//
//  AssetServer.cpp
//  assignment-client/src/assets
//
//  Created by Ryan Huffman on 2015/07/21
//  Copyright 2015 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 "AssetServer.h"

#include <thread>
#include <memory>

#include <QtCore/QCoreApplication>
#include <QtCore/QCryptographicHash>
#include <QtCore/QDateTime>
#include <QtCore/QDir>
#include <QtCore/QDirIterator>
#include <QtCore/QFile>
#include <QtCore/QFileInfo>
#include <QtCore/QJsonDocument>
#include <QtCore/QString>
#include <QtGui/QImageReader>
#include <QtCore/QVector>
#include <qurlquery.h>

#include <ClientServerUtils.h>
#include <FBXBaker.h>
#include <NodeType.h>
#include <SharedUtil.h>
#include <PathUtils.h>

#include "AssetServerLogging.h"
#include "SendAssetTask.h"
#include "UploadAssetTask.h"


static const uint8_t MIN_CORES_FOR_MULTICORE = 4;
static const uint8_t CPU_AFFINITY_COUNT_HIGH = 2;
static const uint8_t CPU_AFFINITY_COUNT_LOW = 1;
#ifdef Q_OS_WIN
static const int INTERFACE_RUNNING_CHECK_FREQUENCY_MS = 1000;
#endif

const QString ASSET_SERVER_LOGGING_TARGET_NAME = "asset-server";

static const QStringList BAKEABLE_MODEL_EXTENSIONS = { "fbx" };
static const QList<QByteArray> BAKEABLE_TEXTURE_EXTENSIONS = QImageReader::supportedImageFormats();
static const QString BAKED_MODEL_SIMPLE_NAME = "asset.fbx";
static const QString BAKED_TEXTURE_SIMPLE_NAME = "texture.ktx";

BakeAssetTask::BakeAssetTask(const QString& assetHash, const QString& assetPath, const QString& filePath)
    : _assetHash(assetHash), _assetPath(assetPath), _filePath(filePath) {
}

void BakeAssetTask::run() {
    qRegisterMetaType<QVector<QString> >("QVector<QString>");
    TextureBakerThreadGetter fn = []() -> QThread* { return QThread::currentThread();  };

    if (_filePath.endsWith(".fbx")) {
        FBXBaker baker(QUrl("file:///" + _filePath), fn, PathUtils::generateTemporaryDir());

        QEventLoop loop;
        connect(&baker, &Baker::finished, &loop, &QEventLoop::quit);
        QMetaObject::invokeMethod(&baker, "bake", Qt::QueuedConnection);
        qDebug() << "Running the bake!";
        loop.exec();

        qDebug() << "Finished baking: " << _assetHash << _assetPath << baker.getOutputFiles();
        emit bakeComplete(_assetHash, _assetPath, QVector<QString>::fromStdVector(baker.getOutputFiles()));
    } else {
        TextureBaker baker(QUrl("file:///" + _filePath), image::TextureUsage::CUBE_TEXTURE, PathUtils::generateTemporaryDir());

        QEventLoop loop;
        connect(&baker, &Baker::finished, &loop, &QEventLoop::quit);
        QMetaObject::invokeMethod(&baker, "bake", Qt::QueuedConnection);
        qDebug() << "Running the bake!";
        loop.exec();

        qDebug() << "Finished baking: " << _assetHash << _assetPath << baker.getBakedTextureFileName();
        emit bakeComplete(_assetHash, _assetPath, { baker.getDestinationFilePath() });
    }
}

void AssetServer::bakeAsset(const QString& assetHash, const QString& assetPath, const QString& filePath) {
    qDebug() << "Starting bake for: " << assetPath << assetHash;
    auto it = _pendingBakes.find(assetHash);
    if (it == _pendingBakes.end()) {
        auto task = std::make_shared<BakeAssetTask>(assetHash, assetPath, filePath);
        task->setAutoDelete(false);
        _pendingBakes[assetHash] = task;

        connect(task.get(), &BakeAssetTask::bakeComplete, this, [this, assetPath](QString assetHash, QString assetPath, QVector<QString> outputFiles) {
            handleCompletedBake(assetPath, assetHash, outputFiles);
        });

        _bakingTaskPool.start(task.get());
    } else {
        qDebug() << "Already in queue";
    }
}

QString AssetServer::getPathToAssetHash(const AssetHash& assetHash) {
    return _filesDirectory.absoluteFilePath(assetHash);
}

void AssetServer::bakeAssets() {
    auto it = _fileMappings.cbegin();
    for (; it != _fileMappings.cend(); ++it) {
        auto path = it.key();
        auto hash = it.value().toString();
        maybeBake(path, hash);
    }
}

void AssetServer::maybeBake(const AssetPath& path, const AssetHash& hash) {
    if (needsToBeBaked(path, hash)) {
        qDebug() << "Queuing bake of: " << path;
        bakeAsset(hash, path, getPathToAssetHash(hash));
    }
}

void AssetServer::createEmptyMetaFile(const AssetHash& hash) {
    QString metaFilePath = "atp:/" + hash + "/meta.json";
    QFile metaFile { metaFilePath };
    
    if (!metaFile.exists()) {
        qDebug() << "Creating metfaile for " << hash;
        if (metaFile.open(QFile::WriteOnly)) {
            qDebug() << "Created metfaile for " << hash;
            metaFile.write("{}");
        }
    }
}

bool AssetServer::hasMetaFile(const AssetHash& hash) {
    QString metaFilePath = "/.baked/" + hash + "/meta.json";
    qDebug() << "in mappings?" << metaFilePath;

    return _fileMappings.contains(metaFilePath);
}

bool AssetServer::needsToBeBaked(const AssetPath& path, const AssetHash& assetHash) {
    if (path.startsWith("/.baked/")) {
        return false;
    }

    auto dotIndex = path.lastIndexOf(".");
    if (dotIndex == -1) {
        return false;
    }

    auto extension = path.mid(dotIndex + 1);

