/****************************************************************************
**
** 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.
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** $QT_BEGIN_LICENSE:LGPL$
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** General Public License version 3 as published by the Free Software
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** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
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** 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
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****************************************************************************/

#include "renderviewjobutils_p.h"
#include "renderlogging_p.h"

#include <Qt3DRender/qgraphicsapifilter.h>
#include <Qt3DRender/private/sphere_p.h>
#include <Qt3DRender/qshaderdata.h>

#include <Qt3DRender/private/cameraselectornode_p.h>
#include <Qt3DRender/private/clearbuffers_p.h>
#include <Qt3DRender/private/layerfilternode_p.h>
#include <Qt3DRender/private/nodemanagers_p.h>
#include <Qt3DRender/private/effect_p.h>
#include <Qt3DRender/private/renderpassfilternode_p.h>
#include <Qt3DRender/private/renderstateset_p.h>
#include <Qt3DRender/private/rendertargetselectornode_p.h>
#include <Qt3DRender/private/renderview_p.h>
#include <Qt3DRender/private/sortpolicy_p.h>
#include <Qt3DRender/private/techniquefilternode_p.h>
#include <Qt3DRender/private/viewportnode_p.h>
#include <Qt3DRender/private/shadervariables_p.h>
#include <Qt3DRender/private/managers_p.h>
#include <Qt3DRender/private/shaderdata_p.h>
#include <Qt3DRender/private/statesetnode_p.h>
#include <Qt3DRender/private/dispatchcompute_p.h>
#include <Qt3DRender/private/rendersurfaceselector_p.h>
#include <Qt3DRender/private/stringtoint_p.h>

QT_BEGIN_NAMESPACE

using namespace Qt3DCore;

namespace Qt3DRender {
namespace Render {

/*!
    \internal
    Walks up the framegraph tree from \a fgLeaf and builds up as much state
    as possible and populates \a rv. For cases where we can't get the specific state
    (e.g. because it depends upon more than just the framegraph) we store the data from
    the framegraph that will be needed to later when the rest of the data becomes available
*/
void setRenderViewConfigFromFrameGraphLeafNode(RenderView *rv, const FrameGraphNode *fgLeaf)
{
    // The specific RenderPass to be used is also dependent upon the Effect and TechniqueFilter
    // which is referenced by the Material which is referenced by the RenderMesh. So we can
    // only store the filter info in the RenderView structure and use it to do the resolving
    // when we build the RenderCommand list.
    const NodeManagers *manager = rv->nodeManagers();
    const FrameGraphNode *node = fgLeaf;

    while (node) {
        FrameGraphNode::FrameGraphNodeType type = node->nodeType();
        if (node->isEnabled())
            switch (type) {
            case FrameGraphNode::InvalidNodeType:
                // A base FrameGraphNode, can be used for grouping purposes
                break;
            case FrameGraphNode::CameraSelector:
                // Can be set only once and we take camera nearest to the leaf node
                if (!rv->renderCameraLens()) {
                    const CameraSelector *cameraSelector = static_cast<const CameraSelector *>(node);
                    Entity *camNode = manager->renderNodesManager()->lookupResource(cameraSelector->cameraUuid());
                    if (camNode) {
                        CameraLens *lens = camNode->renderComponent<CameraLens>();
                        rv->setRenderCameraEntity(camNode);
                        if (lens && lens->isEnabled()) {
                            rv->setRenderCameraLens(lens);
                            // ViewMatrix and ProjectionMatrix are computed
                            // later in updateMatrices()
                            // since at this point the transformation matrices
                            // may not yet have been updated
                        }
                    }
                }
                break;

            case FrameGraphNode::LayerFilter: // Can be set multiple times in the tree
                rv->setHasLayerFilter(true);
                rv->appendLayerFilter(static_cast<const LayerFilterNode *>(node)->layerIds());
                break;

            case FrameGraphNode::RenderPassFilter:
                // Can be set once
                // TODO: Amalgamate all render pass filters from leaf to root
                if (!rv->renderPassFilter())
                    rv->setRenderPassFilter(static_cast<const RenderPassFilter *>(node));
                break;

            case FrameGraphNode::RenderTarget: {
                // Can be set once and we take render target nearest to the leaf node
                const RenderTargetSelector *targetSelector = static_cast<const RenderTargetSelector *>(node);
                QNodeId renderTargetUid = targetSelector->renderTargetUuid();
                HTarget renderTargetHandle = manager->renderTargetManager()->lookupHandle(renderTargetUid);

                // Add renderTarget Handle and build renderCommand AttachmentPack
                if (!rv->renderTargetId()) {
                    rv->setRenderTargetId(renderTargetUid);

