/**
  * WebSocketServer to publish Events
  * $Id$
  * $HeadURL$
  * $Author$
  * Created by Christian Ehrlicher, SLSE, 2017-02-06
  */


#include "web_socket_server.h"

#include <QJsonArray>
#include <QJsonDocument>
#include <QJsonObject>
#include <QSqlError>
#include <QTimer>
#include <QUrlQuery>
#include <QWebSocket>
#include <QWebSocketServer>
#include <ngldb/nsqlquery.h>

namespace ExerciseEventManagement
{
WebSocketEventServer::WebSocketEventServer(const QSqlDatabase &db, QObject *parent)
  : QObject(parent)
  , m_wsServer(nullptr)
  , m_cleanupTimer(new QTimer(this))
  , m_db(db)
  , m_logger(getLogger("WebSocketEventServer"))
{
  m_cleanupTimer->setInterval(10000); // clear every 10s
  connect(m_cleanupTimer, &QTimer::timeout, this, &WebSocketEventServer::onCleanupLiveHistory);
}

WebSocketEventServer::~WebSocketEventServer()
{
  for (auto s : qAsConst(m_liveSockets))
  {
    s->disconnect(this);
    s->close();
  }
  qDeleteAll(m_liveSockets);
}

bool WebSocketEventServer::listen(const QPair<quint16, quint16> &portRange)
{
  for (quint16 currentPort = portRange.first; currentPort <= portRange.second; ++currentPort)
  {
    if (listen(currentPort))
      return true;
  }

  return listen(0);
}

bool WebSocketEventServer::listen(quint16 port)
{
  if (m_wsServer && m_wsServer->isListening())
    return true;

  m_cleanupTimer->start();

  delete m_wsServer;
  m_wsServer = new QWebSocketServer(QStringLiteral("EEM-Events"), QWebSocketServer::NonSecureMode, this);

  connect(m_wsServer, &QWebSocketServer::newConnection,
          this, &WebSocketEventServer::onNewConnection);

  bool bRet = m_wsServer->listen(QHostAddress::Any, port);

  if (bRet)
    NOTICE_LOG(m_logger) << "Listening on port " << listenPort();

  return bRet;
}

quint16 WebSocketEventServer::listenPort() const
{
  return m_wsServer ? m_wsServer->serverPort() : 0;
}

void WebSocketEventServer::sendEvent(const QJsonObject &obj)
{
  const QJsonDocument doc(obj);
  const QString msg = QString::fromUtf8(doc.toJson(QJsonDocument::Compact));
  for (QWebSocket *ws : qAsConst(m_liveSockets))
    ws->sendTextMessage(msg);
  m_liveHistory[time(nullptr)].push_back(msg);
}


void WebSocketEventServer::onNewConnection()
{
  QWebSocket *ws = m_wsServer->nextPendingConnection();
  if (!ws)
    return;
  DEBUG_LOG(m_logger) << "New incoming connection from "
                      << ws->peerAddress().toString() << ":"
                      << ws->peerPort() << ", "
                      << ws->requestUrl().toString();
  const QUrl requestUrl = ws->requestUrl();
  const QString requestPath = requestUrl.path();
  if (requestPath == QStringLiteral("/live"))
  {
    connect(ws, &QWebSocket::disconnected,
            this, &WebSocketEventServer::onSocketDisconnected);
    for (const auto &historyVec : qAsConst(m_liveHistory))
    {
      for (const auto &msg : historyVec)
        ws->sendTextMessage(msg);
    }
    m_liveSockets += ws;
  }
  else if (requestPath.startsWith(QLatin1String("/request")))
    historyDataRequested(m_db, ws, requestUrl);
  else
  {
    WARNING_LOG(m_logger) << "Unknown request path: '" << requestPath << "' - closing";
    ws->close();
    ws->deleteLater();
  }
}

void WebSocketEventServer::onSocketDisconnected()
{
  QWebSocket *ws = qobject_cast<QWebSocket *>(sender());
  if (!ws)
    return;
  DEBUG_LOG(m_logger) << "Disconnected from "
                      << ws->peerAddress().toString() << ":"
                      << ws->peerPort() << ", "
                      << ws->requestUrl().toString();
  ws->deleteLater();
  m_liveSockets -= ws;
}

void WebSocketEventServer::onCleanupLiveHistory()
{
  qint64 tNow = time(nullptr) - 120; // 2min
  auto it = m_liveHistory.begin();
  while (it != m_liveHistory.end() && it.key() < tNow)
    it = m_liveHistory.erase(it);
}

void WebSocketEventServer::historyDataRequested(const QSqlDatabase &db, QWebSocket *ws, const QUrl &requestUrl)
{
  const QUrlQuery query(requestUrl);
  const int requestId = query.queryItemValue(QStringLiteral("requestId")).toInt();
  const qint64 from = query.queryItemValue(QStringLiteral("from")).toLongLong();
  const qint64 to = query.queryItemValue(QStringLiteral("to")).toLongLong();
  if (requestId == 0 || from <= 0 || to <= 0 || from > to)
  {
    WARNING_LOG(m_logger) << "Unknown request: '" << requestUrl.toString() << "' - closing, "
                          << requestId << ", " << from << ", to " << to;
    ws->sendTextMessage(QStringLiteral("{}"));
    ws->close();
    ws->deleteLater();
    return;
  }

