/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2014-2017,  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 "face-system.hpp"
#include "core/logger.hpp"
#include "fw/face-table.hpp"

// ProtocolFactory includes, sorted alphabetically
#ifdef HAVE_LIBPCAP
#include "ethernet-factory.hpp"
#endif // HAVE_LIBPCAP
#include "tcp-factory.hpp"
#include "udp-factory.hpp"
#ifdef HAVE_UNIX_SOCKETS
#include "unix-stream-factory.hpp"
#endif // HAVE_UNIX_SOCKETS
#ifdef HAVE_WEBSOCKET
#include "websocket-factory.hpp"
#endif // HAVE_WEBSOCKET

namespace nfd {
namespace face {

NFD_LOG_INIT("FaceSystem");

FaceSystem::FaceSystem(FaceTable& faceTable)
  : m_faceTable(faceTable)
{
  ///\todo #3904 make a registry, and construct instances from registry

#ifdef HAVE_LIBPCAP
  m_factories["ether"] = make_shared<EthernetFactory>();
#endif // HAVE_LIBPCAP

  m_factories["tcp"] = make_shared<TcpFactory>();

#ifdef HAVE_UNIX_SOCKETS
  m_factories["unix"] = make_shared<UnixStreamFactory>();
#endif // HAVE_UNIX_SOCKETS

#ifdef HAVE_WEBSOCKET
  m_factories["websocket"] = make_shared<WebSocketFactory>();
#endif // HAVE_WEBSOCKET
}

std::set<const ProtocolFactory*>
FaceSystem::listProtocolFactories() const
{
  std::set<const ProtocolFactory*> factories;
  for (const auto& p : m_factoryByScheme) {
    factories.insert(p.second.get());
  }
  return factories;
}

ProtocolFactory*
FaceSystem::getFactoryById(const std::string& id)
{
  auto found = m_factories.find(id);
  return found == m_factories.end() ? nullptr : found->second.get();
}

ProtocolFactory*
FaceSystem::getFactoryByScheme(const std::string& scheme)
{
  auto found = m_factoryByScheme.find(scheme);
  return found == m_factoryByScheme.end() ? nullptr : found->second.get();
}

void
FaceSystem::setConfigFile(ConfigFile& configFile)
{
  configFile.addSectionHandler("face_system", bind(&FaceSystem::processConfig, this, _1, _2, _3));
}

void
FaceSystem::processConfig(const ConfigSection& configSection, bool isDryRun, const std::string& filename)
{
  ConfigContext context;
  context.isDryRun = isDryRun;
  context.addFace = bind(&FaceTable::add, &m_faceTable, _1);
  context.m_netifs = listNetworkInterfaces();

  // process sections in protocol factories
  for (const auto& pair : m_factories) {
    const std::string& sectionName = pair.first;
    shared_ptr<ProtocolFactory> factory = pair.second;

    std::set<std::string> oldProvidedSchemes = factory->getProvidedSchemes();
    factory->processConfig(configSection.get_child_optional(sectionName), context);

    if (!isDryRun) {
      for (const std::string& scheme : factory->getProvidedSchemes()) {
        m_factoryByScheme[scheme] = factory;
        oldProvidedSchemes.erase(scheme);
      }
      for (const std::string& scheme : oldProvidedSchemes) {
        m_factoryByScheme.erase(scheme);
      }
    }
  }

  // process other sections
  std::set<std::string> seenSections;
  for (const auto& pair : configSection) {
    const std::string& sectionName = pair.first;
    const ConfigSection& subSection = pair.second;

    if (!seenSections.insert(sectionName).second) {
      BOOST_THROW_EXCEPTION(ConfigFile::Error("Duplicate section face_system." + sectionName));
    }

    if (m_factories.count(sectionName) > 0) {
      continue;
    }

    ///\todo #3521 nicfaces

    ///\todo #3904 process these in protocol factory
    if (sectionName == "udp") {
      processSectionUdp(subSection, isDryRun, context.m_netifs);
    }
    else {
      BOOST_THROW_EXCEPTION(ConfigFile::Error("Unrecognized option face_system." + sectionName));
    }
  }
}

void
FaceSystem::processSectionUdp(const ConfigSection& configSection, bool isDryRun,
                              const std::vector<NetworkInterfaceInfo>& nicList)
{
  // ; the udp section contains settings of UDP faces and channels
  // udp
  // {
  //   port 6363 ; UDP unicast port number
  //   idle_timeout 600 ; idle time (seconds) before closing a UDP unicast face
  //   keep_alive_interval 25 ; interval (seconds) between keep-alive refreshes

