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#include "qkeyframeanimation.h"
#include "Qt3DExtras/private/qkeyframeanimation_p.h"

#include <cmath>

QT_BEGIN_NAMESPACE

namespace Qt3DExtras {

QKeyframeAnimationPrivate::QKeyframeAnimationPrivate()
    : QAbstractAnimationPrivate(QAbstractAnimation::KeyframeAnimation)
    , m_minposition(0.0f)
    , m_maxposition(0.0f)
    , m_prevPosition(-1.0f)
    , m_target(nullptr)
    , m_startMode(QKeyframeAnimation::Constant)
    , m_endMode(QKeyframeAnimation::Constant)
{

}

QKeyframeAnimation::QKeyframeAnimation(QObject *parent)
    : QAbstractAnimation(*new QKeyframeAnimationPrivate(), parent)
{
    Q_D(QKeyframeAnimation);
    d->m_positionConnection = QObject::connect(this, &QAbstractAnimation::positionChanged,
                                               this, &QKeyframeAnimation::updateAnimation);
}


void QKeyframeAnimation::setFramePositions(const QVector<float> &positions)
{
    Q_D(QKeyframeAnimation);
    d->m_framePositions = positions;
    d->m_prevPosition = -1.0f;
    if (d->m_framePositions.size() == 0) {
        d->m_minposition = d->m_maxposition = 0.0f;
        return;
    }
    d->m_minposition = d->m_framePositions.first();
    d->m_maxposition = d->m_framePositions.last();
    float lastPos = d->m_minposition;
    for (float p : d->m_framePositions) {
        if (p < lastPos || p > d->m_maxposition)
            qWarning() << "positions not ordered correctly";
        lastPos = p;
    }
    setDuration(d->m_maxposition);
}

void QKeyframeAnimation::setKeyframes(const QVector<Qt3DCore::QTransform *> &keyframes)
{
    Q_D(QKeyframeAnimation);
    d->m_keyframes = keyframes;
}

// slerp which allows long path
QQuaternion lslerp(QQuaternion q1, QQuaternion q2, float t)
{
    QQuaternion ret;
    // Handle the easy cases first.
    if (t <= 0.0f)
        return q1;
    else if (t >= 1.0f)
        return q2;

    float cos = qBound(-1.0f, QQuaternion::dotProduct(q1, q2), 1.0f);
    float angle = std::acos(cos);
    float sin = std::sin(angle);
    if (!qFuzzyIsNull(sin)) {
        float a = std::sin((1.0 - t) * angle) / sin;
        float b = std::sin(t * angle) / sin;
        ret = (q1 * a + q2 * b).normalized();
    } else {
        ret = q1 * (1.0f-t) + q2 * t;
    }
    return ret;
}

void QKeyframeAnimationPrivate::calculateFrame(float position)
{
    if (m_target && m_framePositions.size() > 0
        && m_keyframes.size() == m_framePositions.size()
        && m_prevPosition != m_position) {
        if (m_position >= m_minposition && m_position < m_maxposition) {
            for (int i = 0; i < m_framePositions.size() - 1; i++) {
                if (position >= m_framePositions.at(i)
                    && position < m_framePositions.at(i+1)) {
                    float ip = (position - m_framePositions.at(i))
                                / (m_framePositions.at(i+1) - m_framePositions.at(i));
                    float eIp = m_easing.valueForProgress(ip);
                    float eIip = 1.0f - eIp;

                    Qt3DCore::QTransform *a = m_keyframes.at(i);
                    Qt3DCore::QTransform *b = m_keyframes.at(i+1);

                    QVector3D s = a->scale3D() * eIip + b->scale3D() * eIp;
                    QVector3D t = a->translation() * eIip + b->translation() * eIp;
                    QQuaternion r = QQuaternion::slerp(a->rotation(), b->rotation(), eIp);

                    m_target->setRotation(r);
                    m_target->setScale3D(s);
                    m_target->setTranslation(t);
                    return;
                }
            }
        } else if (position < m_minposition) {
            m_target->setRotation(m_keyframes.first()->rotation());
            m_target->setScale3D(m_keyframes.first()->scale3D());
            m_target->setTranslation(m_keyframes.first()->translation());
        } else {
            m_target->setRotation(m_keyframes.last()->rotation());
            m_target->setScale3D(m_keyframes.last()->scale3D());
            m_target->setTranslation(m_keyframes.last()->translation());
        }
        m_prevPosition = m_position;
    }
}

void QKeyframeAnimation::updateAnimation(float position)
{
    Q_D(QKeyframeAnimation);
    d->calculateFrame(position);
}

QVector<float> QKeyframeAnimation::framePositions() const
{
    Q_D(const QKeyframeAnimation);
    return d->m_framePositions;
}

QVector<Qt3DCore::QTransform *> QKeyframeAnimation::keyframeList() const
{
    Q_D(const QKeyframeAnimation);
    return d->m_keyframes;
}

void QKeyframeAnimation::setTarget(Qt3DCore::QTransform *target)
{
    Q_D(QKeyframeAnimation);
    if (d->m_target != target) {
        d->m_target = target;
        emit targetChanged(d->m_target);
        d->m_prevPosition = -1.0f;

        if (target) {
            d->m_baseScale = target->scale3D();
            d->m_baseTranslation = target->translation();
            d->m_baseRotation = target->rotation();
        }
    }
}

QKeyframeAnimation::RepeatMode QKeyframeAnimation::startMode() const
{
    Q_D(const QKeyframeAnimation);
    return d->m_startMode;
}

QKeyframeAnimation::RepeatMode QKeyframeAnimation::endMode() const
{
    Q_D(const QKeyframeAnimation);
    return d->m_endMode;
}

void QKeyframeAnimation::setEasing(QEasingCurve::Type easing)
{
    Q_D(QKeyframeAnimation);
    if (d->m_easing.type() != easing) {
        d->m_easing.setType(easing);
        emit easingChanged(easing);
    }
}

void QKeyframeAnimation::setTargetName(const QString &name)
{
    Q_D(QKeyframeAnimation);
    d->m_targetName = name;
    emit targetNameChanged(name);
}

void QKeyframeAnimation::setStartMode(QKeyframeAnimation::RepeatMode mode)
{
    Q_D(QKeyframeAnimation);
    if (d->m_startMode != mode) {
        d->m_startMode = mode;
        emit startModeChanged(mode);
    }
}

void QKeyframeAnimation::setEndMode(QKeyframeAnimation::RepeatMode mode)
{
    Q_D(QKeyframeAnimation);
    if (mode != d->m_endMode) {
        d->m_endMode = mode;
        emit endModeChanged(mode);
    }
}

void QKeyframeAnimation::addKeyframe(Qt3DCore::QTransform *keyframe)
{
    Q_D(QKeyframeAnimation);
    d->m_keyframes.push_back(keyframe);
}

QString QKeyframeAnimation::targetName() const
{
    Q_D(const QKeyframeAnimation);
    return d->m_targetName;
}

QEasingCurve::Type QKeyframeAnimation::easing() const
{
    Q_D(const QKeyframeAnimation);
    return d->m_easing.type();
}

Qt3DCore::QTransform *QKeyframeAnimation::target() const
{
    Q_D(const QKeyframeAnimation);
    return d->m_target;
}

} // Qt3DExtras

QT_END_NAMESPACE