    QString bakedFilename;
    
    if (BAKEABLE_MODEL_EXTENSIONS.contains(extension)) {
        bakedFilename = BAKED_MODEL_SIMPLE_NAME;
    } else if (BAKEABLE_TEXTURE_EXTENSIONS.contains(extension.toLocal8Bit()) && hasMetaFile(assetHash)) {
        bakedFilename = BAKED_TEXTURE_SIMPLE_NAME;
    } else {
        return false;
    }

    auto bakedPath = "/.baked/" + assetHash + "/" + bakedFilename;
    return !_fileMappings.contains(bakedPath);
}

bool interfaceRunning() {
    bool result = false;

#ifdef Q_OS_WIN
    QSharedMemory sharedMemory { getInterfaceSharedMemoryName() };
    result = sharedMemory.attach(QSharedMemory::ReadOnly);
    if (result) {
        sharedMemory.detach();
    }
#endif
    return result;
}

void updateConsumedCores() {
    static bool wasInterfaceRunning = false;
    bool isInterfaceRunning = interfaceRunning();
    // If state is unchanged, return early
    if (isInterfaceRunning == wasInterfaceRunning) {
        return;
    }

    wasInterfaceRunning = isInterfaceRunning;
    auto coreCount = std::thread::hardware_concurrency();
    if (isInterfaceRunning) {
        coreCount = coreCount > MIN_CORES_FOR_MULTICORE ? CPU_AFFINITY_COUNT_HIGH : CPU_AFFINITY_COUNT_LOW;
    } 
    qCDebug(asset_server) << "Setting max consumed cores to " << coreCount;
    setMaxCores(coreCount);
}


AssetServer::AssetServer(ReceivedMessage& message) :
    ThreadedAssignment(message),
    _transferTaskPool(this),
    _bakingTaskPool(this)
{

    // Most of the work will be I/O bound, reading from disk and constructing packet objects,
    // so the ideal is greater than the number of cores on the system.
    static const int TASK_POOL_THREAD_COUNT = 50;
    _transferTaskPool.setMaxThreadCount(TASK_POOL_THREAD_COUNT);
    _bakingTaskPool.setMaxThreadCount(1);

    auto& packetReceiver = DependencyManager::get<NodeList>()->getPacketReceiver();
    packetReceiver.registerListener(PacketType::AssetGet, this, "handleAssetGet");
    packetReceiver.registerListener(PacketType::AssetGetInfo, this, "handleAssetGetInfo");
    packetReceiver.registerListener(PacketType::AssetUpload, this, "handleAssetUpload");
    packetReceiver.registerListener(PacketType::AssetMappingOperation, this, "handleAssetMappingOperation");
    
#ifdef Q_OS_WIN
    updateConsumedCores();
    QTimer* timer = new QTimer(this);
    auto timerConnection = connect(timer, &QTimer::timeout, [] {
        updateConsumedCores();
    });
    connect(qApp, &QCoreApplication::aboutToQuit, [this, timerConnection] {
        disconnect(timerConnection);
    });
    timer->setInterval(INTERFACE_RUNNING_CHECK_FREQUENCY_MS);
    timer->setTimerType(Qt::CoarseTimer);
    timer->start();
#endif
}

void AssetServer::run() {

    qCDebug(asset_server) << "Waiting for connection to domain to request settings from domain-server.";

    // wait until we have the domain-server settings, otherwise we bail
    DomainHandler& domainHandler = DependencyManager::get<NodeList>()->getDomainHandler();
    connect(&domainHandler, &DomainHandler::settingsReceived, this, &AssetServer::completeSetup);
    connect(&domainHandler, &DomainHandler::settingsReceiveFail, this, &AssetServer::domainSettingsRequestFailed);

    ThreadedAssignment::commonInit(ASSET_SERVER_LOGGING_TARGET_NAME, NodeType::AssetServer);
}

static const QString ASSET_FILES_SUBDIR = "files";

void AssetServer::completeSetup() {
    auto nodeList = DependencyManager::get<NodeList>();

    auto& domainHandler = nodeList->getDomainHandler();
    const QJsonObject& settingsObject = domainHandler.getSettingsObject();

    static const QString ASSET_SERVER_SETTINGS_KEY = "asset_server";

    if (!settingsObject.contains(ASSET_SERVER_SETTINGS_KEY)) {
        qCCritical(asset_server) << "Received settings from the domain-server with no asset-server section. Stopping assignment.";
        setFinished(true);
        return;
    }

    auto assetServerObject = settingsObject[ASSET_SERVER_SETTINGS_KEY].toObject();

    static const QString MAX_BANDWIDTH_OPTION = "max_bandwidth";
    auto maxBandwidthValue = assetServerObject[MAX_BANDWIDTH_OPTION];
    auto maxBandwidthFloat = maxBandwidthValue.toDouble(-1);

    if (maxBandwidthFloat > 0.0) {
        const int BITS_PER_MEGABITS = 1000 * 1000;
        int maxBandwidth = maxBandwidthFloat * BITS_PER_MEGABITS;
        nodeList->setConnectionMaxBandwidth(maxBandwidth);
        qCInfo(asset_server) << "Set maximum bandwith per connection to" << maxBandwidthFloat << "Mb/s."
                    " (" << maxBandwidth << "bits/s)";
    }

