);

    //initializing the image decoder

    mImageDecoder = new GlxImageDecoderWrapper;

    connect(this,SIGNAL( pinchGestureReceived(int) ), this, SLOT( sendDecodeRequest(int) ), Qt::QueuedConnection );

}

GlxZoomWidget::~GlxZoomWidget()

{

    //disconnect all existing signals

    disconnect(this,SIGNAL( pinchGestureReceived(int) ), this, SLOT( sendDecodeRequest(int) ) );

    //no Null checks required

    delete mZoomItem;

//    delete mZoomWidget; //as this is a content widegt it will automatically be deleted

    delete mBlackBackgroundItem;

    //reset the decoder to cancel pending tasks

    if(mImageDecoder) {

        mImageDecoder->resetDecoder();

        delete mImageDecoder;

    }

}

void GlxZoomWidget::setModel (QAbstractItemModel *model)

{

    if(model)

    {

        mModel = model;

        retreiveFocusedImage(); //Update mZoomItem with focused Image

        connect( mModel, SIGNAL( dataChanged(QModelIndex,QModelIndex) ), this, SLOT( dataChanged(QModelIndex,QModelIndex) ) );

    }

}

void GlxZoomWidget::setWindowSize(QSize windowSize)

{

    mWindowSize = windowSize;

    mBlackBackgroundItem->setGeometry(QRectF(QPointF(0,0), mWindowSize));

    //try to reset the max and min zoomed size here

}

void GlxZoomWidget::indexChanged(int index)

{

    Q_UNUSED(index);

    if(mFocusIndex != index) {

        mImageDecoder->resetDecoder();//reset the decoder first to cancel pending tasks

        mImageDecodeRequestSend = false;

        mDecodedImageAvailable = false;

        retreiveFocusedImage();  //Update mZoomItem with focused Image

    }

}

bool GlxZoomWidget::sceneEvent(QEvent *event)

{

    bool consume(false);

    if (event->type() == QEvent::Gesture) {

        consume = executeGestureEvent(this, static_cast<QGestureEvent*>(event));

    }

    if(!consume)

    {

        consume = HbScrollArea::sceneEvent(event);

    }

    return consume;

}

bool GlxZoomWidget::sceneEventFilter(QGraphicsItem *watched,QEvent *event)

{

     qDebug("GlxCoverFlow::eventFilter " );

    bool consume = false;

    if (event->type() == QEvent::Gesture) {

        consume = executeGestureEvent(watched, static_cast<QGestureEvent*>(event));

    }

    if(!consume) {

        consume = HbScrollArea::sceneEventFilter(watched,event);

    }

    return consume;

}

bool GlxZoomWidget::executeGestureEvent(QGraphicsItem *source,QGestureEvent *event)

{

     if (QGesture *pinch = event->gesture(Qt::PinchGesture))  {

       QPinchGesture* pinchG = static_cast<QPinchGesture *>(pinch);

       QPinchGesture::ChangeFlags changeFlags = pinchG->changeFlags();

       if (changeFlags & QPinchGesture::ScaleFactorChanged) {

            mPinchGestureOngoing = true;

            //bring the zoom widget to foreground

            setZValue(MAXZVALUE);

            //show the black background

            mBlackBackgroundItem->setParentItem(parentItem());

            mBlackBackgroundItem->setZValue(MAXZVALUE - 1);

            mBlackBackgroundItem->show();

            //retreive the gesture values

            qreal value = pinchG->scaleFactor() / pinchG->lastScaleFactor();

            QPointF center = pinchG->property("centerPoint").toPointF();

            //set the gesture center to the scene coordinates

            QPointF sceneGestureCenter = source->sceneTransform().map(center);

            zoomImage(value, sceneGestureCenter);

        }

       if (pinchG->state() == Qt::GestureStarted) {

           emit pinchGestureReceived(mFocusIndex);

       }

       if (pinchG->state() == Qt::GestureFinished) {

           if(mStepCurrentSize != mCurrentSize) {

               //For giving a spring effect when user has zoomed more than normal.

               if(mStepCurrentSize.width() > mMaxScaleDecSize.width())   {

                   //scale the image to limited size

                   qreal value = mMaxScaleDecSize.width()/mCurrentSize.width();

                   QPointF center(mWindowSize.width()/2, mWindowSize.height()/2);

                   QPointF sceneGestureCenter = source->sceneTransform().map(center);

                   zoomImage(value, sceneGestureCenter);

               }

               mPinchGestureOngoing = false;

                //finalize the transforms to the geometry else panning will not work

                finalizeWidgetTransform();

           }

//push the Zoom widget to background when zoomed image size nears FS image

           if(mStepCurrentSize.width() <= mMinDecScaleSize.width()*1.3)  {

               mBlackBackgroundItem->hide();

               //push the widget back to background

               setZValue(MINZVALUE);

               emit zoomWidgetMovedBackground(mFocusIndex);

               //do not reset the transform here as it will then zoom-in the widget to decoded image size

           }

       }

       //gesture accepted

       return true;

