/*
 * barrier -- mouse and keyboard sharing utility
 * Copyright (C) 2012-2016 Symless Ltd.
 * Copyright (C) 2004 Chris Schoeneman
 *
 * This package is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * found in the file LICENSE that should have accompanied this file.
 *
 * This package 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "server/ClientListener.h"

#include "server/ClientProxy.h"
#include "server/ClientProxyUnknown.h"
#include "barrier/PacketStreamFilter.h"
#include "net/IDataSocket.h"
#include "net/IListenSocket.h"
#include "net/ISocketFactory.h"
#include "net/XSocket.h"
#include "base/Log.h"
#include "base/IEventQueue.h"
#include "base/TMethodEventJob.h"

//
// ClientListener
//

ClientListener::ClientListener(const NetworkAddress& address,
                ISocketFactory* socketFactory,
                IEventQueue* events,
                               ConnectionSecurityLevel security_level) :
    m_socketFactory(socketFactory),
    m_server(NULL),
    m_events(events),
    security_level_{security_level}
{
    assert(m_socketFactory != NULL);

    try {
        m_listen = m_socketFactory->createListen(ARCH->getAddrFamily(address.getAddress()),
                                                 security_level);

        // setup event handler
        m_events->adoptHandler(m_events->forIListenSocket().connecting(),
                    m_listen,
                    new TMethodEventJob<ClientListener>(this,
                            &ClientListener::handleClientConnecting));

        // bind listen address
        LOG((CLOG_DEBUG1 "binding listen socket"));
        m_listen->bind(address);
    }
    catch (XSocketAddressInUse&) {
        cleanupListenSocket();
        delete m_socketFactory;
        throw;
    }
    catch (XBase&) {
        cleanupListenSocket();
        delete m_socketFactory;
        throw;
    }
    LOG((CLOG_DEBUG1 "listening for clients"));
}

ClientListener::~ClientListener()
{
    LOG((CLOG_DEBUG1 "stop listening for clients"));

    // discard already connected clients
    for (NewClients::iterator index = m_newClients.begin();
                                index != m_newClients.end(); ++index) {
        ClientProxyUnknown* client = *index;
        m_events->removeHandler(
                            m_events->forClientProxyUnknown().success(), client);
        m_events->removeHandler(
                            m_events->forClientProxyUnknown().failure(), client);
        m_events->removeHandler(
                            m_events->forClientProxy().disconnected(), client);
        delete client;
    }

    // discard waiting clients
    ClientProxy* client = getNextClient();
    while (client != NULL) {
        delete client;
        client = getNextClient();
    }

    m_events->removeHandler(m_events->forIListenSocket().connecting(), m_listen);
    cleanupListenSocket();
    cleanupClientSockets();
    delete m_socketFactory;
}

void
ClientListener::setServer(Server* server)
{
    assert(server != NULL);
    m_server = server;
}

ClientProxy*
ClientListener::getNextClient()
{
    ClientProxy* client = NULL;
    if (!m_waitingClients.empty()) {
        client = m_waitingClients.front();
        m_waitingClients.pop_front();
        m_events->removeHandler(m_events->forClientProxy().disconnected(), client);
    }
    return client;
}

void
ClientListener::handleClientConnecting(const Event&, void*)
{
    // accept client connection
    IDataSocket* socket = m_listen->accept();

    if (socket == NULL) {
        return;
    }

    m_clientSockets.insert(socket);

    m_events->adoptHandler(m_events->forClientListener().accepted(),
                socket->getEventTarget(),
                new TMethodEventJob<ClientListener>(this,
                        &ClientListener::handleClientAccepted, socket));

    // When using non SSL, server accepts clients immediately, while SSL
    // has to call secure accept which may require retry
    if (security_level_ == ConnectionSecurityLevel::PLAINTEXT) {
        m_events->addEvent(Event(m_events->forClientListener().accepted(),
                                socket->getEventTarget()));
    }
}

void
ClientListener::handleClientAccepted(const Event&, void* vsocket)
{
    LOG((CLOG_NOTE "accepted client connection"));

    IDataSocket* socket = static_cast<IDataSocket*>(vsocket);

    // filter socket messages, including a packetizing filter
    barrier::IStream* stream = new PacketStreamFilter(m_events, socket, false);
    assert(m_server != NULL);

    // create proxy for unknown client
    ClientProxyUnknown* client = new ClientProxyUnknown(stream, 30.0, m_server, m_events);

    m_newClients.insert(client);

    // watch for events from unknown client
    m_events->adoptHandler(m_events->forClientProxyUnknown().success(),
                client,
                new TMethodEventJob<ClientListener>(this,
                        &ClientListener::handleUnknownClient, client));
    m_events->adoptHandler(m_events->forClientProxyUnknown().failure(),
                client,
                new TMethodEventJob<ClientListener>(this,
                        &ClientListener::handleUnknownClient, client));
}

void
ClientListener::handleUnknownClient(const Event&, void* vclient)
{
    ClientProxyUnknown* unknownClient =
        static_cast<ClientProxyUnknown*>(vclient);

    // we should have the client in our new client list
    assert(m_newClients.count(unknownClient) == 1);

    // get the real client proxy and install it
    ClientProxy* client = unknownClient->orphanClientProxy();
    if (client != NULL) {
        // handshake was successful
        m_waitingClients.push_back(client);
        m_events->addEvent(Event(m_events->forClientListener().connected(),
                                 this));

        // watch for client to disconnect while it's in our queue
        m_events->adoptHandler(m_events->forClientProxy().disconnected(), client,
                            new TMethodEventJob<ClientListener>(this,
                                &ClientListener::handleClientDisconnected,
                                client));
    } else {
        auto* stream = unknownClient->getStream();
        if (stream) {
            stream->close();
        }
    }

    // now finished with unknown client
    m_events->removeHandler(m_events->forClientProxyUnknown().success(), client);
    m_events->removeHandler(m_events->forClientProxyUnknown().failure(), client);
    m_newClients.erase(unknownClient);

    delete unknownClient;
}

void
ClientListener::handleClientDisconnected(const Event&, void* vclient)
{
    ClientProxy* client = static_cast<ClientProxy*>(vclient);

    // find client in waiting clients queue
    for (WaitingClients::iterator i = m_waitingClients.begin(),
                            n = m_waitingClients.end(); i != n; ++i) {
        if (*i == client) {
            m_waitingClients.erase(i);
            m_events->removeHandler(m_events->forClientProxy().disconnected(),
                            client);

            // pull out the socket before deleting the client so
            // we know which socket we no longer need
            IDataSocket* socket = static_cast<IDataSocket*>(client->getStream());
            delete client;
            m_clientSockets.erase(socket);
            delete socket;

            break;
        }
    }
}

void
ClientListener::cleanupListenSocket()
{
    delete m_listen;
}

void
ClientListener::cleanupClientSockets()
{
    ClientSockets::iterator it;
    for (it = m_clientSockets.begin(); it != m_clientSockets.end(); it++) {
        delete *it;
    }
    m_clientSockets.clear();
}
