//
//  OctreeEditPacketSender.cpp
//  interface
//
//  Created by Brad Hefta-Gaub on 8/12/13.
//  Copyright (c) 2013 High Fidelity, Inc. All rights reserved.
//
//  Threaded or non-threaded packet Sender for the Application
//

#include <assert.h>

#include <PerfStat.h>

#include <OctalCode.h>
#include <PacketHeaders.h>
#include "OctreeEditPacketSender.h"


EditPacketBuffer::EditPacketBuffer(PacketType type, unsigned char* buffer, ssize_t length, QUuid nodeUUID) {
    _nodeUUID = nodeUUID;
    _currentType = type;
    _currentSize = length;
    memcpy(_currentBuffer, buffer, length);
};

const int OctreeEditPacketSender::DEFAULT_MAX_PENDING_MESSAGES = PacketSender::DEFAULT_PACKETS_PER_SECOND;


OctreeEditPacketSender::OctreeEditPacketSender() :
    PacketSender(),
    _shouldSend(true),
    _maxPendingMessages(DEFAULT_MAX_PENDING_MESSAGES),
    _releaseQueuedMessagesPending(false),
    _serverJurisdictions(NULL),
    _sequenceNumber(0),
    _maxPacketSize(MAX_PACKET_SIZE) {
    //printf("OctreeEditPacketSender::OctreeEditPacketSender() [%p] created... \n", this);
}

OctreeEditPacketSender::~OctreeEditPacketSender() {
    _pendingPacketsLock.lock();
    while (!_preServerSingleMessagePackets.empty()) {
        EditPacketBuffer* packet = _preServerSingleMessagePackets.front();
        delete packet;
        _preServerSingleMessagePackets.erase(_preServerSingleMessagePackets.begin());
    }
    while (!_preServerPackets.empty()) {
        EditPacketBuffer* packet = _preServerPackets.front();
        delete packet;
        _preServerPackets.erase(_preServerPackets.begin());
    }
    _pendingPacketsLock.unlock();
    //printf("OctreeEditPacketSender::~OctreeEditPacketSender() [%p] destroyed... \n", this);
}


bool OctreeEditPacketSender::serversExist() const {
    bool hasServers = false;
    bool atLeastOnJurisdictionMissing = false; // assume the best
    NodeList* nodeList = NodeList::getInstance();

    foreach (const SharedNodePointer& node, nodeList->getNodeHash()) {
        // only send to the NodeTypes that are getMyNodeType()
        if (node->getType() == getMyNodeType() &&  node->getActiveSocket()) {
            QUuid nodeUUID = node->getUUID();
            // If we've got Jurisdictions set, then check to see if we know the jurisdiction for this server
            if (_serverJurisdictions) {
                // lookup our nodeUUID in the jurisdiction map, if it's missing then we're
                // missing at least one jurisdiction
                if ((*_serverJurisdictions).find(nodeUUID) == (*_serverJurisdictions).end()) {
                    atLeastOnJurisdictionMissing = true;
                }
            }
            hasServers = true;
        }
        if (atLeastOnJurisdictionMissing) {
            break; // no point in looking further...
        }
    }

    return (hasServers && !atLeastOnJurisdictionMissing);
}

// This method is called when the edit packet layer has determined that it has a fully formed packet destined for
// a known nodeID.
void OctreeEditPacketSender::queuePacketToNode(const QUuid& nodeUUID, unsigned char* buffer, ssize_t length) {
    NodeList* nodeList = NodeList::getInstance();

    foreach (const SharedNodePointer& node, nodeList->getNodeHash()) {
        // only send to the NodeTypes that are getMyNodeType()
        if (node->getType() == getMyNodeType() &&
            ((node->getUUID() == nodeUUID) || (nodeUUID.isNull()))) {
            if (node->getActiveSocket()) {
                queuePacketForSending(node, QByteArray(reinterpret_cast<char*>(buffer), length));

                // debugging output...
                bool wantDebugging = false;
                if (wantDebugging) {
                    int numBytesPacketHeader = numBytesForPacketHeader(reinterpret_cast<char*>(buffer));
                    unsigned short int sequence = (*((unsigned short int*)(buffer + numBytesPacketHeader)));
                    quint64 createdAt = (*((quint64*)(buffer + numBytesPacketHeader + sizeof(sequence))));
                    quint64 queuedAt = usecTimestampNow();
                    quint64 transitTime = queuedAt - createdAt;

                    qDebug() << "OctreeEditPacketSender::queuePacketToNode() queued " << buffer[0] <<
                            " - command to node bytes=" << length <<
                            " sequence=" << sequence <<
                            " transitTimeSoFar=" << transitTime << " usecs";
                }
            }
        }
    }
}

void OctreeEditPacketSender::processPreServerExistsPackets() {
    assert(serversExist()); // we should only be here if we have jurisdictions

