/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2014-2018,  The University of Memphis,
 *                           Regents of the University of California,
 *                           Arizona Board of Regents.
 *
 * This file is part of NLSR (Named-data Link State Routing).
 * See AUTHORS.md for complete list of NLSR authors and contributors.
 *
 * NLSR 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.
 *
 * NLSR 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
 * NLSR, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 **/

#ifndef NLSR_NLSR_HPP
#define NLSR_NLSR_HPP

#include "adjacency-list.hpp"
#include "common.hpp"
#include "conf-parameter.hpp"
#include "hello-protocol.hpp"
#include "lsdb.hpp"
#include "name-prefix-list.hpp"
#include "test-access-control.hpp"
#include "publisher/dataset-interest-handler.hpp"
#include "route/fib.hpp"
#include "route/name-prefix-table.hpp"
#include "route/routing-table.hpp"
#include "security/certificate-store.hpp"
#include "update/prefix-update-processor.hpp"
#include "update/nfd-rib-command-processor.hpp"
#include "utility/name-helper.hpp"
#include "stats-collector.hpp"

#include <boost/cstdint.hpp>
#include <stdexcept>
#include <boost/throw_exception.hpp>

#include <ndn-cxx/face.hpp>
#include <ndn-cxx/security/key-chain.hpp>
#include <ndn-cxx/security/validator-config.hpp>
#include <ndn-cxx/security/v2/certificate-fetcher-direct-fetch.hpp>
#include <ndn-cxx/security/signing-helpers.hpp>
#include <ndn-cxx/security/signing-info.hpp>
#include <ndn-cxx/util/scheduler.hpp>
#include <ndn-cxx/mgmt/nfd/face-event-notification.hpp>
#include <ndn-cxx/mgmt/nfd/face-monitor.hpp>
#include <ndn-cxx/mgmt/dispatcher.hpp>
#include <ndn-cxx/mgmt/nfd/face-status.hpp>
#include <ndn-cxx/data.hpp>
#include <ndn-cxx/encoding/block.hpp>
#include <ndn-cxx/encoding/nfd-constants.hpp>
#include <ndn-cxx/mgmt/nfd/control-parameters.hpp>
#include <ndn-cxx/mgmt/nfd/control-response.hpp>

namespace nlsr {

static ndn::Name DEFAULT_BROADCAST_PREFIX("/ndn/broadcast");

class Nlsr
{
public:
  using FetchDatasetCallback = std::function<void(const std::vector<ndn::nfd::FaceStatus>&)>;
  using FetchDatasetTimeoutCallback = std::function<void(uint32_t, const std::string&)>;

  class Error : public std::runtime_error
  {
  public:
    explicit
    Error(const std::string& what)
      : std::runtime_error(what)
    {
    }
  };

  Nlsr(boost::asio::io_service& ioService, ndn::Scheduler& scheduler, ndn::Face& face, ndn::KeyChain& keyChain);

  void
  registrationFailed(const ndn::Name& name);

  void
  onRegistrationSuccess(const ndn::Name& name);

  void
  setInfoInterestFilter();

  void
  setLsaInterestFilter();

  /*! \brief Add top level prefixes for Dispatcher
   *
   * All dispatcher-related sub-prefixes *must* be registered before sub-prefixes
   * must be added before adding top
   */
  void
  addDispatcherTopPrefix(const ndn::Name& topPrefix);

  void
  startEventLoop();

  std::string
  getConfFileName() const
  {
    return m_configFileName;
  }

  void
  setConfFileName(const std::string& fileName)
  {
    m_configFileName = fileName;
  }

  ConfParameter&
  getConfParameter()
  {
    return m_confParam;
  }

  const ConfParameter&
  getConfParameter() const
  {
    return m_confParam;
  }

  AdjacencyList&
  getAdjacencyList()
  {
    return m_adjacencyList;
  }

  const AdjacencyList&
  getAdjacencyList() const
  {
    return m_adjacencyList;
  }

  NamePrefixList&
  getNamePrefixList()
  {
    return m_namePrefixList;
  }

  const NamePrefixList&
  getNamePrefixList() const
  {
    return m_namePrefixList;
  }

  ndn::Face&
  getNlsrFace()
  {
    return m_nlsrFace;
  }

  Lsdb&
  getLsdb()
  {
    return m_nlsrLsdb;
  }

  RoutingTable&
  getRoutingTable()
  {
    return m_routingTable;
  }

  NamePrefixTable&
  getNamePrefixTable()
  {
    return m_namePrefixTable;
  }

  Fib&
  getFib()
  {
    return m_fib;
  }

  long int
  getAdjBuildCount()
  {
    return m_adjBuildCount;
  }

  void
  incrementAdjBuildCount()
  {
    m_adjBuildCount++;
  }

  void
  setAdjBuildCount(int64_t abc)
  {
    m_adjBuildCount = abc;
  }

  bool
  getIsBuildAdjLsaSheduled()
  {
    return m_isBuildAdjLsaSheduled;
  }

  void
  setIsBuildAdjLsaSheduled(bool iabls)
  {
    m_isBuildAdjLsaSheduled = iabls;
  }

  bool
  getIsRoutingTableCalculating()
  {
    return m_isRoutingTableCalculating;
  }

  void
  setIsRoutingTableCalculating(bool irtc)
  {
    m_isRoutingTableCalculating = irtc;
  }

  bool
  getIsRouteCalculationScheduled()
  {
    return m_isRouteCalculationScheduled;
  }

  void
  setIsRouteCalculationScheduled(bool ircs)
  {
    m_isRouteCalculationScheduled = ircs;
  }

