/* -*- c++ -*- */
/*
 * gr-satnogs: SatNOGS GNU Radio Out-Of-Tree Module
 *
 *  Copyright (C) 2016, Libre Space Foundation <http://librespacefoundation.org/>
 *
 *  This program 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 of the License, or
 *  (at your option) 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 General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#define __STDC_FORMAT_MACROS
#include <inttypes.h>

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

#include <gnuradio/io_signature.h>
#include "tcp_rigctl_msg_source_impl.h"
#include <satnogs/log.h>
#include <ifaddrs.h>
#include <errno.h>
#include <limits.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>

namespace gr {
namespace satnogs {

tcp_rigctl_msg_source::sptr
tcp_rigctl_msg_source::make(const std::string &addr, uint16_t port,
                            bool server_mode, size_t interval_ms,
                            size_t mtu)
{
  return gnuradio::get_initial_sptr(
           new tcp_rigctl_msg_source_impl(addr, port, server_mode, interval_ms,
                                          mtu));
}

/*
 * The private constructor
 */
tcp_rigctl_msg_source_impl::tcp_rigctl_msg_source_impl(
  const std::string &addr, uint16_t port, bool server_mode,
  size_t interval_ms, size_t mtu) :
  gr::block("tcp_rigctl_msg_source",
            gr::io_signature::make(0, 0, 0),
            gr::io_signature::make(0, 0, 0)),
  d_ip_addr(addr),
  d_port(port),
  d_is_server(server_mode),
  d_interval_ms(interval_ms),
  d_mtu(mtu),
  d_running(true)
{
  message_port_register_out(pmt::mp("freq"));
  if (d_is_server) {
    d_thread = boost::shared_ptr<boost::thread> (
                 new boost::thread(
                   boost::bind(&tcp_rigctl_msg_source_impl::rigctl_server, this)));
  }
  else {
    d_thread = boost::shared_ptr<boost::thread> (
                 new boost::thread(
                   boost::bind(&tcp_rigctl_msg_source_impl::rigctl_client, this)));
  }
}

static inline void
send_freq(int sock, uint64_t freq)
{
  static char buf[512];
  snprintf(buf, 512, "%" PRIu64 "\n", freq);
  send(sock, buf, strnlen(buf, 512), 0);
}

static inline void
send_report_code(int sock, int code)
{
  static char buf[512];
  snprintf(buf, 512, "RPRT %d\n", code);
  send(sock, buf, strnlen(buf, 512), 0);
}

static inline void
request_freq_msg(int sock)
{
  static const char *cmd = "f\n";
  send(sock, cmd, strnlen(cmd, 2), 0);
}

static inline void
send_quit(int sock)
{
  static const char *cmd = "q\n";
  send(sock, cmd, strnlen(cmd, 2), 0);
}

void
tcp_rigctl_msg_source_impl::rigctl_client()
{
  int sock;
  struct sockaddr_in sin;
  ssize_t ret;
  uint8_t *buf;
  double freq = 0.0;
  int optval = 1;
  struct timeval timeout;
  timeout.tv_sec = 2;
  timeout.tv_usec = 0;

  if ((sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1) {
    perror("opening UDP socket");
    exit(EXIT_FAILURE);
  }

  memset(&sin, 0, sizeof(struct sockaddr_in));
  sin.sin_family = AF_INET;
  sin.sin_port = htons(d_port);
  sin.sin_addr.s_addr = INADDR_ANY;

  if (inet_aton(d_ip_addr.c_str(), &(sin.sin_addr)) == 0) {
    LOG_ERROR("Wrong IP address");
    close(sock);
    exit(EXIT_FAILURE);
  }

  if (connect(sock, (struct sockaddr *)&sin, sizeof(struct sockaddr_in)) != 0) {
    LOG_ERROR("Could not connect at rigctl server %s", d_ip_addr.c_str());
    close(sock);
    exit(EXIT_FAILURE);
  }