    // First send out all the single message packets...
    _pendingPacketsLock.lock();
    while (!_preServerSingleMessagePackets.empty()) {
        EditPacketBuffer* packet = _preServerSingleMessagePackets.front();
        queuePacketToNodes(&packet->_currentBuffer[0], packet->_currentSize);
        delete packet;
        _preServerSingleMessagePackets.erase(_preServerSingleMessagePackets.begin());
    }

    // Then "process" all the packable messages...
    while (!_preServerPackets.empty()) {
        EditPacketBuffer* packet = _preServerPackets.front();
        queueOctreeEditMessage(packet->_currentType, &packet->_currentBuffer[0], packet->_currentSize);
        delete packet;
        _preServerPackets.erase(_preServerPackets.begin());
    }
    _pendingPacketsLock.unlock();

    // if while waiting for the jurisdictions the caller called releaseQueuedMessages()
    // then we want to honor that request now.
    if (_releaseQueuedMessagesPending) {
        releaseQueuedMessages();
        _releaseQueuedMessagesPending = false;
    }
}

void OctreeEditPacketSender::queuePendingPacketToNodes(PacketType type, unsigned char* buffer, ssize_t length) {
    // If we're asked to save messages while waiting for voxel servers to arrive, then do so...

    if (_maxPendingMessages > 0) {
        EditPacketBuffer* packet = new EditPacketBuffer(type, buffer, length);
        _pendingPacketsLock.lock();
        _preServerSingleMessagePackets.push_back(packet);
        // if we've saved MORE than our max, then clear out the oldest packet...
        int allPendingMessages = _preServerSingleMessagePackets.size() + _preServerPackets.size();
        if (allPendingMessages > _maxPendingMessages) {
            EditPacketBuffer* packet = _preServerSingleMessagePackets.front();
            delete packet;
            _preServerSingleMessagePackets.erase(_preServerSingleMessagePackets.begin());
        }
        _pendingPacketsLock.unlock();
    }
}

void OctreeEditPacketSender::queuePacketToNodes(unsigned char* buffer, ssize_t length) {
    if (!_shouldSend) {
        return; // bail early
    }

    assert(serversExist()); // we must have jurisdictions to be here!!

    int headerBytes = numBytesForPacketHeader(reinterpret_cast<char*>(buffer)) + sizeof(short) + sizeof(quint64);
    unsigned char* octCode = buffer + headerBytes; // skip the packet header to get to the octcode

    // We want to filter out edit messages for servers based on the server's Jurisdiction
    // But we can't really do that with a packed message, since each edit message could be destined
    // for a different server... So we need to actually manage multiple queued packets... one
    // for each server

    foreach (const SharedNodePointer& node, NodeList::getInstance()->getNodeHash()) {
        // only send to the NodeTypes that are getMyNodeType()
        if (node->getActiveSocket() && node->getType() == getMyNodeType()) {
            QUuid nodeUUID = node->getUUID();
            bool isMyJurisdiction = true;
            // we need to get the jurisdiction for this
            // here we need to get the "pending packet" for this server
            const JurisdictionMap& map = (*_serverJurisdictions)[nodeUUID];
            isMyJurisdiction = (map.isMyJurisdiction(octCode, CHECK_NODE_ONLY) == JurisdictionMap::WITHIN);
            if (isMyJurisdiction) {
                queuePacketToNode(nodeUUID, buffer, length);
            }
        }
    }
}


// NOTE: codeColorBuffer - is JUST the octcode/color and does not contain the packet header!
void OctreeEditPacketSender::queueOctreeEditMessage(PacketType type, unsigned char* codeColorBuffer, ssize_t length) {

    if (!_shouldSend) {
        return; // bail early
    }

    // If we don't have jurisdictions, then we will simply queue up all of these packets and wait till we have
    // jurisdictions for processing
    if (!serversExist()) {
        if (_maxPendingMessages > 0) {
            EditPacketBuffer* packet = new EditPacketBuffer(type, codeColorBuffer, length);
            _pendingPacketsLock.lock();
            _preServerPackets.push_back(packet);

            // if we've saved MORE than out max, then clear out the oldest packet...
            int allPendingMessages = _preServerSingleMessagePackets.size() + _preServerPackets.size();
            if (allPendingMessages > _maxPendingMessages) {
                EditPacketBuffer* packet = _preServerPackets.front();
                delete packet;
                _preServerPackets.erase(_preServerPackets.begin());
            }
            _pendingPacketsLock.unlock();
    }
        return; // bail early
    }

