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/*!

    \class QSequentialAnimationGroup

    \brief The QSequentialAnimationGroup class provides a sequential group of animations.

    \since 4.6

    \ingroup animation

    QSequentialAnimationGroup is a QAnimationGroup that runs its

    animations in sequence, i.e., it starts one animation after

    another has finished playing. The animations are played in the

    order they are added to the group (using

    \l{QAnimationGroup::}{addAnimation()} or

    \l{QAnimationGroup::}{insertAnimation()}). The animation group

    finishes when its last animation has finished.

    At each moment there is at most one animation that is active in

    the group; it is returned by currentAnimation(). An empty group

    has no current animation.

    A sequential animation group can be treated as any other

    animation, i.e., it can be started, stopped, and added to other

    groups. You can also call addPause() or insertPause() to add a

    pause to a sequential animation group.

    \code

        QSequentialAnimationGroup *group = new QSequentialAnimationGroup;

        group->addAnimation(anim1);

        group->addAnimation(anim2);

        group->start();

    \endcode

    In this example, \c anim1 and \c anim2 are two already set up

    \l{QPropertyAnimation}s.

    \sa QAnimationGroup, QAbstractAnimation, {The Animation Framework}

*/

#include "qsequentialanimationgroup.h"

#include "qsequentialanimationgroup_p.h"

#include "qpauseanimation.h"

#include <QtCore/qdebug.h>

#ifndef QT_NO_ANIMATION

QT_BEGIN_NAMESPACE

bool QSequentialAnimationGroupPrivate::atEnd() const

{

    // we try to detect if we're at the end of the group

    //this is true if the following conditions are true:

    // 1. we're in the last loop

    // 2. the direction is forward

    // 3. the current animation is the last one

    // 4. the current animation has reached its end

    const int animTotalCurrentTime = QAbstractAnimationPrivate::get(currentAnimation)->totalCurrentTime;

    return (currentLoop == loopCount - 1

        && direction == QAbstractAnimation::Forward

        && currentAnimation == animations.last()

        && animTotalCurrentTime == animationActualTotalDuration(currentAnimationIndex));

}

int QSequentialAnimationGroupPrivate::animationActualTotalDuration(int index) const

{

    QAbstractAnimation *anim = animations.at(index);

    int ret = anim->totalDuration();

    if (ret == -1 && actualDuration.size() > index)

        ret = actualDuration.at(index); //we can try the actual duration there

    return ret;

}

QSequentialAnimationGroupPrivate::AnimationIndex QSequentialAnimationGroupPrivate::indexForCurrentTime() const

{

    Q_ASSERT(!animations.isEmpty());

    AnimationIndex ret;

    int duration = 0;

    for (int i = 0; i < animations.size(); ++i) {

        duration = animationActualTotalDuration(i);

        // 'animation' is the current animation if one of these reasons is true:

        // 1. it's duration is undefined

        // 2. it ends after msecs

        // 3. it is the last animation (this can happen in case there is at least 1 uncontrolled animation)

        // 4. it ends exactly in msecs and the direction is backwards

        if (duration == -1 || currentTime < (ret.timeOffset + duration)

            || (currentTime == (ret.timeOffset + duration) && direction == QAbstractAnimation::Backward)) {

            ret.index = i;

            return ret;

        }

        // 'animation' has a non-null defined duration and is not the one at time 'msecs'.

        ret.timeOffset += duration;

    }

    // this can only happen when one of those conditions is true:

    // 1. the duration of the group is undefined and we passed its actual duration

    // 2. there are only 0-duration animations in the group

    ret.timeOffset -= duration;

    ret.index = animations.size() - 1;

    return ret;

}

void QSequentialAnimationGroupPrivate::restart()

{

    // restarting the group by making the first/last animation the current one

    if (direction == QAbstractAnimation::Forward) {

        lastLoop = 0;

        if (currentAnimationIndex == 0)

            activateCurrentAnimation();

        else

            setCurrentAnimation(0);

    } else { // direction == QAbstractAnimation::Backward

        lastLoop = loopCount - 1;

        int index = animations.size() - 1;

        if (currentAnimationIndex == index)

            activateCurrentAnimation();

        else

            setCurrentAnimation(index);

    }

}

/*!

    \internal

    This manages advancing the execution of a group running forwards (time has gone forward),

    which is the same behaviour for rewinding the execution of a group running backwards

    (time has gone backward).

*/

void QSequentialAnimationGroupPrivate::advanceForwards(const AnimationIndex &newAnimationIndex)

{

    if (lastLoop < currentLoop) {

        // we need to fast forward to the end

        for (int i = currentAnimationIndex; i < animations.size(); ++i) {

            QAbstractAnimation *anim = animations.at(i);

            setCurrentAnimation(i, true);

            anim->setCurrentTime(animationActualTotalDuration(i));

        }

        // this will make sure the current animation is reset to the beginning

        if (animations.size() == 1)

            // we need to force activation because setCurrentAnimation will have no effect

            activateCurrentAnimation();

        else

            setCurrentAnimation(0, true);

    }

    // and now we need to fast forward from the current position to

    for (int i = currentAnimationIndex; i < newAnimationIndex.index; ++i) {     //### WRONG,

        QAbstractAnimation *anim = animations.at(i);

        setCurrentAnimation(i, true);

        anim->setCurrentTime(animationActualTotalDuration(i));

    }

    // setting the new current animation will happen later

}

/*!

