//
//  OctreeRenderer.cpp
//  libraries/octree/src
//
//  Created by Brad Hefta-Gaub on 12/6/13.
//  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 <glm/glm.hpp>
#include <stdint.h>

#include <NumericalConstants.h>
#include <PerfStat.h>
#include <RenderArgs.h>
#include <SharedUtil.h>

#include "OctreeLogging.h"
#include "OctreeRenderer.h"

OctreeRenderer::OctreeRenderer() :
    _tree(NULL),
    _managedTree(false),
    _viewFrustum(NULL)
{
}

void OctreeRenderer::init() {
    if (!_tree) {
        _tree = createTree();
        _managedTree = true;
    }
}

OctreeRenderer::~OctreeRenderer() {
}

void OctreeRenderer::setTree(OctreePointer newTree) {
    _tree = newTree;
}

void OctreeRenderer::processDatagram(ReceivedMessage& message, SharedNodePointer sourceNode) {
    bool extraDebugging = false;

    if (extraDebugging) {
        qCDebug(octree) << "OctreeRenderer::processDatagram()";
    }

    if (!_tree) {
        qCDebug(octree) << "OctreeRenderer::processDatagram() called before init, calling init()...";
        this->init();
    }

    bool showTimingDetails = false; // Menu::getInstance()->isOptionChecked(MenuOption::PipelineWarnings);
    PerformanceWarning warn(showTimingDetails, "OctreeRenderer::processDatagram()", showTimingDetails);
    
    if (message.getType() == getExpectedPacketType()) {
        PerformanceWarning warn(showTimingDetails, "OctreeRenderer::processDatagram expected PacketType", showTimingDetails);
        // if we are getting inbound packets, then our tree is also viewing, and we should remember that fact.
        _tree->setIsViewing(true);
        
        OCTREE_PACKET_FLAGS flags;
        message.readPrimitive(&flags);
        
        OCTREE_PACKET_SEQUENCE sequence;
        message.readPrimitive(&sequence);

        OCTREE_PACKET_SENT_TIME sentAt;
        message.readPrimitive(&sentAt);

        bool packetIsColored = oneAtBit(flags, PACKET_IS_COLOR_BIT);
        bool packetIsCompressed = oneAtBit(flags, PACKET_IS_COMPRESSED_BIT);
        
        OCTREE_PACKET_SENT_TIME arrivedAt = usecTimestampNow();
        qint64 clockSkew = sourceNode ? sourceNode->getClockSkewUsec() : 0;
        qint64 flightTime = arrivedAt - sentAt + clockSkew;

        OCTREE_PACKET_INTERNAL_SECTION_SIZE sectionLength = 0;

        if (extraDebugging) {
            qCDebug(octree) << "OctreeRenderer::processDatagram() ... "
                               "Got Packet Section color:" << packetIsColored <<
                               "compressed:" << packetIsCompressed <<
                               "sequence: " <<  sequence << 
                               "flight: " << flightTime << " usec" <<
                               "size:" << message.getSize() <<
                               "data:" << message.getBytesLeftToRead();
        }
        
        _packetsInLastWindow++;
        
        int elementsPerPacket = 0;
        int entitiesPerPacket = 0;
        
        quint64 totalWaitingForLock = 0;
        quint64 totalUncompress = 0;
        quint64 totalReadBitsteam = 0;

        const QUuid& sourceUUID = message.getSourceID();
        
        int subsection = 1;
        
        bool error = false;
        
        while (message.getBytesLeftToRead() > 0 && !error) {
            if (packetIsCompressed) {
                if (message.getBytesLeftToRead() > (qint64) sizeof(OCTREE_PACKET_INTERNAL_SECTION_SIZE)) {
                    message.readPrimitive(&sectionLength);
                } else {
                    sectionLength = 0;
                    error = true;
                }
            } else {
                sectionLength = message.getBytesLeftToRead();
            }
            
            if (sectionLength) {
                // ask the VoxelTree to read the bitstream into the tree
                ReadBitstreamToTreeParams args(WANT_EXISTS_BITS, NULL,
                                                sourceUUID, sourceNode, false, message.getVersion());
                quint64 startUncompress, startLock = usecTimestampNow();
                quint64 startReadBitsteam, endReadBitsteam;
                // FIXME STUTTER - there may be an opportunity to bump this lock outside of the
                // loop to reduce the amount of locking/unlocking we're doing
                _tree->withWriteLock([&] {
                    startUncompress = usecTimestampNow();

