/*

* Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

*

* This program is free software: you can redistribute it and/or modify

* it under the terms of the GNU Lesser General Public License as published by

* the Free Software Foundation, version 2.1 of the License.

*

* This program is distributed in the hope that it will be useful,

* but WITHOUT ANY WARRANTY; without even the implied warranty of

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

* GNU Lesser General Public License for more details.

*

* You should have received a copy of the GNU Lesser General Public License

* along with this program.  If not,

* see "http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html/".

*

* Description:

*

*/

#include "WebContentAnimationItem.h"

#include <QGraphicsWebView>

#include <QtGlobal>

#include <QWebElement>

#include <QWebFrame>

static const int MinDoubleClickZoomTargetWidth = 100;     //Target block width for applying double tap zoom

static const int ZoomCommitDuration = 50;                 //Timeout before commiting zoom

static const qreal ZoomableContentMinWidth = 300.;

namespace GVA {

WebContentAnimationItem::WebContentAnimationItem(QGraphicsWidget* parent, Qt::WindowFlags wFlags)

    : QGraphicsWidget(parent, wFlags)

    , m_zoomCommitTimer(this)

    , m_viewportMetaData(0)

{

    setFlag(QGraphicsItem::ItemHasNoContents, true);

    setFlag(QGraphicsItem::ItemClipsChildrenToShape, true);

    setFlag(QGraphicsItem::ItemClipsToShape, true);

    setFiltersChildEvents(true);

    connect(&m_zoomCommitTimer, SIGNAL(timeout()), this, SLOT(commitZoom()));

    m_zoomCommitTimer.setSingleShot(true);

}

WebContentAnimationItem::~WebContentAnimationItem()

{}

void WebContentAnimationItem::setWebView(QGraphicsWebView* webView)

{

    Q_ASSERT(m_webView);

    m_webView = webView;

    //Enabling resize to contents avoids scrollbars in mainframe

    m_webView->setResizesToContents(true);

    m_webView->setParentItem(this);

    m_webView->setAttribute(Qt::WA_OpaquePaintEvent, true);

}

void WebContentAnimationItem::updatePreferredContentSize(const QSize& size)

{

    // FIXME: we have bug in QtWebKit API when tileCacheEnabled is true.

    // this causes viewport not to reset between the page loads.

    // Thus, we need to update viewport manually until we have fix for this.

    m_webView->page()->setPreferredContentsSize(size);

    resize(contentsSize());

}

QSize WebContentAnimationItem::contentsSize() const

{

    return m_webView->page()->mainFrame()->contentsSize();

}

void WebContentAnimationItem::setZoomScale(qreal value, bool immediateCommit)

{

    value = qBound(m_viewportMetaData->m_minimumScale, value, m_viewportMetaData->m_maximumScale);

    qreal curZoomScale = zoomScale();

    if (qFuzzyCompare(value, curZoomScale)) {

        notifyZoomActions(curZoomScale);

        return;

    }

    if (!immediateCommit)

        disableContentUpdates();

    m_webView->setScale(value);

    if (immediateCommit)

        commitZoom();

    else

        m_zoomCommitTimer.start(ZoomCommitDuration);

}

qreal WebContentAnimationItem::zoomScale() const

{

    if (!m_webView)

        return 1.;

    return m_webView->scale();

}

QRectF WebContentAnimationItem::findZoomableRectForPoint(const QPointF& point)

{

    QPointF zoomPoint = m_webView->mapFromParent(point);

    QWebHitTestResult hitResult = m_webView->page()->mainFrame()->hitTestContent(zoomPoint.toPoint());

    QWebElement targetElement = hitResult.enclosingBlockElement();

    while (!targetElement.isNull() && targetElement.geometry().width() < MinDoubleClickZoomTargetWidth)

        targetElement = targetElement.parent();

    if (!targetElement.isNull()) {

        QRectF elementRect = targetElement.geometry();

        qreal overMinWidth = elementRect.width() - ZoomableContentMinWidth;

        if (overMinWidth < 0)

            elementRect.adjust(overMinWidth / 2, 0, -overMinWidth / 2, 0);

        zoomPoint.setX(elementRect.x());

        QRectF resultRect(zoomPoint, elementRect.size());

        return QRectF(m_webView->mapToParent(resultRect.topLeft()),

                      m_webView->mapToParent(resultRect.bottomRight()));

    }

    return QRectF();

}

void WebContentAnimationItem::disableContentUpdates()

{

    //Disable tiling updates

    m_webView->setTiledBackingStoreFrozen(true);

}

void WebContentAnimationItem::enableContentUpdates()

{

    //Enable tiling updates

    m_webView->setTiledBackingStoreFrozen(false);

}

void WebContentAnimationItem::commitZoom()

{

    m_zoomCommitTimer.stop();

    notifyZoomActions(zoomScale());

    enableContentUpdates();

}

void WebContentAnimationItem::resizeEvent(QGraphicsSceneResizeEvent* event)

{

    QGraphicsWidget::resizeEvent(event);

    setZoomScale(size().width() / contentsSize().width());

}

void WebContentAnimationItem::notifyZoomActions(qreal newScale)

{

    bool enableZoomIn = false;

    bool enableZoomOut = false;

    if (m_viewportMetaData->m_userScalable) {

        if (newScale > m_viewportMetaData->m_minimumScale)

            enableZoomOut = true;

        else

            enableZoomOut = false;

        if (newScale < m_viewportMetaData->m_maximumScale)

            enableZoomIn = true;

        else

            enableZoomIn = false;

	} 

    emit updateZoomActions(enableZoomIn, enableZoomOut);

}

} //namespace GVA