/*  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 "mediaobject.h"

#include "mmf_medianode.h"

QT_BEGIN_NAMESPACE

using namespace Phonon;

using namespace Phonon::MMF;

/*! \class MMF::MediaNode

  \internal

*/

MMF::MediaNode::MediaNode(QObject *parent) : QObject::QObject(parent)

                                           , m_source(0)

                                           , m_target(0)

                                           , m_isApplied(false)

{

}

bool MMF::MediaNode::connectMediaNode(MediaNode *target)

{

    m_target = target;

    m_target->setSource(this);

    return applyNodesOnMediaObject(target);

}

bool MMF::MediaNode::disconnectMediaNode(MediaNode *target)

{

    Q_UNUSED(target);

    m_target = 0;

    m_isApplied = false;

    return true;

}

void MMF::MediaNode::setSource(MediaNode *source)

{

    m_source = source;

}

MMF::MediaNode *MMF::MediaNode::source() const

{

    return m_source;

}

MMF::MediaNode *MMF::MediaNode::target() const

{

    return m_target;

}

bool MMF::MediaNode::applyNodesOnMediaObject(MediaNode *)

{

    // Algorithmically, this can be expressed in a more efficient way by

    // exercising available assumptions, but it complicates code for input

    // data(length of the graph) which typically is very small.

    // First, we go to the very beginning of the graph.

    MMF::MediaNode *current = this;

    do {

        MediaNode *const candidate = current->source();

        if (candidate)

            current = candidate;

        else

            break;

    }

    while (current);

    // Now we do two things, while walking to the other end:

    // 1. Find the MediaObject, if present

    // 2. Collect a list of all unapplied MediaNodes

    QList<MediaNode *> unapplied;

    MMF::MediaObject *mo = 0;

    do {

        if (!current->m_isApplied)

            unapplied.append(current);

        if (!mo)

            mo = qobject_cast<MMF::MediaObject *>(current);

        current = current->target();

    }

    while (current);

    // Now, lets activate all the objects, if we found the MediaObject.

    if (mo) {

        for (int i = 0; i < unapplied.count(); ++i) {

            MediaNode *const at = unapplied.at(i);

            // We don't want to apply MediaObject on itself.

            if (at != mo)

                at->activateOnMediaObject(mo);

        }

    }

    return true;

}

QT_END_NAMESPACE