/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/
**
** This file is part of the QtQml module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** GNU Lesser General Public License Usage
** This file may be used under the terms of the GNU Lesser General Public
** License version 2.1 as published by the Free Software Foundation and
** appearing in the file LICENSE.LGPL included in the packaging of this
** file. Please review the following information to ensure the GNU Lesser
** General Public License version 2.1 requirements will be met:
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU General
** Public License version 3.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of this
** file. Please review the following information to ensure the GNU General
** Public License version 3.0 requirements will be met:
** http://www.gnu.org/copyleft/gpl.html.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms and
** conditions contained in a signed written agreement between you and Nokia.
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qquickpathview_p.h"
#include "qquickpathview_p_p.h"
#include "qquickcanvas.h"

#include <QtQuick/private/qquickstate_p.h>
#include <private/qqmlglobal_p.h>
#include <private/qqmlopenmetaobject_p.h>
#include <private/qlistmodelinterface_p.h>
#include <private/qquickchangeset_p.h>

#include <QtGui/qevent.h>
#include <QtGui/qevent.h>
#include <QtGui/qguiapplication.h>
#include <QtGui/qstylehints.h>
#include <QtCore/qmath.h>
#include <math.h>

// The number of samples to use in calculating the velocity of a flick
#ifndef QML_FLICK_SAMPLEBUFFER
#define QML_FLICK_SAMPLEBUFFER 3
#endif

// The number of samples to discard when calculating the flick velocity.
// Touch panels often produce inaccurate results as the finger is lifted.
#ifndef QML_FLICK_DISCARDSAMPLES
#define QML_FLICK_DISCARDSAMPLES 1
#endif

QT_BEGIN_NAMESPACE

inline qreal qmlMod(qreal x, qreal y)
{
#ifdef QT_USE_MATH_H_FLOATS
    if (sizeof(qreal) == sizeof(float))
        return fmodf(float(x), float(y));
    else
#endif
        return fmod(x, y);
}

static QQmlOpenMetaObjectType *qPathViewAttachedType = 0;

QQuickPathViewAttached::QQuickPathViewAttached(QObject *parent)
: QObject(parent), m_percent(-1), m_view(0), m_onPath(false), m_isCurrent(false)
{
    if (qPathViewAttachedType) {
        m_metaobject = new QQmlOpenMetaObject(this, qPathViewAttachedType);
        m_metaobject->setCached(true);
    } else {
        m_metaobject = new QQmlOpenMetaObject(this);
    }
}

QQuickPathViewAttached::~QQuickPathViewAttached()
{
}

QVariant QQuickPathViewAttached::value(const QByteArray &name) const
{
    return m_metaobject->value(name);
}
void QQuickPathViewAttached::setValue(const QByteArray &name, const QVariant &val)
{
    m_metaobject->setValue(name, val);
}


void QQuickPathViewPrivate::init()
{
    Q_Q(QQuickPathView);
    offset = 0;
    q->setAcceptedMouseButtons(Qt::LeftButton);
    q->setFlag(QQuickItem::ItemIsFocusScope);
    q->setFiltersChildMouseEvents(true);
    FAST_CONNECT(&tl, SIGNAL(updated()), q, SLOT(ticked()))
    lastPosTime.invalidate();
    FAST_CONNECT(&tl, SIGNAL(completed()), q, SLOT(movementEnding()))
}

QQuickItem *QQuickPathViewPrivate::getItem(int modelIndex, qreal z, bool onPath)
{
    Q_Q(QQuickPathView);
    requestedIndex = modelIndex;
    requestedOnPath = onPath;
    requestedZ = z;
    inRequest = true;
    QQuickItem *item = model->item(modelIndex, false);
    if (item) {
        QQml_setParent_noEvent(item, q);
        item->setParentItem(q);
        requestedIndex = -1;
        qPathViewAttachedType = attType;
        QQuickPathViewAttached *att = static_cast<QQuickPathViewAttached *>(qmlAttachedPropertiesObject<QQuickPathView>(item));
        qPathViewAttachedType = 0;
        if (att)
            att->setOnPath(onPath);
        QQuickItemPrivate *itemPrivate = QQuickItemPrivate::get(item);
        itemPrivate->addItemChangeListener(this, QQuickItemPrivate::Geometry);
    }
    inRequest = false;
    return item;
}

void QQuickPathView::createdItem(int index, QQuickItem *item)
{
    Q_D(QQuickPathView);
    if (d->requestedIndex != index) {
        qPathViewAttachedType = d->attachedType();
        QQuickPathViewAttached *att = static_cast<QQuickPathViewAttached *>(qmlAttachedPropertiesObject<QQuickPathView>(item));
        qPathViewAttachedType = 0;
        if (att) {
            att->m_view = this;
            att->setOnPath(false);
        }
        item->setParentItem(this);
        QQml_setParent_noEvent(item, this);
        d->updateItem(item, index < d->firstIndex ? 0.0 : 1.0);
    } else {
        d->requestedIndex = -1;
        if (!d->inRequest)
            refill();
    }
}

void QQuickPathView::initItem(int index, QQuickItem *item)
{
    Q_D(QQuickPathView);
    if (d->requestedIndex == index) {
        item->setParentItem(this);
        qPathViewAttachedType = d->attachedType();
        QQuickPathViewAttached *att = static_cast<QQuickPathViewAttached *>(qmlAttachedPropertiesObject<QQuickPathView>(item));
        qPathViewAttachedType = 0;
        if (att) {
            att->m_view = this;
            qreal percent = d->positionOfIndex(index);
            foreach (const QString &attr, d->path->attributes())
                att->setValue(attr.toUtf8(), d->path->attributeAt(attr, percent));
            item->setZ(d->requestedZ);
            if (att)
                att->setOnPath(d->requestedOnPath);
        }
    }
}

void QQuickPathViewPrivate::releaseItem(QQuickItem *item)
{
    if (!item || !model)
        return;
    QQuickItemPrivate *itemPrivate = QQuickItemPrivate::get(item);
    itemPrivate->removeItemChangeListener(this, QQuickItemPrivate::Geometry);
    if (model->release(item) == 0) {
        // item was not destroyed, and we no longer reference it.
        if (QQuickPathViewAttached *att = attached(item))
            att->setOnPath(false);
    }
}

QQuickPathViewAttached *QQuickPathViewPrivate::attached(QQuickItem *item)
{
    return static_cast<QQuickPathViewAttached *>(qmlAttachedPropertiesObject<QQuickPathView>(item, false));
}

