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**
** Copyright (C) 2015 Klaralvdalens Datakonsult AB (KDAB).
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
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** This file is part of Qt 3D Studio.
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#include "dragontransformjobs_p.h"

#include <private/dragonattribute_p.h>
#include <private/dragonbuffer_p.h>
#include <private/dragongeometry_p.h>
#include <private/dragongeometryrenderer_p.h>
#include <private/dragonjobs_common_p.h>
#include <private/dragonsphere_p.h>
#include <private/dragonbuffervisitor_p.h>

QT_BEGIN_NAMESPACE

using namespace Qt3DCore;

namespace Qt3DRender {
namespace Dragon {

ValueContainer<Matrix4x4> calculateWorldTransforms(ValueContainer<Matrix4x4> worldTransforms,
                                                   const ValueContainer<Entity> &entities,
                                                   const ValueContainer<Transform> &transforms,
                                                   QNodeId rootEntityId)
{
    worldTransforms.reset();

    if (!entities.anythingDirty() && !transforms.anythingDirty())
        return worldTransforms;

    struct Data {
        Data() { }
        Data(QNodeId entityId_, bool dirty_) : entityId(entityId_), dirty(dirty_) { }
        QNodeId entityId;
        bool dirty = false;
    };

    const auto &dirtyTransforms = transforms.dirtyOrNew();
    const auto &dirtyEntities = entities.dirtyOrNew();

    // If entities are dirty, a transform component may have changed and we set the entire tree to
    // be recalculated. Note that this could be optimized.
    bool rootDirty = entities.anythingDirty();

    const auto &rootEntity = entities[rootEntityId];
    if (rootEntity->m_transformComponent.isNull()) {
        worldTransforms[rootEntityId] = Matrix4x4{};
    } else {
        const auto &transform = transforms[rootEntity->m_transformComponent];
        if (transforms.dirty().contains(rootEntity->m_transformComponent))
            rootDirty = true;
        worldTransforms[rootEntityId] = transform->m_transformMatrix;
    }

    QStack<Data> stack;
    stack.reserve(10);
    stack.push({ rootEntityId, rootDirty });

    while (!stack.isEmpty()) {
        auto currentItem = stack.pop();
        QNodeId currentId = currentItem.entityId;
        bool currentDirty = currentItem.dirty;
        if (currentDirty)
            worldTransforms.markDirty(currentId);

        const auto &currentWorldTransform = *worldTransforms[currentId];

        const auto &children = entities[currentId]->treeChildren();

        // Iterate the children in reverse order (because the stack is last-in-first-out)
        // TODO use std::reverse_iterator once we have C++17
        for (auto it = children.rbegin(); it != children.rend(); ++it) {
            const auto &childId = *it;
            const auto &childEntity = entities[childId];
            bool childDirty = currentDirty || dirtyEntities.contains(childId);
            if (!childEntity->m_transformComponent.isNull()) {
                const auto &transform = transforms[childEntity->m_transformComponent];
                childDirty |= dirtyTransforms.contains(childEntity->m_transformComponent);
                if (childDirty)
                    worldTransforms[childId] = currentWorldTransform * transform->m_transformMatrix;
            } else {
                if (childDirty)
                    worldTransforms[childId] = currentWorldTransform;
            }
            stack.push({ childId, childDirty });
        }
    }

    return worldTransforms;
};

bool printTransforms(const ValueContainer<Matrix4x4> &transforms)
{
    Q_UNUSED(transforms);
    //    for (const auto &transform : transforms) {
    //        qDebug() << "Value:" << transform.get();
    //    }
    return true; // dummy, because we currently cannot return void
}

} // namespace Dragon
} // namespace Qt3DRender

QT_END_NAMESPACE