/****************************************************************************
**
** Copyright (C) 2015 Klaralvdalens Datakonsult AB (KDAB).
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt3D module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qobjectpicker.h"
#include "qobjectpicker_p.h"
#include <Qt3DCore/qentity.h>
#include <Qt3DCore/private/qcomponent_p.h>
#include <Qt3DCore/qpropertyupdatedchange.h>
#include <Qt3DRender/qpickevent.h>

QT_BEGIN_NAMESPACE

namespace Qt3DRender {

/*!
    \class Qt3DRender::QObjectPicker
    \inmodule Qt3DRender

    \brief The QObjectPicker class instantiates a component that can
    be used to interact with a QEntity by a process known as picking.

    For every combination of viewport and camera, picking casts a ray through the scene to
    find entities who's bounding volume intersects the ray. The bounding volume is computed using
    the values in the attribute buffer specified by the boundingVolumePositionAttribute of the
    geometry.

    The signals pressed(), released(), clicked(), moved(), entered(), and exited() are
    emitted when the bounding volume defined by the pickAttribute property intersects
    with a ray.

    Most signals carry a QPickEvent instance. If QPickingSettings::pickMode() is set to
    QPickingSettings::TrianglePicking, the actual type of the pick parameter will be
    QPickTriangleEvent.

    Pick queries are performed on mouse press and mouse release.
    If drag is enabled, queries also happen on each mouse move while any button is pressed.
    If hover is enabled, queries happen on every mouse move even if no button is pressed.

    For generalised ray casting queries, see Qt3DRender::QRayCaster and Qt3DRender::QScreenRayCaster.

    \sa Qt3DRender::QPickingSettings, Qt3DRender::QGeometry, Qt3DRender::QAttribute,
        Qt3DRender::QPickEvent, Qt3DRender::QPickTriangleEvent

    \note Instances of this component shouldn't be shared, not respecting that
    condition will most likely result in undefined behavior.

    \since 5.6
*/

/*!
    \qmltype ObjectPicker
    \instantiates Qt3DRender::QObjectPicker
    \inqmlmodule Qt3D.Render
    \brief The ObjectPicker class instantiates a component that can
    be used to interact with an Entity by a process known as picking.

    For every combination of viewport and camera, picking casts a ray through the scene to
    find entities who's bounding volume intersects the ray. The bounding volume is computed using
    the values in the attribute buffer specified by the boundingVolumePositionAttribute of the
    geometry.

    The signals pressed(), released(), clicked(), moved(), entered(), and exited() are
    emitted when the bounding volume defined by the pickAttribute property intersects
    with a ray.

    Most signals carry a PickEvent instance. If PickingSettings.pickMode is set to
    PickingSettings.TrianglePicking, the actual type of the pick parameter will be
    PickTriangleEvent.

    Pick queries are performed on mouse press and mouse release.
    If drag is enabled, queries also happen on each mouse move while any button is pressed.
    If hover is enabled, queries happen on every mouse move even if no button is pressed.

    \sa PickingSettings, Geometry, Attribute, PickEvent, PickTriangleEvent

    \note To receive hover events in QtQuick, the hoverEnabled property of Scene3D must also be set.

    \note Instances of this component shouldn't be shared, not respecting that
    condition will most likely result in undefined behavior.
 */

/*!
    \qmlsignal Qt3D.Render::ObjectPicker::clicked(PickEvent pick)

    This signal is emitted when the bounding volume defined by the pickAttribute
    property intersects with a ray on a mouse click the PickEvent \a pick contains
    details of the event.
*/

/*!
    \qmlsignal Qt3D.Render::ObjectPicker::pressed(PickEvent pick)

    This signal is emitted when the bounding volume defined by the
    pickAttribute property intersects with a ray on a mouse press. Intersection
    information are accessible through the \a pick parameter.
*/

/*!
    \qmlsignal Qt3D.Render::ObjectPicker::released(PickEvent pick)

    This signal is emitted when the bounding volume defined by the
    pickAttribute property intersects with a ray on a mouse release.
    Intersection information are accessible through the \a pick parameter.
*/

/*!
    \qmlsignal Qt3D.Render::ObjectPicker::clicked(PickEvent pick)

    This signal is emitted when the bounding volume defined by the
    pickAttribute property intersects with a ray on a mouse click. Intersection
    information are accessible through the pick \a parameter.
*/

/*!
    \qmlsignal Qt3D.Render::ObjectPicker::moved(PickEvent pick)

    This signal is emitted when the bounding volume defined by the
    pickAttribute property intersects with a ray on a mouse move with a button
    pressed. Intersection information are accessible through the \a pick
    parameter.
*/

/*!
    \qmlsignal Qt3D.Render::ObjectPicker::entered()

    This signal is emitted when the bounding volume defined by the pickAttribute
    property intersects with a ray on the mouse entering the volume.
*/

