/****************************************************************************
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** Copyright (C) 2013 Research In Motion.
** Copyright (C) 2015 Klaralvdalens Datakonsult AB (KDAB).
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****************************************************************************/

#include "quick3dnodeinstantiator_p.h"
#include "quick3dnodeinstantiator_p_p.h"

#include <QtQml/QQmlContext>
#include <QtQml/QQmlComponent>
#include <QtQml/QQmlInfo>
#include <QtQml/QQmlError>
#include <QtQml/private/qqmlobjectmodel_p.h>
#include <QtQml/private/qqmldelegatemodel_p.h>

QT_BEGIN_NAMESPACE

namespace Qt3D {
namespace Quick {

Quick3DNodeInstantiatorPrivate::Quick3DNodeInstantiatorPrivate(QNode *qq)
    : QNodePrivate(qq)
    , m_componentComplete(true)
    , m_effectiveReset(false)
    , m_active(true)
    , m_async(false)
    , m_ownModel(false)
    , m_model(QVariant(1))
    , m_instanceModel(0)
    , m_delegate(0)
{
}

Quick3DNodeInstantiatorPrivate::~Quick3DNodeInstantiatorPrivate()
{
    qDeleteAll(m_objects);
}

void Quick3DNodeInstantiatorPrivate::clear()
{
    Q_Q(Quick3DNodeInstantiator);
    if (!m_instanceModel)
        return;
    if (!m_objects.count())
        return;

    for (int i = 0; i < m_objects.count(); i++) {
        q->objectRemoved(i, m_objects[i]);
        m_instanceModel->release(m_objects[i]);
    }
    m_objects.clear();
    q->objectChanged();
}

void Quick3DNodeInstantiatorPrivate::regenerate()
{
    Q_Q(Quick3DNodeInstantiator);
    if (!m_componentComplete)
        return;

    int prevCount = q->count();

    clear();

    if (!m_active || !m_instanceModel || !m_instanceModel->count() || !m_instanceModel->isValid()) {
        if (prevCount)
            q->countChanged();
        return;
    }

    for (int i = 0; i < m_instanceModel->count(); i++) {
        QObject *object = m_instanceModel->object(i, m_async);
        // If the item was already created we won't get a createdItem
        if (object)
            _q_createdItem(i, object);
    }
    if (q->count() != prevCount)
        q->countChanged();
}

void Quick3DNodeInstantiatorPrivate::_q_createdItem(int idx, QObject *item)
{
    Q_Q(Quick3DNodeInstantiator);
    if (m_objects.contains(item)) //Case when it was created synchronously in regenerate
        return;
    item->setParent(q);
    m_objects.insert(idx, item);
    if (m_objects.count() == 1)
        q->objectChanged();
    q->objectAdded(idx, item);
}

void Quick3DNodeInstantiatorPrivate::_q_modelUpdated(const QQmlChangeSet &changeSet, bool reset)
{
    Q_Q(Quick3DNodeInstantiator);

    if (!m_componentComplete || m_effectiveReset)
        return;

    if (reset) {
        regenerate();
        if (changeSet.difference() != 0)
            q->countChanged();
        return;
    }

    int difference = 0;
    QHash<int, QVector<QPointer<QObject> > > moved;
    Q_FOREACH (const QQmlChangeSet::Change &remove, changeSet.removes()) {
        int index = qMin(remove.index, m_objects.count());
        int count = qMin(remove.index + remove.count, m_objects.count()) - index;
        if (remove.isMove()) {
            moved.insert(remove.moveId, m_objects.mid(index, count));
            m_objects.erase(
                    m_objects.begin() + index,
                    m_objects.begin() + index + count);
        } else {
            while (count--) {
                QObject *obj = m_objects.at(index);
                m_objects.remove(index);
                q->objectRemoved(index, obj);
                if (obj)
                    m_instanceModel->release(obj);
            }
        }

        difference -= remove.count;
    }

    Q_FOREACH (const QQmlChangeSet::Change &insert, changeSet.inserts()) {
        int index = qMin(insert.index, m_objects.count());
        if (insert.isMove()) {
            QVector<QPointer<QObject> > movedObjects = moved.value(insert.moveId);
            m_objects = m_objects.mid(0, index) + movedObjects + m_objects.mid(index);
        } else for (int i = 0; i < insert.count; ++i) {
            int modelIndex = index + i;
            QObject *obj = m_instanceModel->object(modelIndex, m_async);
            if (obj)
                _q_createdItem(modelIndex, obj);
        }
        difference += insert.count;
    }

    if (difference != 0)
        q->countChanged();
}

void Quick3DNodeInstantiatorPrivate::makeModel()
{
    Q_Q(Quick3DNodeInstantiator);
    QQmlDelegateModel* delegateModel = new QQmlDelegateModel(qmlContext(q));
    m_instanceModel = delegateModel;
    m_ownModel = true;
    delegateModel->setDelegate(m_delegate);
    delegateModel->classBegin(); //Pretend it was made in QML
    if (m_componentComplete)
        delegateModel->componentComplete();
}

/*!
    \qmltype NodeInstantiator
    \instantiates Quick3DNodeInstantiator
    \inqmlmodule Quick3D
    \brief Dynamically creates nodes
    \since 5.5

    A NodeInstantiator can be used to control the dynamic creation of nodes, or to dynamically
    create multiple objects from a template.