    // get the path to the asset folder from the domain server settings
    static const QString ASSETS_PATH_OPTION = "assets_path";
    auto assetsJSONValue = assetServerObject[ASSETS_PATH_OPTION];

    if (!assetsJSONValue.isString()) {
        qCCritical(asset_server) << "Received an assets path from the domain-server that could not be parsed. Stopping assignment.";
        setFinished(true);
        return;
    }

    auto assetsPathString = assetsJSONValue.toString();
    QDir assetsPath { assetsPathString };
    QString absoluteFilePath = assetsPath.absolutePath();

    if (assetsPath.isRelative()) {
        // if the domain settings passed us a relative path, make an absolute path that is relative to the
        // default data directory
        absoluteFilePath = PathUtils::getAppDataFilePath("assets/" + assetsPathString);
    }

    _resourcesDirectory = QDir(absoluteFilePath);

    qCDebug(asset_server) << "Creating resources directory";
    _resourcesDirectory.mkpath(".");
    _filesDirectory = _resourcesDirectory;

    if (!_resourcesDirectory.mkpath(ASSET_FILES_SUBDIR) || !_filesDirectory.cd(ASSET_FILES_SUBDIR)) {
        qCCritical(asset_server) << "Unable to create file directory for asset-server files. Stopping assignment.";
        setFinished(true);
        return;
    }

    // load whatever mappings we currently have from the local file
    if (loadMappingsFromFile()) {
        qCInfo(asset_server) << "Serving files from: " << _filesDirectory.path();

        // Check the asset directory to output some information about what we have
        auto files = _filesDirectory.entryList(QDir::Files);

        QRegExp hashFileRegex { ASSET_HASH_REGEX_STRING };
        auto hashedFiles = files.filter(hashFileRegex);

        qCInfo(asset_server) << "There are" << hashedFiles.size() << "asset files in the asset directory.";

        if (_fileMappings.count() > 0) {
            cleanupUnmappedFiles();
        }

        nodeList->addSetOfNodeTypesToNodeInterestSet({ NodeType::Agent, NodeType::EntityScriptServer });

        bakeAssets();
    } else {
        qCCritical(asset_server) << "Asset Server assignment will not continue because mapping file could not be loaded.";
        setFinished(true);
    }

    QRegExp hashFileRegex { "^[a-f0-9]{" + QString::number(SHA256_HASH_HEX_LENGTH) + "}" };
    auto files = _filesDirectory.entryInfoList(QDir::Files);
    for (auto& it = _fileMappings.cbegin(); it != _fileMappings.cend(); ++it) {
        AssetPath path = it.key();
        AssetHash hash = it.value().toString();
        if (_baker.assetNeedsBaking(path, hash)) {
            _baker.addPendingBake(hash);
        }
    }
}

void AssetServer::cleanupUnmappedFiles() {
    QRegExp hashFileRegex { "^[a-f0-9]{" + QString::number(SHA256_HASH_HEX_LENGTH) + "}" };

    auto files = _filesDirectory.entryInfoList(QDir::Files);

    // grab the currently mapped hashes
    auto mappedHashes = _fileMappings.values();

    qCInfo(asset_server) << "Performing unmapped asset cleanup.";

    for (const auto& fileInfo : files) {
        if (hashFileRegex.exactMatch(fileInfo.fileName())) {
            if (!mappedHashes.contains(fileInfo.fileName())) {
                // remove the unmapped file
                QFile removeableFile { fileInfo.absoluteFilePath() };

                if (removeableFile.remove()) {
                    qCDebug(asset_server) << "\tDeleted" << fileInfo.fileName() << "from asset files directory since it is unmapped.";
                } else {
                    qCDebug(asset_server) << "\tAttempt to delete unmapped file" << fileInfo.fileName() << "failed";
                }
            }
        }
    }
}

void AssetServer::handleAssetMappingOperation(QSharedPointer<ReceivedMessage> message, SharedNodePointer senderNode) {
    MessageID messageID;
    message->readPrimitive(&messageID);

    AssetMappingOperationType operationType;
    message->readPrimitive(&operationType);

    auto replyPacket = NLPacketList::create(PacketType::AssetMappingOperationReply, QByteArray(), true, true);
    replyPacket->writePrimitive(messageID);

    switch (operationType) {
        case AssetMappingOperationType::Get:
            handleGetMappingOperation(*message, senderNode, *replyPacket);
            break;
        case AssetMappingOperationType::GetAll:
            handleGetAllMappingOperation(*message, senderNode, *replyPacket);
            break;
        case AssetMappingOperationType::Set:
            handleSetMappingOperation(*message, senderNode, *replyPacket);
            break;
        case AssetMappingOperationType::Delete:
            handleDeleteMappingsOperation(*message, senderNode, *replyPacket);
            break;
        case AssetMappingOperationType::Rename:
            handleRenameMappingOperation(*message, senderNode, *replyPacket);
            break;
        case AssetMappingOperationType::SetBakingEnabled:
            handleSetBakingEnabledOperation(*message, senderNode, *replyPacket);
            break;
    }

    auto nodeList = DependencyManager::get<NodeList>();
    nodeList->sendPacketList(std::move(replyPacket), *senderNode);
}

void AssetServer::handleGetMappingOperation(ReceivedMessage& message, SharedNodePointer senderNode, NLPacketList& replyPacket) {
    QString assetPath = message.readString();

