/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 *                                                                         *
 *  Copyright (C) 2015 Simon Stuerz <simon.stuerz@guh.guru>                *
 *                                                                         *
 *  This file is part of guh.                                              *
 *                                                                         *
 *  Guh is free software: you can redistribute it and/or modify            *
 *  it under the terms of the GNU General Public License as published by   *
 *  the Free Software Foundation, version 2 of the License.                *
 *                                                                         *
 *  Guh is distributed in the hope that it will be useful,                 *
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of         *
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the          *
 *  GNU General Public License for more details.                           *
 *                                                                         *
 *  You should have received a copy of the GNU General Public License      *
 *  along with guh. If not, see <http://www.gnu.org/licenses/>.            *
 *                                                                         *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*!
    \class guhserver::WebSocketServer
    \brief This class represents the websocket server for guhd.

    \ingroup core
    \inmodule server

    The websocket server provides a server for websocket clients based on
    \l{http://tools.ietf.org/html/rfc6455}{Protocol Version 13}. The default
    port for the websocket server is 4444, which is according to this
    \l{https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers}{list}
    officially free.

    The URL for the insecure websocket:
    \code ws://localhost:4444\endcode

    The URL for the secure websocket (TLS 1.2):
    \code wss://localhost:4444\endcode

    You can turn on the \tt wss server in the \tt WebServerServer section of the \tt /etc/guh/guhd.conf file.

    \note For \tt wss you need to have a certificate and configure it in the \tt SSL-configuration
    section of the \tt /etc/guh/guhd.conf file.

    \sa WebServer, TcpServer, TransportInterface
*/

#include "websocketserver.h"
#include "guhsettings.h"
#include "loggingcategories.h"

#include <QJsonDocument>
#include <QSslConfiguration>

namespace guhserver {

/*! Constructs a \l{WebSocketServer} with the given \a sslConfiguration and \a parent.
 *
 *  \sa ServerManager
 */
WebSocketServer::WebSocketServer(const QSslConfiguration &sslConfiguration, QObject *parent) :
    TransportInterface(parent),
    m_server(0),
    m_sslConfiguration(sslConfiguration),
    m_useSsl(false),
    m_enabled(false)
{
    // load webserver settings
    GuhSettings settings(GuhSettings::SettingsRoleGlobal);
    qCDebug(dcWebServer) << "Loading webserver settings from" << settings.fileName();

    settings.beginGroup("WebSocketServer");
    // 4444 Official free according to https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers
    m_port = settings.value("port", 4444).toInt();
    m_useSsl = settings.value("https", false).toBool();
    settings.endGroup();

    // check SSL
    if (m_useSsl && m_sslConfiguration.isNull())
        m_useSsl = false;
}

/*! Destructor of this \l{WebSocketServer}. */
WebSocketServer::~WebSocketServer()
{
}

/*! Send the given \a data map to the client with the given \a clientId.
 *
 * \sa TransportInterface::sendData()
 */
void WebSocketServer::sendData(const QUuid &clientId, const QVariantMap &data)
{
    QWebSocket *client = 0;
    client = m_clientList.value(clientId);
    if (client) {
        client->sendTextMessage(QJsonDocument::fromVariant(data).toJson());
    }
}

/*! Send the given \a data map to the given list of \a clients.
 *
 * \sa TransportInterface::sendData()
 */
void WebSocketServer::sendData(const QList<QUuid> &clients, const QVariantMap &data)
{
    foreach (const QUuid &client, clients) {
        sendData(client, data);
    }
}

void WebSocketServer::onClientConnected()
{
    // got a new client connected
    QWebSocket *client = m_server->nextPendingConnection();
    qCDebug(dcConnection) << "Websocket server: new client connected:" << client->peerAddress().toString();

    // check websocket version
    if (client->version() != QWebSocketProtocol::Version13) {
        qCWarning(dcWebSocketServer) << "Client with invalid protocol version" << client->version() << ". Rejecting.";
        client->close(QWebSocketProtocol::CloseCodeProtocolError, QString("invalid protocol version: %1 != Supported Version 13").arg(client->version()));
        delete client;
        return;
    }

    QUuid clientId = QUuid::createUuid();

