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** This file is part of the QtDeclarative module of the Qt Toolkit.

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****************************************************************************/

#include "private/qdeclarativetransitionmanager_p_p.h"

#include "private/qdeclarativestate_p_p.h"

#include "private/qdeclarativestate_p.h"

#include <qdeclarativebinding_p.h>

#include <qdeclarativeglobal_p.h>

#include <qdeclarativeproperty_p.h>

QT_BEGIN_NAMESPACE

DEFINE_BOOL_CONFIG_OPTION(stateChangeDebug, STATECHANGE_DEBUG);

class QDeclarativeTransitionManagerPrivate

{

public:

    QDeclarativeTransitionManagerPrivate()

    : state(0), transition(0) {}

    void applyBindings();

    typedef QList<QDeclarativeSimpleAction> SimpleActionList;

    QDeclarativeState *state;

    QDeclarativeTransition *transition;

    QDeclarativeStateOperation::ActionList bindingsList;

    SimpleActionList completeList;

};

QDeclarativeTransitionManager::QDeclarativeTransitionManager()

: d(new QDeclarativeTransitionManagerPrivate)

{

}

void QDeclarativeTransitionManager::setState(QDeclarativeState *s)

{

    d->state = s;

}

QDeclarativeTransitionManager::~QDeclarativeTransitionManager()

{

    delete d; d = 0;

}

void QDeclarativeTransitionManager::complete() 

{

    d->applyBindings();

    for (int ii = 0; ii < d->completeList.count(); ++ii) {

        const QDeclarativeProperty &prop = d->completeList.at(ii).property;

        prop.write(d->completeList.at(ii).value);

    }

    d->completeList.clear();

    if (d->state) 

        static_cast<QDeclarativeStatePrivate*>(QObjectPrivate::get(d->state))->complete();

}

void QDeclarativeTransitionManagerPrivate::applyBindings()

{

    foreach(const QDeclarativeAction &action, bindingsList) {

        if (action.toBinding) {

            QDeclarativePropertyPrivate::setBinding(action.property, action.toBinding);

        } else if (action.event) {

            if (action.reverseEvent)

                action.event->reverse();

            else

                action.event->execute();

        }

    }

    bindingsList.clear();

}

void QDeclarativeTransitionManager::transition(const QList<QDeclarativeAction> &list,

                                      QDeclarativeTransition *transition)

{

    cancel();

    QDeclarativeStateOperation::ActionList applyList = list;

    // Determine which actions are binding changes.

    foreach(const QDeclarativeAction &action, applyList) {

        if (action.toBinding)

            d->bindingsList << action;

        if (action.fromBinding)

            QDeclarativePropertyPrivate::setBinding(action.property, 0); // Disable current binding

        if (action.event && action.event->changesBindings()) {  //### assume isReversable()?

            d->bindingsList << action;

            action.event->clearBindings();

        }

    }

    // Animated transitions need both the start and the end value for

    // each property change.  In the presence of bindings, the end values

    // are non-trivial to calculate.  As a "best effort" attempt, we first

    // apply all the property and binding changes, then read all the actual

    // final values, then roll back the changes and proceed as normal.

    //

    // This doesn't catch everything, and it might be a little fragile in

    // some cases - but whatcha going to do?

    if (!d->bindingsList.isEmpty()) {

        // Apply all the property and binding changes

        for (int ii = 0; ii < applyList.size(); ++ii) {

            const QDeclarativeAction &action = applyList.at(ii);

            if (action.toBinding) {

                QDeclarativePropertyPrivate::setBinding(action.property, action.toBinding, QDeclarativePropertyPrivate::BypassInterceptor | QDeclarativePropertyPrivate::DontRemoveBinding);

            } else if (!action.event) {

                QDeclarativePropertyPrivate::write(action.property, action.toValue, QDeclarativePropertyPrivate::BypassInterceptor | QDeclarativePropertyPrivate::DontRemoveBinding);

            } else if (action.event->isReversable()) {

                if (action.reverseEvent)

                    action.event->reverse(QDeclarativeActionEvent::FastForward);

                else

                    action.event->execute(QDeclarativeActionEvent::FastForward);

            }

        }

        // Read all the end values for binding changes

        for (int ii = 0; ii < applyList.size(); ++ii) {

            QDeclarativeAction *action = &applyList[ii];

            if (action->event) {

                action->event->saveTargetValues();

                continue;

            }

            const QDeclarativeProperty &prop = action->property;

            if (action->toBinding || !action->toValue.isValid()) {

                action->toValue = prop.read();

            }

        }

        // Revert back to the original values

        foreach(const QDeclarativeAction &action, applyList) {

            if (action.event) {

                if (action.event->isReversable()) {

                    action.event->clearBindings();

                    action.event->rewind();

                    action.event->clearBindings();

                }

                continue;

            }

            if (action.toBinding)

                QDeclarativePropertyPrivate::setBinding(action.property, 0); // Make sure this is disabled during the transition

            QDeclarativePropertyPrivate::write(action.property, action.fromValue, QDeclarativePropertyPrivate::BypassInterceptor | QDeclarativePropertyPrivate::DontRemoveBinding);

        }

    }

    if (transition) {

        QList<QDeclarativeProperty> touched;

        d->transition = transition;

        d->transition->prepare(applyList, touched, this);

        // Modify the action list to remove actions handled in the transition

        for (int ii = 0; ii < applyList.count(); ++ii) {

            const QDeclarativeAction &action = applyList.at(ii);

            if (action.event) {

                if (action.actionDone) {

                    applyList.removeAt(ii);

                    --ii;

                }

            } else {

                if (touched.contains(action.property)) {

                    if (action.toValue != action.fromValue) 

                        d->completeList << 

                            QDeclarativeSimpleAction(action, QDeclarativeSimpleAction::EndState);

                    applyList.removeAt(ii);

                    --ii;

                }

            }

        }

    }

    // Any actions remaining have not been handled by the transition and should

    // be applied immediately.  We skip applying bindings, as they are all

    // applied at the end in applyBindings() to avoid any nastiness mid 

    // transition

    foreach(const QDeclarativeAction &action, applyList) {

        if (action.event && !action.event->changesBindings()) {

            if (action.event->isReversable() && action.reverseEvent)

                action.event->reverse();

            else

                action.event->execute();

        } else if (!action.event && !action.toBinding) {

            action.property.write(action.toValue);

        }

    }

    if (stateChangeDebug()) {

        foreach(const QDeclarativeAction &action, applyList) {

            if (action.event)

                qWarning() << "    No transition for event:" << action.event->typeName();

            else

                qWarning() << "    No transition for:" << action.property.object()

                           << action.property.name() << "From:" << action.fromValue 

                           << "To:" << action.toValue;

        }

    }

    if (!transition)

        d->applyBindings();

}

void QDeclarativeTransitionManager::cancel()

{

    if (d->transition) {

        // ### this could potentially trigger a complete in rare circumstances

        d->transition->stop();  

        d->transition = 0;

    }

    for(int i = 0; i < d->bindingsList.count(); ++i) {

        QDeclarativeAction action = d->bindingsList[i];

        if (action.toBinding && action.deletableToBinding) {

            QDeclarativePropertyPrivate::setBinding(action.property, 0);

            action.toBinding->destroy();

            action.toBinding = 0;

            action.deletableToBinding = false;

        } else if (action.event) {

            //### what do we do here?

        }

    }

    d->bindingsList.clear();

    d->completeList.clear();

}

QT_END_NAMESPACE