                    RenderTarget *renderTarget = manager->renderTargetManager()->data(renderTargetHandle);
                    if (renderTarget)
                        rv->setAttachmentPack(AttachmentPack(targetSelector, renderTarget, manager->attachmentManager()));
                }
                break;
            }

            case FrameGraphNode::ClearBuffers: {
                const ClearBuffers *cbNode = static_cast<const ClearBuffers *>(node);
                rv->addClearBuffers(cbNode);
                break;
            }

            case FrameGraphNode::TechniqueFilter:
                // Can be set once
                // TODO Amalgamate all technique filters from leaf to root
                if (!rv->techniqueFilter())
                    rv->setTechniqueFilter(static_cast<const TechniqueFilter *>(node));
                break;

            case FrameGraphNode::Viewport: {
                // If the Viewport has already been set in a lower node
                // Make it so that the new viewport is actually
                // a subregion relative to that of the parent viewport
                const ViewportNode *vpNode = static_cast<const ViewportNode *>(node);
                rv->setViewport(computeViewport(rv->viewport(), vpNode));
                break;
            }

            case FrameGraphNode::SortMethod: {
                const Render::SortPolicy *sortPolicy = static_cast<const Render::SortPolicy *>(node);
                rv->addSortType(sortPolicy->sortTypes());
                break;
            }

            case FrameGraphNode::SubtreeSelector:
                // Has no meaning here. SubtreeSelector was used
                // in a prior step to build the list of RenderViewJobs
                break;

            case FrameGraphNode::StateSet: {
                const Render::StateSetNode *rStateSet = static_cast<const Render::StateSetNode *>(node);
                // Create global RenderStateSet for renderView if no stateSet was set before
                RenderStateSet *stateSet = rv->stateSet();
                if (stateSet == nullptr && rStateSet->hasRenderStates()) {
                    stateSet = new RenderStateSet();
                    rv->setStateSet(stateSet);
                }

                if (rStateSet->hasRenderStates())
                    addToRenderStateSet(stateSet, rStateSet->renderStates(), manager->renderStateManager());
                break;
            }

            case FrameGraphNode::NoDraw: {
                rv->setNoDraw(true);
                break;
            }

            case FrameGraphNode::FrustumCulling: {
                rv->setFrustumCulling(true);
                break;
            }

            case FrameGraphNode::ComputeDispatch: {
                const Render::DispatchCompute *dispatchCompute = static_cast<const Render::DispatchCompute *>(node);
                rv->setCompute(true);
                rv->setComputeWorkgroups(dispatchCompute->x(),
                                         dispatchCompute->y(),
                                         dispatchCompute->z());
                break;
            }

            case FrameGraphNode::Lighting: {
                // TODO
                break;
            }

            case FrameGraphNode::Surface: {
                // Use the surface closest to leaf node
                if (rv->surface() == nullptr) {
                    const Render::RenderSurfaceSelector *surfaceSelector
                            = static_cast<const Render::RenderSurfaceSelector *>(node);
                    rv->setSurface(surfaceSelector->surface());
                    rv->setSurfaceSize(surfaceSelector->renderTargetSize() * surfaceSelector->devicePixelRatio());
                }
                break;
            }

            default:
                // Should never get here
                qCWarning(Backend) << "Unhandled FrameGraphNode type";
            }

        node = node->parent();
    }
}

/*!
    \internal
    Searches the \a renderer for the best matching Technique from
    \a effect specified by the \a renderView.
*/
Technique *findTechniqueForEffect(Renderer *renderer,
                                  const TechniqueFilter *techniqueFilter,
                                  Effect *effect)
{
    if (!effect)
        return nullptr;

    NodeManagers *manager = renderer->nodeManagers();
    QVector<Technique*> matchingTechniques;

    // Iterate through the techniques in the effect
    const auto techniqueIds = effect->techniques();
    for (const QNodeId techniqueId : techniqueIds) {
        Technique *technique = manager->techniqueManager()->lookupResource(techniqueId);

        if (!technique)
            continue;

        // We need to be sure the renderer is still running <=> still has a GraphicsContext
        if (renderer->isRunning() && *renderer->contextInfo() == *technique->graphicsApiFilter()) {

            // If no techniqueFilter is present, we return the technique as it satisfies OpenGL version
            bool foundMatch = (techniqueFilter == nullptr || techniqueFilter->filters().isEmpty());
            if (foundMatch) {
                matchingTechniques.append(technique);
                continue;
            }

            // There is a technique filter so we need to check for a technique with suitable criteria.
            // Check for early bail out if the technique doesn't have sufficient number of criteria and
            // can therefore never satisfy the filter
            if (technique->filterKeys().size() < techniqueFilter->filters().size())
                continue;