    // append the new client to the client list
    m_clientList.insert(clientId, client);

    connect(client, SIGNAL(pong(quint64,QByteArray)), this, SLOT(onPing(quint64,QByteArray)));
    connect(client, SIGNAL(binaryMessageReceived(QByteArray)), this, SLOT(onBinaryMessageReceived(QByteArray)));
    connect(client, SIGNAL(textMessageReceived(QString)), this, SLOT(onTextMessageReceived(QString)));
    connect(client, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(onClientError(QAbstractSocket::SocketError)));
    connect(client, SIGNAL(disconnected()), this, SLOT(onClientDisconnected()));

    emit clientConnected(clientId);
}

void WebSocketServer::onClientDisconnected()
{
    QWebSocket *client = qobject_cast<QWebSocket *>(sender());
    qCDebug(dcConnection) << "Websocket server: client disconnected:" << client->peerAddress().toString();
    QUuid clientId = m_clientList.key(client);
    m_clientList.take(clientId)->deleteLater();
}

void WebSocketServer::onBinaryMessageReceived(const QByteArray &data)
{
    QWebSocket *client = qobject_cast<QWebSocket *>(sender());
    qCDebug(dcWebSocketServer) << "Binary message from" << client->peerAddress().toString() << ":" << data;
}

void WebSocketServer::onTextMessageReceived(const QString &message)
{
    QWebSocket *client = qobject_cast<QWebSocket *>(sender());
    qCDebug(dcWebSocketServer) << "Text message from" << client->peerAddress().toString() << ":" << message;
    validateMessage(m_clientList.key(client), message.toUtf8());
}

void WebSocketServer::onClientError(QAbstractSocket::SocketError error)
{
    QWebSocket *client = qobject_cast<QWebSocket *>(sender());
    qCWarning(dcConnection) << "Websocket client error:" << error << client->errorString();
}

void WebSocketServer::onServerError(QAbstractSocket::SocketError error)
{
    qCWarning(dcConnection) << "Websocket server error:" << error << m_server->errorString();
}

void WebSocketServer::onPing(quint64 elapsedTime, const QByteArray &payload)
{
    QWebSocket *client = qobject_cast<QWebSocket *>(sender());
    qCDebug(dcWebSocketServer) << "ping response" << client->peerAddress() << elapsedTime << payload;
}

/*! Returns true if this \l{WebSocketServer} started successfully.
 *
 * \sa TransportInterface::startServer()
 */
bool WebSocketServer::startServer()
{
    if (m_server) {
        qCWarning(dcConnection) << "There is allready a websocket server instance. This should never happen!!! Please report this bug!";
        return false;
    }

    if (m_useSsl) {
        m_server = new QWebSocketServer("guh", QWebSocketServer::SecureMode, this);
        m_server->setSslConfiguration(m_sslConfiguration);
    } else {
        m_server = new QWebSocketServer("guh", QWebSocketServer::NonSecureMode, this);
    }
    connect (m_server, &QWebSocketServer::newConnection, this, &WebSocketServer::onClientConnected);
    connect (m_server, &QWebSocketServer::acceptError, this, &WebSocketServer::onServerError);

    if (!m_server->listen(QHostAddress::Any, m_port)) {
        qCWarning(dcConnection) << "Websocket server" << m_server->serverName() << QString("could not listen on %1:%2").arg(m_server->serverAddress().toString()).arg(m_port);
        return false;
    }

    if (m_server->secureMode() == QWebSocketServer::NonSecureMode) {
        qCDebug(dcConnection) << "Started websocket server" << m_server->serverName() << QString("on ws://%1:%2").arg(m_server->serverAddress().toString()).arg(m_port);
    } else {
        qCDebug(dcConnection) << "Started websocket server" << m_server->serverName() << QString("on wss://%1:%2").arg(m_server->serverAddress().toString()).arg(m_port);
    }
    return true;
}

/*! Returns true if this \l{WebSocketServer} stopped successfully.
 *
 * \sa TransportInterface::stopServer()
 */
bool WebSocketServer::stopServer()
{
    qCDebug(dcConnection) << "Stopping websocket server";
    m_server->close();
    delete m_server;
    m_server = 0;
    return false;
}

}