/*

* 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:

*

*/

#ifndef GRAPHICSITEMANIMATION_H

#define GRAPHICSITEMANIMATION_H

#include <QObject>

#include <QTimeLine>

#include <assert.h>

#include "ChromeSnippet.h"

//#include "utilities.h"

namespace GVA {

// Base class for ChromeSnippet animations.

class GraphicsItemAnimator

{

    friend class GraphicsItemAnimation;

    virtual void apply(ChromeSnippet *snippet, qreal value) = 0;

  public:

    virtual ~GraphicsItemAnimator() {}

};

// ----------------------

/**

 * \brief Provides fade animations for ChromeSnippets.

 *

 * \sa GraphicsItemAnimation

 */

class GraphicsItemAnimatorFade : public GraphicsItemAnimator

{

public:

    GraphicsItemAnimatorFade(ChromeSnippet *snippet, qreal opacityDelta)

      : m_opacityOriginal(snippet->opacity()),

        m_opacityDelta(opacityDelta) {

    }

    virtual void apply(ChromeSnippet *snippet, qreal value) {

        snippet->setOpacity(m_opacityOriginal + value * m_opacityDelta);

    }

private:

    qreal m_opacityOriginal;

    qreal m_opacityDelta;

};

// ----------------------

/**

 * \brief Provides translation animations for ChromeSnippets.

 *

 * \sa GraphicsItemAnimation

 */

class GraphicsItemAnimatorTranslate : public GraphicsItemAnimator

{

public:

    GraphicsItemAnimatorTranslate(ChromeSnippet *snippet, qreal dx, qreal dy)

      : m_posOriginal(snippet->position()),

        m_xDelta(dx),

        m_yDelta(dy) {

    }

    virtual void apply(ChromeSnippet *snippet, qreal value) {

        snippet->setPosition(m_posOriginal.x() + m_xDelta * value, m_posOriginal.y() + m_yDelta * value);

    }

private:

    QPointF m_posOriginal;

    qreal m_xDelta;

    qreal m_yDelta;

};

// ----------------------

/**

v * \brief Provides rotation animations for ChromeSnippets.

 *

 * \sa GraphicsItemAnimation

 */

class GraphicsItemAnimatorRotate : public GraphicsItemAnimator

{

public:

    GraphicsItemAnimatorRotate(ChromeSnippet *snippet, qreal angleDelta, qreal xCenter, qreal yCenter)

      : m_originalTransform(snippet->transform()),

        m_angleDelta(angleDelta),

        m_xCenter(xCenter),

        m_yCenter(yCenter)

    {

    }

    virtual void apply(ChromeSnippet *snippet, qreal value) {

        QTransform transform = m_originalTransform;

        transform.translate(m_xCenter, m_yCenter);

        transform.rotate(m_angleDelta * value);

        transform.translate(-m_xCenter, -m_yCenter);

        snippet->setTransform(transform);

    }

private:

    QTransform m_originalTransform;

    qreal m_angleDelta;

    qreal m_xCenter, m_yCenter;

};

// ----------------------

/**

 * \brief Basic animations for ChromeSnippets

 *

 * The GraphicsItemAnimation class provides basic animations for ChromeSnippets.

 *

 * Calls to translateTo(), translateBy(), fadeTo() etc. can be chained together in javascript as follows:

 *   \code window.snippets.TopChromeId.animate(500).translateBy(10,30).fadeBy(-0.5).start()\endcode

 *

 * \sa ChromeSnippet::animate()

 * \sa GraphicsItemAnimator

 * \sa AttentionAnimator

 * \sa VisibilityAnimator

 */

class GraphicsItemAnimation : public QObject

{

    Q_OBJECT

public:

    GraphicsItemAnimation(ChromeSnippet *snippet, int duration = 500)

      : m_snippet(snippet),

        m_timeLine(duration)

    {

        setObjectName("animation");

        m_timeLine.setFrameRange(0, duration/50);

        connect(&m_timeLine, SIGNAL(valueChanged(qreal)), this, SLOT(update(qreal)));

        connect(&m_timeLine, SIGNAL(finished()), this, SIGNAL(finished()));

    }

    ~GraphicsItemAnimation();

public slots:

    QObject *translateTo(int x, int y)

    {

        QPointF pos = m_snippet->position();

        m_animators.append(new GraphicsItemAnimatorTranslate(m_snippet, x - pos.x(), y - pos.y()));

        return this;

    }

    QObject *translateBy(int dx, int dy)

    {

        m_animators.append(new GraphicsItemAnimatorTranslate(m_snippet, dx, dy));

        return this;

    }

    QObject *fadeTo(qreal opacity)

    {

        m_animators.append(new GraphicsItemAnimatorFade(m_snippet, opacity - m_snippet->opacity()));

        return this;

    }

    QObject *fadeBy(qreal dOpacity)

    {

        m_animators.append(new GraphicsItemAnimatorFade(m_snippet, dOpacity));

        return this;

    }

    QObject *rotateBy(qreal angle, qreal xCenter, qreal yCenter)

    {

        m_animators.append(new GraphicsItemAnimatorRotate(m_snippet, angle, xCenter, yCenter));

        return this;

    }

    QObject *start()

    {

        m_timeLine.stop();

        m_timeLine.start();

        return this;

    }

    QObject *stop()

    {

        m_timeLine.stop();

        return this;

    }

signals:

    void finished();

    void updated(qreal value);

protected slots:

    void update(qreal value)

    {

        foreach(GraphicsItemAnimator *animator, m_animators)

        {

            animator->apply(m_snippet, value);

        }

        emit updated(value);

    }

private:

    ChromeSnippet *m_snippet;   // not owned

    QTimeLine m_timeLine;

    QList<GraphicsItemAnimator *> m_animators;

};

}

#endif // GRAPHICSITEMANIMATION_H