    \internal

    This manages rewinding the execution of a group running forwards (time has gone forward),

    which is the same behaviour for advancing the execution of a group running backwards

    (time has gone backward).

*/

void QSequentialAnimationGroupPrivate::rewindForwards(const AnimationIndex &newAnimationIndex)

{

    if (lastLoop > currentLoop) {

        // we need to fast rewind to the beginning

        for (int i = currentAnimationIndex; i >= 0 ; --i) {

            QAbstractAnimation *anim = animations.at(i);

            setCurrentAnimation(i, true);

            anim->setCurrentTime(0);

        }

        // this will make sure the current animation is reset to the end

        if (animations.size() == 1)

            // we need to force activation because setCurrentAnimation will have no effect

            activateCurrentAnimation();

        else

            setCurrentAnimation(animations.count() - 1, true);

    }

    // and now we need to fast rewind from the current position to

    for (int i = currentAnimationIndex; i > newAnimationIndex.index; --i) {

        QAbstractAnimation *anim = animations.at(i);

        setCurrentAnimation(i, true);

        anim->setCurrentTime(0);

    }

    // setting the new current animation will happen later

}

/*!

    \fn QSequentialAnimationGroup::currentAnimationChanged(QAbstractAnimation *current)

    QSequentialAnimationGroup emits this signal when currentAnimation

    has been changed. \a current is the current animation.

    \sa currentAnimation()

*/

/*!

    Constructs a QSequentialAnimationGroup.

    \a parent is passed to QObject's constructor.

*/

QSequentialAnimationGroup::QSequentialAnimationGroup(QObject *parent)

    : QAnimationGroup(*new QSequentialAnimationGroupPrivate, parent)

{

}

/*!

    \internal

*/

QSequentialAnimationGroup::QSequentialAnimationGroup(QSequentialAnimationGroupPrivate &dd,

                                                     QObject *parent)

    : QAnimationGroup(dd, parent)

{

}

/*!

    Destroys the animation group. It will also destroy all its animations.

*/

QSequentialAnimationGroup::~QSequentialAnimationGroup()

{

}

/*!

    Adds a pause of \a msecs to this animation group.

    The pause is considered as a special type of animation, thus 

    \l{QAnimationGroup::animationCount()}{animationCount} will be 

    increased by one.

    \sa insertPause(), QAnimationGroup::addAnimation()

*/

QPauseAnimation *QSequentialAnimationGroup::addPause(int msecs)

{

    QPauseAnimation *pause = new QPauseAnimation(msecs);

    addAnimation(pause);

    return pause;

}

/*!

    Inserts a pause of \a msecs milliseconds at \a index in this animation

    group.

    \sa addPause(), QAnimationGroup::insertAnimation()

*/

QPauseAnimation *QSequentialAnimationGroup::insertPause(int index, int msecs)

{

    Q_D(const QSequentialAnimationGroup);

    if (index < 0 || index > d->animations.size()) {

        qWarning("QSequentialAnimationGroup::insertPause: index is out of bounds");

        return 0;

    }

    QPauseAnimation *pause = new QPauseAnimation(msecs);

    insertAnimation(index, pause);

    return pause;

}

/*!

    \property QSequentialAnimationGroup::currentAnimation

    Returns the animation in the current time.

    \sa currentAnimationChanged()

*/

QAbstractAnimation *QSequentialAnimationGroup::currentAnimation() const

{

    Q_D(const QSequentialAnimationGroup);

    return d->currentAnimation;

}

/*!

    \reimp

*/

int QSequentialAnimationGroup::duration() const

{

    Q_D(const QSequentialAnimationGroup);

    int ret = 0;

    for (int i = 0; i < d->animations.size(); ++i) {

        QAbstractAnimation *animation = d->animations.at(i);

        const int currentDuration = animation->totalDuration();

        if (currentDuration == -1)

            return -1; // Undetermined length

        ret += currentDuration;

    }

    return ret;

}

/*!

    \reimp

*/

void QSequentialAnimationGroup::updateCurrentTime(int currentTime)

{

    Q_D(QSequentialAnimationGroup);

    if (!d->currentAnimation)

        return;

    const QSequentialAnimationGroupPrivate::AnimationIndex newAnimationIndex = d->indexForCurrentTime();

    // remove unneeded animations from actualDuration list

    while (newAnimationIndex.index < d->actualDuration.size())

        d->actualDuration.removeLast();

    // newAnimationIndex.index is the new current animation

    if (d->lastLoop < d->currentLoop

        || (d->lastLoop == d->currentLoop && d->currentAnimationIndex < newAnimationIndex.index)) {

            // advancing with forward direction is the same as rewinding with backwards direction

            d->advanceForwards(newAnimationIndex);