            // Iterate through the filter criteria and for each one search for a criteria on the
            // technique that satisfies it
            const auto filterKeyIds = techniqueFilter->filters();
            for (const QNodeId filterKeyId : filterKeyIds) {
                foundMatch = false;
                FilterKey *filterKey = manager->filterKeyManager()->lookupResource(filterKeyId);

                const auto techniqueFilterKeyIds = technique->filterKeys();
                for (const QNodeId techniqueFilterKeyId : techniqueFilterKeyIds) {
                    FilterKey *techniqueFilterKey = manager->filterKeyManager()->lookupResource(techniqueFilterKeyId);
                    if ((foundMatch = (*techniqueFilterKey == *filterKey)))
                        break;
                }

                if (!foundMatch) {
                    // No match for TechniqueFilter criterion in any of the technique's criteria.
                    // So no way this can match. Don't bother checking the rest of the criteria.
                    break;
                }
            }

            if (foundMatch) {
                // All criteria matched - we have a winner!
                matchingTechniques.append(technique);
            }
        }
    }

    if (matchingTechniques.size() == 0) // We failed to find a suitable technique to use :(
        return nullptr;

    if (matchingTechniques.size() == 1)
        return matchingTechniques[0];

    // Several compatible techniques, return technique with highest major and minor version
    Technique* highest = matchingTechniques[0];
    GraphicsApiFilterData filter = *highest->graphicsApiFilter();
    for (auto it = matchingTechniques.cbegin() + 1; it < matchingTechniques.cend(); ++it) {
        if (filter < *(*it)->graphicsApiFilter()) {
            filter = *(*it)->graphicsApiFilter();
            highest = *it;
        }
    }
    return highest;
}


RenderPassList findRenderPassesForTechnique(NodeManagers *manager,
                                            const RenderPassFilter *passFilter,
                                            Technique *technique)
{
    Q_ASSERT(manager);
    Q_ASSERT(technique);

    RenderPassList passes;
    const auto passIds = technique->renderPasses();
    for (const QNodeId passId : passIds) {
        RenderPass *renderPass = manager->renderPassManager()->lookupResource(passId);

        if (renderPass && renderPass->isEnabled()) {
            bool foundMatch = (!passFilter || passFilter->filters().size() == 0);

            // A pass filter is present so we need to check for matching criteria
            if (!foundMatch && renderPass->filterKeys().size() >= passFilter->filters().size()) {

                // Iterate through the filter criteria and look for render passes with criteria that satisfy them
                const auto filterKeyIds = passFilter->filters();
                for (const QNodeId filterKeyId : filterKeyIds) {
                    foundMatch = false;
                    FilterKey *filterFilterKey = manager->filterKeyManager()->lookupResource(filterKeyId);

                    const auto passFilterKeyIds = renderPass->filterKeys();
                    for (const QNodeId passFilterKeyId : passFilterKeyIds) {
                        FilterKey *passFilterKey = manager->filterKeyManager()->lookupResource(passFilterKeyId);
                        if ((foundMatch = (*passFilterKey == *filterFilterKey)))
                            break;
                    }

                    if (!foundMatch) {
                        // No match for criterion in any of the render pass' criteria
                        break;
                    }
                }
            }

            if (foundMatch) {
                // Found a renderpass that satisfies our needs. Add it in order
                passes << renderPass;
            }
        }
    }

    return passes;
}


ParameterInfoList::const_iterator findParamInfo(ParameterInfoList *params, const int nameId)
{
    const ParameterInfoList::const_iterator end = params->cend();
    ParameterInfoList::const_iterator it = std::lower_bound(params->cbegin(), end, nameId);
    if (it != end && it->nameId != nameId)
        return end;
    return it;
}

void addParametersForIds(ParameterInfoList *params, ParameterManager *manager,
                         const Qt3DCore::QNodeIdVector &parameterIds)
{
    for (const QNodeId paramId : parameterIds) {
        Parameter *param = manager->lookupResource(paramId);
        ParameterInfoList::iterator it = std::lower_bound(params->begin(), params->end(), param->nameId());
        if (it == params->end() || it->nameId != param->nameId())
            params->insert(it, ParameterInfo(param->nameId(), param->value()));
    }
}

void parametersFromMaterialEffectTechnique(ParameterInfoList *infoList,
                                           ParameterManager *manager,
                                           Material *material,
                                           Effect *effect,
                                           Technique *technique)
{
    // The parameters are taken in the following priority order:
    //
    // 1) Material
    // 2) Technique
    // 3) Effect
    //
    // That way a user can override defaults in Effect's and Techniques on a
    // object manner and a Technique can override global defaults from the Effect.
    parametersFromParametersProvider(infoList, manager, material);
    parametersFromParametersProvider(infoList, manager, technique);
    parametersFromParametersProvider(infoList, manager, effect);
}

