/*  This file is part of the KDE project.

    Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

    This library 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, either version 2.1 or 3 of the License.

    This library 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 library.  If not, see <http://www.gnu.org/licenses/>.

*/

#include "volumefadereffect.h"

#include "common.h"

#include <QtCore>

QT_BEGIN_NAMESPACE

#ifndef QT_NO_PHONON_VOLUMEFADEREFFECT

namespace Phonon

{

namespace Gstreamer

{

VolumeFaderEffect::VolumeFaderEffect(Backend *backend, QObject *parent) 

    : Effect(backend, parent, AudioSource | AudioSink)

    , m_fadeCurve(Phonon::VolumeFaderEffect::Fade3Decibel)

    , m_fadeTimer(0)

    , m_fadeDuration(0)

    , m_fadeFromVolume(0)

    , m_fadeToVolume(0)

{

    m_effectElement = gst_element_factory_make ("volume", NULL);

    if (m_effectElement)

        init();

}

VolumeFaderEffect::~VolumeFaderEffect()

{

    if (m_fadeTimer)

        killTimer(m_fadeTimer);

}

GstElement* VolumeFaderEffect::createEffectBin()

{

    GstElement *audioBin = gst_bin_new(NULL);

    // We need a queue to handle tee-connections from parent node

    GstElement *queue= gst_element_factory_make ("queue", NULL);

    gst_bin_add(GST_BIN(audioBin), queue);

    GstElement *mconv= gst_element_factory_make ("audioconvert", NULL);

    gst_bin_add(GST_BIN(audioBin), mconv);

    gst_bin_add(GST_BIN(audioBin), m_effectElement);

    // Link src pad

    GstPad *srcPad= gst_element_get_pad (m_effectElement, "src");

    gst_element_add_pad (audioBin, gst_ghost_pad_new ("src", srcPad));

    gst_object_unref (srcPad);

    // Link sink pad

    gst_element_link_many(queue, mconv, m_effectElement, (const char*)NULL);

    GstPad *sinkpad = gst_element_get_pad (queue, "sink");

    gst_element_add_pad (audioBin, gst_ghost_pad_new ("sink", sinkpad));

    gst_object_unref (sinkpad);

    return audioBin;

}

float VolumeFaderEffect::volume() const

{

    gdouble val = 0.0;

    if (m_effectElement)

        g_object_get(G_OBJECT(m_effectElement), "volume", &val, (const char*)NULL);

    return (float)val;

}

void VolumeFaderEffect::setVolume(float volume)

{

    g_object_set(G_OBJECT(m_effectElement), "volume", volume, (const char*)NULL);

}

Phonon::VolumeFaderEffect::FadeCurve VolumeFaderEffect::fadeCurve() const

{

    return m_fadeCurve;

}

void VolumeFaderEffect::setFadeCurve(Phonon::VolumeFaderEffect::FadeCurve fadeCurve)

{

    m_fadeCurve = fadeCurve;

}

void VolumeFaderEffect::fadeTo(float targetVolume, int fadeTime)

{

    m_fadeToVolume = targetVolume;

    m_fadeDuration = fadeTime;

    m_fadeFromVolume = volume();

    m_fadeStartTime.start();

    if (m_fadeTimer)

        killTimer(m_fadeTimer);

    m_fadeTimer = startTimer(30);

}

void VolumeFaderEffect::updateFade()

{

    double currVal = 0.0;

    float step = float(m_fadeStartTime.elapsed()) / float(m_fadeDuration);

    if (step > 1){

        step = 1;

        if (m_fadeTimer) {

            killTimer(m_fadeTimer);

            m_fadeTimer = 0;

        }

    }

    // This is a very loose and interpretation of the API

    // But in fact when fading between arbitrary values, the decibel values make no sense

    // Note : seems like we will change the API to re-use names from QTimeline for this

    switch (fadeCurve()) {

        case Phonon::VolumeFaderEffect::Fade3Decibel: // Slow in the beginning

            currVal = step * step;

            break;

        case Phonon::VolumeFaderEffect::Fade6Decibel: // Linear fade

            currVal = step;

            break;

        case Phonon::VolumeFaderEffect::Fade9Decibel: // Fast in the beginning / Linear

            currVal = step * 0.5 + (1.0-(1.0-step)*(1.0-step)) * 0.5; 

            break;

        case Phonon::VolumeFaderEffect::Fade12Decibel: // Fast in the beginning

            currVal = 1.0 - (1.0-step) * (1.0-step);  

            break;

        default:

            break;

    }

    const double volume = (1.0 - currVal) * m_fadeFromVolume + currVal * m_fadeToVolume;

    setVolume(volume);

}

bool VolumeFaderEffect::event(QEvent *event)

{

    switch (event->type()){

        case QEvent::Timer:

        {

            QTimerEvent *timerEvent = static_cast<QTimerEvent *>(event);

            if (timerEvent->timerId() == m_fadeTimer)

                updateFade();

            break;

        }

        default:

            break;

    }

    return QObject::event(event);

}

}} //namespace Phonon::Gstreamer

#endif //QT_NO_PHONON_VOLUMEFADEREFFECT

QT_END_NAMESPACE

#include "moc_volumefadereffect.cpp"