    } else if (d->lastLoop > d->currentLoop

        || (d->lastLoop == d->currentLoop && d->currentAnimationIndex > newAnimationIndex.index)) {

            // rewinding with forward direction is the same as advancing with backwards direction

            d->rewindForwards(newAnimationIndex);

    }

    d->setCurrentAnimation(newAnimationIndex.index);

    const int newCurrentTime = currentTime - newAnimationIndex.timeOffset;

    if (d->currentAnimation) {

        d->currentAnimation->setCurrentTime(newCurrentTime);

        if (d->atEnd()) {

            //we make sure that we don't exceed the duration here

            d->currentTime += QAbstractAnimationPrivate::get(d->currentAnimation)->totalCurrentTime - newCurrentTime;

            stop();

        }

    } else {

        //the only case where currentAnimation could be null

        //is when all animations have been removed

        Q_ASSERT(d->animations.isEmpty());

        d->currentTime = 0;

        stop();

    }

    d->lastLoop = d->currentLoop;

}

/*!

    \reimp

*/

void QSequentialAnimationGroup::updateState(QAbstractAnimation::State newState,

                                            QAbstractAnimation::State oldState)

{

    Q_D(QSequentialAnimationGroup);

    QAnimationGroup::updateState(newState, oldState);

    if (!d->currentAnimation)

        return;

    switch (newState) {

    case Stopped:

        d->currentAnimation->stop();

        break;

    case Paused:

        if (oldState == d->currentAnimation->state()

            && oldState == QSequentialAnimationGroup::Running) {

                d->currentAnimation->pause();

            }

        else

            d->restart();

        break;

    case Running:

        if (oldState == d->currentAnimation->state()

            && oldState == QSequentialAnimationGroup::Paused)

            d->currentAnimation->start();

        else

            d->restart();

        break;

    }

}

/*!

    \reimp

*/

void QSequentialAnimationGroup::updateDirection(QAbstractAnimation::Direction direction)

{

    Q_D(QSequentialAnimationGroup);

    // we need to update the direction of the current animation

    if (state() != Stopped && d->currentAnimation)

        d->currentAnimation->setDirection(direction);

}

/*!

    \reimp

*/

bool QSequentialAnimationGroup::event(QEvent *event)

{

    return QAnimationGroup::event(event);

}

void QSequentialAnimationGroupPrivate::setCurrentAnimation(int index, bool intermediate)

{

    Q_Q(QSequentialAnimationGroup);

    index = qMin(index, animations.count() - 1);

    if (index == -1) {

        Q_ASSERT(animations.isEmpty());

        currentAnimationIndex = -1;

        currentAnimation = 0;

        return;

    }

    // need these two checks below because this func can be called after the current animation

    // has been removed

    if (index == currentAnimationIndex && animations.at(index) == currentAnimation)

        return;

    // stop the old current animation

    if (currentAnimation)

        currentAnimation->stop();

    currentAnimation = animations.at(index);

    currentAnimationIndex = index;

    emit q->currentAnimationChanged(currentAnimation);

    activateCurrentAnimation(intermediate);

}

void QSequentialAnimationGroupPrivate::activateCurrentAnimation(bool intermediate)

{

    Q_Q(QSequentialAnimationGroup);

    if (!currentAnimation)

        return;

    if (state == QSequentialAnimationGroup::Stopped)

        return;

    currentAnimation->stop();

    // we ensure the direction is consistent with the group's direction

    currentAnimation->setDirection(direction);

    // connects to the finish signal of uncontrolled animations

    if (currentAnimation->totalDuration() == -1)

    currentAnimation->start();

    if (!intermediate && state == QSequentialAnimationGroup::Paused)

        currentAnimation->pause();

}

void QSequentialAnimationGroupPrivate::_q_uncontrolledAnimationFinished()

{

    Q_Q(QSequentialAnimationGroup);

    Q_ASSERT(qobject_cast<QAbstractAnimation *>(q->sender()) == currentAnimation);

    // we trust the duration returned by the animation

    while (actualDuration.size() < (currentAnimationIndex + 1))

        actualDuration.append(-1);

    actualDuration[currentAnimationIndex] = currentAnimation->currentTime();

    if ((direction == QAbstractAnimation::Forward && currentAnimation == animations.last())

        || (direction == QAbstractAnimation::Backward && currentAnimationIndex == 0)) {

        // we don't handle looping of a group with undefined duration

        q->stop();

    } else if (direction == QAbstractAnimation::Forward) {

        // set the current animation to be the next one

        setCurrentAnimation(currentAnimationIndex + 1);

    } else {

        // set the current animation to be the previous one

        setCurrentAnimation(currentAnimationIndex - 1);

    }

}

/*!

    \internal

    This method is called whenever an animation is added to

    the group at index \a index.

    Note: We only support insertion after the current animation

*/

void QSequentialAnimationGroupPrivate::animationInsertedAt(int index)

{

    if (currentAnimation == 0)

        setCurrentAnimation(0); // initialize the current animation

    if (currentAnimationIndex == index