    QUrl url { assetPath };
    assetPath = url.path();

    auto it = _fileMappings.find(assetPath);
    if (it != _fileMappings.end()) {

        // check if we should re-direct to a baked asset

        // first, figure out from the mapping extension what type of file this is
        auto assetPathExtension = assetPath.mid(assetPath.lastIndexOf('.') + 1).toLower();
        QString bakedRootFile;

        if (BAKEABLE_MODEL_EXTENSIONS.contains(assetPathExtension)) {
            bakedRootFile = BAKED_MODEL_SIMPLE_NAME;
        } else if (BAKEABLE_TEXTURE_EXTENSIONS.contains(assetPathExtension.toLocal8Bit())) {
            bakedRootFile = BAKED_TEXTURE_SIMPLE_NAME;
        }
        qDebug() << bakedRootFile << assetPathExtension;
        
        auto originalAssetHash = it->toString();
        QString redirectedAssetHash;
        QString bakedAssetPath;
        quint8 wasRedirected = false;

        if (!bakedRootFile.isEmpty()) {
            // we ran into an asset for which we could have a baked version, let's check if it's ready
            bakedAssetPath = "/.baked/" + originalAssetHash + "/" + bakedRootFile;
            auto bakedIt = _fileMappings.find(bakedAssetPath);

            if (bakedIt != _fileMappings.end()) {
                qDebug() << "Did find baked version for: " << originalAssetHash << assetPath;
                // we found a baked version of the requested asset to serve, redirect to that
                redirectedAssetHash = bakedIt->toString();
                wasRedirected = true;
            } else {
                qDebug() << "Did not find baked version for: " << originalAssetHash << assetPath;
            }
        }

        replyPacket.writePrimitive(AssetServerError::NoError);

        if (wasRedirected) {
            qDebug() << "Writing re-directed hash for" << originalAssetHash << "to" << redirectedAssetHash;
            replyPacket.write(QByteArray::fromHex(redirectedAssetHash.toUtf8()));

            // add a flag saying that this mapping request was redirect
            replyPacket.writePrimitive(wasRedirected);

            // include the re-directed path in case the caller needs to make relative path requests for the baked asset
            replyPacket.writeString(bakedAssetPath);

        } else {
            replyPacket.write(QByteArray::fromHex(originalAssetHash.toUtf8()));
            replyPacket.writePrimitive(wasRedirected);


            auto query = QUrlQuery(url.query());
            bool isSkybox = query.hasQueryItem("skybox");
            qDebug() << "Is skybox? " << isSkybox;
            if (isSkybox) {
                createMetaFile(originalAssetHash);
                maybeBake(originalAssetHash, assetPath);
            }
        }
    } else {
        replyPacket.writePrimitive(AssetServerError::AssetNotFound);
    }
}

void AssetServer::handleGetAllMappingOperation(ReceivedMessage& message, SharedNodePointer senderNode, NLPacketList& replyPacket) {
    replyPacket.writePrimitive(AssetServerError::NoError);

    auto count = _fileMappings.size();

    replyPacket.writePrimitive(count);

    for (auto it = _fileMappings.cbegin(); it != _fileMappings.cend(); ++ it) {
        replyPacket.writeString(it.key());
        replyPacket.write(QByteArray::fromHex(it.value().toString().toUtf8()));
        replyPacket.writePrimitive(_baker.getAssetStatus(it.value().toString()));
    }
}

void AssetServer::handleSetMappingOperation(ReceivedMessage& message, SharedNodePointer senderNode, NLPacketList& replyPacket) {
    if (senderNode->getCanWriteToAssetServer()) {
        QString assetPath = message.readString();

        auto assetHash = message.read(SHA256_HASH_LENGTH).toHex();

        if (setMapping(assetPath, assetHash)) {
            replyPacket.writePrimitive(AssetServerError::NoError);
        } else {
            replyPacket.writePrimitive(AssetServerError::MappingOperationFailed);
        }
    } else {
        replyPacket.writePrimitive(AssetServerError::PermissionDenied);
    }
}

void AssetServer::handleDeleteMappingsOperation(ReceivedMessage& message, SharedNodePointer senderNode, NLPacketList& replyPacket) {
    if (senderNode->getCanWriteToAssetServer()) {
        int numberOfDeletedMappings { 0 };
        message.readPrimitive(&numberOfDeletedMappings);

        QStringList mappingsToDelete;

        for (int i = 0; i < numberOfDeletedMappings; ++i) {
            mappingsToDelete << message.readString();
        }

        if (deleteMappings(mappingsToDelete)) {
            replyPacket.writePrimitive(AssetServerError::NoError);
        } else {
            replyPacket.writePrimitive(AssetServerError::MappingOperationFailed);
        }
    } else {
        replyPacket.writePrimitive(AssetServerError::PermissionDenied);
    }
}

void AssetServer::handleRenameMappingOperation(ReceivedMessage& message, SharedNodePointer senderNode, NLPacketList& replyPacket) {
    if (senderNode->getCanWriteToAssetServer()) {
        QString oldPath = message.readString();
        QString newPath = message.readString();

        if (renameMapping(oldPath, newPath)) {
            replyPacket.writePrimitive(AssetServerError::NoError);
        } else {
            replyPacket.writePrimitive(AssetServerError::MappingOperationFailed);
        }
    } else {
        replyPacket.writePrimitive(AssetServerError::PermissionDenied);
    }
}

void AssetServer::handleSetBakingEnabledOperation(ReceivedMessage& message, SharedNodePointer senderNode, NLPacketList& replyPacket) {
    if (senderNode->getCanWriteToAssetServer()) {
        bool enabled { true };
        message.readPrimitive(&enabled);

        int numberOfMappings{ 0 };
        message.readPrimitive(&numberOfMappings);