QQmlOpenMetaObjectType *QQuickPathViewPrivate::attachedType()
{
    Q_Q(QQuickPathView);
    if (!attType) {
        // pre-create one metatype to share with all attached objects
        attType = new QQmlOpenMetaObjectType(&QQuickPathViewAttached::staticMetaObject, qmlEngine(q));
        foreach (const QString &attr, path->attributes())
            attType->createProperty(attr.toUtf8());
    }

    return attType;
}

void QQuickPathViewPrivate::clear()
{
    if (currentItem) {
        releaseItem(currentItem);
        currentItem = 0;
    }
    for (int i=0; i<items.count(); i++){
        QQuickItem *p = items[i];
        releaseItem(p);
    }
    items.clear();
}

void QQuickPathViewPrivate::updateMappedRange()
{
    if (model && pathItems != -1 && pathItems < modelCount)
        mappedRange = qreal(pathItems)/modelCount;
    else
        mappedRange = 1.0;
}

qreal QQuickPathViewPrivate::positionOfIndex(qreal index) const
{
    qreal pos = -1.0;

    if (model && index >= 0 && index < modelCount) {
        qreal start = 0.0;
        if (haveHighlightRange && highlightRangeMode != QQuickPathView::NoHighlightRange)
            start = highlightRangeStart;
        qreal globalPos = index + offset;
        globalPos = qmlMod(globalPos, qreal(modelCount)) / modelCount;
        if (pathItems != -1 && pathItems < modelCount) {
            globalPos += start * mappedRange;
            globalPos = qmlMod(globalPos, 1.0);
            if (globalPos < mappedRange)
                pos = globalPos / mappedRange;
        } else {
            pos = qmlMod(globalPos + start, 1.0);
        }
    }

    return pos;
}

void QQuickPathViewPrivate::createHighlight()
{
    Q_Q(QQuickPathView);
    if (!q->isComponentComplete())
        return;

    bool changed = false;
    if (highlightItem) {
        highlightItem->setParentItem(0);
        highlightItem->deleteLater();
        highlightItem = 0;
        changed = true;
    }

    QQuickItem *item = 0;
    if (highlightComponent) {
        QQmlContext *creationContext = highlightComponent->creationContext();
        QQmlContext *highlightContext = new QQmlContext(
                creationContext ? creationContext : qmlContext(q));
        QObject *nobj = highlightComponent->create(highlightContext);
        if (nobj) {
            QQml_setParent_noEvent(highlightContext, nobj);
            item = qobject_cast<QQuickItem *>(nobj);
            if (!item)
                delete nobj;
        } else {
            delete highlightContext;
        }
    } else {
        item = new QQuickItem;
    }
    if (item) {
        QQml_setParent_noEvent(item, q);
        item->setParentItem(q);
        highlightItem = item;
        changed = true;
    }
    if (changed)
        emit q->highlightItemChanged();
}

void QQuickPathViewPrivate::updateHighlight()
{
    Q_Q(QQuickPathView);
    if (!q->isComponentComplete() || !isValid())
        return;
    if (highlightItem) {
        if (haveHighlightRange && highlightRangeMode == QQuickPathView::StrictlyEnforceRange) {
            updateItem(highlightItem, highlightRangeStart);
        } else {
            qreal target = currentIndex;

            offsetAdj = 0.0;
            tl.reset(moveHighlight);
            moveHighlight.setValue(highlightPosition);

            const int duration = highlightMoveDuration;

            if (target - highlightPosition > modelCount/2) {
                highlightUp = false;
                qreal distance = modelCount - target + highlightPosition;
                tl.move(moveHighlight, 0.0, QEasingCurve(QEasingCurve::InQuad), int(duration * highlightPosition / distance));
                tl.set(moveHighlight, modelCount-0.01);
                tl.move(moveHighlight, target, QEasingCurve(QEasingCurve::OutQuad), int(duration * (modelCount-target) / distance));
            } else if (target - highlightPosition <= -modelCount/2) {
                highlightUp = true;
                qreal distance = modelCount - highlightPosition + target;
                tl.move(moveHighlight, modelCount-0.01, QEasingCurve(QEasingCurve::InQuad), int(duration * (modelCount-highlightPosition) / distance));
                tl.set(moveHighlight, 0.0);
                tl.move(moveHighlight, target, QEasingCurve(QEasingCurve::OutQuad), int(duration * target / distance));
            } else {
                highlightUp = highlightPosition - target < 0;
                tl.move(moveHighlight, target, QEasingCurve(QEasingCurve::InOutQuad), duration);
            }
        }
    }
}

void QQuickPathViewPrivate::setHighlightPosition(qreal pos)
{
    if (pos != highlightPosition) {
        qreal start = 0.0;
        qreal end = 1.0;
        if (haveHighlightRange && highlightRangeMode != QQuickPathView::NoHighlightRange) {
            start = highlightRangeStart;
            end = highlightRangeEnd;
        }

        qreal range = qreal(modelCount);
        // calc normalized position of highlight relative to offset
        qreal relativeHighlight = qmlMod(pos + offset, range) / range;

        if (!highlightUp && relativeHighlight > end * mappedRange) {
            qreal diff = 1.0 - relativeHighlight;
            setOffset(offset + diff * range);
        } else if (highlightUp && relativeHighlight >= (end - start) * mappedRange) {
            qreal diff = relativeHighlight - (end - start) * mappedRange;
            setOffset(offset - diff * range - 0.00001);
        }

        highlightPosition = pos;
        qreal pathPos = positionOfIndex(pos);
        updateItem(highlightItem, pathPos);
        if (QQuickPathViewAttached *att = attached(highlightItem))
            att->setOnPath(pathPos != -1.0);
    }
}

void QQuickPathView::pathUpdated()
{
    Q_D(QQuickPathView);
    QList<QQuickItem*>::iterator it = d->items.begin();
    while (it != d->items.end()) {
        QQuickItem *item = *it;
        if (QQuickPathViewAttached *att = d->attached(item))
            att->m_percent = -1;
        ++it;
    }
    refill();
}

void QQuickPathViewPrivate::updateItem(QQuickItem *item, qreal percent)
{
    if (QQuickPathViewAttached *att = attached(item)) {
        if (qFuzzyCompare(att->m_percent, percent))
            return;
        att->m_percent = percent;
        foreach (const QString &attr, path->attributes())
            att->setValue(attr.toUtf8(), path->attributeAt(attr, percent));
    }
    QPointF pf = path->pointAt(percent);
    item->setX(pf.x() - item->width()/2);
    item->setY(pf.y() - item->height()/2);
}

void QQuickPathViewPrivate::regenerate()
{
    Q_Q(QQuickPathView);
    if (!q->isComponentComplete())
        return;

    clear();

    if (!isValid())
        return;

    firstIndex = -1;
    updateMappedRange();
    q->refill();
}

/*!
    \qmlclass PathView QQuickPathView
    \inqmlmodule QtQuick 2
    \ingroup qml-view-elements
    \brief The PathView element lays out model-provided items on a path.
    \inherits Item

    A PathView displays data from models created from built-in QML elements like ListModel
    and XmlListModel, or custom model classes defined in C++ that inherit from
    QAbstractListModel.

    The view has a \l model, which defines the data to be displayed, and
    a \l delegate, which defines how the data should be displayed.
    The \l delegate is instantiated for each item on the \l path.
    The items may be flicked to move them along the path.

    For example, if there is a simple list model defined in a file \c ContactModel.qml like this:

    \snippet doc/src/snippets/qml/pathview/ContactModel.qml 0

    This data can be represented as a PathView, like this:

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

    \image pathview.gif

    (Note the above example uses PathAttribute to scale and modify the
    opacity of the items as they rotate. This additional code can be seen in the
    PathAttribute documentation.)

    PathView does not automatically handle keyboard navigation.  This is because
    the keys to use for navigation will depend upon the shape of the path.  Navigation
    can be added quite simply by setting \c focus to \c true and calling
    \l decrementCurrentIndex() or \l incrementCurrentIndex(), for example to navigate
    using the left and right arrow keys:

    \qml
    PathView {
        // ...
        focus: true
        Keys.onLeftPressed: decrementCurrentIndex()
        Keys.onRightPressed: incrementCurrentIndex()
    }
    \endqml

    The path view itself is a focus scope (see \l{qmlfocus#Acquiring Focus and Focus Scopes}{the focus documentation page} for more details).

