/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2015-2016, 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 ndn-cxx library (NDN C++ library with eXperimental eXtensions).
 *
 * ndn-cxx library is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later version.
 *
 * ndn-cxx library 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 Lesser General Public License for more details.
 *
 * You should have received copies of the GNU General Public License and GNU Lesser
 * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
 * <http://www.gnu.org/licenses/>.
 *
 * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
 */

#include "face-uri.hpp"
#include "dns.hpp"

#include <set>
#include <boost/concept_check.hpp>
#include <boost/regex.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/mpl/vector.hpp>
#include <boost/mpl/for_each.hpp>

namespace ndn {
namespace util {

BOOST_CONCEPT_ASSERT((boost::EqualityComparable<FaceUri>));

FaceUri::FaceUri()
  : m_isV6(false)
{
}

FaceUri::FaceUri(const std::string& uri)
{
  if (!parse(uri)) {
    BOOST_THROW_EXCEPTION(Error("Malformed URI: " + uri));
  }
}

FaceUri::FaceUri(const char* uri)
{
  if (!parse(uri)) {
    BOOST_THROW_EXCEPTION(Error("Malformed URI: " + std::string(uri)));
  }
}

bool
FaceUri::parse(const std::string& uri)
{
  m_scheme.clear();
  m_host.clear();
  m_isV6 = false;
  m_port.clear();
  m_path.clear();

  static const boost::regex protocolExp("(\\w+\\d?)://([^/]*)(\\/[^?]*)?");
  boost::smatch protocolMatch;
  if (!boost::regex_match(uri, protocolMatch, protocolExp)) {
    return false;
  }
  m_scheme = protocolMatch[1];
  const std::string& authority = protocolMatch[2];
  m_path = protocolMatch[3];

  // pattern for IPv6 address enclosed in [ ], with optional port number
  static const boost::regex v6Exp("^\\[([a-fA-F0-9:]+)\\](?:\\:(\\d+))?$");
  // pattern for Ethernet address in standard hex-digits-and-colons notation
  static const boost::regex etherExp("^\\[((?:[a-fA-F0-9]{1,2}\\:){5}(?:[a-fA-F0-9]{1,2}))\\]$");
  // pattern for IPv4-mapped IPv6 address, with optional port number
  static const boost::regex v4MappedV6Exp("^\\[::ffff:(\\d+(?:\\.\\d+){3})\\](?:\\:(\\d+))?$");
  // pattern for IPv4/hostname/fd/ifname, with optional port number
  static const boost::regex v4HostExp("^([^:]+)(?:\\:(\\d+))?$");

  if (authority.empty()) {
    // UNIX, internal
  }
  else {
    boost::smatch match;
    m_isV6 = boost::regex_match(authority, match, v6Exp);
    if (m_isV6 ||
        boost::regex_match(authority, match, etherExp) ||
        boost::regex_match(authority, match, v4MappedV6Exp) ||
        boost::regex_match(authority, match, v4HostExp)) {
      m_host = match[1];
      m_port = match[2];
    }
    else {
      return false;
    }
  }

  return true;
}

FaceUri::FaceUri(const boost::asio::ip::udp::endpoint& endpoint)
{
  m_isV6 = endpoint.address().is_v6();
  m_scheme = m_isV6 ? "udp6" : "udp4";
  m_host = endpoint.address().to_string();
  m_port = boost::lexical_cast<std::string>(endpoint.port());
}

FaceUri::FaceUri(const boost::asio::ip::tcp::endpoint& endpoint)
{
  m_isV6 = endpoint.address().is_v6();
  m_scheme = m_isV6 ? "tcp6" : "tcp4";
  m_host = endpoint.address().to_string();
  m_port = boost::lexical_cast<std::string>(endpoint.port());
}

FaceUri::FaceUri(const boost::asio::ip::tcp::endpoint& endpoint, const std::string& scheme)
  : m_scheme(scheme)
{
  m_isV6 = endpoint.address().is_v6();
  m_host = endpoint.address().to_string();
  m_port = boost::lexical_cast<std::string>(endpoint.port());
}