/*!
    \qmlsignal Qt3D.Render::ObjectPicker::exited()

    This signal is emitted when the bounding volume defined by the pickAttribute
    property intersects with a ray on the ray exiting the volume.
*/

/*!
    \fn Qt3DRender::QObjectPicker::clicked(Qt3DRender::QPickEvent *pick)

    This signal is emitted when the bounding volume defined by the pickAttribute
    property intersects with a ray on a mouse click the QPickEvent \a pick contains
    details of the event.
*/

/*!
    \fn Qt3DRender::QObjectPicker::entered()

    This signal is emitted when the bounding volume defined by the pickAttribute
    property intersects with a ray on the mouse entering the volume.
*/

/*!
    \fn Qt3DRender::QObjectPicker::exited()

    This signal is emitted when the bounding volume defined by the pickAttribute
    property intersects with a ray on the ray exiting the volume.
*/

/*!
    \fn Qt3DRender::QObjectPicker::moved(Qt3DRender::QPickEvent *pick)

    This signal is emitted when the bounding volume defined by the
    pickAttribute property intersects with a ray on a mouse move with a button
    pressed the QPickEvent \a pick contains details of the event.
*/

/*!
    \fn Qt3DRender::QObjectPicker::pressed(Qt3DRender::QPickEvent *pick)

    This signal is emitted when the bounding volume defined by the
    pickAttribute property intersects with a ray on a mouse press the
    QPickEvent \a pick contains details of the event.
*/

/*!
    \fn Qt3DRender::QObjectPicker::released(Qt3DRender::QPickEvent *pick)

    This signal is emitted when the bounding volume defined by the
    pickAttribute property intersects with a ray on a mouse release the
    QPickEvent \a pick contains details of the event.
*/

QObjectPicker::QObjectPicker(Qt3DCore::QNode *parent)
    : Qt3DCore::QComponent(*new QObjectPickerPrivate(), parent)
{
}

/*! \internal */
QObjectPicker::~QObjectPicker()
{
}

/*!
 * Sets the hoverEnabled Property to \a hoverEnabled
 */
void QObjectPicker::setHoverEnabled(bool hoverEnabled)
{
    Q_D(QObjectPicker);
    if (hoverEnabled != d->m_hoverEnabled) {
        d->m_hoverEnabled = hoverEnabled;
        emit hoverEnabledChanged(hoverEnabled);
    }
}

/*!
    \qmlproperty bool Qt3D.Render::ObjectPicker::hoverEnabled
    Specifies if hover is enabled
*/
/*!
  \property Qt3DRender::QObjectPicker::hoverEnabled
    Specifies if hover is enabled
 */
/*!
 * \return true if hover enabled
 */
bool QObjectPicker::isHoverEnabled() const
{
    Q_D(const QObjectPicker);
    return d->m_hoverEnabled;
}

/*!
 * Sets the dragEnabled Property to \a dragEnabled
 */
void QObjectPicker::setDragEnabled(bool dragEnabled)
{
    Q_D(QObjectPicker);
    if (dragEnabled != d->m_dragEnabled) {
        d->m_dragEnabled = dragEnabled;
        emit dragEnabledChanged(dragEnabled);
    }
}

/*!
    \qmlproperty bool Qt3D.Render::ObjectPicker::dragEnabled
*/
/*!
  \property Qt3DRender::QObjectPicker::dragEnabled
    Specifies if drag is enabled
 */
/*!
 * \return true if dragging is enabled
 */
bool QObjectPicker::isDragEnabled() const
{
    Q_D(const QObjectPicker);
    return d->m_dragEnabled;
}

/*!
    \qmlproperty bool Qt3D.Render::ObjectPicker::containsMouse
    Specifies if the object picker currently contains the mouse
*/
/*!
  \property Qt3DRender::QObjectPicker::containsMouse
    Specifies if the object picker currently contains the mouse
 */
/*!
 * \return true if the object picker currently contains the mouse
 */
bool QObjectPicker::containsMouse() const
{
    Q_D(const QObjectPicker);
    return d->m_containsMouse;
}

/*!
    \qmlproperty bool Qt3D.Render::ObjectPicker::pressed
    Specifies if the object picker is currently pressed
*/
/*!
  \property Qt3DRender::QObjectPicker::pressed
    Specifies if the object picker is currently pressed
 */
bool QObjectPicker::isPressed() const
{
    Q_D(const QObjectPicker);
    return d->m_pressed;
}