    Delegates are instantiated as needed and may be destroyed at any time.
    State should \e never be stored in a delegate.

    PathView attaches a number of properties to the root item of the delegate, for example
    \c {PathView.isCurrentItem}.  In the following example, the root delegate item can access
    this attached property directly as \c PathView.isCurrentItem, while the child
    \c nameText object must refer to this property as \c wrapper.PathView.isCurrentItem.

    \snippet doc/src/snippets/qml/pathview/pathview.qml 1

    \bold Note that views do not enable \e clip automatically.  If the view
    is not clipped by another item or the screen, it will be necessary
    to set \e {clip: true} in order to have the out of view items clipped
    nicely.

    \sa Path, {declarative/modelviews/pathview}{PathView example}
*/

QQuickPathView::QQuickPathView(QQuickItem *parent)
  : QQuickItem(*(new QQuickPathViewPrivate), parent)
{
    Q_D(QQuickPathView);
    d->init();
}

QQuickPathView::~QQuickPathView()
{
    Q_D(QQuickPathView);
    d->clear();
    if (d->attType)
        d->attType->release();
    if (d->ownModel)
        delete d->model;
}

/*!
    \qmlattachedproperty PathView QtQuick2::PathView::view
    This attached property holds the view that manages this delegate instance.

    It is attached to each instance of the delegate.
*/

/*!
    \qmlattachedproperty bool QtQuick2::PathView::onPath
    This attached property holds whether the item is currently on the path.

    If a pathItemCount has been set, it is possible that some items may
    be instantiated, but not considered to be currently on the path.
    Usually, these items would be set invisible, for example:

    \qml
    Component {
        Rectangle {
            visible: PathView.onPath
            // ...
        }
    }
    \endqml

    It is attached to each instance of the delegate.
*/

/*!
    \qmlattachedproperty bool QtQuick2::PathView::isCurrentItem
    This attached property is true if this delegate is the current item; otherwise false.

    It is attached to each instance of the delegate.

    This property may be used to adjust the appearance of the current item.

    \snippet doc/src/snippets/qml/pathview/pathview.qml 1
*/

/*!
    \qmlproperty model QtQuick2::PathView::model
    This property holds the model providing data for the view.

    The model provides a set of data that is used to create the items for the view.
    For large or dynamic datasets the model is usually provided by a C++ model object.
    Models can also be created directly in QML, using the ListModel element.

    \sa {qmlmodels}{Data Models}
*/
QVariant QQuickPathView::model() const
{
    Q_D(const QQuickPathView);
    return d->modelVariant;
}

void QQuickPathView::setModel(const QVariant &model)
{
    Q_D(QQuickPathView);
    if (d->modelVariant == model)
        return;

    if (d->model) {
        disconnect(d->model, SIGNAL(modelUpdated(QQuickChangeSet,bool)),
                this, SLOT(modelUpdated(QQuickChangeSet,bool)));
        disconnect(d->model, SIGNAL(createdItem(int,QQuickItem*)), this, SLOT(createdItem(int,QQuickItem*)));
        disconnect(d->model, SIGNAL(initItem(int,QQuickItem*)), this, SLOT(initItem(int,QQuickItem*)));
        for (int i=0; i<d->items.count(); i++){
            QQuickItem *p = d->items[i];
            d->releaseItem(p);
        }
        d->items.clear();
    }

    d->modelVariant = model;
    QObject *object = qvariant_cast<QObject*>(model);
    QQuickVisualModel *vim = 0;
    if (object && (vim = qobject_cast<QQuickVisualModel *>(object))) {
        if (d->ownModel) {
            delete d->model;
            d->ownModel = false;
        }
        d->model = vim;
    } else {
        if (!d->ownModel) {
            d->model = new QQuickVisualDataModel(qmlContext(this));
            d->ownModel = true;
            if (isComponentComplete())
                static_cast<QQuickVisualDataModel *>(d->model.data())->componentComplete();
        }
        if (QQuickVisualDataModel *dataModel = qobject_cast<QQuickVisualDataModel*>(d->model))
            dataModel->setModel(model);
    }
    d->modelCount = 0;
    if (d->model) {
        connect(d->model, SIGNAL(modelUpdated(QQuickChangeSet,bool)),
                this, SLOT(modelUpdated(QQuickChangeSet,bool)));
        connect(d->model, SIGNAL(createdItem(int,QQuickItem*)), this, SLOT(createdItem(int,QQuickItem*)));
        connect(d->model, SIGNAL(initItem(int,QQuickItem*)), this, SLOT(initItem(int,QQuickItem*)));
        d->modelCount = d->model->count();
        if (d->model->count())
            d->offset = qmlMod(d->offset, qreal(d->model->count()));
        if (d->offset < 0)
            d->offset = d->model->count() + d->offset;
}
    d->regenerate();
    if (d->currentIndex < d->modelCount)
        setOffset(qmlMod(d->modelCount - d->currentIndex, d->modelCount));
    else
        d->fixOffset();
    emit countChanged();
    emit modelChanged();
}

/*!
    \qmlproperty int QtQuick2::PathView::count
    This property holds the number of items in the model.
*/
int QQuickPathView::count() const
{
    Q_D(const QQuickPathView);
    return d->model ? d->modelCount : 0;
}

/*!
    \qmlproperty Path QtQuick2::PathView::path
    This property holds the path used to lay out the items.
    For more information see the \l Path documentation.
*/
QQuickPath *QQuickPathView::path() const
{
    Q_D(const QQuickPathView);
    return d->path;
}

void QQuickPathView::setPath(QQuickPath *path)
{
    Q_D(QQuickPathView);
    if (d->path == path)
        return;
    if (d->path)
        disconnect(d->path, SIGNAL(changed()), this, SLOT(pathUpdated()));
    d->path = path;
    connect(d->path, SIGNAL(changed()), this, SLOT(pathUpdated()));
    if (d->isValid() && isComponentComplete()) {
        d->clear();
        if (d->attType) {
            d->attType->release();
            d->attType = 0;
        }
        d->regenerate();
    }
    emit pathChanged();
}

/*!
    \qmlproperty int QtQuick2::PathView::currentIndex
    This property holds the index of the current item.
*/
int QQuickPathView::currentIndex() const
{
    Q_D(const QQuickPathView);
    return d->currentIndex;
}

void QQuickPathView::setCurrentIndex(int idx)
{
    Q_D(QQuickPathView);
    if (d->model && d->modelCount)
        idx = qAbs(idx % d->modelCount);
    if (d->model && (idx != d->currentIndex || !d->currentItem)) {
        if (d->currentItem) {
            if (QQuickPathViewAttached *att = d->attached(d->currentItem))
                att->setIsCurrentItem(false);
            d->releaseItem(d->currentItem);
        }
        int oldCurrentIdx = d->currentIndex;
        QQuickItem *oldCurrentItem = d->currentItem;
        d->currentItem = 0;
        d->moveReason = QQuickPathViewPrivate::SetIndex;
        d->currentIndex = idx;
        if (d->modelCount) {
            d->createCurrentItem();
            if (d->haveHighlightRange && d->highlightRangeMode == QQuickPathView::StrictlyEnforceRange)
                d->snapToCurrent();
            d->currentItemOffset = d->positionOfIndex(d->currentIndex);
            d->updateHighlight();
        }
        if (oldCurrentIdx != d->currentIndex)
            emit currentIndexChanged();
        if (oldCurrentItem != d->currentItem)
            emit currentItemChanged();
    }
}

QQuickItem *QQuickPathView::currentItem() const
{
    Q_D(const QQuickPathView);
    return d->currentItem;
}

/*!
    \qmlmethod QtQuick2::PathView::incrementCurrentIndex()

    Increments the current index.