        QStringList mappings;

        for (int i = 0; i < numberOfMappings; ++i) {
            mappings << message.readString();
        }

        if (setBakingEnabled(mappings, enabled)) {
            replyPacket.writePrimitive(AssetServerError::NoError);
        } else {
            replyPacket.writePrimitive(AssetServerError::MappingOperationFailed);
        }
    } else {
        replyPacket.writePrimitive(AssetServerError::PermissionDenied);
    }
}

void AssetServer::handleAssetGetInfo(QSharedPointer<ReceivedMessage> message, SharedNodePointer senderNode) {
    QByteArray assetHash;
    MessageID messageID;

    if (message->getSize() < qint64(SHA256_HASH_LENGTH + sizeof(messageID))) {
        qCDebug(asset_server) << "ERROR bad file request";
        return;
    }

    message->readPrimitive(&messageID);
    assetHash = message->readWithoutCopy(SHA256_HASH_LENGTH);

    auto size = qint64(sizeof(MessageID) + SHA256_HASH_LENGTH + sizeof(AssetServerError) + sizeof(qint64));
    auto replyPacket = NLPacket::create(PacketType::AssetGetInfoReply, size, true);

    QByteArray hexHash = assetHash.toHex();

    replyPacket->writePrimitive(messageID);
    replyPacket->write(assetHash);

    QString fileName = QString(hexHash);
    QFileInfo fileInfo { _filesDirectory.filePath(fileName) };

    if (fileInfo.exists() && fileInfo.isReadable()) {
        qCDebug(asset_server) << "Opening file: " << fileInfo.filePath();
        replyPacket->writePrimitive(AssetServerError::NoError);
        replyPacket->writePrimitive(fileInfo.size());
    } else {
        qCDebug(asset_server) << "Asset not found: " << QString(hexHash);
        replyPacket->writePrimitive(AssetServerError::AssetNotFound);
    }

    auto nodeList = DependencyManager::get<NodeList>();
    nodeList->sendPacket(std::move(replyPacket), *senderNode);
}

void AssetServer::handleAssetGet(QSharedPointer<ReceivedMessage> message, SharedNodePointer senderNode) {

    auto minSize = qint64(sizeof(MessageID) + SHA256_HASH_LENGTH + sizeof(DataOffset) + sizeof(DataOffset));

    if (message->getSize() < minSize) {
        qCDebug(asset_server) << "ERROR bad file request";
        return;
    }

    // Queue task
    auto task = new SendAssetTask(message, senderNode, _filesDirectory);
    _transferTaskPool.start(task);
}

void AssetServer::handleAssetUpload(QSharedPointer<ReceivedMessage> message, SharedNodePointer senderNode) {

    if (senderNode->getCanWriteToAssetServer()) {
        qCDebug(asset_server) << "Starting an UploadAssetTask for upload from" << uuidStringWithoutCurlyBraces(senderNode->getUUID());

        auto task = new UploadAssetTask(message, senderNode, _filesDirectory);
        _transferTaskPool.start(task);
    } else {
        // this is a node the domain told us is not allowed to rez entities
        // for now this also means it isn't allowed to add assets
        // so return a packet with error that indicates that

        auto permissionErrorPacket = NLPacket::create(PacketType::AssetUploadReply, sizeof(MessageID) + sizeof(AssetServerError), true);

        MessageID messageID;
        message->readPrimitive(&messageID);

        // write the message ID and a permission denied error
        permissionErrorPacket->writePrimitive(messageID);
        permissionErrorPacket->writePrimitive(AssetServerError::PermissionDenied);

        // send off the packet
        auto nodeList = DependencyManager::get<NodeList>();
        nodeList->sendPacket(std::move(permissionErrorPacket), *senderNode);
    }
}

void AssetServer::sendStatsPacket() {
    QJsonObject serverStats;

    auto stats = DependencyManager::get<NodeList>()->sampleStatsForAllConnections();

    for (const auto& stat : stats) {
        QJsonObject nodeStats;
        auto endTimeMs = std::chrono::duration_cast<std::chrono::milliseconds>(stat.second.endTime);
        QDateTime date = QDateTime::fromMSecsSinceEpoch(endTimeMs.count());

        static const float USEC_PER_SEC = 1000000.0f;
        static const float MEGABITS_PER_BYTE = 8.0f / 1000000.0f; // Bytes => Mbits
        float elapsed = (float)(stat.second.endTime - stat.second.startTime).count() / USEC_PER_SEC; // sec
        float megabitsPerSecPerByte = MEGABITS_PER_BYTE / elapsed; // Bytes => Mb/s

        QJsonObject connectionStats;
        connectionStats["1. Last Heard"] = date.toString();
        connectionStats["2. Est. Max (P/s)"] = stat.second.estimatedBandwith;
        connectionStats["3. RTT (ms)"] = stat.second.rtt;
        connectionStats["4. CW (P)"] = stat.second.congestionWindowSize;
        connectionStats["5. Period (us)"] = stat.second.packetSendPeriod;
        connectionStats["6. Up (Mb/s)"] = stat.second.sentBytes * megabitsPerSecPerByte;
        connectionStats["7. Down (Mb/s)"] = stat.second.receivedBytes * megabitsPerSecPerByte;
        nodeStats["Connection Stats"] = connectionStats;

        using Events = udt::ConnectionStats::Stats::Event;
        const auto& events = stat.second.events;

