/*
 * nghttp2 - HTTP/2 C Library
 *
 * Copyright (c) 2014 Tatsuhiro Tsujikawa
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
// We wrote this code based on the original code which has the
// following license:
//
// connection.hpp
// ~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2013 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#ifndef HTTP_SERVER2_CONNECTION_HPP
#define HTTP_SERVER2_CONNECTION_HPP

#include "nghttp2_config.h"

#include <memory>

#include <boost/asio.hpp>
#include <boost/noncopyable.hpp>
#include <boost/array.hpp>

#include <nghttp2/asio_http2.h>
#include "asio_http2_handler.h"
#include "util.h"

namespace nghttp2 {

namespace asio_http2 {

namespace server {

/// Represents a single connection from a client.
template<typename socket_type>
class connection
  : public std::enable_shared_from_this<connection<socket_type>>,
    private boost::noncopyable
{
public:
  /// Construct a connection with the given io_service.
  template<typename... SocketArgs>
  explicit connection(request_cb cb,
                      boost::asio::io_service& task_io_service,
                      SocketArgs&&... args)
    : socket_(std::forward<SocketArgs>(args)...),
      request_cb_(std::move(cb)),
      task_io_service_(task_io_service),
      writing_(false)
  {}

  /// Start the first asynchronous operation for the connection.
  void start()
  {
    handler_ = std::make_shared<http2_handler>
      (socket_.get_io_service(),
       task_io_service_,
       [this]()
       {
         do_write();
       },
       request_cb_);
    if(handler_->start() != 0) {
      return;
    }
    do_read();
  }

  socket_type& socket()
  {
    return socket_;
  }

  void do_read()
  {
    auto self = this->shared_from_this();

    socket_.async_read_some
      (boost::asio::buffer(buffer_),
       [this, self](const boost::system::error_code& e,
                    std::size_t bytes_transferred)
       {
         if (!e) {
           if(handler_->on_read(buffer_, bytes_transferred) != 0) {
             return;
           }

           do_write();

           if(!writing_ && handler_->should_stop()) {
             return;
           }

           do_read();
         }

         // If an error occurs then no new asynchronous operations are
         // started. This means that all shared_ptr references to the
         // connection object will disappear and the object will be
         // destroyed automatically after this handler returns. The
         // connection class's destructor closes the socket.
       });
  }

  void do_write()
  {
    auto self = this->shared_from_this();

    if(writing_) {
      return;
    }

    int rv;
    std::size_t nwrite;

    rv = handler_->on_write(outbuf_, nwrite);

    if(rv != 0) {
      return;
    }

    if(nwrite == 0) {
      return;
    }

    writing_ = true;

    boost::asio::async_write
      (socket_, boost::asio::buffer(outbuf_, nwrite),
       [this, self](const boost::system::error_code& e,
                    std::size_t)
       {
         if(!e) {
           writing_ = false;

           do_write();
         }
       });

    // No new asynchronous operations are started. This means that all
    // shared_ptr references to the connection object will disappear and
    // the object will be destroyed automatically after this handler
    // returns. The connection class's destructor closes the socket.
  }

private:
  socket_type socket_;

  request_cb request_cb_;

  boost::asio::io_service& task_io_service_;

  std::shared_ptr<http2_handler> handler_;

  /// Buffer for incoming data.
  boost::array<uint8_t, 8192> buffer_;

  boost::array<uint8_t, 16394> outbuf_;

  bool writing_;
};

} // namespace server

} // namespace asio_http2

} // namespace nghttp2

#endif // HTTP_SERVER2_CONNECTION_HPP