    \bold Note: methods should only be called after the Component has completed.
*/
void QQuickPathView::incrementCurrentIndex()
{
    Q_D(QQuickPathView);
    d->moveDirection = QQuickPathViewPrivate::Positive;
    setCurrentIndex(currentIndex()+1);
}

/*!
    \qmlmethod QtQuick2::PathView::decrementCurrentIndex()

    Decrements the current index.

    \bold Note: methods should only be called after the Component has completed.
*/
void QQuickPathView::decrementCurrentIndex()
{
    Q_D(QQuickPathView);
    if (d->model && d->modelCount) {
        int idx = currentIndex()-1;
        if (idx < 0)
            idx = d->modelCount - 1;
        d->moveDirection = QQuickPathViewPrivate::Negative;
        setCurrentIndex(idx);
    }
}

/*!
    \qmlproperty real QtQuick2::PathView::offset

    The offset specifies how far along the path the items are from their initial positions.
    This is a real number that ranges from 0.0 to the count of items in the model.
*/
qreal QQuickPathView::offset() const
{
    Q_D(const QQuickPathView);
    return d->offset;
}

void QQuickPathView::setOffset(qreal offset)
{
    Q_D(QQuickPathView);
    d->setOffset(offset);
    d->updateCurrent();
}

void QQuickPathViewPrivate::setOffset(qreal o)
{
    Q_Q(QQuickPathView);
    if (offset != o) {
        if (isValid() && q->isComponentComplete()) {
            offset = qmlMod(o, qreal(modelCount));
            if (offset < 0)
                offset += qreal(modelCount);
            q->refill();
        } else {
            offset = o;
        }
        emit q->offsetChanged();
    }
}

void QQuickPathViewPrivate::setAdjustedOffset(qreal o)
{
    setOffset(o+offsetAdj);
}

/*!
    \qmlproperty Component QtQuick2::PathView::highlight
    This property holds the component to use as the highlight.

    An instance of the highlight component will be created for each view.
    The geometry of the resultant component instance will be managed by the view
    so as to stay with the current item.

    The below example demonstrates how to make a simple highlight.  Note the use
    of the \l{PathView::onPath}{PathView.onPath} attached property to ensure that
    the highlight is hidden when flicked away from the path.

    \qml
    Component {
        Rectangle {
            visible: PathView.onPath
            // ...
        }
    }
    \endqml

    \sa highlightItem, highlightRangeMode
*/

QQmlComponent *QQuickPathView::highlight() const
{
    Q_D(const QQuickPathView);
    return d->highlightComponent;
}

void QQuickPathView::setHighlight(QQmlComponent *highlight)
{
    Q_D(QQuickPathView);
    if (highlight != d->highlightComponent) {
        d->highlightComponent = highlight;
        d->createHighlight();
        d->updateHighlight();
        emit highlightChanged();
    }
}

/*!
  \qmlproperty Item QtQuick2::PathView::highlightItem

  \c highlightItem holds the highlight item, which was created
  from the \l highlight component.

  \sa highlight
*/
QQuickItem *QQuickPathView::highlightItem()
{
    Q_D(const QQuickPathView);
    return d->highlightItem;
}
/*!
    \qmlproperty real QtQuick2::PathView::preferredHighlightBegin
    \qmlproperty real QtQuick2::PathView::preferredHighlightEnd
    \qmlproperty enumeration QtQuick2::PathView::highlightRangeMode

    These properties set the preferred range of the highlight (current item)
    within the view.  The preferred values must be in the range 0.0-1.0.

    If highlightRangeMode is set to \e PathView.NoHighlightRange

    If highlightRangeMode is set to \e PathView.ApplyRange the view will
    attempt to maintain the highlight within the range, however
    the highlight can move outside of the range at the ends of the path
    or due to a mouse interaction.

    If highlightRangeMode is set to \e PathView.StrictlyEnforceRange the highlight will never
    move outside of the range.  This means that the current item will change
    if a keyboard or mouse action would cause the highlight to move
    outside of the range.

    Note that this is the correct way to influence where the
    current item ends up when the view moves. For example, if you want the
    currently selected item to be in the middle of the path, then set the
    highlight range to be 0.5,0.5 and highlightRangeMode to PathView.StrictlyEnforceRange.
    Then, when the path scrolls,
    the currently selected item will be the item at that position. This also applies to
    when the currently selected item changes - it will scroll to within the preferred
    highlight range. Furthermore, the behaviour of the current item index will occur
    whether or not a highlight exists.

    The default value is \e PathView.StrictlyEnforceRange.

    Note that a valid range requires preferredHighlightEnd to be greater
    than or equal to preferredHighlightBegin.
*/
qreal QQuickPathView::preferredHighlightBegin() const
{
    Q_D(const QQuickPathView);
    return d->highlightRangeStart;
}

void QQuickPathView::setPreferredHighlightBegin(qreal start)
{
    Q_D(QQuickPathView);
    if (d->highlightRangeStart == start || start < 0 || start > 1.0)
        return;
    d->highlightRangeStart = start;
    d->haveHighlightRange = d->highlightRangeMode != NoHighlightRange && d->highlightRangeStart <= d->highlightRangeEnd;
    refill();
    emit preferredHighlightBeginChanged();
}

qreal QQuickPathView::preferredHighlightEnd() const
{
    Q_D(const QQuickPathView);
    return d->highlightRangeEnd;
}

void QQuickPathView::setPreferredHighlightEnd(qreal end)
{
    Q_D(QQuickPathView);
    if (d->highlightRangeEnd == end || end < 0 || end > 1.0)
        return;
    d->highlightRangeEnd = end;
    d->haveHighlightRange = d->highlightRangeMode != NoHighlightRange && d->highlightRangeStart <= d->highlightRangeEnd;
    refill();
    emit preferredHighlightEndChanged();
}

QQuickPathView::HighlightRangeMode QQuickPathView::highlightRangeMode() const
{
    Q_D(const QQuickPathView);
    return d->highlightRangeMode;
}

void QQuickPathView::setHighlightRangeMode(HighlightRangeMode mode)
{
    Q_D(QQuickPathView);
    if (d->highlightRangeMode == mode)
        return;
    d->highlightRangeMode = mode;
    d->haveHighlightRange = d->highlightRangeMode != NoHighlightRange && d->highlightRangeStart <= d->highlightRangeEnd;
    if (d->haveHighlightRange) {
        d->regenerate();
        d->snapToCurrent();
    }
    emit highlightRangeModeChanged();
}

/*!
    \qmlproperty int QtQuick2::PathView::highlightMoveDuration
    This property holds the move animation duration of the highlight delegate.

    If the highlightRangeMode is StrictlyEnforceRange then this property
    determines the speed that the items move along the path.

