/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (C) 2014 Named Data Networking Project
 * See COPYING for copyright and distribution information.
 */

#include "tcp-channel.hpp"

namespace nfd {

NFD_LOG_INIT("TcpChannel");

using namespace boost::asio;

TcpChannel::TcpChannel(io_service& ioService,
                       const tcp::Endpoint& localEndpoint)
  : m_ioService(ioService)
  , m_localEndpoint(localEndpoint)
{
}

void
TcpChannel::listen(const FaceCreatedCallback& onFaceCreated,
                   const ConnectFailedCallback& onAcceptFailed,
                   int backlog/* = tcp::acceptor::max_connections*/)
{
  m_acceptor = make_shared<ip::tcp::acceptor>(boost::ref(m_ioService));
  m_acceptor->open(m_localEndpoint.protocol());
  m_acceptor->set_option(ip::tcp::acceptor::reuse_address(true));
  m_acceptor->bind(m_localEndpoint);
  m_acceptor->listen(backlog);

  shared_ptr<ip::tcp::socket> clientSocket =
    make_shared<ip::tcp::socket>(boost::ref(m_ioService));
  m_acceptor->async_accept(*clientSocket,
                           bind(&TcpChannel::handleSuccessfulAccept, this, _1,
                                clientSocket,
                                onFaceCreated, onAcceptFailed));
}

void
TcpChannel::connect(const tcp::Endpoint& remoteEndpoint,
                    const TcpChannel::FaceCreatedCallback& onFaceCreated,
                    const TcpChannel::ConnectFailedCallback& onConnectFailed,
                    const time::Duration& timeout/* = time::seconds(4)*/)
{
  ChannelFaceMap::iterator i = m_channelFaces.find(remoteEndpoint);
  if (i != m_channelFaces.end()) {
    onFaceCreated(i->second);
    return;
  }

  shared_ptr<ip::tcp::socket> clientSocket =
    make_shared<ip::tcp::socket>(boost::ref(m_ioService));

  shared_ptr<monotonic_deadline_timer> connectTimeoutTimer =
    make_shared<monotonic_deadline_timer>(boost::ref(m_ioService));

  clientSocket->open(m_localEndpoint.protocol());

  // The following does not work and CCNx does not bind the local
  // socket to a fixed port number for TCP connections

  // clientSocket->set_option(ip::tcp::socket::reuse_address(true));
  // clientSocket->bind(m_localEndpoint);

  clientSocket->async_connect(remoteEndpoint,
                              bind(&TcpChannel::handleSuccessfulConnect, this, _1,
                                   clientSocket, connectTimeoutTimer,
                                   onFaceCreated, onConnectFailed));

  connectTimeoutTimer->expires_from_now(timeout);
  connectTimeoutTimer->async_wait(bind(&TcpChannel::handleFailedConnect, this, _1,
                                       clientSocket, connectTimeoutTimer,
                                       onConnectFailed));
}

void
TcpChannel::connect(const std::string& remoteHost, const std::string& remotePort,
                    const TcpChannel::FaceCreatedCallback& onFaceCreated,
                    const TcpChannel::ConnectFailedCallback& onConnectFailed,
                    const time::Duration& timeout/* = time::seconds(4)*/)
{
  shared_ptr<ip::tcp::socket> clientSocket =
    make_shared<ip::tcp::socket>(boost::ref(m_ioService));

  shared_ptr<monotonic_deadline_timer> connectTimeoutTimer =
    make_shared<monotonic_deadline_timer>(boost::ref(m_ioService));

  clientSocket->open(m_localEndpoint.protocol());

  // The following does not work and CCNx does not bind the local
  // socket to a fixed port number for TCP connections

  // clientSocket->set_option(ip::tcp::socket::reuse_address(true));
  // clientSocket->bind(m_localEndpoint);

  ip::tcp::resolver::query query(remoteHost, remotePort);
  shared_ptr<ip::tcp::resolver> resolver =
    make_shared<ip::tcp::resolver>(boost::ref(m_ioService));

  resolver->async_resolve(query,
                          bind(&TcpChannel::handleEndpointResolution, this, _1, _2,
                               clientSocket, connectTimeoutTimer,
                               onFaceCreated, onConnectFailed,
                               resolver));

  connectTimeoutTimer->expires_from_now(timeout);
  connectTimeoutTimer->async_wait(bind(&TcpChannel::handleFailedConnect, this, _1,
                                       clientSocket, connectTimeoutTimer,
                                       onConnectFailed));
}