    // We want to filter out edit messages for servers based on the server's Jurisdiction
    // But we can't really do that with a packed message, since each edit message could be destined
    // for a different server... So we need to actually manage multiple queued packets... one
    // for each server

    foreach (const SharedNodePointer& node, NodeList::getInstance()->getNodeHash()) {
        // only send to the NodeTypes that are getMyNodeType()
        if (node->getActiveSocket() && node->getType() == getMyNodeType()) {
            QUuid nodeUUID = node->getUUID();
            bool isMyJurisdiction = true;

            if (_serverJurisdictions) {
                // we need to get the jurisdiction for this
                // here we need to get the "pending packet" for this server
                if ((*_serverJurisdictions).find(nodeUUID) != (*_serverJurisdictions).end()) {
                    const JurisdictionMap& map = (*_serverJurisdictions)[nodeUUID];
                    isMyJurisdiction = (map.isMyJurisdiction(codeColorBuffer, CHECK_NODE_ONLY) == JurisdictionMap::WITHIN);
                } else {
                    isMyJurisdiction = false;
                }
            }
            if (isMyJurisdiction) {
                EditPacketBuffer& packetBuffer = _pendingEditPackets[nodeUUID];
                packetBuffer._nodeUUID = nodeUUID;

                // If we're switching type, then we send the last one and start over
                if ((type != packetBuffer._currentType && packetBuffer._currentSize > 0) ||
                    (packetBuffer._currentSize + length >= _maxPacketSize)) {
                    releaseQueuedPacket(packetBuffer);
                    initializePacket(packetBuffer, type);
                }

                // If the buffer is empty and not correctly initialized for our type...
                if (type != packetBuffer._currentType && packetBuffer._currentSize == 0) {
                    initializePacket(packetBuffer, type);
                }

                // This is really the first time we know which server/node this particular edit message
                // is going to, so we couldn't adjust for clock skew till now. But here's our chance.
                // We call this virtual function that allows our specific type of EditPacketSender to
                // fixup the buffer for any clock skew
                if (node->getClockSkewUsec() != 0) {
                    adjustEditPacketForClockSkew(codeColorBuffer, length, node->getClockSkewUsec());
                }

                memcpy(&packetBuffer._currentBuffer[packetBuffer._currentSize], codeColorBuffer, length);
                packetBuffer._currentSize += length;
            }
        }
    }
}

void OctreeEditPacketSender::releaseQueuedMessages() {
    // if we don't yet have jurisdictions then we can't actually release messages yet because we don't
    // know where to send them to. Instead, just remember this request and when we eventually get jurisdictions
    // call release again at that time.
    if (!serversExist()) {
        _releaseQueuedMessagesPending = true;
    } else {
        for (std::map<QUuid, EditPacketBuffer>::iterator i = _pendingEditPackets.begin(); i != _pendingEditPackets.end(); i++) {
            releaseQueuedPacket(i->second);
        }
    }
}

void OctreeEditPacketSender::releaseQueuedPacket(EditPacketBuffer& packetBuffer) {
    if (packetBuffer._currentSize > 0 && packetBuffer._currentType != PacketTypeUnknown) {
        queuePacketToNode(packetBuffer._nodeUUID, &packetBuffer._currentBuffer[0], packetBuffer._currentSize);
    }
    packetBuffer._currentSize = 0;
    packetBuffer._currentType = PacketTypeUnknown;
}

void OctreeEditPacketSender::initializePacket(EditPacketBuffer& packetBuffer, PacketType type) {
    packetBuffer._currentSize = populatePacketHeader(reinterpret_cast<char*>(&packetBuffer._currentBuffer[0]), type);

    // pack in sequence numbers
    unsigned short int* sequenceAt = (unsigned short int*)&packetBuffer._currentBuffer[packetBuffer._currentSize];
    *sequenceAt = _sequenceNumber;
    packetBuffer._currentSize += sizeof(unsigned short int); // nudge past sequence
    _sequenceNumber++;

    // pack in timestamp
    quint64 now = usecTimestampNow();
    quint64* timeAt = (quint64*)&packetBuffer._currentBuffer[packetBuffer._currentSize];
    *timeAt = now;
    packetBuffer._currentSize += sizeof(quint64); // nudge past timestamp

    packetBuffer._currentType = type;
}

bool OctreeEditPacketSender::process() {
    // if we have server jurisdiction details, and we have pending pre-jurisdiction packets, then process those
    // before doing our normal process step. This processPreJurisdictionPackets()
    if (serversExist() && (!_preServerPackets.empty() || !_preServerSingleMessagePackets.empty() )) {
        processPreServerExistsPackets();
    }

    // base class does most of the work.
    return PacketSender::process();
}