//
//  MetavoxelSystem.cpp
//  interface/src
//
//  Created by Andrzej Kapolka on 12/10/13.
//  Copyright 2013 High Fidelity, Inc.
//
//  Distributed under the Apache License, Version 2.0.
//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//

#include <QMutexLocker>
#include <QtDebug>

#include <glm/gtx/transform.hpp>

#include <SharedUtil.h>

#include <MetavoxelUtil.h>
#include <ScriptCache.h>

#include "Application.h"
#include "MetavoxelSystem.h"
#include "renderer/Model.h"

REGISTER_META_OBJECT(SphereRenderer)
REGISTER_META_OBJECT(StaticModelRenderer)

ProgramObject MetavoxelSystem::_program;
int MetavoxelSystem::_pointScaleLocation;

MetavoxelSystem::MetavoxelSystem() :
    _simulateVisitor(_points),
    _buffer(QOpenGLBuffer::VertexBuffer) {
}

void MetavoxelSystem::init() {
    MetavoxelClientManager::init();
    
    if (!_program.isLinked()) {
        _program.addShaderFromSourceFile(QGLShader::Vertex, Application::resourcesPath() + "shaders/metavoxel_point.vert");
        _program.link();
       
        _pointScaleLocation = _program.uniformLocation("pointScale");
    }
    _buffer.setUsagePattern(QOpenGLBuffer::DynamicDraw);
    _buffer.create();
    _pointBufferAttribute = AttributeRegistry::getInstance()->registerAttribute(new PointBufferAttribute());
}

MetavoxelLOD MetavoxelSystem::getLOD() const {
    // the LOD threshold is temporarily tied to the avatar LOD parameter
    const float BASE_LOD_THRESHOLD = 0.01f;
    return MetavoxelLOD(Application::getInstance()->getCamera()->getPosition(),
        BASE_LOD_THRESHOLD * Menu::getInstance()->getAvatarLODDistanceMultiplier());
}

void MetavoxelSystem::simulate(float deltaTime) {
    // update the clients
    _points.clear();
    _simulateVisitor.setDeltaTime(deltaTime);
    _simulateVisitor.setOrder(-Application::getInstance()->getViewFrustum()->getDirection());
    update();
    
    _buffer.bind();
    int bytes = _points.size() * sizeof(Point);
    if (_buffer.size() < bytes) {
        _buffer.allocate(_points.constData(), bytes);
    } else {
        _buffer.write(0, _points.constData(), bytes);
    }
    _buffer.release();
}

void MetavoxelSystem::render() {
    int viewport[4];
    glGetIntegerv(GL_VIEWPORT, viewport);
    const int VIEWPORT_WIDTH_INDEX = 2;
    const int VIEWPORT_HEIGHT_INDEX = 3;
    float viewportWidth = viewport[VIEWPORT_WIDTH_INDEX];
    float viewportHeight = viewport[VIEWPORT_HEIGHT_INDEX];
    float viewportDiagonal = sqrtf(viewportWidth*viewportWidth + viewportHeight*viewportHeight);
    float worldDiagonal = glm::distance(Application::getInstance()->getViewFrustum()->getNearBottomLeft(),
        Application::getInstance()->getViewFrustum()->getNearTopRight());

    _program.bind();
    _program.setUniformValue(_pointScaleLocation, viewportDiagonal *
        Application::getInstance()->getViewFrustum()->getNearClip() / worldDiagonal);
        
    _buffer.bind();

    Point* pt = 0;
    glVertexPointer(4, GL_FLOAT, sizeof(Point), &pt->vertex);
    glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(Point), &pt->color);
    glNormalPointer(GL_BYTE, sizeof(Point), &pt->normal);    

    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_COLOR_ARRAY);
    glEnableClientState(GL_NORMAL_ARRAY);

    glEnable(GL_VERTEX_PROGRAM_POINT_SIZE_ARB);

    glDrawArrays(GL_POINTS, 0, _points.size());
    
    glDisable(GL_VERTEX_PROGRAM_POINT_SIZE_ARB);
    
    glDisableClientState(GL_VERTEX_ARRAY);
    glDisableClientState(GL_COLOR_ARRAY);
    glDisableClientState(GL_NORMAL_ARRAY);
    
    _buffer.release();
    