     }

     //gesture rejected

     if(!mPinchGestureOngoing) {

         return false; 

     }

     return true;

}

void GlxZoomWidget::zoomImage(qreal zoomFactor, QPointF center)

{

    adjustGestureCenter(center, zoomFactor);

    QSizeF requiredSize(mCurrentSize.width()*zoomFactor, mCurrentSize.height()*zoomFactor);

    limitRequiredSize(requiredSize);

    if(requiredSize != mCurrentSize) {

        QTransform zoomTransform = mZoomWidget->transform();

        QPointF transformedCenter = mZoomWidget->sceneTransform().inverted().map(center);

        zoomTransform.translate(transformedCenter.x(),transformedCenter.y());

        zoomTransform.scale(requiredSize.width()/mCurrentSize.width(), requiredSize.height()/mCurrentSize.height());

        zoomTransform.translate(-transformedCenter.x(),-transformedCenter.y());

        mZoomWidget->setTransform(zoomTransform);

        mCurrentSize = requiredSize;

    }

}

void GlxZoomWidget::limitRequiredSize(QSizeF &requiredSize)

{

    if(requiredSize.width() > mMaxScaleSize.width() ) {

        requiredSize = mMaxScaleSize ;

    }

    else if(requiredSize.width() < mMinDecScaleSize.width() ) {

        requiredSize = mMinDecScaleSize ;

    }

}

//makes sure that the gesture is on the screen center if the image is smaller than the screen

void GlxZoomWidget::adjustGestureCenter(QPointF & gestureCenter, qreal& zoomFactor)

{

    if(zoomFactor > 1 &&zoomFactor > 1.2 )  {

        zoomFactor = 1.2;

    }

    if(zoomFactor < 1 &&zoomFactor < 0.8 )   {

        zoomFactor = 0.8;

    }

    QSizeF requiredSize(mCurrentSize.width()*zoomFactor, mCurrentSize.height()*zoomFactor);

    //keep smaller image centered

    if(mCurrentSize.width() <= mWindowSize.width() )

    {

        gestureCenter.setX(mWindowSize.width()/2);

    }

    if(mCurrentSize.height() <= mWindowSize.height())

    {

        gestureCenter.setY(mWindowSize.height()/2);

    }

    //maintains the boundary of the edges for zoom out conditions

    if(zoomFactor < 1)

    {

        QPointF itemOriginPos = mZoomWidget->sceneTransform().map(QPointF(0,0));

        bool hasWidthExceededWindow = mCurrentSize.width() > mWindowSize.width();

        bool hasHeightExceededWindow = mCurrentSize.height() > mWindowSize.height();

        if(itemOriginPos.x() >= 0)  {

        //image has crossed left boundry leaving blank space

            if(hasWidthExceededWindow) {

                //stick the gesture to the left corner

                gestureCenter.setX(itemOriginPos.x());

            }

        }

        //Check if the right boundry can be adjusted

        if(itemOriginPos.x()+ mCurrentSize.width() <= mWindowSize.width()) {

                //Image is before the right boundry leaving blank space

                if(hasWidthExceededWindow) {

                    //stick the gesture to the right corner

                    gestureCenter.setX(itemOriginPos.x()+ mCurrentSize.width());

                }

        }

        //check if the upper boundry could be adjusted

        if(itemOriginPos.y() >= 0) {

                //image has crossed the upper boundry leaving blank space

                if(hasHeightExceededWindow) {

                    //stick the image to the upper boundry

                    gestureCenter.setY(itemOriginPos.y());

                }

        }

        //check if the lower boundry could be adjusted

        if(itemOriginPos.y()+ mCurrentSize.height() <= mWindowSize.height()) {

        //Image is before the right boundry leaving blank space

            if(hasHeightExceededWindow) {

                //stick the image to the right corner

                gestureCenter.setY(itemOriginPos.y()+ mCurrentSize.height());

            }

        }

    }

    //control the zoom Factor to boundaries

    if(mCurrentSize.width() > mWindowSize.width() && requiredSize.width() <= mWindowSize.width())

    {

        zoomFactor =  mWindowSize.width()/mCurrentSize.width();

    }

    else if(mCurrentSize.height() > mWindowSize.height() && requiredSize.height() <= mWindowSize.height())

    {

        zoomFactor =  mWindowSize.height()/mCurrentSize.height();

    }

    //reduce the ZF so as to show a decelerated effect at max/min levels

    if(mCurrentSize.width() > mMaxScaleDecSize.width() && zoomFactor > 1 ) {

        zoomFactor = 1.0 + ((zoomFactor-1.0)/6) ;

    }

        if(mCurrentSize.width() < mMinDecScaleSize.width() && zoomFactor < 1 ) {

        zoomFactor = 1.0 - ((1.0-zoomFactor)/6) ;

    }

}

//get the latest focused image and set it to mZoomItem

void GlxZoomWidget::retreiveFocusedImage()

{

    QPixmap targetPixmap(getFocusedImage());