#ifdef BOOST_ASIO_HAS_LOCAL_SOCKETS
FaceUri::FaceUri(const boost::asio::local::stream_protocol::endpoint& endpoint)
  : m_isV6(false)
{
  m_scheme = "unix";
  m_path = endpoint.path();
}
#endif // BOOST_ASIO_HAS_LOCAL_SOCKETS

FaceUri
FaceUri::fromFd(int fd)
{
  FaceUri uri;
  uri.m_scheme = "fd";
  uri.m_host = boost::lexical_cast<std::string>(fd);
  return uri;
}

FaceUri::FaceUri(const ethernet::Address& address)
  : m_isV6(true)
{
  m_scheme = "ether";
  m_host = address.toString();
}

FaceUri
FaceUri::fromDev(const std::string& ifname)
{
  FaceUri uri;
  uri.m_scheme = "dev";
  uri.m_host = ifname;
  return uri;
}

bool
FaceUri::operator==(const FaceUri& rhs) const
{
  return (m_scheme == rhs.m_scheme &&
          m_host == rhs.m_host &&
          m_isV6 == rhs.m_isV6 &&
          m_port == rhs.m_port &&
          m_path == rhs.m_path);
}

bool
FaceUri::operator!=(const FaceUri& rhs) const
{
  return !(*this == rhs);
}

std::string
FaceUri::toString() const
{
  std::ostringstream os;
  os << *this;
  return os.str();
}

std::ostream&
operator<<(std::ostream& os, const FaceUri& uri)
{
  os << uri.m_scheme << "://";
  if (uri.m_isV6) {
    os << "[" << uri.m_host << "]";
  }
  else {
    os << uri.m_host;
  }
  if (!uri.m_port.empty()) {
    os << ":" << uri.m_port;
  }
  os << uri.m_path;
  return os;
}

/** \brief a CanonizeProvider provides FaceUri canonization functionality for a group of schemes
 */
class CanonizeProvider : noncopyable
{
public:
  virtual
  ~CanonizeProvider() = default;

  virtual std::set<std::string>
  getSchemes() const = 0;

  virtual bool
  isCanonical(const FaceUri& faceUri) const = 0;

  virtual void
  canonize(const FaceUri& faceUri,
           const FaceUri::CanonizeSuccessCallback& onSuccess,
           const FaceUri::CanonizeFailureCallback& onFailure,
           boost::asio::io_service& io, const time::nanoseconds& timeout) const = 0;
};

template<typename Protocol>
class IpHostCanonizeProvider : public CanonizeProvider
{
public:
  virtual std::set<std::string>
  getSchemes() const override
  {
    std::set<std::string> schemes;
    schemes.insert(m_baseScheme);
    schemes.insert(m_v4Scheme);
    schemes.insert(m_v6Scheme);
    return schemes;
  }

  virtual bool
  isCanonical(const FaceUri& faceUri) const override
  {
    if (faceUri.getPort().empty()) {
      return false;
    }
    if (!faceUri.getPath().empty()) {
      return false;
    }

    boost::system::error_code ec;
    boost::asio::ip::address addr;
    if (faceUri.getScheme() == m_v4Scheme) {
      addr = boost::asio::ip::address_v4::from_string(faceUri.getHost(), ec);
    }
    else if (faceUri.getScheme() == m_v6Scheme) {
      addr = boost::asio::ip::address_v6::from_string(faceUri.getHost(), ec);
    }
    else {
      return false;
    }
    return !static_cast<bool>(ec) && addr.to_string() == faceUri.getHost() &&
           this->checkAddress(addr).first;
  }

  virtual void
  canonize(const FaceUri& faceUri,
           const FaceUri::CanonizeSuccessCallback& onSuccess,
           const FaceUri::CanonizeFailureCallback& onFailure,
           boost::asio::io_service& io, const time::nanoseconds& timeout) const override
  {
    if (this->isCanonical(faceUri)) {
      onSuccess(faceUri);
      return;
    }

    dns::AddressSelector addressSelector;
    if (faceUri.getScheme() == m_v4Scheme) {
      addressSelector = dns::Ipv4Only();
    }
    else if (faceUri.getScheme() == m_v6Scheme) {
      addressSelector = dns::Ipv6Only();
    }
    else {
      BOOST_ASSERT(faceUri.getScheme() == m_baseScheme);
      addressSelector = dns::AnyAddress();
    }