    The NodeInstantiator element will manage the objects it creates. Those
    objects are parented to the Instantiator and can also be deleted by the
    NodeInstantiator if the NodeInstantiator's properties change. Nodes can
    also be destroyed dynamically through other means, and the NodeInstantiator
    will not recreate them unless the properties of the NodeInstantiator
    change.

*/
Quick3DNodeInstantiator::Quick3DNodeInstantiator(QNode *parent)
    : QNode(*(new Quick3DNodeInstantiatorPrivate(this)), parent)
{
}

Quick3DNodeInstantiator::~Quick3DNodeInstantiator()
{
}

/*!
    \qmlsignal Quick3D::NodeInstantiator::objectAdded(int index, QtObject node)

    This signal is emitted when a node is added to the NodeInstantiator. The \a index
    parameter holds the index which the node has been given, and the \a node
    parameter holds the \l Node that has been added.

    The corresponding handler is \c onNodeAdded.
*/

/*!
    \qmlsignal Quick3D::NodeInstantiator::objectRemoved(int index, QtObject object)

    This signal is emitted when an object is removed from the Instantiator. The \a index
    parameter holds the index which the object had been given, and the \a object
    parameter holds the \l QtObject that has been removed.

    Do not keep a reference to \a object if it was created by this Instantiator, as
    in these cases it will be deleted shortly after the signal is handled.

    The corresponding handler is \c onObjectRemoved.
*/
/*!
    \qmlproperty bool Quick3D::NodeInstantiator::active

    When active is true, and the delegate component is ready, the Instantiator will
    create objects according to the model. When active is false, no objects
    will be created and any previously created objects will be destroyed.

    Default is true.
*/
bool Quick3DNodeInstantiator::isActive() const
{
    Q_D(const Quick3DNodeInstantiator);
    return d->m_active;
}

void Quick3DNodeInstantiator::setActive(bool newVal)
{
    Q_D(Quick3DNodeInstantiator);
    if (newVal == d->m_active)
        return;
    d->m_active = newVal;
    emit activeChanged();
    d->regenerate();
}

/*!
    \qmlproperty bool Quick3D::NodeInstantiator::asynchronous

    When asynchronous is true the Instantiator will attempt to create objects
    asynchronously. This means that objects may not be available immediately,
    even if active is set to true.

    You can use the objectAdded signal to respond to items being created.

    Default is false.
*/
bool Quick3DNodeInstantiator::isAsync() const
{
    Q_D(const Quick3DNodeInstantiator);
    return d->m_async;
}

void Quick3DNodeInstantiator::setAsync(bool newVal)
{
    Q_D(Quick3DNodeInstantiator);
    if (newVal == d->m_async)
        return;
    d->m_async = newVal;
    emit asynchronousChanged();
}


/*!
    \qmlproperty int Quick3D::NodeInstantiator::count

    The number of objects the Instantiator is currently managing.
*/

int Quick3DNodeInstantiator::count() const
{
    Q_D(const Quick3DNodeInstantiator);
    return d->m_objects.count();
}

/*!
    \qmlproperty QtQml::Component Quick3D::NodeInstantiator::delegate
    \default

    The component used to create all objects.

    Note that an extra variable, index, will be available inside instances of the
    delegate. This variable refers to the index of the instance inside the Instantiator,
    and can be used to obtain the object through the itemAt method of the Instantiator.

    If this property is changed, all instances using the old delegate will be destroyed
    and new instances will be created using the new delegate.
*/
QQmlComponent *Quick3DNodeInstantiator::delegate()
{
    Q_D(Quick3DNodeInstantiator);
    return d->m_delegate;
}

void Quick3DNodeInstantiator::setDelegate(QQmlComponent *c)
{
    Q_D(Quick3DNodeInstantiator);
    if (c == d->m_delegate)
        return;

    d->m_delegate = c;
    emit delegateChanged();

    if (!d->m_ownModel)
        return;

    if (QQmlDelegateModel *dModel = qobject_cast<QQmlDelegateModel*>(d->m_instanceModel))
        dModel->setDelegate(c);
    if (d->m_componentComplete)
        d->regenerate();
}

/*!
    \qmlproperty variant Quick3D::NodeInstantiator::model

    This property can be set to any of the supported \l {qml-data-models}{data models}:

    \list
    \li A number that indicates the number of delegates to be created by the repeater
    \li A model (e.g. a ListModel item, or a QAbstractItemModel subclass)
    \li A string list
    \li An object list
    \endlist

    The type of model affects the properties that are exposed to the \l delegate.