        QJsonObject upstreamStats;
        upstreamStats["1. Sent (P/s)"] = stat.second.sendRate;
        upstreamStats["2. Sent Packets"] = stat.second.sentPackets;
        upstreamStats["3. Recvd ACK"] = events[Events::ReceivedACK];
        upstreamStats["4. Procd ACK"] = events[Events::ProcessedACK];
        upstreamStats["5. Recvd LACK"] = events[Events::ReceivedLightACK];
        upstreamStats["6. Recvd NAK"] = events[Events::ReceivedNAK];
        upstreamStats["7. Recvd TNAK"] = events[Events::ReceivedTimeoutNAK];
        upstreamStats["8. Sent ACK2"] = events[Events::SentACK2];
        upstreamStats["9. Retransmitted"] = events[Events::Retransmission];
        nodeStats["Upstream Stats"] = upstreamStats;

        QJsonObject downstreamStats;
        downstreamStats["1. Recvd (P/s)"] = stat.second.receiveRate;
        downstreamStats["2. Recvd Packets"] = stat.second.receivedPackets;
        downstreamStats["3. Sent ACK"] = events[Events::SentACK];
        downstreamStats["4. Sent LACK"] = events[Events::SentLightACK];
        downstreamStats["5. Sent NAK"] = events[Events::SentNAK];
        downstreamStats["6. Sent TNAK"] = events[Events::SentTimeoutNAK];
        downstreamStats["7. Recvd ACK2"] = events[Events::ReceivedACK2];
        downstreamStats["8. Duplicates"] = events[Events::Duplicate];
        nodeStats["Downstream Stats"] = downstreamStats;

        QString uuid;
        auto nodelist = DependencyManager::get<NodeList>();
        if (stat.first == nodelist->getDomainHandler().getSockAddr()) {
            uuid = uuidStringWithoutCurlyBraces(nodelist->getDomainHandler().getUUID());
            nodeStats[USERNAME_UUID_REPLACEMENT_STATS_KEY] = "DomainServer";
        } else {
            auto node = nodelist->findNodeWithAddr(stat.first);
            uuid = uuidStringWithoutCurlyBraces(node ? node->getUUID() : QUuid());
            nodeStats[USERNAME_UUID_REPLACEMENT_STATS_KEY] = uuid;
        }

        serverStats[uuid] = nodeStats;
    }

    // send off the stats packets
    ThreadedAssignment::addPacketStatsAndSendStatsPacket(serverStats);
}

static const QString MAP_FILE_NAME = "map.json";

bool AssetServer::loadMappingsFromFile() {

    auto mapFilePath = _resourcesDirectory.absoluteFilePath(MAP_FILE_NAME);

    QFile mapFile { mapFilePath };
    if (mapFile.exists()) {
        if (mapFile.open(QIODevice::ReadOnly)) {
            QJsonParseError error;

            auto jsonDocument = QJsonDocument::fromJson(mapFile.readAll(), &error);

            if (error.error == QJsonParseError::NoError) {
                _fileMappings = jsonDocument.object().toVariantHash();

                // remove any mappings that don't match the expected format
                auto it = _fileMappings.begin();
                while (it != _fileMappings.end()) {
                    bool shouldDrop = false;

                    if (!isValidFilePath(it.key())) {
                        qCWarning(asset_server) << "Will not keep mapping for" << it.key() << "since it is not a valid path.";
                        shouldDrop = true;
                    }

                    if (!isValidHash(it.value().toString())) {
                        qCWarning(asset_server) << "Will not keep mapping for" << it.key() << "since it does not have a valid hash.";
                        shouldDrop = true;
                    }

                    if (shouldDrop) {
                        it = _fileMappings.erase(it);
                    } else {
                        ++it;
                    }
                }

                qCInfo(asset_server) << "Loaded" << _fileMappings.count() << "mappings from map file at" << mapFilePath;
                return true;
            }
        }

        qCCritical(asset_server) << "Failed to read mapping file at" << mapFilePath;
        return false;
    } else {
        qCInfo(asset_server) << "No existing mappings loaded from file since no file was found at" << mapFilePath;
    }

    return true;
}

bool AssetServer::writeMappingsToFile() {
    auto mapFilePath = _resourcesDirectory.absoluteFilePath(MAP_FILE_NAME);

    QFile mapFile { mapFilePath };
    if (mapFile.open(QIODevice::WriteOnly)) {
        auto jsonObject = QJsonObject::fromVariantHash(_fileMappings);
        QJsonDocument jsonDocument { jsonObject };

        if (mapFile.write(jsonDocument.toJson()) != -1) {
            qCDebug(asset_server) << "Wrote JSON mappings to file at" << mapFilePath;
            return true;
        } else {
            qCWarning(asset_server) << "Failed to write JSON mappings to file at" << mapFilePath;
        }
    } else {
        qCWarning(asset_server) << "Failed to open map file at" << mapFilePath;
    }

    return false;
}

bool AssetServer::setMapping(AssetPath path, AssetHash hash) {
    path = path.trimmed();

    if (!isValidFilePath(path)) {
        qCWarning(asset_server) << "Cannot set a mapping for invalid path:" << path << "=>" << hash;
        return false;
    }

    if (!isValidHash(hash)) {
        qCWarning(asset_server) << "Cannot set a mapping for invalid hash" << path << "=>" << hash;
        return false;
    }

    // remember what the old mapping was in case persistence fails
    auto oldMapping = _fileMappings.value(path).toString();

    // update the in memory QHash
    _fileMappings[path] = hash;