  //   ; NFD creates one UDP multicast face per NIC
  //   mcast yes ; set to 'no' to disable UDP multicast, default 'yes'
  //   mcast_port 56363 ; UDP multicast port number
  //   mcast_group 224.0.23.170 ; UDP multicast group (IPv4 only)
  // }

  uint16_t port = 6363;
  bool enableV4 = true;
  bool enableV6 = true;
  size_t timeout = 600;
  size_t keepAliveInterval = 25;
  bool useMcast = true;
  auto mcastGroup = boost::asio::ip::address_v4::from_string("224.0.23.170");
  uint16_t mcastPort = 56363;

  for (const auto& i : configSection) {
    if (i.first == "port") {
      port = ConfigFile::parseNumber<uint16_t>(i, "udp");
      NFD_LOG_TRACE("UDP unicast port set to " << port);
    }
    else if (i.first == "enable_v4") {
      enableV4 = ConfigFile::parseYesNo(i, "udp");
    }
    else if (i.first == "enable_v6") {
      enableV6 = ConfigFile::parseYesNo(i, "udp");
    }
    else if (i.first == "idle_timeout") {
      try {
        timeout = i.second.get_value<size_t>();
      }
      catch (const boost::property_tree::ptree_bad_data&) {
        BOOST_THROW_EXCEPTION(ConfigFile::Error("Invalid value for option \"" +
                                                i.first + "\" in \"udp\" section"));
      }
    }
    else if (i.first == "keep_alive_interval") {
      try {
        keepAliveInterval = i.second.get_value<size_t>();
        /// \todo Make use of keepAliveInterval
        (void)(keepAliveInterval);
      }
      catch (const boost::property_tree::ptree_bad_data&) {
        BOOST_THROW_EXCEPTION(ConfigFile::Error("Invalid value for option \"" +
                                                i.first + "\" in \"udp\" section"));
      }
    }
    else if (i.first == "mcast") {
      useMcast = ConfigFile::parseYesNo(i, "udp");
    }
    else if (i.first == "mcast_port") {
      mcastPort = ConfigFile::parseNumber<uint16_t>(i, "udp");
      NFD_LOG_TRACE("UDP multicast port set to " << mcastPort);
    }
    else if (i.first == "mcast_group") {
      boost::system::error_code ec;
      mcastGroup = boost::asio::ip::address_v4::from_string(i.second.get_value<std::string>(), ec);
      if (ec) {
        BOOST_THROW_EXCEPTION(ConfigFile::Error("Invalid value for option \"" +
                                                i.first + "\" in \"udp\" section"));
      }
      NFD_LOG_TRACE("UDP multicast group set to " << mcastGroup);
    }
    else {
      BOOST_THROW_EXCEPTION(ConfigFile::Error("Unrecognized option \"" +
                                              i.first + "\" in \"udp\" section"));
    }
  }

  if (!enableV4 && !enableV6) {
    BOOST_THROW_EXCEPTION(ConfigFile::Error("IPv4 and IPv6 UDP channels have been disabled."
                                            " Remove \"udp\" section to disable UDP channels or"
                                            " re-enable at least one channel type."));
  }
  else if (useMcast && !enableV4) {
    BOOST_THROW_EXCEPTION(ConfigFile::Error("IPv4 multicast requested, but IPv4 channels"
                                            " have been disabled (conflicting configuration options set)"));
  }

  if (!isDryRun) {
    shared_ptr<UdpFactory> factory;
    bool isReload = false;
    if (m_factoryByScheme.count("udp") > 0) {
      isReload = true;
      factory = static_pointer_cast<UdpFactory>(m_factoryByScheme["udp"]);
    }
    else {
      factory = make_shared<UdpFactory>();
      m_factoryByScheme.emplace("udp", factory);
    }

    if (!isReload && enableV4) {
      udp::Endpoint endpoint(boost::asio::ip::udp::v4(), port);
      shared_ptr<UdpChannel> v4Channel = factory->createChannel(endpoint, time::seconds(timeout));
      v4Channel->listen(bind(&FaceTable::add, &m_faceTable, _1), nullptr);

      m_factoryByScheme.emplace("udp4", factory);
    }

    if (!isReload && enableV6) {
      udp::Endpoint endpoint(boost::asio::ip::udp::v6(), port);
      shared_ptr<UdpChannel> v6Channel = factory->createChannel(endpoint, time::seconds(timeout));
      v6Channel->listen(bind(&FaceTable::add, &m_faceTable, _1), nullptr);

      m_factoryByScheme.emplace("udp6", factory);
    }

    std::set<shared_ptr<Face>> multicastFacesToRemove;
    for (const auto& i : factory->getMulticastFaces()) {
      multicastFacesToRemove.insert(i.second);
    }

    if (useMcast && enableV4) {
      std::vector<NetworkInterfaceInfo> ipv4MulticastInterfaces;
      for (const auto& nic : nicList) {
        if (nic.isUp() && nic.isMulticastCapable() && !nic.ipv4Addresses.empty()) {
          ipv4MulticastInterfaces.push_back(nic);
        }
      }

      bool isNicNameNecessary = false;
#if defined(__linux__)
      if (ipv4MulticastInterfaces.size() > 1) {
        // On Linux if we have more than one MulticastUdpFace
        // we need to specify the name of the interface
        isNicNameNecessary = true;
      }
#endif

      udp::Endpoint mcastEndpoint(mcastGroup, mcastPort);
      for (const auto& nic : ipv4MulticastInterfaces) {
        udp::Endpoint localEndpoint(nic.ipv4Addresses[0], mcastPort);
        auto newFace = factory->createMulticastFace(localEndpoint, mcastEndpoint,
                                                    isNicNameNecessary ? nic.name : "");
        m_faceTable.add(newFace);
        multicastFacesToRemove.erase(newFace);
      }
    }

    for (const auto& face : multicastFacesToRemove) {
      face->close();
    }
  }
}

} // namespace face
} // namespace nfd