  QString stmt(QLatin1String(" SELECT id, event_type_id, participant_id, party_id, equipment_number, properties, sample_time, position_x, position_y, position_z"
                             " FROM eem_event WHERE sample_time > ") + QString::number(from) +
               QLatin1String(" AND sample_time <= ") + QString::number(to));
  // add event type filter to query if preset
  if (query.hasQueryItem(QStringLiteral("eventTypeId")))
  {
    const QString ids = query.queryItemValue(QStringLiteral("eventTypeId"));
    // split/unsplit to make sure only integers are there
    const QVector<QStringRef> idVec = ids.splitRef(QLatin1Char(','));
    QStringList eventList;
    eventList.reserve(idVec.size());
    for (const auto &id : idVec)
    {
      int i = id.toInt();
      if (i == 0)
        continue;
      eventList += QString::number(i);
    }
    const QString eventStr = eventList.join(QLatin1Char(','));
    stmt += QStringLiteral(" AND event_type_id IN (") + eventStr + QLatin1Char(')');
  }

  // add Json properties filter to query if present
  if (query.hasQueryItem(QStringLiteral("filter")))
  {
    const QString filterString = query.queryItemValue(QStringLiteral("filter"));
    DEBUG_LOG(m_logger) << "filter string: " << filterString;
    const QJsonObject obj(QJsonDocument::fromJson(filterString.toUtf8()).object());
    if (obj.keys().size() == 1)
    {
      const QJsonValue val = obj.value(obj.keys().constFirst());
      if (val.isObject())
        stmt += QStringLiteral(" AND properties @> '") + filterString + QLatin1Char('\'');
      else if (val.isArray())
      {
        // currently we only support int arrays
        const QJsonArray arr(val.toArray());
        QStringList sl;
        sl.reserve(arr.size());
        for (const auto &ele : arr)
          sl += QString::number(ele.toInt());
        if (sl.size() > 0)
          stmt += QStringLiteral(" AND CAST (properties ->> '%1' AS int) IN (").arg(obj.keys().constFirst()) +
                  sl.join(QLatin1Char(',')) + QLatin1Char(')');
      }
    }
  }

  // add a limit for max query rows
  if (query.hasQueryItem(QStringLiteral("limit")))
  {
    const QString limitString = query.queryItemValue(QStringLiteral("limit"));
    DEBUG_LOG(m_logger) << "limiting query to " << limitString << " events";
    stmt += QStringLiteral(" LIMIT ") + limitString;
  }

  DEBUG_LOG(m_logger) << "stmt: " << stmt;

  NSqlQuery q(db);
  if (!q.exec(stmt))
  {
    ERROR_LOG(m_logger) << "Error while selecting event-data: " << stmt << ", " << q.lastError().databaseText();
    ws->sendTextMessage(QStringLiteral("{}"));
    ws->close();
    ws->deleteLater();
    return;
  }

  QJsonArray events;
  Database::EemEvent data;
  while (q.next())
  {
    int i = 0;
    data.id = q.value(i++).toInt();
    data.eventTypeId = static_cast<ProjectDataManagement::EventType_def::type>(q.value(i++).toInt());
    data.participantId = q.value(i++).toInt();
    data.partyId = q.value(i++).toInt();
    data.equipmentNumber = q.value(i++).toInt();
    data.properties = q.value(i++).toString();
    data.sampleTime = q.value(i++).toLongLong();
    double pos_lon = q.value(i++).toDouble();
    double pos_lat = q.value(i++).toDouble();
    double pos_z = q.value(i++).toDouble();
    data.position = LtsUtils::QPoint3D(pos_lon, pos_lat, pos_z);

    events.append(Database::toJson(data));
    if (events.size() > 100)
    {
      INFO_LOG(m_logger) << "Sending an answer with " << events.size() << " events for query " << stmt;
      const QJsonDocument doc(events);
      ws->sendTextMessage(QString::fromUtf8(doc.toJson(QJsonDocument::Compact)));
      events = QJsonArray();
    }
  }
  if (!events.isEmpty())
  {
    INFO_LOG(m_logger) << "Sending an answer with " << events.size() << " events for query " << stmt;
    const QJsonDocument doc(events);
    ws->sendTextMessage(QString::fromUtf8(doc.toJson(QJsonDocument::Compact)));
  }

  // finished
  ws->sendTextMessage(QStringLiteral("{}"));
}

}