    // attempt to write to file
    if (writeMappingsToFile()) {
        // persistence succeeded, we are good to go
        qCDebug(asset_server) << "Set mapping:" << path << "=>" << hash;
        maybeBake(path, hash);
        return true;
    } else {
        // failed to persist this mapping to file - put back the old one in our in-memory representation
        if (oldMapping.isEmpty()) {
            _fileMappings.remove(path);
        } else {
            _fileMappings[path] = oldMapping;
        }

        qCWarning(asset_server) << "Failed to persist mapping:" << path << "=>" << hash;

        return false;
    }
}

bool pathIsFolder(const AssetPath& path) {
    return path.endsWith('/');
}

bool AssetServer::deleteMappings(AssetPathList& paths) {
    // take a copy of the current mappings in case persistence of these deletes fails
    auto oldMappings = _fileMappings;

    QSet<QString> hashesToCheckForDeletion;

    // enumerate the paths to delete and remove them all
    for (auto& path : paths) {

        path = path.trimmed();

        // figure out if this path will delete a file or folder
        if (pathIsFolder(path)) {
            // enumerate the in memory file mappings and remove anything that matches
            auto it = _fileMappings.begin();
            auto sizeBefore = _fileMappings.size();

            while (it != _fileMappings.end()) {
                if (it.key().startsWith(path)) {
                    // add this hash to the list we need to check for asset removal from the server
                    hashesToCheckForDeletion << it.value().toString();

                    it = _fileMappings.erase(it);
                } else {
                    ++it;
                }
            }

            auto sizeNow = _fileMappings.size();
            if (sizeBefore != sizeNow) {
                qCDebug(asset_server) << "Deleted" << sizeBefore - sizeNow << "mappings in folder: " << path;
            } else {
                qCDebug(asset_server) << "Did not find any mappings to delete in folder:" << path;
            }

        } else {
            auto oldMapping = _fileMappings.take(path);
            if (!oldMapping.isNull()) {
                // add this hash to the list we need to check for asset removal from server
                hashesToCheckForDeletion << oldMapping.toString();

                qCDebug(asset_server) << "Deleted a mapping:" << path << "=>" << oldMapping.toString();
            } else {
                qCDebug(asset_server) << "Unable to delete a mapping that was not found:" << path;
            }
        }
    }

    // deleted the old mappings, attempt to persist to file
    if (writeMappingsToFile()) {
        // persistence succeeded we are good to go

        // grab the current mapped hashes
        auto mappedHashes = _fileMappings.values();

        // enumerate the mapped hashes and clear the list of hashes to check for anything that's present
        for (auto& hashVariant : mappedHashes) {
            auto it = hashesToCheckForDeletion.find(hashVariant.toString());
            if (it != hashesToCheckForDeletion.end()) {
                hashesToCheckForDeletion.erase(it);
            }
        }

        // we now have a set of hashes that are unmapped - we will delete those asset files
        for (auto& hash : hashesToCheckForDeletion) {
            // remove the unmapped file
            QFile removeableFile { _filesDirectory.absoluteFilePath(hash) };

            if (removeableFile.remove()) {
                qCDebug(asset_server) << "\tDeleted" << hash << "from asset files directory since it is now unmapped.";
            } else {
                qCDebug(asset_server) << "\tAttempt to delete unmapped file" << hash << "failed";
            }
        }

        return true;
    } else {
        qCWarning(asset_server) << "Failed to persist deleted mappings, rolling back";

        // we didn't delete the previous mapping, put it back in our in-memory representation
        _fileMappings = oldMappings;

        return false;
    }
}

bool AssetServer::renameMapping(AssetPath oldPath, AssetPath newPath) {
    oldPath = oldPath.trimmed();
    newPath = newPath.trimmed();

    if (!isValidFilePath(oldPath) || !isValidFilePath(newPath)) {
        qCWarning(asset_server) << "Cannot perform rename with invalid paths - both should have leading forward and no ending slashes:"
            << oldPath << "=>" << newPath;

        return false;
    }

    // figure out if this rename is for a file or folder
    if (pathIsFolder(oldPath)) {
        if (!pathIsFolder(newPath)) {
            // we were asked to rename a path to a folder to a path that isn't a folder, this is a fail
            qCWarning(asset_server) << "Cannot rename mapping from folder path" << oldPath << "to file path" << newPath;

            return false;
        }

        // take a copy of the old mappings
        auto oldMappings = _fileMappings;

        // iterate the current mappings and adjust any that matches the renamed folder
        auto it = oldMappings.begin();

        while (it != oldMappings.end()) {
            if (it.key().startsWith(oldPath)) {
                auto newKey = it.key();
                newKey.replace(0, oldPath.size(), newPath);

                // remove the old version from the in memory file mappings
                _fileMappings.remove(it.key());
                _fileMappings.insert(newKey, it.value());
            }

            ++it;
        }

        if (writeMappingsToFile()) {
            // persisted the changed mappings, return success
            qCDebug(asset_server) << "Renamed folder mapping:" << oldPath << "=>" << newPath;

            return true;
        } else {
            // couldn't persist the renamed paths, rollback and return failure
            _fileMappings = oldMappings;

            qCWarning(asset_server) << "Failed to persist renamed folder mapping:" << oldPath << "=>" << newPath;

            return false;
        }
    } else {
        if (pathIsFolder(newPath)) {
            // we were asked to rename a path to a file to a path that is a folder, this is a fail
            qCWarning(asset_server) << "Cannot rename mapping from file path" << oldPath << "to folder path" << newPath;

            return false;
        }

        // take the old hash to remove the old mapping
        auto oldSourceMapping = _fileMappings.take(oldPath).toString();