    _program.release();
    
    foreach (const SharedNodePointer& node, NodeList::getInstance()->getNodeHash()) {
        if (node->getType() == NodeType::MetavoxelServer) {
            QMutexLocker locker(&node->getMutex());
            MetavoxelSystemClient* client = static_cast<MetavoxelSystemClient*>(node->getLinkedData());
            if (client) {
                client->guide(_renderVisitor);
            }
        }
    }
}

MetavoxelClient* MetavoxelSystem::createClient(const SharedNodePointer& node) {
    return new MetavoxelSystemClient(node, this);
}

void MetavoxelSystem::updateClient(MetavoxelClient* client) {
    MetavoxelClientManager::updateClient(client);
    client->guide(_simulateVisitor);
}

MetavoxelSystem::SimulateVisitor::SimulateVisitor(QVector<Point>& points) :
    SpannerVisitor(QVector<AttributePointer>() << AttributeRegistry::getInstance()->getSpannersAttribute(),
        QVector<AttributePointer>(), QVector<AttributePointer>() << AttributeRegistry::getInstance()->getColorAttribute() <<
            AttributeRegistry::getInstance()->getNormalAttribute() <<
            AttributeRegistry::getInstance()->getSpannerColorAttribute() <<
            AttributeRegistry::getInstance()->getSpannerNormalAttribute()),
    _points(points) {
}

bool MetavoxelSystem::SimulateVisitor::visit(Spanner* spanner, const glm::vec3& clipMinimum, float clipSize) {
    spanner->getRenderer()->simulate(_deltaTime);
    return true;
}

int MetavoxelSystem::SimulateVisitor::visit(MetavoxelInfo& info) {
    SpannerVisitor::visit(info);

    if (!info.isLeaf) {
        return _order;
    }
    QRgb color = info.inputValues.at(0).getInlineValue<QRgb>();
    QRgb normal = info.inputValues.at(1).getInlineValue<QRgb>();
    quint8 alpha = qAlpha(color);
    if (!info.isLODLeaf) {
        if (alpha > 0) {
            Point point = { glm::vec4(info.minimum + glm::vec3(info.size, info.size, info.size) * 0.5f, info.size),
                { quint8(qRed(color)), quint8(qGreen(color)), quint8(qBlue(color)), alpha }, 
                { quint8(qRed(normal)), quint8(qGreen(normal)), quint8(qBlue(normal)) } };
            _points.append(point);
        }
    } else {
        QRgb spannerColor = info.inputValues.at(2).getInlineValue<QRgb>();
        QRgb spannerNormal = info.inputValues.at(3).getInlineValue<QRgb>();
        quint8 spannerAlpha = qAlpha(spannerColor);
        if (spannerAlpha > 0) {
            if (alpha > 0) {
                Point point = { glm::vec4(info.minimum + glm::vec3(info.size, info.size, info.size) * 0.5f, info.size),
                    { quint8(qRed(spannerColor)), quint8(qGreen(spannerColor)), quint8(qBlue(spannerColor)), spannerAlpha }, 
                    { quint8(qRed(spannerNormal)), quint8(qGreen(spannerNormal)), quint8(qBlue(spannerNormal)) } };
                _points.append(point);
                
            } else {
                Point point = { glm::vec4(info.minimum + glm::vec3(info.size, info.size, info.size) * 0.5f, info.size),
                    { quint8(qRed(spannerColor)), quint8(qGreen(spannerColor)), quint8(qBlue(spannerColor)), spannerAlpha }, 
                    { quint8(qRed(spannerNormal)), quint8(qGreen(spannerNormal)), quint8(qBlue(spannerNormal)) } };
                _points.append(point);
            }
        } else if (alpha > 0) {
            Point point = { glm::vec4(info.minimum + glm::vec3(info.size, info.size, info.size) * 0.5f, info.size),
                { quint8(qRed(color)), quint8(qGreen(color)), quint8(qBlue(color)), alpha }, 
                { quint8(qRed(normal)), quint8(qGreen(normal)), quint8(qBlue(normal)) } };
            _points.append(point);
        }
    }
    return STOP_RECURSION;
}

MetavoxelSystem::RenderVisitor::RenderVisitor() :
    SpannerVisitor(QVector<AttributePointer>() << AttributeRegistry::getInstance()->getSpannersAttribute(),
        QVector<AttributePointer>() << AttributeRegistry::getInstance()->getSpannerMaskAttribute()) {
}

bool MetavoxelSystem::RenderVisitor::visit(Spanner* spanner, const glm::vec3& clipMinimum, float clipSize) {
    spanner->getRenderer()->render(1.0f, SpannerRenderer::DEFAULT_MODE, clipMinimum, clipSize);
    return true;
}