    The default value for the duration is 300ms.
*/
int QQuickPathView::highlightMoveDuration() const
{
    Q_D(const QQuickPathView);
    return d->highlightMoveDuration;
}

void QQuickPathView::setHighlightMoveDuration(int duration)
{
    Q_D(QQuickPathView);
    if (d->highlightMoveDuration == duration)
        return;
    d->highlightMoveDuration = duration;
    emit highlightMoveDurationChanged();
}

/*!
    \qmlproperty real QtQuick2::PathView::dragMargin
    This property holds the maximum distance from the path that initiate mouse dragging.

    By default the path can only be dragged by clicking on an item.  If
    dragMargin is greater than zero, a drag can be initiated by clicking
    within dragMargin pixels of the path.
*/
qreal QQuickPathView::dragMargin() const
{
    Q_D(const QQuickPathView);
    return d->dragMargin;
}

void QQuickPathView::setDragMargin(qreal dragMargin)
{
    Q_D(QQuickPathView);
    if (d->dragMargin == dragMargin)
        return;
    d->dragMargin = dragMargin;
    emit dragMarginChanged();
}

/*!
    \qmlproperty real QtQuick2::PathView::flickDeceleration
    This property holds the rate at which a flick will decelerate.

    The default is 100.
*/
qreal QQuickPathView::flickDeceleration() const
{
    Q_D(const QQuickPathView);
    return d->deceleration;
}

void QQuickPathView::setFlickDeceleration(qreal dec)
{
    Q_D(QQuickPathView);
    if (d->deceleration == dec)
        return;
    d->deceleration = dec;
    emit flickDecelerationChanged();
}

/*!
    \qmlproperty bool QtQuick2::PathView::interactive

    A user cannot drag or flick a PathView that is not interactive.

    This property is useful for temporarily disabling flicking. This allows
    special interaction with PathView's children.
*/
bool QQuickPathView::isInteractive() const
{
    Q_D(const QQuickPathView);
    return d->interactive;
}

void QQuickPathView::setInteractive(bool interactive)
{
    Q_D(QQuickPathView);
    if (interactive != d->interactive) {
        d->interactive = interactive;
        if (!interactive)
            d->tl.clear();
        emit interactiveChanged();
    }
}

/*!
    \qmlproperty bool QtQuick2::PathView::moving

    This property holds whether the view is currently moving
    due to the user either dragging or flicking the view.
*/
bool QQuickPathView::isMoving() const
{
    Q_D(const QQuickPathView);
    return d->moving;
}

/*!
    \qmlproperty bool QtQuick2::PathView::flicking

    This property holds whether the view is currently moving
    due to the user flicking the view.
*/
bool QQuickPathView::isFlicking() const
{
    Q_D(const QQuickPathView);
    return d->flicking;
}

/*!
    \qmlsignal QtQuick2::PathView::onMovementStarted()

    This handler is called when the view begins moving due to user
    interaction.
*/

/*!
    \qmlsignal QtQuick2::PathView::onMovementEnded()

    This handler is called when the view stops moving due to user
    interaction.  If a flick was generated, this handler will
    be triggered once the flick stops.  If a flick was not
    generated, the handler will be triggered when the
    user stops dragging - i.e. a mouse or touch release.
*/

/*!
    \qmlsignal QtQuick2::PathView::onFlickStarted()

    This handler is called when the view is flicked.  A flick
    starts from the point that the mouse or touch is released,
    while still in motion.
*/

/*!
    \qmlsignal QtQuick2::PathView::onFlickEnded()

    This handler is called when the view stops moving due to a flick.
*/

/*!
    \qmlproperty Component QtQuick2::PathView::delegate

    The delegate provides a template defining each item instantiated by the view.
    The index is exposed as an accessible \c index property.  Properties of the
    model are also available depending upon the type of \l {qmlmodels}{Data Model}.

    The number of elements in the delegate has a direct effect on the
    flicking performance of the view when pathItemCount is specified.  If at all possible, place functionality
    that is not needed for the normal display of the delegate in a \l Loader which
    can load additional elements when needed.

    Note that the PathView will layout the items based on the size of the root
    item in the delegate.

    Here is an example delegate:
    \snippet doc/src/snippets/qml/pathview/pathview.qml 1
*/
QQmlComponent *QQuickPathView::delegate() const
{
    Q_D(const QQuickPathView);
     if (d->model) {
        if (QQuickVisualDataModel *dataModel = qobject_cast<QQuickVisualDataModel*>(d->model))
            return dataModel->delegate();
    }

    return 0;
}

void QQuickPathView::setDelegate(QQmlComponent *delegate)
{
    Q_D(QQuickPathView);
    if (delegate == this->delegate())
        return;
    if (!d->ownModel) {
        d->model = new QQuickVisualDataModel(qmlContext(this));
        d->ownModel = true;
    }
    if (QQuickVisualDataModel *dataModel = qobject_cast<QQuickVisualDataModel*>(d->model)) {
        int oldCount = dataModel->count();
        dataModel->setDelegate(delegate);
        d->modelCount = dataModel->count();
        d->regenerate();
        if (oldCount != dataModel->count())
            emit countChanged();
        emit delegateChanged();
    }
}

/*!
  \qmlproperty int QtQuick2::PathView::pathItemCount
  This property holds the number of items visible on the path at any one time.
*/
int QQuickPathView::pathItemCount() const
{
    Q_D(const QQuickPathView);
    return d->pathItems;
}

void QQuickPathView::setPathItemCount(int i)
{
    Q_D(QQuickPathView);
    if (i == d->pathItems)
        return;
    if (i < 1)
        i = 1;
    d->pathItems = i;
    d->updateMappedRange();
    if (d->isValid() && isComponentComplete()) {
        d->regenerate();
    }
    emit pathItemCountChanged();
}

QPointF QQuickPathViewPrivate::pointNear(const QPointF &point, qreal *nearPercent) const
{
    qreal samples = qMin(path->path().length()/5, qreal(500.0));
    qreal res = path->path().length()/samples;

    qreal mindist = 1e10; // big number
    QPointF nearPoint = path->pointAt(0);
    qreal nearPc = 0;

    // get rough pos
    for (qreal i=1; i < samples; i++) {
        QPointF pt = path->pointAt(i/samples);
        QPointF diff = pt - point;
        qreal dist = diff.x()*diff.x() + diff.y()*diff.y();
        if (dist < mindist) {
            nearPoint = pt;
            nearPc = i;
            mindist = dist;
        }
    }

