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** Public License version 3.0 as published by the Free Software Foundation
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****************************************************************************/

#include "qsgdroparea_p.h"
#include "qsgdrag_p.h"
#include "qsgitem_p.h"
#include "qsgcanvas.h"

#include <private/qdeclarativeengine_p.h>

QSGDropAreaDrag::QSGDropAreaDrag(QSGDropAreaPrivate *d, QObject *parent)
    : QObject(parent)
    , d(d)
{
}

QSGDropAreaDrag::~QSGDropAreaDrag()
{
}

class QSGDropAreaPrivate : public QSGItemPrivate
{
    Q_DECLARE_PUBLIC(QSGDropArea)

public:
    QSGDropAreaPrivate();
    ~QSGDropAreaPrivate();

    bool hasMatchingKey(const QStringList &keys) const;

    QStringList getKeys(const QMimeData *mimeData) const;

    QStringList keys;
    QRegExp keyRegExp;
    QPointF dragPosition;
    QSGDropAreaDrag *drag;
    QDeclarativeGuard<QObject> source;
    QDeclarativeGuard<QMimeData> mimeData;
};

QSGDropAreaPrivate::QSGDropAreaPrivate()
    : drag(0)
{
}

QSGDropAreaPrivate::~QSGDropAreaPrivate()
{
    delete drag;
}

/*!
    \qmlclass DropArea QSGDropArea
    \inqmlmodule QtQuick 2
    \brief The DropArea item provides drag and drop handling.

    A DropArea is an invisible item which receives events when other items are
    dragged over it.

    The Drag attached property can be used to notify the DropArea when an Item is
    dragged over it.

    The \l keys property can be used to filter drag events which don't include
    a matching key.

    The \l dropItem property is communicated to the source of a drag event as
    the recipient of a drop on the drag target.

    The \l delegate property provides a means to specify a component to be
    instantiated for each active drag over a drag target.
*/

QSGDropArea::QSGDropArea(QSGItem *parent)
    : QSGItem(*new QSGDropAreaPrivate, parent)
{
    setFlags(ItemAcceptsDrops);
}

QSGDropArea::~QSGDropArea()
{
}

/*!
    \qmlproperty bool QtQuick2::DropArea::containsDrag

    This property identifies whether the DropArea currently contains any
    dragged items.
*/

bool QSGDropArea::containsDrag() const
{
    Q_D(const QSGDropArea);
    return d->mimeData;
}

/*!
    \qmlproperty stringlist QtQuick2::DropArea::keys

    This property holds a list of drag keys a DropArea will accept.

    If no keys are listed the DropArea will accept events from any drag source,
    otherwise the drag source must have at least one compatible key.

    \sa QtQuick2::Drag::keys
*/

QStringList QSGDropArea::keys() const
{
    Q_D(const QSGDropArea);
    return d->keys;
}

void QSGDropArea::setKeys(const QStringList &keys)
{
    Q_D(QSGDropArea);
    if (d->keys != keys) {
        d->keys = keys;

        if (keys.isEmpty()) {
            d->keyRegExp = QRegExp();
        } else {
            QString pattern = QLatin1Char('(') + QRegExp::escape(keys.first());
            for (int i = 1; i < keys.count(); ++i)
                pattern += QLatin1Char('|') + QRegExp::escape(keys.at(i));
            pattern += QLatin1Char(')');
            d->keyRegExp = QRegExp(pattern.replace(QLatin1String("\\*"), QLatin1String(".+")));
        }
        emit keysChanged();
    }
}

QSGDropAreaDrag *QSGDropArea::drag()
{
    Q_D(QSGDropArea);
    if (!d->drag)
        d->drag = new QSGDropAreaDrag(d);
    return d->drag;
}

/*!
    \qmlproperty Object QtQuick2::DropArea::drag.source

    This property holds the source of a drag.
*/

QObject *QSGDropAreaDrag::source() const
{
    return d->source;
}

/*!
    \qmlproperty qreal QtQuick2::DropArea::drag.x
    \qmlproperty qreal QtQuick2::DropArea::drag.y

    These properties hold the coordinates of the last drag event.
*/

qreal QSGDropAreaDrag::x() const
{
    return d->dragPosition.x();
}

qreal QSGDropAreaDrag::y() const
{
    return d->dragPosition.y();
}

/*!
    \qmlsignal QtQuick2::DropArea::onPositionChanged(DragEvent drag)

    This handler is called when the position of a drag has changed.
*/

void QSGDropArea::dragMoveEvent(QDragMoveEvent *event)
{
    Q_D(QSGDropArea);
    if (!d->mimeData)
        return;

    d->dragPosition = event->pos();
    if (d->drag)
        emit d->drag->positionChanged();

    event->accept();
    QSGDropEvent dragTargetEvent(d, event);
    emit positionChanged(&dragTargetEvent);
}

bool QSGDropAreaPrivate::hasMatchingKey(const QStringList &keys) const
{
    if (keyRegExp.isEmpty())
        return true;

    foreach (const QString &key, keys) {
        if (keyRegExp.exactMatch(key))
            return true;
    }
    return false;
}