    // make a copy because caller may modify faceUri
    shared_ptr<FaceUri> uri = make_shared<FaceUri>(faceUri);
    dns::asyncResolve(faceUri.getHost(),
      bind(&IpHostCanonizeProvider<Protocol>::onDnsSuccess, this, uri, onSuccess, onFailure, _1),
      bind(&IpHostCanonizeProvider<Protocol>::onDnsFailure, this, uri, onFailure, _1),
      io, addressSelector, timeout);
  }

protected:
  explicit
  IpHostCanonizeProvider(const std::string& baseScheme,
                         uint32_t defaultUnicastPort = 6363,
                         uint32_t defaultMulticastPort = 56363)
    : m_baseScheme(baseScheme)
    , m_v4Scheme(baseScheme + "4")
    , m_v6Scheme(baseScheme + "6")
    , m_defaultUnicastPort(defaultUnicastPort)
    , m_defaultMulticastPort(defaultMulticastPort)
  {
  }

private:
  // faceUri is a shared_ptr passed by value because this function can take ownership
  void
  onDnsSuccess(shared_ptr<FaceUri> faceUri,
               const FaceUri::CanonizeSuccessCallback& onSuccess,
               const FaceUri::CanonizeFailureCallback& onFailure,
               const dns::IpAddress& ipAddress) const
  {
    std::pair<bool, std::string> checkAddressRes = this->checkAddress(ipAddress);
    if (!checkAddressRes.first) {
      onFailure(checkAddressRes.second);
      return;
    }

    uint32_t port = 0;
    if (faceUri->getPort().empty()) {
      port = ipAddress.is_multicast() ? m_defaultMulticastPort : m_defaultUnicastPort;
    }
    else {
      try {
        port = boost::lexical_cast<uint32_t>(faceUri->getPort());
      }
      catch (boost::bad_lexical_cast&) {
        onFailure("invalid port number");
        return;
      }
    }

    FaceUri canonicalUri(typename Protocol::endpoint(ipAddress, port));
    BOOST_ASSERT(canonicalUri.isCanonical());
    onSuccess(canonicalUri);
  }

  // faceUri is a shared_ptr passed by value because this function can take ownership
  void
  onDnsFailure(shared_ptr<FaceUri> faceUri, const FaceUri::CanonizeFailureCallback& onFailure,
               const std::string& reason) const
  {
    onFailure(reason);
  }

  /** \brief when overriden in a subclass, check the IP address is allowable
   *  \return (true,ignored) if the address is allowable;
   *          (false,reason) if the address is not allowable.
   */
  virtual std::pair<bool, std::string>
  checkAddress(const dns::IpAddress& ipAddress) const
  {
    return {true, ""};
  }

private:
  std::string m_baseScheme;
  std::string m_v4Scheme;
  std::string m_v6Scheme;
  uint32_t m_defaultUnicastPort;
  uint32_t m_defaultMulticastPort;
};

class UdpCanonizeProvider : public IpHostCanonizeProvider<boost::asio::ip::udp>
{
public:
  UdpCanonizeProvider()
    : IpHostCanonizeProvider("udp")
  {
  }

protected:
  // checkAddress is not overriden:
  // Although NFD doesn't support IPv6 multicast, it's an implementation limitation.
  // FaceMgmt protocol allows IPv6 multicast address in UDP.
};

class TcpCanonizeProvider : public IpHostCanonizeProvider<boost::asio::ip::tcp>
{
public:
  TcpCanonizeProvider()
    : IpHostCanonizeProvider("tcp")
  {
  }