MetavoxelSystemClient::MetavoxelSystemClient(const SharedNodePointer& node, MetavoxelSystem* system) :
    MetavoxelClient(node, system) {
}

int MetavoxelSystemClient::parseData(const QByteArray& packet) {
    // process through sequencer
    QMetaObject::invokeMethod(&_sequencer, "receivedDatagram", Q_ARG(const QByteArray&, packet));
    Application::getInstance()->getBandwidthMeter()->inputStream(BandwidthMeter::METAVOXELS).updateValue(packet.size());
    return packet.size();
}

class BufferBuilder : public MetavoxelVisitor {
public:

    BufferBuilder(const MetavoxelLOD& lod);
    
    virtual int visit(MetavoxelInfo& info);
    virtual bool postVisit(MetavoxelInfo& info);

private:
    
    QVector<BufferPointVectorPair> _depthPoints;
};

BufferBuilder::BufferBuilder(const MetavoxelLOD& lod) :
    MetavoxelVisitor(QVector<AttributePointer>() << AttributeRegistry::getInstance()->getColorAttribute() <<
        AttributeRegistry::getInstance()->getNormalAttribute() <<
            Application::getInstance()->getMetavoxels()->getPointBufferAttribute(), QVector<AttributePointer>() <<
                Application::getInstance()->getMetavoxels()->getPointBufferAttribute(), lod) {
}

const int ALPHA_RENDER_THRESHOLD = 0;

int BufferBuilder::visit(MetavoxelInfo& info) {
    if (info.inputValues.at(2).getInlineValue<PointBufferPointer>()) {
        info.outputValues[0] = AttributeValue(_outputs.at(0));
    }
    if (_depth >= _depthPoints.size()) {
        _depthPoints.resize(_depth + 1);
    }
    QRgb color = info.inputValues.at(0).getInlineValue<QRgb>();
    quint8 alpha = qAlpha(color);
    if (alpha <= ALPHA_RENDER_THRESHOLD) {
        return info.isLeaf ? STOP_RECURSION : DEFAULT_ORDER;
    }
    QRgb normal = info.inputValues.at(1).getInlineValue<QRgb>();
    BufferPoint point = { glm::vec4(info.minimum + glm::vec3(info.size, info.size, info.size) * 0.5f, info.size),
        { quint8(qRed(color)), quint8(qGreen(color)), quint8(qBlue(color)) }, 
        { quint8(qRed(normal)), quint8(qGreen(normal)), quint8(qBlue(normal)) } };
    if (info.isLeaf) {
        _depthPoints[_depth].first.append(point);
        return STOP_RECURSION;
    }
    _depthPoints[_depth].second.append(point);
    return DEFAULT_ORDER;
}

const int BUFFER_LEVELS = 5;

bool BufferBuilder::postVisit(MetavoxelInfo& info) {
    if (_depth % BUFFER_LEVELS != 0) {
        return false;
    }
    QVector<int> offsets;
    offsets.append(0);
    int leafCount = 0;
    int totalPoints = 0;
    int lastDepth = qMin(_depth + BUFFER_LEVELS, _depthPoints.size());
    for (int i = _depth; i < lastDepth; i++) {
        const BufferPointVectorPair& pair = _depthPoints.at(i);
        offsets.append(totalPoints += ((leafCount += pair.first.size()) + pair.second.size()));
    }
    QOpenGLBuffer buffer;
    buffer.setUsagePattern(QOpenGLBuffer::StaticDraw);
    buffer.create();
    buffer.bind();
    buffer.allocate(totalPoints * sizeof(BufferPoint));
    int offset = 0;
    for (int i = _depth; i < lastDepth; i++) {
        // write the internal nodes from the current level
        BufferPointVector& internal = _depthPoints[i].second;
        int length = internal.size() * sizeof(BufferPoint);
        buffer.write(offset, internal.constData(), length);
        offset += length;
        internal.clear();
        