                    OctreePacketData packetData(packetIsCompressed);
                    packetData.loadFinalizedContent(reinterpret_cast<const unsigned char*>(message.getRawMessage() + message.getPosition()),
                        sectionLength);
                    if (extraDebugging) {
                        qCDebug(octree) << "OctreeRenderer::processDatagram() ... "
                            "Got Packet Section color:" << packetIsColored <<
                            "compressed:" << packetIsCompressed <<
                            "sequence: " << sequence <<
                            "flight: " << flightTime << " usec" <<
                            "size:" << message.getSize() <<
                            "data:" << message.getBytesLeftToRead() <<
                            "subsection:" << subsection <<
                            "sectionLength:" << sectionLength <<
                            "uncompressed:" << packetData.getUncompressedSize();
                    }

                    if (extraDebugging) {
                        qCDebug(octree) << "OctreeRenderer::processDatagram() ******* START _tree->readBitstreamToTree()...";
                    }
                    startReadBitsteam = usecTimestampNow();
                    _tree->readBitstreamToTree(packetData.getUncompressedData(), packetData.getUncompressedSize(), args);
                    endReadBitsteam = usecTimestampNow();
                    if (extraDebugging) {
                        qCDebug(octree) << "OctreeRenderer::processDatagram() ******* END _tree->readBitstreamToTree()...";
                    }
                });
                
                // seek forwards in packet
                message.seek(message.getPosition() + sectionLength);

                elementsPerPacket += args.elementsPerPacket;
                entitiesPerPacket += args.entitiesPerPacket;

                _elementsInLastWindow += args.elementsPerPacket;
                _entitiesInLastWindow += args.entitiesPerPacket;

                totalWaitingForLock += (startUncompress - startLock);
                totalUncompress += (startReadBitsteam - startUncompress);
                totalReadBitsteam += (endReadBitsteam - startReadBitsteam);

            }
            subsection++;
        }
        _elementsPerPacket.updateAverage(elementsPerPacket);
        _entitiesPerPacket.updateAverage(entitiesPerPacket);

        _waitLockPerPacket.updateAverage(totalWaitingForLock);
        _uncompressPerPacket.updateAverage(totalUncompress);
        _readBitstreamPerPacket.updateAverage(totalReadBitsteam);
        
        quint64 now = usecTimestampNow();
        if (_lastWindowAt == 0) {
            _lastWindowAt = now;
        }
        quint64 sinceLastWindow = now - _lastWindowAt;
        
        if (sinceLastWindow > USECS_PER_SECOND) {
            float packetsPerSecondInWindow = (float)_packetsInLastWindow / (float)(sinceLastWindow / USECS_PER_SECOND);
            float elementsPerSecondInWindow = (float)_elementsInLastWindow / (float)(sinceLastWindow / USECS_PER_SECOND);
            float entitiesPerSecondInWindow = (float)_entitiesInLastWindow / (float)(sinceLastWindow / USECS_PER_SECOND);
            _packetsPerSecond.updateAverage(packetsPerSecondInWindow);
            _elementsPerSecond.updateAverage(elementsPerSecondInWindow);
            _entitiesPerSecond.updateAverage(entitiesPerSecondInWindow);

            _lastWindowAt = now;
            _packetsInLastWindow = 0;
            _elementsInLastWindow = 0;
            _entitiesInLastWindow = 0;
        }
    }
}

bool OctreeRenderer::renderOperation(OctreeElementPointer element, void* extraData) {
    RenderArgs* args = static_cast<RenderArgs*>(extraData);
    if (element->isInView(*args->_viewFrustum)) {
        if (element->hasContent()) {
            if (element->calculateShouldRender(args->_viewFrustum, args->_sizeScale, args->_boundaryLevelAdjust)) {
                args->_renderer->renderElement(element, args);
            } else {
                return false; // if we shouldn't render, then we also should stop recursing.
            }
        }
        return true; // continue recursing
    }
    // if not in view stop recursing
    return false;
}

void OctreeRenderer::render(RenderArgs* renderArgs) {
    if (_tree) {
        renderArgs->_renderer = this;
        _tree->withReadLock([&] {
            _tree->recurseTreeWithOperation(renderOperation, renderArgs);
        });
    }
}

void OctreeRenderer::clear() {
    if (_tree) {
        _tree->withWriteLock([&] {
            _tree->eraseAllOctreeElements();
        });
    }
}