    Default value is 1, which creates a single delegate instance.

    \sa {qml-data-models}{Data Models}
*/

QVariant Quick3DNodeInstantiator::model() const
{
    Q_D(const Quick3DNodeInstantiator);
    return d->m_model;
}

void Quick3DNodeInstantiator::setModel(const QVariant &v)
{
    Q_D(Quick3DNodeInstantiator);
    if (d->m_model == v)
        return;

    d->m_model = v;
    //Don't actually set model until componentComplete in case it wants to create its delegates immediately
    if (!d->m_componentComplete)
        return;

    QQmlInstanceModel *prevModel = d->m_instanceModel;
    QObject *object = qvariant_cast<QObject*>(v);
    QQmlInstanceModel *vim = 0;
    if (object && (vim = qobject_cast<QQmlInstanceModel *>(object))) {
        if (d->m_ownModel) {
            delete d->m_instanceModel;
            prevModel = 0;
            d->m_ownModel = false;
        }
        d->m_instanceModel = vim;
    } else if (v != QVariant(0)){
        if (!d->m_ownModel)
            d->makeModel();

        if (QQmlDelegateModel *dataModel = qobject_cast<QQmlDelegateModel *>(d->m_instanceModel)) {
            d->m_effectiveReset = true;
            dataModel->setModel(v);
            d->m_effectiveReset = false;
        }
    }

    if (d->m_instanceModel != prevModel) {
        if (prevModel) {
            disconnect(prevModel, SIGNAL(modelUpdated(QQmlChangeSet,bool)),
                    this, SLOT(_q_modelUpdated(QQmlChangeSet,bool)));
            disconnect(prevModel, SIGNAL(createdItem(int,QObject*)), this, SLOT(_q_createdItem(int,QObject*)));
            //disconnect(prevModel, SIGNAL(initItem(int,QObject*)), this, SLOT(initItem(int,QObject*)));
        }

        connect(d->m_instanceModel, SIGNAL(modelUpdated(QQmlChangeSet,bool)),
                this, SLOT(_q_modelUpdated(QQmlChangeSet,bool)));
        connect(d->m_instanceModel, SIGNAL(createdItem(int,QObject*)), this, SLOT(_q_createdItem(int,QObject*)));
        //connect(d->m_instanceModel, SIGNAL(initItem(int,QObject*)), this, SLOT(initItem(int,QObject*)));
    }

    d->regenerate();
    emit modelChanged();
}

/*!
    \qmlproperty QtQml::QtObject Quick3D::NodeInstantiator::object

    This is a reference to the first created object, intended as a convenience
    for the case where only one object has been created.
*/
QObject *Quick3DNodeInstantiator::object() const
{
    Q_D(const Quick3DNodeInstantiator);
    if (d->m_objects.count())
        return d->m_objects[0];
    return 0;
}

/*!
    \qmlmethod QtQml::QtObject Quick3D::NodeInstantiator::objectAt

    Returns a reference to the object with the given \a index.
*/
QObject *Quick3DNodeInstantiator::objectAt(int index) const
{
    Q_D(const Quick3DNodeInstantiator);
    if (index >= 0 && index < d->m_objects.count())
        return d->m_objects[index];
    return 0;
}

/*!
 \internal
*/
void Quick3DNodeInstantiator::classBegin()
{
    Q_D(Quick3DNodeInstantiator);
    d->m_componentComplete = false;
}

/*!
 \internal
*/
void Quick3DNodeInstantiator::componentComplete()
{
    Q_D(Quick3DNodeInstantiator);
    d->m_componentComplete = true;
    if (d->m_ownModel) {
        static_cast<QQmlDelegateModel *>(d->m_instanceModel)->componentComplete();
        d->regenerate();
    } else {
        QVariant realModel = d->m_model;
        d->m_model = QVariant(0);
        setModel(realModel); //If realModel == d->m_model this won't do anything, but that's fine since the model's 0
        //setModel calls regenerate
    }
}

void Quick3DNodeInstantiator::copy(const QNode *ref)
{
    QNode::copy(ref);
    const Quick3DNodeInstantiator *instantiator = static_cast<const Quick3DNodeInstantiator*>(ref);
    // We only need to clone the children as the instantiator itself has no
    // corresponding backend node type.
    for (int i = 0; i < instantiator->d_func()->m_objects.size(); ++i) {
        QNode *n = qobject_cast<QNode *>(instantiator->d_func()->m_objects.at(i));
        if (!n)
            continue;
        QNode *clonedNode = QNode::clone(n);
        clonedNode->setParent(this);
        d_func()->m_objects.append(clonedNode);
    }
}

} // namespace Quick
} // namespace Qt3D

QT_END_NAMESPACE

#include "moc_quick3dnodeinstantiator_p.cpp"