        // and the leaves from the top down
        for (int j = _depth; j <= i; j++) {
            const BufferPointVector& leaves = _depthPoints.at(j).first;
            length = leaves.size() * sizeof(BufferPoint);
            buffer.write(offset, leaves.constData(), length);
            offset += length;
        }
    }
    // clear the leaves now that we're done with them
    for (int i = _depth; i < lastDepth; i++) {
        _depthPoints[i].first.clear();
    }
    buffer.release();
    info.outputValues[0] = AttributeValue(_outputs.at(0), encodeInline(PointBufferPointer(
        new PointBuffer(buffer, offsets, leafCount))));
    return true;
}

void MetavoxelSystemClient::dataChanged(const MetavoxelData& oldData) {
    BufferBuilder builder(_remoteDataLOD);
    _data.guideToDifferent(oldData, builder);
}

void MetavoxelSystemClient::sendDatagram(const QByteArray& data) {
    NodeList::getInstance()->writeDatagram(data, _node);
    Application::getInstance()->getBandwidthMeter()->outputStream(BandwidthMeter::METAVOXELS).updateValue(data.size());
}

PointBuffer::PointBuffer(const QOpenGLBuffer& buffer, const QVector<int>& offsets, int lastLeafCount) :
    _buffer(buffer),
    _offsets(offsets),
    _lastLeafCount(lastLeafCount) {
}

void PointBuffer::render(int level) {
    _buffer.bind();
    
    BufferPoint* point = 0;
    glVertexPointer(4, GL_FLOAT, sizeof(BufferPoint), &point->vertex);
    glColorPointer(3, GL_UNSIGNED_BYTE, sizeof(BufferPoint), &point->color);
    glNormalPointer(GL_BYTE, sizeof(BufferPoint), &point->normal);
    
    int nextLevel = level + 1;
    if (nextLevel >= _offsets.size()) {
        glDrawArrays(GL_POINTS, _offsets.last() - _lastLeafCount, _lastLeafCount);
        
    } else {
        int first = _offsets.at(level);
        glDrawArrays(GL_POINTS, first, _offsets.at(nextLevel) - first);
    }
    _buffer.release();
}

PointBufferAttribute::PointBufferAttribute() :
    InlineAttribute<PointBufferPointer>("pointBuffer") {
}

MetavoxelNode* PointBufferAttribute::createMetavoxelNode(const AttributeValue& value, const MetavoxelNode* original) const {
    return new MetavoxelNode(value, original);
}

bool PointBufferAttribute::merge(void*& parent, void* children[], bool postRead) const {
    for (int i = 0; i < MERGE_COUNT; i++) {
        if (decodeInline<PointBufferPointer>(children[i])) {
            return false;
        }
    }
    return true;
}

AttributeValue PointBufferAttribute::inherit(const AttributeValue& parentValue) const {
    return AttributeValue(parentValue.getAttribute());
}

static void enableClipPlane(GLenum plane, float x, float y, float z, float w) {
    GLdouble coefficients[] = { x, y, z, w };
    glClipPlane(plane, coefficients);
    glEnable(plane);
}

void ClippedRenderer::render(float alpha, Mode mode, const glm::vec3& clipMinimum, float clipSize) {
    if (clipSize == 0.0f) {
        renderUnclipped(alpha, mode);
        return;
    }
    enableClipPlane(GL_CLIP_PLANE0, -1.0f, 0.0f, 0.0f, clipMinimum.x + clipSize);
    enableClipPlane(GL_CLIP_PLANE1, 1.0f, 0.0f, 0.0f, -clipMinimum.x);
    enableClipPlane(GL_CLIP_PLANE2, 0.0f, -1.0f, 0.0f, clipMinimum.y + clipSize);
    enableClipPlane(GL_CLIP_PLANE3, 0.0f, 1.0f, 0.0f, -clipMinimum.y);
    enableClipPlane(GL_CLIP_PLANE4, 0.0f, 0.0f, -1.0f, clipMinimum.z + clipSize);
    enableClipPlane(GL_CLIP_PLANE5, 0.0f, 0.0f, 1.0f, -clipMinimum.z);
    
    renderUnclipped(alpha, mode);
    
    glDisable(GL_CLIP_PLANE0);
    glDisable(GL_CLIP_PLANE1);
    glDisable(GL_CLIP_PLANE2);
    glDisable(GL_CLIP_PLANE3);
    glDisable(GL_CLIP_PLANE4);
    glDisable(GL_CLIP_PLANE5);
}

