/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2014-2015,  Regents of the University of California,
 *                           Arizona Board of Regents,
 *                           Colorado State University,
 *                           University Pierre & Marie Curie, Sorbonne University,
 *                           Washington University in St. Louis,
 *                           Beijing Institute of Technology,
 *                           The University of Memphis.
 *
 * This file is part of NFD (Named Data Networking Forwarding Daemon).
 * See AUTHORS.md for complete list of NFD authors and contributors.
 *
 * NFD 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,
 * either version 3 of the License, or (at your option) any later version.
 *
 * NFD 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
 * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "websocket-channel.hpp"
#include "core/global-io.hpp"
#include "core/scheduler.hpp"

#include <boost/date_time/posix_time/posix_time.hpp>

namespace nfd {

NFD_LOG_INIT("WebSocketChannel");

WebSocketChannel::WebSocketChannel(const websocket::Endpoint& localEndpoint)
  : m_localEndpoint(localEndpoint)
  , m_isListening(false)
  , m_pingInterval(10000)
{
  setUri(FaceUri(m_localEndpoint, "ws"));

  // Setup WebSocket server
  m_server.clear_access_channels(websocketpp::log::alevel::all);
  m_server.clear_error_channels(websocketpp::log::alevel::all);

  m_server.set_message_handler(bind(&WebSocketChannel::handleMessage, this, _1, _2));
  m_server.set_open_handler(bind(&WebSocketChannel::handleOpen, this, _1));
  m_server.set_close_handler(bind(&WebSocketChannel::handleClose, this, _1));
  m_server.init_asio(&getGlobalIoService());

  // Detect disconnections using ping-pong messages
  m_server.set_pong_handler(bind(&WebSocketChannel::handlePong, this, _1, _2));
  m_server.set_pong_timeout_handler(bind(&WebSocketChannel::handlePongTimeout, this, _1, _2));

  // Always set SO_REUSEADDR flag
  m_server.set_reuse_addr(true);
}

void
WebSocketChannel::setPingInterval(time::milliseconds interval)
{
  m_pingInterval = interval;
}

void
WebSocketChannel::setPongTimeout(time::milliseconds timeout)
{
  m_server.set_pong_timeout(static_cast<long>(timeout.count()));
}

void
WebSocketChannel::handlePongTimeout(websocketpp::connection_hdl hdl, std::string msg)
{
  auto it = m_channelFaces.find(hdl);
  if (it != m_channelFaces.end()) {
    NFD_LOG_TRACE(__func__ << ": " << it->second->getRemoteUri());
    it->second->close();
    m_channelFaces.erase(it);
  }
}

void
WebSocketChannel::handlePong(websocketpp::connection_hdl hdl, std::string msg)
{
  auto it = m_channelFaces.find(hdl);
  if (it != m_channelFaces.end()) {
    NFD_LOG_TRACE("Pong from " << it->second->getRemoteUri());
  }
}

void
WebSocketChannel::handleMessage(websocketpp::connection_hdl hdl,
                                websocket::Server::message_ptr msg)
{
  auto it = m_channelFaces.find(hdl);
  if (it != m_channelFaces.end()) {
    it->second->handleReceive(msg->get_payload());
  }
}

void
WebSocketChannel::handleOpen(websocketpp::connection_hdl hdl)
{
  try {
    std::string remote = "wsclient://" + m_server.get_con_from_hdl(hdl)->get_remote_endpoint();
    auto face = make_shared<WebSocketFace>(FaceUri(remote), this->getUri(),
                                           hdl, ref(m_server));
    m_onFaceCreatedCallback(face);
    m_channelFaces[hdl] = face;
    // Schedule ping message
    scheduler::EventId pingEvent = scheduler::schedule(m_pingInterval,
                                                       bind(&WebSocketChannel::sendPing,
                                                            this, hdl));
    face->setPingEventId(pingEvent);
  }
  catch (const FaceUri::Error& e) {
    NFD_LOG_WARN(e.what());
    websocketpp::lib::error_code ec;
    m_server.close(hdl, websocketpp::close::status::normal, "closed by channel", ec);
    // ignore error on close
  }
  catch (const websocketpp::exception& e) {
    NFD_LOG_WARN("Cannot get remote connection: " << e.what());
    websocketpp::lib::error_code ec;
    m_server.close(hdl, websocketpp::close::status::normal, "closed by channel", ec);
    // ignore error on close
  }
}

void
WebSocketChannel::sendPing(websocketpp::connection_hdl hdl)
{
  auto it = m_channelFaces.find(hdl);
  if (it != m_channelFaces.end()) {
    NFD_LOG_TRACE("Sending ping to " << it->second->getRemoteUri());

    websocketpp::lib::error_code ec;
    m_server.ping(hdl, "NFD-WebSocket", ec);
    if (ec)
      {
        NFD_LOG_WARN("Failed to ping " << it->second->getRemoteUri() << ": " << ec.message());
        it->second->close();
        m_channelFaces.erase(it);
        return;
      }

    // Schedule next ping message
    scheduler::EventId pingEvent = scheduler::schedule(m_pingInterval,
                                                       bind(&WebSocketChannel::sendPing,
                                                            this, hdl));
    it->second->setPingEventId(pingEvent);
  }
}

void
WebSocketChannel::handleClose(websocketpp::connection_hdl hdl)
{
  auto it = m_channelFaces.find(hdl);
  if (it != m_channelFaces.end()) {
    NFD_LOG_TRACE(__func__ << ": " << it->second->getRemoteUri());
    it->second->close();
    m_channelFaces.erase(it);
  }
}

void
WebSocketChannel::listen(const FaceCreatedCallback& onFaceCreated)
{
  if (isListening()) {
    NFD_LOG_WARN("[" << m_localEndpoint << "] Already listening");
    return;
  }
  m_isListening = true;

  m_onFaceCreatedCallback = onFaceCreated;
  m_server.listen(m_localEndpoint);
  m_server.start_accept();
}

size_t
WebSocketChannel::size() const
{
  return m_channelFaces.size();
}

} // namespace nfd