        // in case we're overwriting, keep the current destination mapping for potential rollback
        auto oldDestinationMapping = _fileMappings.value(newPath);

        if (!oldSourceMapping.isEmpty()) {
            _fileMappings[newPath] = oldSourceMapping;

            if (writeMappingsToFile()) {
                // persisted the renamed mapping, return success
                qCDebug(asset_server) << "Renamed mapping:" << oldPath << "=>" << newPath;

                return true;
            } else {
                // we couldn't persist the renamed mapping, rollback and return failure
                _fileMappings[oldPath] = oldSourceMapping;

                if (!oldDestinationMapping.isNull()) {
                    // put back the overwritten mapping for the destination path
                    _fileMappings[newPath] = oldDestinationMapping.toString();
                } else {
                    // clear the new mapping
                    _fileMappings.remove(newPath);
                }

                qCDebug(asset_server) << "Failed to persist renamed mapping:" << oldPath << "=>" << newPath;

                return false;
            }
        } else {
            // failed to find a mapping that was to be renamed, return failure
            return false;
        }
    }
}

static const QString HIDDEN_BAKED_CONTENT_FOLDER = "/.baked/";

void AssetServer::handleCompletedBake(AssetPath originalAssetPath, AssetHash originalAssetHash, QVector<QString> bakedFilePaths) {
    bool errorCompletingBake { false };

    qDebug() << "Completing bake for " << originalAssetHash;

    for (auto& filePath: bakedFilePaths) {
        // figure out the hash for the contents of this file
        QFile file(filePath);

        qDebug() << "File path: " << filePath;

        AssetHash bakedFileHash;

        if (file.open(QIODevice::ReadOnly)) {
            QCryptographicHash hasher(QCryptographicHash::Sha256);

            if (hasher.addData(&file)) {
                bakedFileHash = hasher.result().toHex();
            } else {
                // stop handling this bake, couldn't hash the contents of the file
                errorCompletingBake = true;
                break;
            }

            // first check that we don't already have this bake file in our list
            auto bakeFileDestination = _filesDirectory.absoluteFilePath(bakedFileHash);
            if (!QFile::exists(bakeFileDestination)) {
                // copy each to our files folder (with the hash as their filename)
                if (!file.copy(_filesDirectory.absoluteFilePath(bakedFileHash))) {
                    // stop handling this bake, couldn't copy the bake file into our files directory
                    errorCompletingBake = true;
                    break;
                }
            }

            // setup the mapping for this bake file
            auto relativeFilePath = QUrl(filePath).fileName();
            qDebug() << "Relative file path is: " << relativeFilePath;
            static const QString BAKED_ASSET_SIMPLE_FBX_NAME = "asset.fbx";
            static const QString BAKED_ASSET_SIMPLE_TEXTURE_NAME = "texture.ktx";

            if (relativeFilePath.endsWith(".fbx", Qt::CaseInsensitive)) {
                // for an FBX file, we replace the filename with the simple name
                // (to handle the case where two mapped assets have the same hash but different names)
                relativeFilePath = BAKED_ASSET_SIMPLE_FBX_NAME;
            } else if (!originalAssetPath.endsWith(".fbx")) {
                relativeFilePath = BAKED_ASSET_SIMPLE_TEXTURE_NAME;

            }

            QString bakeMapping = HIDDEN_BAKED_CONTENT_FOLDER + originalAssetHash + "/" + relativeFilePath;

            // add a mapping (under the hidden baked folder) for this file resulting from the bake
            if (setMapping(bakeMapping, bakedFileHash)) {
                qDebug() << "Added" << bakeMapping << "for bake file" << bakedFileHash << "from bake of" << originalAssetHash;
            } else {
                qDebug() << "Failed to set mapping";
                // stop handling this bake, couldn't add a mapping for this bake file
                errorCompletingBake = true;
                break;
            }
        } else {
            qDebug() << "Failed to open baked file: " << filePath;
            // stop handling this bake, we couldn't open one of the files for reading
            errorCompletingBake = true;
            break;
        }
    }

    if (!errorCompletingBake) {
        // create the meta file to store which version of the baking process we just completed
        createMetaFile(originalAssetHash);
    } else {
        qWarning() << "Could not complete bake for" << originalAssetHash;
    }
}

bool AssetServer::createMetaFile(AssetHash originalAssetHash) {
    // construct the JSON that will be in the meta file
    QJsonObject metaFileObject;

    static const int BAKE_VERSION = 1;
    static const QString VERSION_KEY = "version";

    metaFileObject[VERSION_KEY] = BAKE_VERSION;

    QJsonDocument metaFileDoc;
    metaFileDoc.setObject(metaFileObject);

    auto metaFileJSON = metaFileDoc.toJson();

    // get a hash for the contents of the meta-file
    AssetHash metaFileHash = QCryptographicHash::hash(metaFileJSON, QCryptographicHash::Sha256).toHex();

    // create the meta file in our files folder, named by the hash of its contents
    QFile metaFile(_filesDirectory.absoluteFilePath(metaFileHash));

    if (metaFile.open(QIODevice::WriteOnly)) {
        metaFile.write(metaFileJSON);
        metaFile.close();

        // add a mapping to the meta file so it doesn't get deleted because it is unmapped
        auto metaFileMapping = HIDDEN_BAKED_CONTENT_FOLDER + originalAssetHash + "/" + "meta.json";

        return setMapping(metaFileMapping, metaFileHash);
    } else {
        return false;
    }

bool AssetServer::setBakingEnabled(AssetPathList& paths, bool enabled) {
    return "test";
}