SphereRenderer::SphereRenderer() {
}

void SphereRenderer::render(float alpha, Mode mode, const glm::vec3& clipMinimum, float clipSize) {
    if (clipSize == 0.0f) {
        renderUnclipped(alpha, mode);
        return;
    }
    // slight performance optimization: don't render if clip bounds are entirely within sphere
    Sphere* sphere = static_cast<Sphere*>(parent());
    Box clipBox(clipMinimum, clipMinimum + glm::vec3(clipSize, clipSize, clipSize));
    for (int i = 0; i < Box::VERTEX_COUNT; i++) {
        const float CLIP_PROPORTION = 0.95f;
        if (glm::distance(sphere->getTranslation(), clipBox.getVertex(i)) >= sphere->getScale() * CLIP_PROPORTION) {
            ClippedRenderer::render(alpha, mode, clipMinimum, clipSize);
            return;
        }
    }
}

void SphereRenderer::renderUnclipped(float alpha, Mode mode) {
    Sphere* sphere = static_cast<Sphere*>(parent());
    const QColor& color = sphere->getColor();
    glColor4f(color.redF(), color.greenF(), color.blueF(), color.alphaF() * alpha);
    
    glPushMatrix();
    const glm::vec3& translation = sphere->getTranslation();
    glTranslatef(translation.x, translation.y, translation.z);
    glm::quat rotation = sphere->getRotation();
    glm::vec3 axis = glm::axis(rotation);
    glRotatef(glm::angle(rotation), axis.x, axis.y, axis.z);
    
    glutSolidSphere(sphere->getScale(), 10, 10);
    
    glPopMatrix();
}

StaticModelRenderer::StaticModelRenderer() :
    _model(new Model(this)) {
}

void StaticModelRenderer::init(Spanner* spanner) {
    _model->init();
    
    StaticModel* staticModel = static_cast<StaticModel*>(spanner);
    applyTranslation(staticModel->getTranslation());
    applyRotation(staticModel->getRotation());
    applyScale(staticModel->getScale());
    applyURL(staticModel->getURL());
    
    connect(spanner, SIGNAL(translationChanged(const glm::vec3&)), SLOT(applyTranslation(const glm::vec3&)));
    connect(spanner, SIGNAL(rotationChanged(const glm::quat&)), SLOT(applyRotation(const glm::quat&)));
    connect(spanner, SIGNAL(scaleChanged(float)), SLOT(applyScale(float)));
    connect(spanner, SIGNAL(urlChanged(const QUrl&)), SLOT(applyURL(const QUrl&)));
}

void StaticModelRenderer::simulate(float deltaTime) {
    // update the bounds
    Box bounds;
    if (_model->isActive()) {
        const Extents& extents = _model->getGeometry()->getFBXGeometry().meshExtents;
        bounds = Box(extents.minimum, extents.maximum);
    }
    static_cast<StaticModel*>(parent())->setBounds(glm::translate(_model->getTranslation()) *
        glm::mat4_cast(_model->getRotation()) * glm::scale(_model->getScale()) * bounds);
    _model->simulate(deltaTime);
}

void StaticModelRenderer::renderUnclipped(float alpha, Mode mode) {
    switch (mode) {
        case DIFFUSE_MODE:
            _model->render(alpha, Model::DIFFUSE_RENDER_MODE);
            break;
            
        case NORMAL_MODE:
            _model->render(alpha, Model::NORMAL_RENDER_MODE);
            break;
            
        default:
            _model->render(alpha);
            break;
    }
    _model->render(alpha);
}

bool StaticModelRenderer::findRayIntersection(const glm::vec3& origin, const glm::vec3& direction,
        const glm::vec3& clipMinimum, float clipSize, float& distance) const {
    return _model->findRayIntersection(origin, direction, distance);
}

void StaticModelRenderer::applyTranslation(const glm::vec3& translation) {
    _model->setTranslation(translation);
}

void StaticModelRenderer::applyRotation(const glm::quat& rotation) {
    _model->setRotation(rotation);
}

void StaticModelRenderer::applyScale(float scale) {
    const float SCALE_MULTIPLIER = 0.0006f;
    _model->setScale(glm::vec3(scale, scale, scale) * SCALE_MULTIPLIER);
}

void StaticModelRenderer::applyURL(const QUrl& url) {
    _model->setURL(url);
}