/* -*- c++ -*- */
/*
 * Copyright 2013 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * GNU Radio 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, or (at your option)
 * any later version.
 *
 * GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "tcp_connection.h"
#include <gnuradio/basic_block.h>
#include <gnuradio/blocks/pdu.h>

namespace gr {
namespace blocks {

tcp_connection::sptr tcp_connection::make(boost::asio::io_service& io_service,
                                          int MTU /*= 10000*/,
                                          bool no_delay /*=false*/)
{
    return sptr(new tcp_connection(io_service, MTU, no_delay));
}

tcp_connection::tcp_connection(boost::asio::io_service& io_service,
                               int MTU /*= 10000*/,
                               bool no_delay /*=false*/)
    : d_socket(io_service), d_block(NULL), d_no_delay(no_delay)
{
    d_buf.resize(MTU);
    try {
        d_socket.set_option(boost::asio::ip::tcp::no_delay(no_delay));
    } catch (...) {
        // Silently ignore failure (socket might be current in accept stage) and try again
        // in 'start'
    }
}

void tcp_connection::send(pmt::pmt_t vector)
{
    size_t len = pmt::blob_length(vector);

    // Asio async_write() requires the buffer to remain valid until the handler is called.
    boost::shared_ptr<char[]> txbuf(new char[len]);

    size_t temp = 0;
    memcpy(txbuf.get(), pmt::uniform_vector_elements(vector, temp), len);

    size_t offset = 0;
    while (offset < len) {
        // Limit the size of each write() to the MTU.
        // FIXME: Note that this has the effect of breaking a large PDU into several
        // smaller PDUs, each containing <= MTU bytes. Is this the desired behavior?
        size_t send_len = std::min((len - offset), d_buf.size());
        boost::asio::async_write(
            d_socket,
            boost::asio::buffer(txbuf.get() + offset, send_len),
            boost::bind(&tcp_connection::handle_write,
                        this,
                        txbuf,
                        boost::asio::placeholders::error,
                        boost::asio::placeholders::bytes_transferred));
        offset += send_len;
    }
}

void tcp_connection::start(gr::basic_block* block)
{
    d_block = block;
    d_socket.set_option(boost::asio::ip::tcp::no_delay(d_no_delay));
    d_socket.async_read_some(boost::asio::buffer(d_buf),
                             boost::bind(&tcp_connection::handle_read,
                                         this,
                                         boost::asio::placeholders::error,
                                         boost::asio::placeholders::bytes_transferred));
}

void tcp_connection::handle_read(const boost::system::error_code& error,
                                 size_t bytes_transferred)
{
    if (!error) {
        if (d_block) {
            pmt::pmt_t vector =
                pmt::init_u8vector(bytes_transferred, (const uint8_t*)&d_buf[0]);
            pmt::pmt_t pdu = pmt::cons(pmt::PMT_NIL, vector);

            d_block->message_port_pub(pdu::pdu_port_id(), pdu);
        }

        d_socket.async_read_some(
            boost::asio::buffer(d_buf),
            boost::bind(&tcp_connection::handle_read,
                        this,
                        boost::asio::placeholders::error,
                        boost::asio::placeholders::bytes_transferred));
    } else {
        d_socket.shutdown(boost::asio::ip::tcp::socket::shutdown_both);
        d_socket.close();
    }
}
} /* namespace blocks */
} /* namespace gr */