void addToRenderStateSet(RenderStateSet *stateSet,
                         const QVector<Qt3DCore::QNodeId> stateIds,
                         RenderStateManager *manager)
{
    for (const Qt3DCore::QNodeId &stateId : stateIds)
        stateSet->addState(manager->lookupResource(stateId)->impl());
}

namespace {

const QString blockArray = QStringLiteral("[%1]");
const int qNodeIdTypeId = qMetaTypeId<QNodeId>();

}

UniformBlockValueBuilder::UniformBlockValueBuilder()
    : shaderDataManager(nullptr)
{
}

UniformBlockValueBuilder::~UniformBlockValueBuilder()
{
}

void UniformBlockValueBuilder::buildActiveUniformNameValueMapHelper(ShaderData *currentShaderData, const QString &blockName, const QString &qmlPropertyName, const QVariant &value)
{
    // In the end, values are either scalar or a scalar array
    // Composed elements (structs, structs array) are simplified into simple scalars
    if (value.userType() == QMetaType::QVariantList) { // Array
        QVariantList list = value.value<QVariantList>();
        if (list.at(0).userType() == qNodeIdTypeId) { // Array of struct qmlPropertyName[i].structMember
            for (int i = 0; i < list.size(); ++i) {
                if (list.at(i).userType() == qNodeIdTypeId) {
                    ShaderData *subShaderData = shaderDataManager->lookupResource(list.at(i).value<QNodeId>());
                    if (subShaderData)
                        buildActiveUniformNameValueMapStructHelper(subShaderData,
                                                                   blockName + QLatin1Char('.') + qmlPropertyName + blockArray.arg(i),
                                                                   QLatin1String(""));
                }
            }
        } else { // Array of scalar/vec  qmlPropertyName[0]
            QString varName = blockName + QLatin1String(".") + qmlPropertyName + QLatin1String("[0]");
            if (uniforms.contains(varName)) {
                qCDebug(Shaders) << "UBO array member " << varName << " set for update";
                activeUniformNamesToValue.insert(StringToInt::lookupId(varName), value);
            }
        }
    } else if (value.userType() == qNodeIdTypeId) { // Struct qmlPropertyName.structMember
        ShaderData *rSubShaderData = shaderDataManager->lookupResource(value.value<QNodeId>());
        if (rSubShaderData)
            buildActiveUniformNameValueMapStructHelper(rSubShaderData,
                                                       blockName,
                                                       qmlPropertyName);
    } else { // Scalar / Vec
        QString varName = blockName + QLatin1Char('.') + qmlPropertyName;
        if (uniforms.contains(varName)) {
            qCDebug(Shaders) << "UBO scalar member " << varName << " set for update";

            // If the property needs to be transformed, we transform it here as
            // the shaderdata cannot hold transformed properties for multiple
            // thread contexts at once
            if (currentShaderData->propertyTransformType(qmlPropertyName) != ShaderData::NoTransform)
                activeUniformNamesToValue.insert(StringToInt::lookupId(varName),
                                                 currentShaderData->getTransformedProperty(qmlPropertyName, viewMatrix));
            else
                activeUniformNamesToValue.insert(StringToInt::lookupId(varName), value);
        }
    }
}

void UniformBlockValueBuilder::buildActiveUniformNameValueMapStructHelper(ShaderData *rShaderData, const QString &blockName, const QString &qmlPropertyName)
{
    const QHash<QString, QVariant> &properties = rShaderData->properties();
    QHash<QString, QVariant>::const_iterator it = properties.begin();
    const QHash<QString, QVariant>::const_iterator end = properties.end();

    while (it != end) {
        const auto prefix = qmlPropertyName.isEmpty() ? QLatin1String("") : QLatin1String(".");
        buildActiveUniformNameValueMapHelper(rShaderData,
                                             blockName + prefix + qmlPropertyName,
                                             it.key(),
                                             it.value());
        ++it;
    }
}

ParameterInfo::ParameterInfo(const int nameId, const QVariant &value)
    : nameId(nameId)
    , value(value)
{}

bool ParameterInfo::operator<(const ParameterInfo &other) const Q_DECL_NOEXCEPT
{
    return nameId < other.nameId;
}

bool ParameterInfo::operator<(const int otherNameId) const Q_DECL_NOEXCEPT
{
    return nameId < otherNameId;
}

} // namespace Render
} // namespace Qt3DRender

QT_END_NAMESPACE