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#include "buffer_p.h"
#include <Qt3DCore/qpropertyupdatedchange.h>
#include <Qt3DRender/private/buffermanager_p.h>
#include <Qt3DRender/private/qbuffer_p.h>

QT_BEGIN_NAMESPACE

using namespace Qt3DCore;

namespace Qt3DRender {
namespace Render {

Buffer::Buffer()
    : BackendNode(QBackendNode::ReadWrite)
    , m_type(QBuffer::VertexBuffer)
    , m_usage(QBuffer::StaticDraw)
    , m_bufferDirty(false)
    , m_syncData(false)
    , m_manager(nullptr)
{
    // Maybe it could become read write if we want to inform
    // the frontend QBuffer node of any backend issue
}

Buffer::~Buffer()
{
}

void Buffer::cleanup()
{
    m_type = QBuffer::VertexBuffer;
    m_usage = QBuffer::StaticDraw;
    m_data.clear();
    m_functor.reset();
    m_bufferDirty = false;
    m_syncData = false;
}


void Buffer::setManager(BufferManager *manager)
{
    m_manager = manager;
}

void Buffer::executeFunctor()
{
    Q_ASSERT(m_functor);
    m_data = (*m_functor)();
    if (m_syncData) {
        // Send data back to the frontend
        auto e = Qt3DCore::QPropertyUpdatedChangePtr::create(peerId());
        e->setDeliveryFlags(Qt3DCore::QSceneChange::DeliverToAll);
        e->setPropertyName("data");
        e->setValue(QVariant::fromValue(m_data));
        notifyObservers(e);
    }
}

void Buffer::initializeFromPeer(const Qt3DCore::QNodeCreatedChangeBasePtr &change)
{
    const auto typedChange = qSharedPointerCast<Qt3DCore::QNodeCreatedChange<QBufferData>>(change);
    const auto &data = typedChange->data;
    m_data = data.data;
    m_type = data.type;
    m_usage = data.usage;
    m_syncData = data.syncData;
    m_bufferDirty = true;

    m_functor = data.functor;
    Q_ASSERT(m_manager);
    if (m_functor)
        m_manager->addDirtyBuffer(peerId());
}

void Buffer::sceneChangeEvent(const Qt3DCore::QSceneChangePtr &e)
{
    if (e->type() == PropertyUpdated) {
        QPropertyUpdatedChangePtr propertyChange = qSharedPointerCast<QPropertyUpdatedChange>(e);
        QByteArray propertyName = propertyChange->propertyName();
        if (propertyName == QByteArrayLiteral("data")) {
            QByteArray newData = propertyChange->value().value<QByteArray>();
            m_bufferDirty |= m_data != newData;
            m_data = newData;
        } else if (propertyName == QByteArrayLiteral("type")) {
            m_type = static_cast<QBuffer::BufferType>(propertyChange->value().value<int>());
            m_bufferDirty = true;
        } else if (propertyName == QByteArrayLiteral("usage")) {
            m_usage = static_cast<QBuffer::UsageType>(propertyChange->value().value<int>());
            m_bufferDirty = true;
        } else if (propertyName == QByteArrayLiteral("dataGenerator")) {
            QBufferDataGeneratorPtr newGenerator = propertyChange->value().value<QBufferDataGeneratorPtr>();
            m_bufferDirty |= !(newGenerator && m_functor && *newGenerator == *m_functor);
            m_functor = newGenerator;
            if (m_functor && m_manager != nullptr)
                m_manager->addDirtyBuffer(peerId());
        } else if (propertyName == QByteArrayLiteral("syncData")) {
            m_syncData = propertyChange->value().toBool();
        }
        markDirty(AbstractRenderer::AllDirty);
    }
    BackendNode::sceneChangeEvent(e);
}

// Called by Renderer once the buffer has been uploaded to OpenGL
void Buffer::unsetDirty()
{
    m_bufferDirty = false;
}

BufferFunctor::BufferFunctor(AbstractRenderer *renderer, BufferManager *manager)
    : m_manager(manager)
    , m_renderer(renderer)
{
}

Qt3DCore::QBackendNode *BufferFunctor::create(const Qt3DCore::QNodeCreatedChangeBasePtr &change) const
{
    Buffer *buffer = m_manager->getOrCreateResource(change->subjectId());
    buffer->setManager(m_manager);
    buffer->setRenderer(m_renderer);
    return buffer;
}

Qt3DCore::QBackendNode *BufferFunctor::get(Qt3DCore::QNodeId id) const
{
    return m_manager->lookupResource(id);
}

void BufferFunctor::destroy(Qt3DCore::QNodeId id) const
{
    return m_manager->releaseResource(id);
}

} // namespace Render
} // namespace Qt3DRender

QT_END_NAMESPACE