protected:
  virtual std::pair<bool, std::string>
  checkAddress(const dns::IpAddress& ipAddress) const override
  {
    if (ipAddress.is_multicast()) {
      return {false, "cannot use multicast address"};
    }
    return {true, ""};
  }
};

class EtherCanonizeProvider : public CanonizeProvider
{
public:
  virtual std::set<std::string>
  getSchemes() const override
  {
    std::set<std::string> schemes;
    schemes.insert("ether");
    return schemes;
  }

  virtual bool
  isCanonical(const FaceUri& faceUri) const override
  {
    if (!faceUri.getPort().empty()) {
      return false;
    }
    if (!faceUri.getPath().empty()) {
      return false;
    }

    ethernet::Address addr = ethernet::Address::fromString(faceUri.getHost());
    return addr.toString() == faceUri.getHost();
  }

  virtual void
  canonize(const FaceUri& faceUri,
           const FaceUri::CanonizeSuccessCallback& onSuccess,
           const FaceUri::CanonizeFailureCallback& onFailure,
           boost::asio::io_service& io, const time::nanoseconds& timeout) const override
  {
    ethernet::Address addr = ethernet::Address::fromString(faceUri.getHost());
    if (addr.isNull()) {
      onFailure("cannot parse address");
      return;
    }

    FaceUri canonicalUri(addr);
    BOOST_ASSERT(canonicalUri.isCanonical());
    onSuccess(canonicalUri);
  }
};

typedef boost::mpl::vector<
    UdpCanonizeProvider*,
    TcpCanonizeProvider*,
    EtherCanonizeProvider*
  > CanonizeProviders;
typedef std::map<std::string, shared_ptr<CanonizeProvider> > CanonizeProviderTable;

class CanonizeProviderTableInitializer
{
public:
  explicit
  CanonizeProviderTableInitializer(CanonizeProviderTable& providerTable)
    : m_providerTable(providerTable)
  {
  }

  template<typename CP> void
  operator()(CP*)
  {
    shared_ptr<CanonizeProvider> cp = make_shared<CP>();

    std::set<std::string> schemes = cp->getSchemes();
    BOOST_ASSERT(!schemes.empty());
    for (std::set<std::string>::iterator it = schemes.begin();
         it != schemes.end(); ++it) {
      BOOST_ASSERT(m_providerTable.count(*it) == 0);
      m_providerTable[*it] = cp;
    }
  }

private:
  CanonizeProviderTable& m_providerTable;
};

static const CanonizeProvider*
getCanonizeProvider(const std::string& scheme)
{
  static CanonizeProviderTable providerTable;
  if (providerTable.empty()) {
    boost::mpl::for_each<CanonizeProviders>(CanonizeProviderTableInitializer(providerTable));
    BOOST_ASSERT(!providerTable.empty());
  }

  auto it = providerTable.find(scheme);
  if (it == providerTable.end()) {
    return nullptr;
  }
  return it->second.get();
}

bool
FaceUri::canCanonize(const std::string& scheme)
{
  return getCanonizeProvider(scheme) != 0;
}

bool
FaceUri::isCanonical() const
{
  const CanonizeProvider* cp = getCanonizeProvider(this->getScheme());
  if (cp == 0) {
    return false;
  }

  return cp->isCanonical(*this);
}

void
FaceUri::canonize(const CanonizeSuccessCallback& onSuccess,
                  const CanonizeFailureCallback& onFailure,
                  boost::asio::io_service& io, const time::nanoseconds& timeout) const
{
  const CanonizeProvider* cp = getCanonizeProvider(this->getScheme());
  if (cp == nullptr) {
    if (onFailure) {
      onFailure("scheme not supported");
    }
    return;
  }

  static CanonizeSuccessCallback successNop = bind([]{});
  static CanonizeFailureCallback failureNop = bind([]{});

  cp->canonize(*this,
               onSuccess ? onSuccess : successNop,
               onFailure ? onFailure : failureNop,
               io, timeout);
}

} // namespace util
} // namespace ndn