  DatasetInterestHandler&
  getDatasetHandler()
  {
    return m_datasetHandler;
  }

  void
  initialize();

  /*! \brief Initializes neighbors' Faces using information from NFD.
   * \sa Nlsr::initialize()
   * \sa Nlsr::processFaceDataset()
   *
   * This function serves as the entry-point for initializing the
   * neighbors listed in nlsr.conf during Nlsr::initialize(). NLSR
   * will attempt to fetch a dataset of Faces from NFD, and configure
   * each of its neighbors using information from that dataset. The
   * explicit callbacks allow for better testability.
   */
  void
  initializeFaces(const FetchDatasetCallback& onFetchSuccess,
                  const FetchDatasetTimeoutCallback& onFetchFailure);

  void
  onFaceDatasetFetchTimeout(uint32_t code,
                            const std::string& reason,
                            uint32_t nRetriesSoFar);

  /*! \brief Consumes a Face StatusDataset to configure NLSR neighbors.
   * \sa Nlsr::initializeFaces
   * \param faces A Face Dataset that should conform to FaceMgmt specifications.
   *
   * This function processes a Face StatusDataset that should conform
   * to the FaceMgmt specifications listed
   * [here](https://redmine.named-data.net/projects/nfd/wiki/FaceMgmt#Face-Dataset).
   * Any newly configured neighbors will have prefixes registered with NFD
   * and be sent Hello Interests as well.
   */
  void
  processFaceDataset(const std::vector<ndn::nfd::FaceStatus>& faces);

  /*! \brief Registers NLSR-specific prefixes for a neighbor (Adjacent)
   * \sa Nlsr::initializeFaces
   * \param adj A reference to the neighbor to register prefixes for
   * \param timeout The amount of time to give NFD to respond to *each* registration request.
   *
   * Registers the prefixes in NFD that NLSR needs to route with a
   * neighbor. The timeout given is how long to set the timeout for
   * *each* registration request that is made.
   */
  void
  registerAdjacencyPrefixes(const Adjacent& adj,
                            const ndn::time::milliseconds& timeout);

  /*! \brief Add a certificate NLSR claims to be authoritative for to the certificate store.
   *
   * \sa CertificateStore
   */
  void
  loadCertToPublish(const ndn::security::v2::Certificate& certificate);

  void
  connectToFetcher(ndn::util::SegmentFetcher& fetcher);

  /*! \brief Callback when SegmentFetcher retrieves a segment.
   */
  void
  afterFetcherSignalEmitted(const ndn::Data& lsaSegment);

  /*! \brief Retrieves the chain of certificates from Validator's cache and
   *   store them in Nlsr's own CertificateStore.
   * \param keyName Name of the first key in the certificate chain.
   */
  void
  publishCertFromCache(const ndn::Name& keyName);

  void
  initializeKey();

  void
  loadValidator(boost::property_tree::ptree section,
                const std::string& filename)
  {
    m_validator.load(section, filename);
  }

  ndn::security::ValidatorConfig&
  getValidator()
  {
    return m_validator;
  }

  /*! \brief Find a certificate
   *
   * Find a certificate that NLSR has. First it checks against the
   * certificates this NLSR claims to be authoritative for, usually
   * something like this specific router's certificate, and then
   * checks the cache of certficates it has already fetched. If none
   * can be found, it will return an empty pointer.
   */
  const ndn::security::v2::Certificate*
  getCertificate(const ndn::Name& certificateKeyName)
  {
    const ndn::security::v2::Certificate* cert =
      m_certStore.find(certificateKeyName);

    return cert;
  }

  ndn::security::v2::KeyChain&
  getKeyChain()
  {
    return m_keyChain;
  }

  const ndn::Name&
  getDefaultCertName()
  {
    return m_defaultCertName;
  }

  const ndn::security::SigningInfo&
  getSigningInfo()
  {
    return m_signingInfo;
  }

  update::PrefixUpdateProcessor&
  getPrefixUpdateProcessor()
  {
    return m_prefixUpdateProcessor;
  }

  update::NfdRibCommandProcessor&
  getNfdRibCommandProcessor()
  {
    return m_nfdRibCommandProcessor;
  }

  ndn::mgmt::Dispatcher&
  getDispatcher()
  {
    return m_dispatcher;
  }

  void
  setStrategies();

  uint32_t
  getFirstHelloInterval() const
  {
    return m_firstHelloInterval;
  }

