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#include "qquickbehavior_p.h"

#include "qquickanimation_p.h"
#include <qqmlcontext.h>
#include <qqmlinfo.h>
#include <private/qqmlproperty_p.h>
#include <private/qqmlguard_p.h>
#include <private/qqmlengine_p.h>
#include <private/qabstractanimationjob_p.h>
#include <private/qquicktransition_p.h>

#include <private/qobject_p.h>

QT_BEGIN_NAMESPACE

class QQuickBehaviorPrivate : public QObjectPrivate, public QAnimationJobChangeListener
{
    Q_DECLARE_PUBLIC(QQuickBehavior)
public:
    QQuickBehaviorPrivate() : animation(0), animationInstance(0), enabled(true), finalized(false)
      , blockRunningChanged(false) {}

    virtual void animationStateChanged(QAbstractAnimationJob *, QAbstractAnimationJob::State newState, QAbstractAnimationJob::State oldState);

    QQmlProperty property;
    QVariant targetValue;
    QQmlGuard<QQuickAbstractAnimation> animation;
    QAbstractAnimationJob *animationInstance;
    bool enabled;
    bool finalized;
    bool blockRunningChanged;
};

/*!
    \qmlclass Behavior QQuickBehavior
    \inqmlmodule QtQuick 2
    \ingroup qml-animation-transition
    \brief The Behavior element allows you to specify a default animation for a property change.

    A Behavior defines the default animation to be applied whenever a
    particular property value changes.

    For example, the following Behavior defines a NumberAnimation to be run
    whenever the \l Rectangle's \c width value changes. When the MouseArea
    is clicked, the \c width is changed, triggering the behavior's animation:

    \snippet doc/src/snippets/qml/behavior.qml 0

    Note that a property cannot have more than one assigned Behavior. To provide
    multiple animations within a Behavior, use ParallelAnimation or
    SequentialAnimation.

    If a \l{QML States}{state change} has a \l Transition that matches the same property as a
    Behavior, the \l Transition animation overrides the Behavior for that
    state change. For general advice on using Behaviors to animate state changes, see
    \l{Using QML Behaviors with States}.

    \sa {QML Animation and Transitions}, {declarative/animation/behaviors}{Behavior example}, QtQml
*/


QQuickBehavior::QQuickBehavior(QObject *parent)
    : QObject(*(new QQuickBehaviorPrivate), parent)
{
}

QQuickBehavior::~QQuickBehavior()
{
    Q_D(QQuickBehavior);
    delete d->animationInstance;
}

/*!
    \qmlproperty Animation QtQuick2::Behavior::animation
    \default

    This property holds the animation to run when the behavior is triggered.
*/

QQuickAbstractAnimation *QQuickBehavior::animation()
{
    Q_D(QQuickBehavior);
    return d->animation;
}

void QQuickBehavior::setAnimation(QQuickAbstractAnimation *animation)
{
    Q_D(QQuickBehavior);
    if (d->animation) {
        qmlInfo(this) << tr("Cannot change the animation assigned to a Behavior.");
        return;
    }

    d->animation = animation;
    if (d->animation) {
        d->animation->setDefaultTarget(d->property);
        d->animation->setDisableUserControl();
    }
}


void QQuickBehaviorPrivate::animationStateChanged(QAbstractAnimationJob *, QAbstractAnimationJob::State newState,QAbstractAnimationJob::State)
{
    if (!blockRunningChanged)
        animation->notifyRunningChanged(newState == QAbstractAnimationJob::Running);
}

/*!
    \qmlproperty bool QtQuick2::Behavior::enabled

    This property holds whether the behavior will be triggered when the tracked
    property changes value.

    By default a Behavior is enabled.
*/

bool QQuickBehavior::enabled() const
{
    Q_D(const QQuickBehavior);
    return d->enabled;
}

void QQuickBehavior::setEnabled(bool enabled)
{
    Q_D(QQuickBehavior);
    if (d->enabled == enabled)
        return;
    d->enabled = enabled;
    emit enabledChanged();
}

void QQuickBehavior::write(const QVariant &value)
{
    Q_D(QQuickBehavior);
    bool bypass = !d->enabled || !d->finalized;
    if (!bypass)
        qmlExecuteDeferred(this);
    if (!d->animation || bypass) {
        QQmlPropertyPrivate::write(d->property, value, QQmlPropertyPrivate::BypassInterceptor | QQmlPropertyPrivate::DontRemoveBinding);
        d->targetValue = value;
        return;
    }

    if (d->animation->isRunning() && value == d->targetValue)
        return;

    const QVariant &currentValue = d->property.read();
    d->targetValue = value;

    if (d->animationInstance && d->animationInstance->duration() != -1
            && !d->animationInstance->isStopped()) {
        d->blockRunningChanged = true;
        d->animationInstance->stop();
    }

    QQuickStateOperation::ActionList actions;
    QQuickAction action;
    action.property = d->property;
    action.fromValue = currentValue;
    action.toValue = value;
    actions << action;

    QList<QQmlProperty> after;
    QAbstractAnimationJob *prev = d->animationInstance;
    d->animationInstance = d->animation->transition(actions, after, QQuickAbstractAnimation::Forward);
    if (d->animationInstance != prev) {
        d->animationInstance->addAnimationChangeListener(d, QAbstractAnimationJob::StateChange);
        if (prev)
            delete prev;
    }
    d->animationInstance->start();
    d->blockRunningChanged = false;
    if (!after.contains(d->property))
        QQmlPropertyPrivate::write(d->property, value, QQmlPropertyPrivate::BypassInterceptor | QQmlPropertyPrivate::DontRemoveBinding);
}

void QQuickBehavior::setTarget(const QQmlProperty &property)
{
    Q_D(QQuickBehavior);
    d->property = property;
    if (d->animation)
        d->animation->setDefaultTarget(property);

    QQmlEnginePrivate *engPriv = QQmlEnginePrivate::get(qmlEngine(this));
    static int finalizedIdx = -1;
    if (finalizedIdx < 0)
        finalizedIdx = metaObject()->indexOfSlot("componentFinalized()");
    engPriv->registerFinalizeCallback(this, finalizedIdx);
}

void QQuickBehavior::componentFinalized()
{
    Q_D(QQuickBehavior);
    d->finalized = true;
}

QT_END_NAMESPACE