/*! \internal */
void QObjectPicker::sceneChangeEvent(const Qt3DCore::QSceneChangePtr &change)
{
    Q_D(QObjectPicker);
    Qt3DCore::QPropertyUpdatedChangePtr e = qSharedPointerCast<Qt3DCore::QPropertyUpdatedChange>(change);
    if (e->type() == Qt3DCore::PropertyUpdated) {
        // TO DO: Complete this part
        // to emit the correct signals
        const QByteArray propertyName = e->propertyName();
        if (propertyName == QByteArrayLiteral("pressed")) {
            QPickEventPtr ev = e->value().value<QPickEventPtr>();
            d->pressedEvent(ev.data());
        } else if (propertyName == QByteArrayLiteral("released")) {
            QPickEventPtr ev = e->value().value<QPickEventPtr>();
            d->releasedEvent(ev.data());
        } else if (propertyName == QByteArrayLiteral("clicked")) {
            QPickEventPtr ev = e->value().value<QPickEventPtr>();
            d->clickedEvent(ev.data());
        } else if (propertyName == QByteArrayLiteral("moved")) {
            QPickEventPtr ev = e->value().value<QPickEventPtr>();
            d->movedEvent(ev.data());
        } else if (propertyName == QByteArrayLiteral("entered")) {
            emit entered();
            d->setContainsMouse(true);
        } else if (propertyName == QByteArrayLiteral("exited")) {
            d->setContainsMouse(false);
            emit exited();
        }
    }
}

/*!
    \internal
 */
void QObjectPickerPrivate::setPressed(bool pressed)
{
    Q_Q(QObjectPicker);
    if (m_pressed != pressed) {
        const bool blocked = q->blockNotifications(true);
        m_pressed = pressed;
        emit q->pressedChanged(pressed);
        q->blockNotifications(blocked);
    }
}

/*!
    \internal
*/
void QObjectPickerPrivate::setContainsMouse(bool containsMouse)
{
    Q_Q(QObjectPicker);
    if (m_containsMouse != containsMouse) {
        const bool blocked = q->blockNotifications(true);
        m_containsMouse = containsMouse;
        emit q->containsMouseChanged(containsMouse);
        q->blockNotifications(blocked);
    }
}

void QObjectPickerPrivate::propagateEvent(QPickEvent *event, EventType type)
{
    if (!m_entities.isEmpty()) {
        Qt3DCore::QEntity *entity = m_entities.first();
        Qt3DCore::QEntity *parentEntity = nullptr;
        while (entity != nullptr && entity->parentEntity() != nullptr && !event->isAccepted()) {
            parentEntity = entity->parentEntity();
            const auto components = parentEntity->components();
            for (Qt3DCore::QComponent *c : components) {
                if (auto objectPicker = qobject_cast<Qt3DRender::QObjectPicker *>(c)) {
                    QObjectPickerPrivate *objectPickerPrivate = static_cast<QObjectPickerPrivate *>(QObjectPickerPrivate::get(objectPicker));
                    switch (type) {
                    case Pressed:
                        objectPickerPrivate->pressedEvent(event);
                        break;
                    case Released:
                        objectPickerPrivate->releasedEvent(event);
                        break;
                    case Clicked:
                        objectPickerPrivate->clickedEvent(event);
                        break;
                    case EventType::Moved:
                        objectPickerPrivate->movedEvent(event);
                        break;
                    }
                    break;
                }
            }
            entity = parentEntity;
        }
    }
}

/*!
    \internal
 */
void QObjectPickerPrivate::pressedEvent(QPickEvent *event)
{
    Q_Q(QObjectPicker);
    emit q->pressed(event);

    m_acceptedLastPressedEvent = event->isAccepted();
    if (!m_acceptedLastPressedEvent) {
        // Travel parents to transmit the event
        propagateEvent(event, Pressed);
    } else {
        setPressed(true);
    }
}

/*!
    \internal
 */
void QObjectPickerPrivate::clickedEvent(QPickEvent *event)
{
    Q_Q(QObjectPicker);
    emit q->clicked(event);
    if (!event->isAccepted())
        propagateEvent(event, Clicked);
}

/*!
    \internal
 */
void QObjectPickerPrivate::movedEvent(QPickEvent *event)
{
    Q_Q(QObjectPicker);
    emit q->moved(event);
    if (!event->isAccepted())
        propagateEvent(event, EventType::Moved);
}

/*!
    \internal
 */
void QObjectPickerPrivate::releasedEvent(QPickEvent *event)
{
    Q_Q(QObjectPicker);
    if (m_acceptedLastPressedEvent) {
        emit q->released(event);
        setPressed(false);
    } else {
        event->setAccepted(false);
        propagateEvent(event, Released);
    }
}

Qt3DCore::QNodeCreatedChangeBasePtr QObjectPicker::createNodeCreationChange() const
{
    auto creationChange = Qt3DCore::QNodeCreatedChangePtr<QObjectPickerData>::create(this);
    auto &data = creationChange->data;
    Q_D(const QObjectPicker);
    data.hoverEnabled = d->m_hoverEnabled;
    data.dragEnabled = d->m_dragEnabled;
    return creationChange;
}

} // Qt3DRender

QT_END_NAMESPACE