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

void
TcpChannel::createFace(const shared_ptr<ip::tcp::socket>& socket,
                       const FaceCreatedCallback& onFaceCreated)
{
  tcp::Endpoint remoteEndpoint = socket->remote_endpoint();

  shared_ptr<Face> face;
  if (socket->local_endpoint().address().is_loopback())
    face = make_shared<TcpLocalFace>(boost::cref(socket));
  else
    face = make_shared<TcpFace>(boost::cref(socket));
  
  face->onFail += bind(&TcpChannel::afterFaceFailed, this, remoteEndpoint);

  onFaceCreated(face);
  m_channelFaces[remoteEndpoint] = face;
}

void
TcpChannel::afterFaceFailed(tcp::Endpoint &remoteEndpoint)
{
  NFD_LOG_DEBUG("afterFaceFailed: " << remoteEndpoint);
  m_channelFaces.erase(remoteEndpoint);
}

void
TcpChannel::handleSuccessfulAccept(const boost::system::error_code& error,
                                   const shared_ptr<boost::asio::ip::tcp::socket>& socket,
                                   const FaceCreatedCallback& onFaceCreated,
                                   const ConnectFailedCallback& onAcceptFailed)
{
  if (error) {
    if (error == boost::system::errc::operation_canceled) // when socket is closed by someone
      return;

    NFD_LOG_DEBUG("Connect to remote endpoint failed: "
                  << error.category().message(error.value()));
    
    onAcceptFailed("Connect to remote endpoint failed: " +
                   error.category().message(error.value()));
    return;
  }

  // prepare accepting the next connection
  shared_ptr<ip::tcp::socket> clientSocket =
    make_shared<ip::tcp::socket>(boost::ref(m_ioService));
  m_acceptor->async_accept(*clientSocket,
                           bind(&TcpChannel::handleSuccessfulAccept, this, _1,
                                clientSocket,
                                onFaceCreated, onAcceptFailed));

  NFD_LOG_DEBUG("[" << m_localEndpoint << "] "
                "<< Connection from " << socket->remote_endpoint());
  createFace(socket, onFaceCreated);
}

void
TcpChannel::handleSuccessfulConnect(const boost::system::error_code& error,
                                    const shared_ptr<ip::tcp::socket>& socket,
                                    const shared_ptr<monotonic_deadline_timer>& timer,
                                    const FaceCreatedCallback& onFaceCreated,
                                    const ConnectFailedCallback& onConnectFailed)
{
  timer->cancel();

  if (error) {
    if (error == boost::system::errc::operation_canceled) // when socket is closed by someone
      return;

    socket->close();
    
    NFD_LOG_DEBUG("Connect to remote endpoint failed: "
                  << error.category().message(error.value()));
    
    onConnectFailed("Connect to remote endpoint failed: " +
                    error.category().message(error.value()));
    return;
  }

  NFD_LOG_DEBUG("[" << m_localEndpoint << "] "
                ">> Connection to " << socket->remote_endpoint());
  
  createFace(socket, onFaceCreated);
}

void
TcpChannel::handleFailedConnect(const boost::system::error_code& error,
                                const shared_ptr<ip::tcp::socket>& socket,
                                const shared_ptr<monotonic_deadline_timer>& timer,
                                const ConnectFailedCallback& onConnectFailed)
{
  if (error) { // e.g., cancelled
    return;
  }

  NFD_LOG_DEBUG("Connect to remote endpoint timed out: "
                << error.category().message(error.value()));
  
  onConnectFailed("Connect to remote endpoint timed out: " +
                  error.category().message(error.value()));
  socket->close(); // abort the connection
}

void
TcpChannel::handleEndpointResolution(const boost::system::error_code& error,
                                     ip::tcp::resolver::iterator remoteEndpoint,
                                     const shared_ptr<boost::asio::ip::tcp::socket>& socket,
                                     const shared_ptr<boost::asio::monotonic_deadline_timer>& timer,
                                     const FaceCreatedCallback& onFaceCreated,
                                     const ConnectFailedCallback& onConnectFailed,
                                     const shared_ptr<ip::tcp::resolver>& resolver)
{
  if (error ||
      remoteEndpoint == ip::tcp::resolver::iterator())
    {
      if (error == boost::system::errc::operation_canceled) // when socket is closed by someone
        return;

      socket->close();
      timer->cancel();

      NFD_LOG_DEBUG("Remote endpoint hostname or port cannot be resolved: "
                    << error.category().message(error.value()));
      
      onConnectFailed("Remote endpoint hostname or port cannot be resolved: " +
                      error.category().message(error.value()));
      return;
    }

  // got endpoint, now trying to connect (only try the first resolution option)
  socket->async_connect(*remoteEndpoint,
                        bind(&TcpChannel::handleSuccessfulConnect, this, _1,
                             socket, timer,
                             onFaceCreated, onConnectFailed));
}

} // namespace nfd