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#include "qsgparticlepainter_p.h"
#include <QDebug>
QT_BEGIN_NAMESPACE
QSGParticlePainter::QSGParticlePainter(QSGItem *parent) :
    QSGItem(parent),
    m_system(0), m_count(0), m_lastStart(0)
{
    connect(this, SIGNAL(xChanged()),
            this, SLOT(calcSystemOffset()));
    connect(this, SIGNAL(yChanged()),
            this, SLOT(calcSystemOffset()));
}

void QSGParticlePainter::componentComplete()
{
    if(!m_system && qobject_cast<QSGParticleSystem*>(parentItem()))
        setSystem(qobject_cast<QSGParticleSystem*>(parentItem()));
    if(!m_system)
        qWarning() << "ParticlePainter created without a particle system specified";//TODO: useful QML warnings, like line number?
    QSGItem::componentComplete();
}


void QSGParticlePainter::setSystem(QSGParticleSystem *arg)
{
    if (m_system != arg) {
        m_system = arg;
        if(m_system){
            m_system->registerParticlePainter(this);
            connect(m_system, SIGNAL(xChanged()),
                    this, SLOT(calcSystemOffset()));
            connect(m_system, SIGNAL(yChanged()),
                    this, SLOT(calcSystemOffset()));
            calcSystemOffset();
        }
        emit systemChanged(arg);
    }
}

void QSGParticlePainter::load(QSGParticleData*)
{
}

void QSGParticlePainter::reload(QSGParticleData*)
{
}

void QSGParticlePainter::reset()
{
    //Have to every time because what it's emitting may have changed and that affects particleTypeIndex
    if(m_system)
        updateParticleStarts();
}

void QSGParticlePainter::resize(int, int)
{
}


void QSGParticlePainter::setCount(int c)
{
    Q_ASSERT(c >= 0); //XXX
    if(c == m_count)
        return;
    int lastCount = m_count;
    m_count = c;
    resize(lastCount, m_count);//### is virtual needed? Or should I just use the signal?
    updateParticleStarts();
    emit countChanged();
}

int QSGParticlePainter::count()
{
    return m_count;
}


void QSGParticlePainter::updateParticleStarts()
{
    m_particleStarts.clear();
    m_lastStart = 0;
    QList<int> particleList;
    if(m_particles.isEmpty())
        particleList << 0;
    foreach(const QString &s, m_particles)
        particleList << m_system->m_groupIds[s];
    foreach(int gIdx, particleList){
        QSGParticleGroupData *gd = m_system->m_groupData[gIdx];
        m_particleStarts.insert(gIdx, qMakePair<int, int>(gd->size, m_lastStart));
        m_lastStart += gd->size;
    }
}

int QSGParticlePainter::particleTypeIndex(QSGParticleData* d)
{
    Q_ASSERT(d && m_particleStarts.contains(d->group));//XXX
    int ret = m_particleStarts[d->group].second + d->index;
    Q_ASSERT(ret >=0 && ret < m_count);//XXX:shouldn't assert, but bugs here were hard to find in the past
    return ret;
}


void QSGParticlePainter::calcSystemOffset()
{
    if(!m_system)
        return;
    QPointF lastOffset = m_systemOffset;
    m_systemOffset = -1 * this->mapFromItem(m_system, QPointF());
    if(lastOffset != m_systemOffset){
        //Reload all particles//TODO: Necessary?
        foreach(const QString &g, m_particles){
            int gId = m_system->m_groupIds[g];
            foreach(QSGParticleData* d, m_system->m_groupData[gId]->data)
                reload(d);
        }
    }
}
QT_END_NAMESPACE