    //initialize all the variables wrt the focussed pixmap

    mZoomWidget->resetTransform();

    mItemSize = targetPixmap.size();

    mMaxScaleSize = mItemSize;

    mMaxScaleSize.scale(mWindowSize*13, Qt::KeepAspectRatio);

    mMaxScaleDecSize = mItemSize;

    mMaxScaleDecSize.scale(mWindowSize*7, Qt::KeepAspectRatio);

    mMinScaleSize = mItemSize* 0.7;

    mMinDecScaleSize = mItemSize;

    QPointF originPos = sceneTransform().map(QPointF(0,0));

    mZoomWidget->setGeometry(QRectF(QPointF(mWindowSize.width()/2 - mItemSize.width()/2,mWindowSize.height()/2 - mItemSize.height()/2),mItemSize )); //chk this

    mZoomWidget->setPreferredSize(mItemSize);

    mZoomItem->setPixmap(targetPixmap);

    mCurrentSize = mItemSize;

    mStepCurrentSize = mItemSize;

    setContentWidget(mZoomWidget);

    show();

}

void GlxZoomWidget::dataChanged(QModelIndex startIndex, QModelIndex endIndex)

{

    if(mFocusIndex >= startIndex.row() && mFocusIndex <= endIndex.row()) {

        //get the latest image from the model

        //will replace a decoded image if callback is received after decoded image is received so a fix is required

        //retreiveFocusedImage();

        if(!mDecodedImageAvailable)  {

        QPixmap targetPixmap(getFocusedImage());

        mZoomItem->setPixmap(targetPixmap);

        finalizeWidgetTransform();

        }

    }

}

void GlxZoomWidget::decodedImageAvailable()

{

    //new bitmap with better resolution is available

    //so set it to the item

    QPixmap decodedPixmap = mImageDecoder->getPixmap();

    disconnect(mImageDecoder, SIGNAL(pixmapDecoded()), this, SLOT(decodedImageAvailable()));

    if(decodedPixmap.isNull()){

        return;

    }

    mDecodedImageAvailable = true;

    mZoomItem->setPixmap(decodedPixmap);

    mItemSize = decodedPixmap.size();

    //this is important if not done then old transforms will be applied on the new image

    finalizeWidgetTransform();

}

void GlxZoomWidget::sendDecodeRequest(int index)

{

    if(!mImageDecodeRequestSend) {

        QString imagePath = (mModel->data(mModel->index(index,0),GlxUriRole)).value<QString>();

        mImageDecoder->decodeImage(imagePath);

        connect(mImageDecoder, SIGNAL(pixmapDecoded()), this, SLOT(decodedImageAvailable()));

        mImageDecodeRequestSend = true;

    }

}

void GlxZoomWidget::finalizeWidgetTransform()

{

    QPointF widgetPos = mZoomWidget->sceneTransform().map(QPointF(0,0)); //Map the origin wrt scene

    mZoomWidget->resetTransform();

    mZoomWidget->scale(mCurrentSize.width()/mItemSize.width(), mCurrentSize.height()/mItemSize.height());

    mZoomWidget->setGeometry(QRectF(widgetPos , mCurrentSize));

    // this updates HbScrollArea on the sizeHint of ZoomWidget

    mZoomWidget->setPreferredSize(mCurrentSize);

    mStepCurrentSize = mCurrentSize;

}

QPixmap GlxZoomWidget::getFocusedImage()

{

    mFocusIndex = mModel->data(mModel->index(0,0),GlxFocusIndexRole).value<int>();

    QVariant iconVariant = mModel->data(mModel->index(mFocusIndex,0),GlxFsImageRole);

    QVariant sizeVariant = mModel->data(mModel->index(mFocusIndex,0),GlxDimensionsRole);

    QPixmap targetPixmap;

    //retreive pixmap from the HbIcon received from model

    //should change the model to return and save pixmaps and convert to HbIcons Instead

    if ( iconVariant.isValid() &&  iconVariant.canConvert<HbIcon> () ) {

         QIcon itemIcon = iconVariant.value<HbIcon>().qicon();

         QSize itemSize = itemIcon.actualSize(mWindowSize);

         QSize scaleSize;

         if(sizeVariant.isValid() &&  sizeVariant.canConvert<QSize> ()) {

             scaleSize = sizeVariant.toSize();

             if(!(scaleSize.width() < mWindowSize.width() && scaleSize.height() < mWindowSize.height()))  {

                 scaleSize = mWindowSize;

             }

         }

         targetPixmap = itemIcon.pixmap(itemSize).scaled(scaleSize, Qt::KeepAspectRatio);

         mItemSize = targetPixmap.size();

    }

    return targetPixmap;

}

void GlxZoomWidget::cleanUp()

{

//    disconnect( mModel, SIGNAL( dataChanged(QModelIndex,QModelIndex) ), this, SLOT( dataChanged(QModelIndex,QModelIndex) ) );

    if(mImageDecoder) {

        mImageDecoder->resetDecoder();

    }

    mZoomItem->setPixmap(QPixmap());

}

void GlxZoomWidget::activate()

{

}