/****************************************************************************
**
** Copyright (C) 2014 Klaralvdalens Datakonsult AB (KDAB).
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt3D module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
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** 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.
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** $QT_END_LICENSE$
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****************************************************************************/

#include "quick3dentityloader_p_p.h"

#include <QQmlContext>
#include <QQmlEngine>
#include <QQmlIncubator>

#include <QtQml/private/qqmlengine_p.h>

QT_BEGIN_NAMESPACE

namespace Qt3DCore {
namespace Quick {

class Quick3DEntityLoaderIncubator : public QQmlIncubator
{
public:
    Quick3DEntityLoaderIncubator(Quick3DEntityLoader *loader)
        : QQmlIncubator(Asynchronous),
          m_loader(loader)
    {
    }

protected:
    void statusChanged(Status status) Q_DECL_FINAL
    {
        Quick3DEntityLoaderPrivate *priv = Quick3DEntityLoaderPrivate::get(m_loader);

        switch (status) {
        case Ready: {
            Q_ASSERT(priv->m_entity == nullptr);
            priv->m_entity = qobject_cast<QEntity *>(object());
            Q_ASSERT(priv->m_entity != nullptr);
            priv->m_entity->setParent(m_loader);
            emit m_loader->entityChanged();
            break;
        }

        case Error: {
            QQmlEnginePrivate::warning(qmlEngine(m_loader), errors());
            priv->clear();
            emit m_loader->entityChanged();
            break;
        }

        default:
            break;
        }
    }

private:
    Quick3DEntityLoader *m_loader;
};

/*!
    \qmltype EntityLoader
    \inqmlmodule Qt3D.Core
    \since 5.5
*/
Quick3DEntityLoader::Quick3DEntityLoader(QNode *parent)
    : QEntity(*new Quick3DEntityLoaderPrivate, parent)
{
}

/*!
    \qmlproperty QtQml::QtObject Qt3DCore::EntityLoader::entity
    \readonly
*/
QObject *Quick3DEntityLoader::entity() const
{
    Q_D(const Quick3DEntityLoader);
    return d->m_entity;
}

/*!
    \qmlproperty url Qt3DCore::EntityLoader::source
*/
QUrl Quick3DEntityLoader::source() const
{
    Q_D(const Quick3DEntityLoader);
    return d->m_source;
}

void Quick3DEntityLoader::setSource(const QUrl &url)
{
    Q_D(Quick3DEntityLoader);

    if (url == d->m_source)
        return;

    d->clear();
    d->m_source = url;
    emit sourceChanged();
    d->loadFromSource();
}

Quick3DEntityLoaderPrivate::Quick3DEntityLoaderPrivate()
    : QEntityPrivate(),
      m_incubator(nullptr),
      m_context(nullptr),
      m_component(nullptr),
      m_entity(nullptr)
{
}

void Quick3DEntityLoaderPrivate::clear()
{
    if (m_incubator) {
        m_incubator->clear();
        delete m_incubator;
        m_incubator = nullptr;
    }

    if (m_entity) {
        m_entity->setParent(Q_NODE_NULLPTR);
        delete m_entity;
        m_entity = nullptr;
    }

    if (m_component) {
        delete m_component;
        m_component = nullptr;
    }

    if (m_context) {
        delete m_context;
        m_context = nullptr;
    }
}

void Quick3DEntityLoaderPrivate::loadFromSource()
{
    Q_Q(Quick3DEntityLoader);

    if (m_source.isEmpty()) {
        emit q->entityChanged();
        return;
    }

    loadComponent(m_source);
}

void Quick3DEntityLoaderPrivate::loadComponent(const QUrl &source)
{
    Q_Q(Quick3DEntityLoader);

    Q_ASSERT(m_entity == nullptr);
    Q_ASSERT(m_component == nullptr);
    Q_ASSERT(m_context == nullptr);

    m_component = new QQmlComponent(qmlEngine(q), q);
    QObject::connect(m_component, SIGNAL(statusChanged(QQmlComponent::Status)),
                     q, SLOT(_q_componentStatusChanged(QQmlComponent::Status)));
    m_component->loadUrl(source, QQmlComponent::Asynchronous);
}

void Quick3DEntityLoaderPrivate::_q_componentStatusChanged(QQmlComponent::Status status)
{
    Q_Q(Quick3DEntityLoader);

    Q_ASSERT(m_entity == nullptr);
    Q_ASSERT(m_component != nullptr);
    Q_ASSERT(m_context == nullptr);
    Q_ASSERT(m_incubator == nullptr);

    if (!m_component->errors().isEmpty()) {
        QQmlEnginePrivate::warning(qmlEngine(q), m_component->errors());
        clear();
        emit q->entityChanged();
        return;
    }

    // Still loading
    if (status != QQmlComponent::Ready)
        return;

    m_context = new QQmlContext(qmlContext(q));
    m_context->setContextObject(q);

    m_incubator = new Quick3DEntityLoaderIncubator(q);
    m_component->create(*m_incubator, m_context);
}

} // namespace Quick
} // namespace Qt3DCore

QT_END_NAMESPACE

#include "moc_quick3dentityloader_p.cpp"