  /*! \brief Canonize the URI for this and all proceeding neighbors in a list.
   *
   * This function canonizes the URI of the Adjacent object pointed to
   * by currentNeighbor. It then executes the then callback, providing
   * the next iterator in the list to the callback. A standard
   * invocation would be to pass the begin() iterator of NLSR's
   * adjacency list, and to provide Nlsr::canonizeContinuation as the
   * callback. Because every URI must be canonical before we begin
   * operations, the canonize function provides a finally() function
   * to resume whatever needs to occur.
   *
   * \sa Nlsr::canonizeContinuation
   * \sa Nlsr::initialize
   * \sa NlsrRunner::run
   */
  void
  canonizeNeighborUris(std::list<Adjacent>::iterator currentNeighbor,
                       std::function<void(std::list<Adjacent>::iterator)> then,
                       std::function<void(void)> finally);

  StatsCollector&
  getStatsCollector()
  {
    return m_statsCollector;
  }

PUBLIC_WITH_TESTS_ELSE_PRIVATE:

  security::CertificateStore&
  getCertificateStore()
  {
    return m_certStore;
  }

private:
  /*! \brief Registers the prefix that NLSR will use for key/certificate interests.
   */
  void
  registerKeyPrefix();

  /*! \brief Registers the prefix that NLSR will consider to be the machine-local, secure prefix.
   */
  void
  registerLocalhostPrefix();

  /*! \brief Attempts to satisfy an Interest for a certificate, and send it back.
   */
  void
  onKeyInterest(const ndn::Name& name, const ndn::Interest& interest);

  /*! \brief Do nothing.
   */
  void
  onKeyPrefixRegSuccess(const ndn::Name& name);

  /*! \brief Do nothing.
   */
  void
  onFaceEventNotification(const ndn::nfd::FaceEventNotification& faceEventNotification);

  void
  setFirstHelloInterval(uint32_t interval)
  {
    m_firstHelloInterval = interval;
  }

  /*! \brief Continues canonizing neighbor URIs.
   *
   * For testability reasons, we want what each instance of
   * canonization does after completion to be controllable. The best
   * way to do this is to control that by simply passing a
   * continuation function.
   */
  void
  canonizeContinuation(std::list<Adjacent>::iterator iterator,
                       std::function<void(void)> finally);

  void
  scheduleDatasetFetch();

  /*! \brief Enables NextHopFaceId indication in NFD for incoming data packet.
   *
   * After enabling, when NFD gets a data packet, it will put the incoming face id
   * of the data in NextHopFaceId field of the packet. The NextHopFaceId will be used
   * by DirectFetcher to fetch the certificates needed to validate the data packet.
   * \sa https://redmine.named-data.net/projects/nfd/wiki/NDNLPv2#Consumer-Controlled-Forwarding
   */
  void
  enableIncomingFaceIdIndication();

  void
  onFaceIdIndicationSuccess(const ndn::nfd::ControlParameters& cp);

  void
  onFaceIdIndicationFailure(const ndn::nfd::ControlResponse& cr);

public:
  static const ndn::Name LOCALHOST_PREFIX;

private:
  ndn::Face& m_nlsrFace;
  ndn::Scheduler& m_scheduler;
  ndn::security::v2::KeyChain& m_keyChain;
  ConfParameter m_confParam;
  AdjacencyList m_adjacencyList;
  NamePrefixList m_namePrefixList;
  std::string m_configFileName;
  Lsdb m_nlsrLsdb;
  int64_t m_adjBuildCount;
  bool m_isBuildAdjLsaSheduled;
  bool m_isRouteCalculationScheduled;
  bool m_isRoutingTableCalculating;
  RoutingTable m_routingTable;
  Fib m_fib;
  NamePrefixTable m_namePrefixTable;

  ndn::mgmt::Dispatcher m_dispatcher;

  DatasetInterestHandler m_datasetHandler;

PUBLIC_WITH_TESTS_ELSE_PRIVATE:
  HelloProtocol m_helloProtocol;

  ndn::security::ValidatorConfig m_validator;

private:
  /*! \brief Where NLSR stores certificates it claims to be
   * authoritative for. Usually the router certificate.
   */
  security::CertificateStore m_certStore;

  ndn::nfd::Controller m_controller;
  ndn::nfd::Controller m_faceDatasetController;
  ndn::security::SigningInfo m_signingInfo;
  ndn::Name m_defaultCertName;
  update::PrefixUpdateProcessor m_prefixUpdateProcessor;
  update::NfdRibCommandProcessor m_nfdRibCommandProcessor;
  StatsCollector m_statsCollector;

  ndn::nfd::FaceMonitor m_faceMonitor;

  uint32_t m_firstHelloInterval;

  friend class NlsrRunner;
};

} // namespace nlsr

#endif // NLSR_NLSR_HPP