/*
    open source routing machine
    Copyright (C) Dennis Luxen, others 2010

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU AFFERO General Public License as published by
the Free Software Foundation; either version 3 of the License, or
any later version.

This program 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 Affero General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
or see http://www.gnu.org/licenses/agpl.txt.
*/

#ifndef HTTP_SERVER3_CONNECTION_HPP
#define HTTP_CONNECTION_HPP

#include <vector>

#include <boost/asio.hpp>
#include <boost/array.hpp>
#include <boost/bind.hpp>
#include <boost/noncopyable.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/enable_shared_from_this.hpp>
#include "reply.h"
#include "request.h"
#include "request_handler.h"
#include "request_parser.h"

namespace http {


/// Represents a single connection from a client.
class connection
: public boost::enable_shared_from_this<connection>,
private boost::noncopyable
{
public:
    /// Construct a connection with the given io_service.
    explicit connection(boost::asio::io_service& io_service,
            request_handler& handler);

    /// Get the socket associated with the connection.
    boost::asio::ip::tcp::socket& socket();

    /// Start the first asynchronous operation for the connection.
    void start();

private:
    /// Handle completion of a read operation.
    void handle_read(const boost::system::error_code& e,
            std::size_t bytes_transferred);

    /// Handle completion of a write operation.
    void handle_write(const boost::system::error_code& e);

    /// Strand to ensure the connection's handlers are not called concurrently.
    boost::asio::io_service::strand strand_;

    /// Socket for the connection.
    boost::asio::ip::tcp::socket socket_;

    /// The handler used to process the incoming request.
    request_handler& request_handler_;

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

    /// The incoming request.
    request request_;

    /// The parser for the incoming request.
    request_parser request_parser_;

    /// The reply to be sent back to the client.
    reply reply_;
};

typedef boost::shared_ptr<connection> connection_ptr;


connection::connection(boost::asio::io_service& io_service,
        request_handler& handler)
: strand_(io_service),
  socket_(io_service),
  request_handler_(handler)
{
}

boost::asio::ip::tcp::socket& connection::socket()
{
    return socket_;
}

void connection::start()
{
    socket_.async_read_some(boost::asio::buffer(buffer_),
            strand_.wrap(
                    boost::bind(&connection::handle_read, shared_from_this(),
                            boost::asio::placeholders::error,
                            boost::asio::placeholders::bytes_transferred)));
}

void connection::handle_read(const boost::system::error_code& e,
        std::size_t bytes_transferred)
{
    if (!e)
    {
        boost::tribool result;
        boost::tie(result, boost::tuples::ignore) = request_parser_.parse(
                request_, buffer_.data(), buffer_.data() + bytes_transferred);

        if (result)
        {
            request_handler_.handle_request(request_, reply_);
            boost::asio::async_write(socket_, reply_.to_buffers(),
                    strand_.wrap(
                            boost::bind(&connection::handle_write, shared_from_this(),
                                    boost::asio::placeholders::error)));
        }
        else if (!result)
        {
            reply_ = reply::stock_reply(reply::bad_request);
            boost::asio::async_write(socket_, reply_.to_buffers(),
                    strand_.wrap(
                            boost::bind(&connection::handle_write, shared_from_this(),
                                    boost::asio::placeholders::error)));
        }
        else
        {
            socket_.async_read_some(boost::asio::buffer(buffer_),
                    strand_.wrap(
                            boost::bind(&connection::handle_read, shared_from_this(),
                                    boost::asio::placeholders::error,
                                    boost::asio::placeholders::bytes_transferred)));
        }
    }
}

void connection::handle_write(const boost::system::error_code& e)
{
    if (!e)
    {
        // Initiate graceful connection closure.
        boost::system::error_code ignored_ec;
        socket_.shutdown(boost::asio::ip::tcp::socket::shutdown_both, ignored_ec);
    }

    // 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.
}

} // namespace http

#endif /* CONNECTION_HPP_ */