    // now refine
    qreal approxPc = nearPc;
    for (qreal i = approxPc-1.0; i < approxPc+1.0; i += 1/(2*res)) {
        QPointF pt = path->pointAt(i/samples);
        QPointF diff = pt - point;
        qreal dist = diff.x()*diff.x() + diff.y()*diff.y();
        if (dist < mindist) {
            nearPoint = pt;
            nearPc = i;
            mindist = dist;
        }
    }

    if (nearPercent)
        *nearPercent = nearPc / samples;

    return nearPoint;
}

void QQuickPathViewPrivate::addVelocitySample(qreal v)
{
    velocityBuffer.append(v);
    if (velocityBuffer.count() > QML_FLICK_SAMPLEBUFFER)
        velocityBuffer.remove(0);
}

qreal QQuickPathViewPrivate::calcVelocity() const
{
    qreal velocity = 0;
    if (velocityBuffer.count() > QML_FLICK_DISCARDSAMPLES) {
        int count = velocityBuffer.count()-QML_FLICK_DISCARDSAMPLES;
        for (int i = 0; i < count; ++i) {
            qreal v = velocityBuffer.at(i);
            velocity += v;
        }
        velocity /= count;
    }
    return velocity;
}

void QQuickPathView::mousePressEvent(QMouseEvent *event)
{
    Q_D(QQuickPathView);
    if (d->interactive) {
        d->handleMousePressEvent(event);
        event->accept();
    } else {
        QQuickItem::mousePressEvent(event);
    }
}

void QQuickPathViewPrivate::handleMousePressEvent(QMouseEvent *event)
{
    Q_Q(QQuickPathView);
    if (!interactive || !items.count())
        return;
    velocityBuffer.clear();
    QPointF scenePoint = q->mapToScene(event->localPos());
    int idx = 0;
    for (; idx < items.count(); ++idx) {
        QRectF rect = items.at(idx)->boundingRect();
        rect = items.at(idx)->mapRectToScene(rect);
        if (rect.contains(scenePoint))
            break;
    }
    if (idx == items.count() && dragMargin == 0.)  // didn't click on an item
        return;

    startPoint = pointNear(event->localPos(), &startPc);
    if (idx == items.count()) {
        qreal distance = qAbs(event->localPos().x() - startPoint.x()) + qAbs(event->localPos().y() - startPoint.y());
        if (distance > dragMargin)
            return;
    }


    if (tl.isActive() && flicking && flickDuration && qreal(tl.time())/flickDuration < 0.8)
        stealMouse = true; // If we've been flicked then steal the click.
    else
        stealMouse = false;

    lastElapsed = 0;
    lastDist = 0;
    QQuickItemPrivate::start(lastPosTime);
    tl.clear();
}

void QQuickPathView::mouseMoveEvent(QMouseEvent *event)
{
    Q_D(QQuickPathView);
    if (d->interactive) {
        d->handleMouseMoveEvent(event);
        if (d->stealMouse)
            setKeepMouseGrab(true);
        event->accept();
    } else {
        QQuickItem::mouseMoveEvent(event);
    }
}

void QQuickPathViewPrivate::handleMouseMoveEvent(QMouseEvent *event)
{
    Q_Q(QQuickPathView);
    if (!interactive || !lastPosTime.isValid())
        return;

    qreal newPc;
    QPointF pathPoint = pointNear(event->localPos(), &newPc);
    if (!stealMouse) {
        QPointF delta = pathPoint - startPoint;
        if (qAbs(delta.x()) > qApp->styleHints()->startDragDistance() || qAbs(delta.y()) > qApp->styleHints()->startDragDistance()) {
            stealMouse = true;
            startPc = newPc;
        }
    }

    if (stealMouse) {
        moveReason = QQuickPathViewPrivate::Mouse;
        qreal diff = (newPc - startPc)*modelCount*mappedRange;
        if (diff) {
            q->setOffset(offset + diff);

            if (diff > modelCount/2)
                diff -= modelCount;
            else if (diff < -modelCount/2)
                diff += modelCount;

            lastElapsed = QQuickItemPrivate::restart(lastPosTime);
            lastDist = diff;
            startPc = newPc;
            addVelocitySample(diff / (qreal(lastElapsed) / 1000.));
        }
        if (!moving) {
            moving = true;
            emit q->movingChanged();
            emit q->movementStarted();
        }
    }
}

void QQuickPathView::mouseReleaseEvent(QMouseEvent *event)
{
    Q_D(QQuickPathView);
    if (d->interactive) {
        d->handleMouseReleaseEvent(event);
        event->accept();
        ungrabMouse();
    } else {
        QQuickItem::mouseReleaseEvent(event);
    }
}

void QQuickPathViewPrivate::handleMouseReleaseEvent(QMouseEvent *)
{
    Q_Q(QQuickPathView);
    stealMouse = false;
    q->setKeepMouseGrab(false);
    if (!interactive || !lastPosTime.isValid())
        return;

    qreal velocity = calcVelocity();
    if (model && modelCount && qAbs(velocity) > 0.5) {
        qreal count = pathItems == -1 ? modelCount : pathItems;
        if (qAbs(velocity) > count * 2) // limit velocity
            velocity = (velocity > 0 ? count : -count) * 2;
        // Calculate the distance to be travelled
        qreal v2 = velocity*velocity;
        qreal accel = deceleration/10;
        qreal dist = 0;
        if (haveHighlightRange && highlightRangeMode == QQuickPathView::StrictlyEnforceRange) {
            // + 0.25 to encourage moving at least one item in the flick direction
            dist = qMin(qreal(modelCount-1), qreal(v2 / (accel * 2.0) + 0.25));
            // round to nearest item.
            if (velocity > 0.)
                dist = qRound(dist + offset) - offset;
            else
                dist = qRound(dist - offset) + offset;
            // Calculate accel required to stop on item boundary
            if (dist <= 0.) {
                dist = 0.;
                accel = 0.;
            } else {
                accel = v2 / (2.0f * qAbs(dist));
            }
        } else {
            dist = qMin(qreal(modelCount-1), qreal(v2 / (accel * 2.0)));
        }
        flickDuration = static_cast<int>(1000 * qAbs(velocity) / accel);
        offsetAdj = 0.0;
        moveOffset.setValue(offset);
        tl.accel(moveOffset, velocity, accel, dist);
        tl.callback(QQuickTimeLineCallback(&moveOffset, fixOffsetCallback, this));
        if (!flicking) {
            flicking = true;
            emit q->flickingChanged();
            emit q->flickStarted();
        }
    } else {
        fixOffset();
    }

    lastPosTime.invalidate();
    if (!tl.isActive())
        q->movementEnding();
}

bool QQuickPathView::sendMouseEvent(QMouseEvent *event)
{
    Q_D(QQuickPathView);
    QRectF myRect = mapRectToScene(QRectF(0, 0, width(), height()));
    QQuickCanvas *c = canvas();
    QQuickItem *grabber = c ? c->mouseGrabberItem() : 0;
    bool stealThisEvent = d->stealMouse;
    if ((stealThisEvent || myRect.contains(event->windowPos())) && (!grabber || !grabber->keepMouseGrab())) {
        QMouseEvent mouseEvent(event->type(), mapFromScene(event->windowPos()), event->windowPos(), event->screenPos(),
                               event->button(), event->buttons(), event->modifiers());
        mouseEvent.setAccepted(false);

        switch (mouseEvent.type()) {
        case QEvent::MouseMove:
            d->handleMouseMoveEvent(&mouseEvent);
            break;
        case QEvent::MouseButtonPress:
            d->handleMousePressEvent(&mouseEvent);
            stealThisEvent = d->stealMouse;   // Update stealThisEvent in case changed by function call above
            break;
        case QEvent::MouseButtonRelease:
            d->handleMouseReleaseEvent(&mouseEvent);
            break;
        default:
            break;
        }
        grabber = c->mouseGrabberItem();
        if (grabber && stealThisEvent && !grabber->keepMouseGrab() && grabber != this)
            grabMouse();

        return d->stealMouse;
    } else if (d->lastPosTime.isValid()) {
        d->lastPosTime.invalidate();
        d->fixOffset();
    }
    if (event->type() == QEvent::MouseButtonRelease)
        d->stealMouse = false;
    return false;
}