QStringList QSGDropAreaPrivate::getKeys(const QMimeData *mimeData) const
{
    if (const QSGDragMimeData *dragMime = qobject_cast<const QSGDragMimeData *>(mimeData))
        return dragMime->keys();
    return mimeData->formats();
}

/*!
    \qmlsignal QtQuick2::DropArea::onEntered(DragEvent drag)

    This handler is called when a \a drag enters the bounds of a DropArea.
*/

void QSGDropArea::dragEnterEvent(QDragEnterEvent *event)
{
    Q_D(QSGDropArea);
    const QMimeData *mimeData = event->mimeData();
    if (!d->effectiveEnable || d->mimeData || !mimeData || !d->hasMatchingKey(d->getKeys(mimeData)))
        return;

    d->dragPosition = event->pos();

    event->accept();
    QSGDropEvent dragTargetEvent(d, event);
    emit entered(&dragTargetEvent);

    if (event->isAccepted()) {
        d->mimeData = const_cast<QMimeData *>(mimeData);
        if (QSGDragMimeData *dragMime = qobject_cast<QSGDragMimeData *>(d->mimeData))
            d->source = dragMime->source();
        else
            d->source = event->source();
        d->dragPosition = event->pos();
        if (d->drag) {
            emit d->drag->positionChanged();
            emit d->drag->sourceChanged();
        }
        emit containsDragChanged();
    }
}

/*!
    \qmlsignal QtQuick2::DropArea::onExited()

    This handler is called when a drag exits the bounds of a DropArea.
*/

void QSGDropArea::dragLeaveEvent(QDragLeaveEvent *)
{
    Q_D(QSGDropArea);
    if (!d->mimeData)
        return;

    emit exited();

    d->mimeData = 0;
    d->source = 0;
    emit containsDragChanged();
    if (d->drag)
        emit d->drag->sourceChanged();
}

/*!
    \qmlsignal QtQuick2::DropArea::onDropped(DragEvent drop)

    This handler is called when a drop event occurs within the bounds of a
    a DropArea.
*/

void QSGDropArea::dropEvent(QDropEvent *event)
{
    Q_D(QSGDropArea);
    if (!d->mimeData)
        return;

    QSGDropEvent dragTargetEvent(d, event);
    emit dropped(&dragTargetEvent);

    d->mimeData = 0;
    d->source = 0;
    emit containsDragChanged();
    if (d->drag)
        emit d->drag->sourceChanged();
}

/*!
    \qmlclass DragEvent QSGDragEvent
    \inqmlmodule QtQuick 2
    \brief The DragEvent object provides information about a drag event.

    The position of the drag event can be obtained from the \l x and \l y
    properties, and the \l keys property identifies the drag keys of the event
    \l source.
*/

/*!
    \qmlproperty real QtQuick2::DragEvent::x

    This property holds the x coordinate of a drag event.
*/

/*!
    \qmlproperty real QtQuick2::DragEvent::y

    This property holds the y coordinate of a drag event.
*/

/*!
    \qmlproperty Object QtQuick2::DragEvent::drag.source

    This property holds the source of a drag event.
*/

QObject *QSGDropEvent::source()
{
    if (const QSGDragMimeData *dragMime = qobject_cast<const QSGDragMimeData *>(event->mimeData()))
        return dragMime->source();
    else
        return event->source();
}

/*!
    \qmlproperty stringlist QtQuick2::DragEvent::keys

    This property holds a list of keys identifying the data type or source of a
    drag event.
*/

QStringList QSGDropEvent::keys() const
{
    return d->getKeys(event->mimeData());
}

/*!
    \qmlproperty enum QtQuick2::DragEvent::action

    This property holds the action that the \l source is to perform on an accepted drop.

    The drop action may be one of:

    \list
    \o Qt.CopyAction Copy the data to the target
    \o Qt.MoveAction Move the data from the source to the target
    \o Qt.LinkAction Create a link from the source to the target.
    \o Qt.IgnoreAction Ignore the action (do nothing with the data).
    \endlist
*/

/*!
    \qmlproperty flags QtQuick2::DragEvent::supportedActions

    This property holds the set of \l {action}{actions} supported by the
    drag source.
*/

/*!
    \qmlproperty real QtQuick2::DragEvent::accepted

    This property holds whether the drag event was accepted by a handler.

    The default value is true.
*/

/*!
    \qmlmethod void QtQuick2::DragEvent::accept()
    \qmlmethod void QtQuick2::DragEvent::accept(enum action)

    Accepts the drag event.

    If an \a action is specified it will overwrite the value of the \l action property.
*/

void QSGDropEvent::accept(QDeclarativeV8Function *args)
{
    Qt::DropAction action = event->dropAction();

    if (args->Length() >= 1) {
        v8::Local<v8::Value> v = (*args)[0];
        if (v->IsInt32())
            action = Qt::DropAction(v->Int32Value());
    }
    // get action from arguments.
    event->setDropAction(action);
    event->accept();
}


QT_END_NAMESPACE