bool QQuickPathView::childMouseEventFilter(QQuickItem *i, QEvent *e)
{
    Q_D(QQuickPathView);
    if (!isVisible() || !d->interactive)
        return QQuickItem::childMouseEventFilter(i, e);

    switch (e->type()) {
    case QEvent::MouseButtonPress:
    case QEvent::MouseMove:
    case QEvent::MouseButtonRelease:
        return sendMouseEvent(static_cast<QMouseEvent *>(e));
    default:
        break;
    }

    return QQuickItem::childMouseEventFilter(i, e);
}

void QQuickPathView::mouseUngrabEvent()
{
    Q_D(QQuickPathView);
    if (d->stealMouse) {
        // if our mouse grab has been removed (probably by a Flickable),
        // fix our state
        d->stealMouse = false;
        setKeepMouseGrab(false);
        d->lastPosTime.invalidate();
    }
}

void QQuickPathView::updatePolish()
{
    QQuickItem::updatePolish();
    refill();
}

void QQuickPathView::componentComplete()
{
    Q_D(QQuickPathView);
    if (d->model && d->ownModel)
        static_cast<QQuickVisualDataModel *>(d->model.data())->componentComplete();

    QQuickItem::componentComplete();

    d->createHighlight();
    // It is possible that a refill has already happended to to Path
    // bindings being handled in the componentComplete().  If so
    // don't do it again.
    if (d->items.count() == 0 && d->model) {
        d->modelCount = d->model->count();
        d->regenerate();
    }
    d->updateHighlight();

    if (d->modelCount)
        emit countChanged();
}

void QQuickPathView::refill()
{
    Q_D(QQuickPathView);
    if (!d->isValid() || !isComponentComplete())
        return;

    d->layoutScheduled = false;
    bool currentVisible = false;

    // first move existing items and remove items off path
    int idx = d->firstIndex;
    QList<QQuickItem*>::iterator it = d->items.begin();
    while (it != d->items.end()) {
        qreal pos = d->positionOfIndex(idx);
        QQuickItem *item = *it;
        if (pos >= 0.0) {
            d->updateItem(item, pos);
            if (idx == d->currentIndex) {
                currentVisible = true;
                d->currentItemOffset = pos;
            }
            ++it;
        } else {
            // qDebug() << "release";
            d->updateItem(item, 1.0);
            d->releaseItem(item);
            if (it == d->items.begin()) {
                if (++d->firstIndex >= d->modelCount)
                    d->firstIndex = 0;
            }
            it = d->items.erase(it);
        }
        ++idx;
        if (idx >= d->modelCount)
            idx = 0;
    }
    if (!d->items.count())
        d->firstIndex = -1;

    bool waiting = false;
    if (d->modelCount) {
        // add items to beginning and end
        int count = d->pathItems == -1 ? d->modelCount : qMin(d->pathItems, d->modelCount);
        if (d->items.count() < count) {
            int idx = qRound(d->modelCount - d->offset) % d->modelCount;
            qreal startPos = 0.0;
            if (d->haveHighlightRange && d->highlightRangeMode != QQuickPathView::NoHighlightRange)
                startPos = d->highlightRangeStart;
            if (d->firstIndex >= 0) {
                startPos = d->positionOfIndex(d->firstIndex);
                idx = (d->firstIndex + d->items.count()) % d->modelCount;
            }
            qreal pos = d->positionOfIndex(idx);
            while ((pos > startPos || !d->items.count()) && d->items.count() < count) {
//                qDebug() << "append" << idx;
                QQuickItem *item = d->getItem(idx, idx+1);
                if (!item) {
                    waiting = true;
                    break;
                }
                if (d->currentIndex == idx) {
                    currentVisible = true;
                    d->currentItemOffset = pos;
                }
                if (d->items.count() == 0)
                    d->firstIndex = idx;
                d->items.append(item);
                d->updateItem(item, pos);
                ++idx;
                if (idx >= d->modelCount)
                    idx = 0;
                pos = d->positionOfIndex(idx);
            }

            idx = d->firstIndex - 1;
            if (idx < 0)
                idx = d->modelCount - 1;
            pos = d->positionOfIndex(idx);
            while (!waiting && (pos >= 0.0 && pos < startPos) && d->items.count() < count) {
//                 qDebug() << "prepend" << idx;
                QQuickItem *item = d->getItem(idx, idx+1);
                if (!item) {
                    waiting = true;
                    break;
                }
                if (d->currentIndex == idx) {
                    currentVisible = true;
                    d->currentItemOffset = pos;
                }
                d->items.prepend(item);
                d->updateItem(item, pos);
                d->firstIndex = idx;
                idx = d->firstIndex - 1;
                if (idx < 0)
                    idx = d->modelCount - 1;
                pos = d->positionOfIndex(idx);
            }
        }
    }

    if (!currentVisible) {
        d->currentItemOffset = 1.0;
        if (d->currentItem) {
            if (QQuickPathViewAttached *att = d->attached(d->currentItem))
                att->setOnPath(false);
        } else if (!waiting && d->currentIndex >= 0 && d->currentIndex < d->modelCount) {
            if ((d->currentItem = d->getItem(d->currentIndex, d->currentIndex, false))) {
                d->updateItem(d->currentItem, d->currentIndex < d->firstIndex ? 0.0 : 1.0);
                if (QQuickPathViewAttached *att = d->attached(d->currentItem))
                    att->setIsCurrentItem(true);
            }
        }
    } else if (!waiting && !d->currentItem) {
        if ((d->currentItem = d->getItem(d->currentIndex, d->currentIndex, true))) {
            d->currentItem->setFocus(true);
            if (QQuickPathViewAttached *att = d->attached(d->currentItem))
                att->setIsCurrentItem(true);
        }
    }

    if (d->highlightItem && d->haveHighlightRange && d->highlightRangeMode == QQuickPathView::StrictlyEnforceRange) {
        d->updateItem(d->highlightItem, d->highlightRangeStart);
        if (QQuickPathViewAttached *att = d->attached(d->highlightItem))
            att->setOnPath(true);
    } else if (d->highlightItem && d->moveReason != QQuickPathViewPrivate::SetIndex) {
        d->updateItem(d->highlightItem, d->currentItemOffset);
        if (QQuickPathViewAttached *att = d->attached(d->highlightItem))
            att->setOnPath(currentVisible);
    }
    while (d->itemCache.count())
        d->releaseItem(d->itemCache.takeLast());
}

void QQuickPathView::modelUpdated(const QQuickChangeSet &changeSet, bool reset)
{
    Q_D(QQuickPathView);
    if (!d->model || !d->model->isValid() || !d->path || !isComponentComplete())
        return;

    if (reset) {
        d->modelCount = d->model->count();
        d->regenerate();
        emit countChanged();
        return;
    }

    if (changeSet.removes().isEmpty() && changeSet.inserts().isEmpty())
        return;

    const int modelCount = d->modelCount;
    int moveId = -1;
    int moveOffset;
    bool currentChanged = false;
    bool changedOffset = false;
    foreach (const QQuickChangeSet::Remove &r, changeSet.removes()) {
        if (moveId == -1 && d->currentIndex >= r.index + r.count) {
            d->currentIndex -= r.count;
            currentChanged = true;
        } else if (moveId == -1 && d->currentIndex >= r.index && d->currentIndex < r.index + r.count) {
            // current item has been removed.
            d->currentIndex = qMin(r.index, d->modelCount - r.count - 1);
            if (r.isMove()) {
                moveId = r.moveId;
                moveOffset = d->currentIndex - r.index;
            } else if (d->currentItem) {
                if (QQuickPathViewAttached *att = d->attached(d->currentItem))
                    att->setIsCurrentItem(true);
                d->releaseItem(d->currentItem);
                d->currentItem = 0;
            }
            currentChanged = true;
        }

        if (r.index > d->currentIndex) {
            changedOffset = true;
            d->offset -= r.count;
            d->offsetAdj -= r.count;
        }
        d->modelCount -= r.count;
    }
    foreach (const QQuickChangeSet::Insert &i, changeSet.inserts()) {
        if (d->modelCount) {
            if (moveId == -1 && i.index <= d->currentIndex) {
                d->currentIndex += i.count;
                currentChanged = true;
            } else {
                if (moveId != -1 && moveId == i.moveId) {
                    d->currentIndex = i.index + moveOffset;
                    currentChanged = true;
                }
                if (i.index > d->currentIndex) {
                    d->offset += i.count;
                    d->offsetAdj += i.count;
                    changedOffset = true;
                }
            }
        }
        d->modelCount += i.count;
    }

    d->offset = qmlMod(d->offset, d->modelCount);
    if (d->offset < 0)
        d->offset += d->modelCount;

    d->itemCache += d->items;
    d->items.clear();

    if (!d->modelCount) {
        while (d->itemCache.count())
            d->releaseItem(d->itemCache.takeLast());
        d->offset = 0;
        changedOffset = true;
        d->tl.reset(d->moveOffset);
    } else {
        if (!d->flicking && !d->moving && d->haveHighlightRange && d->highlightRangeMode == QQuickPathView::StrictlyEnforceRange) {
            d->offset = qmlMod(d->modelCount - d->currentIndex, d->modelCount);
            changedOffset = true;
        }
        d->firstIndex = -1;
        d->updateMappedRange();
        d->scheduleLayout();
    }
    if (changedOffset)
        emit offsetChanged();
    if (currentChanged)
        emit currentIndexChanged();
    if (d->modelCount != modelCount)
        emit countChanged();
}

void QQuickPathView::destroyingItem(QQuickItem *item)
{
    Q_UNUSED(item);
}

void QQuickPathView::ticked()
{
    Q_D(QQuickPathView);
    d->updateCurrent();
}

void QQuickPathView::movementEnding()
{
    Q_D(QQuickPathView);
    if (d->flicking) {
        d->flicking = false;
        emit flickingChanged();
        emit flickEnded();
    }
    if (d->moving && !d->stealMouse) {
        d->moving = false;
        emit movingChanged();
        emit movementEnded();
    }
}

// find the item closest to the snap position
int QQuickPathViewPrivate::calcCurrentIndex()
{
    int current = -1;
    if (modelCount && model && items.count()) {
        offset = qmlMod(offset, modelCount);
        if (offset < 0)
            offset += modelCount;
        current = qRound(qAbs(qmlMod(modelCount - offset, modelCount)));
        current = current % modelCount;
    }

    return current;
}

void QQuickPathViewPrivate::createCurrentItem()
{
    if (requestedIndex != -1)
        return;
    int itemIndex = (currentIndex - firstIndex + modelCount) % modelCount;
    if (itemIndex < items.count()) {
        if ((currentItem = getItem(currentIndex, currentIndex, true))) {
            currentItem->setFocus(true);
            if (QQuickPathViewAttached *att = attached(currentItem))
                att->setIsCurrentItem(true);
        }
    } else if (currentIndex >= 0 && currentIndex < modelCount) {
        if ((currentItem = getItem(currentIndex, currentIndex, false))) {
            updateItem(currentItem, currentIndex < firstIndex ? 0.0 : 1.0);
            if (QQuickPathViewAttached *att = attached(currentItem))
                att->setIsCurrentItem(true);
        }
    }
}

void QQuickPathViewPrivate::updateCurrent()
{
    Q_Q(QQuickPathView);
    if (moveReason != Mouse)
        return;
    if (!modelCount || !haveHighlightRange || highlightRangeMode != QQuickPathView::StrictlyEnforceRange)
        return;

    int idx = calcCurrentIndex();
    if (model && idx != currentIndex) {
        if (currentItem) {
            if (QQuickPathViewAttached *att = attached(currentItem))
                att->setIsCurrentItem(false);
            releaseItem(currentItem);
        }
        currentIndex = idx;
        currentItem = 0;
        createCurrentItem();
        emit q->currentIndexChanged();
    }
}

void QQuickPathViewPrivate::fixOffsetCallback(void *d)
{
    ((QQuickPathViewPrivate *)d)->fixOffset();
}

void QQuickPathViewPrivate::fixOffset()
{
    Q_Q(QQuickPathView);
    if (model && items.count()) {
        if (haveHighlightRange && highlightRangeMode == QQuickPathView::StrictlyEnforceRange) {
            int curr = calcCurrentIndex();
            if (curr != currentIndex)
                q->setCurrentIndex(curr);
            else
                snapToCurrent();
        }
    }
}

void QQuickPathViewPrivate::snapToCurrent()
{
    if (!model || modelCount <= 0)
        return;

    qreal targetOffset = qmlMod(modelCount - currentIndex, modelCount);

    if (offset == targetOffset)
        return;

    moveReason = Other;
    offsetAdj = 0.0;
    tl.reset(moveOffset);
    moveOffset.setValue(offset);

    const int duration = highlightMoveDuration;

    if (!duration) {
        tl.set(moveOffset, targetOffset);
    } else if (moveDirection == Positive || (moveDirection == Shortest && targetOffset - offset > modelCount/2)) {
        qreal distance = modelCount - targetOffset + offset;
        if (targetOffset > moveOffset) {
            tl.move(moveOffset, 0.0, QEasingCurve(QEasingCurve::InQuad), int(duration * offset / distance));
            tl.set(moveOffset, modelCount);
            tl.move(moveOffset, targetOffset, QEasingCurve(offset == 0.0 ? QEasingCurve::InOutQuad : QEasingCurve::OutQuad), int(duration * (modelCount-targetOffset) / distance));
        } else {
            tl.move(moveOffset, targetOffset, QEasingCurve(QEasingCurve::InOutQuad), duration);
        }
    } else if (moveDirection == Negative || targetOffset - offset <= -modelCount/2) {
        qreal distance = modelCount - offset + targetOffset;
        if (targetOffset < moveOffset) {
            tl.move(moveOffset, modelCount, QEasingCurve(targetOffset == 0 ? QEasingCurve::InOutQuad : QEasingCurve::InQuad), int(duration * (modelCount-offset) / distance));
            tl.set(moveOffset, 0.0);
            tl.move(moveOffset, targetOffset, QEasingCurve(QEasingCurve::OutQuad), int(duration * targetOffset / distance));
        } else {
            tl.move(moveOffset, targetOffset, QEasingCurve(QEasingCurve::InOutQuad), duration);
        }
    } else {
        tl.move(moveOffset, targetOffset, QEasingCurve(QEasingCurve::InOutQuad), duration);
    }
    moveDirection = Shortest;
}

QQuickPathViewAttached *QQuickPathView::qmlAttachedProperties(QObject *obj)
{
    return new QQuickPathViewAttached(obj);
}

QT_END_NAMESPACE