  /*
   * Apply the TCP_NODELAY option at the socket for a packet based
   * behavior.
   */
  if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, &optval, sizeof(int))
      < 0) {
    perror("TCP setsockopt TCP_NODELAY");
    shutdown(sock, SHUT_RDWR);
    close(sock);
    exit(EXIT_FAILURE);
  }

  /* Set a reasonable timeout at the response from the server */
  if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout))
      < 0) {
    perror("TCP setsockopt SO_RCVTIMEO");
    shutdown(sock, SHUT_RDWR);
    close(sock);
    exit(EXIT_FAILURE);
  }

  /* All good until now. Allocate buffer memory and proceed */
  buf = new uint8_t[d_mtu];
  sleep(2);
  while (d_running) {
    /* Request frequency from rigctl */
    request_freq_msg(sock);
    ret = recv(sock, buf, d_mtu, 0);
    if (ret > 0) {
      freq = get_freq_from_buf(buf);
      /*
       * If the frequency is different than 0, then the parsed value
       * is valid and an appropriate message can be generated
       *
       * NOTE: Comparison for equality in floats is a bit tricky.
       * But here the get_freq_from_buf() will assign a 0.0 explicitly
       * if something goes wrong. For this reason it is safe to compare
       * the in-equality against 0.0.
       */
      if (freq != 0.0 && !std::isnan(freq)) {
        message_port_pub(pmt::mp("freq"), pmt::from_double(freq));
      }
    }
    boost::this_thread::sleep(boost::posix_time::milliseconds(d_interval_ms));
  }

  send_quit(sock);
  shutdown(sock, SHUT_RDWR);
  close(sock);
  delete[] buf;
  exit(EXIT_SUCCESS);
}

void
tcp_rigctl_msg_source_impl::rigctl_server()
{
  int sock;
  int listen_sock;
  struct sockaddr_in sin;
  struct sockaddr client_addr;
  socklen_t client_addr_len;
  ssize_t ret;
  uint8_t *buf;
  double freq = 0.0;
  uint64_t reported_freq = 0;
  int error_code = 0;
  int optval = 1;

  if ((listen_sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1) {
    perror("opening UDP socket");
    exit(EXIT_FAILURE);
  }

  memset(&client_addr, 0, sizeof(struct sockaddr));
  memset(&sin, 0, sizeof(struct sockaddr_in));
  sin.sin_family = AF_INET;
  sin.sin_port = htons(d_port);
  sin.sin_addr.s_addr = INADDR_ANY;

  if (inet_aton(d_ip_addr.c_str(), &(sin.sin_addr)) == 0) {
    LOG_ERROR("Wrong IP address");
    close(listen_sock);
    exit(EXIT_FAILURE);
  }

  if (bind(listen_sock, (struct sockaddr *) &sin,
           sizeof(struct sockaddr_in)) == -1) {
    perror("TCP bind");
    close(listen_sock);
    exit(EXIT_FAILURE);
  }

  if (listen(listen_sock, 1000) == -1) {
    perror("TCP listen");
    close(listen_sock);
    exit(EXIT_FAILURE);
  }

  /* All good until now. Allocate buffer memory and proceed */
  buf = new uint8_t[d_mtu];

  while (d_running) {
    sock = accept(listen_sock, &client_addr, &client_addr_len);
    if (sock <= 0) {
      perror("TCP accept");
      exit(EXIT_FAILURE);
    }

    /* Apply the TCP_NODELAY option at the accepted socket */
    if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, &optval, sizeof(int))
        < 0) {
      perror("TCP setsockopt");
      shutdown(sock, SHUT_RDWR);
      close(sock);
      exit(EXIT_FAILURE);
    }

    while ((ret = recv(sock, buf, d_mtu, 0)) > 0 && d_running) {
      switch (buf[0]) {
      case 'F':
        freq = get_freq_from_buf(buf + 2);
        /*
         * If the frequency is different than 0, then the parsed value
         * is valid and an appropriate message can be generated
         *
         * NOTE: Comparison for equality in floats is a bit tricky.
         * But here the get_freq_from_buf() will assign a 0.0 explicitly
         * if something goes wrong. For this reason it is safe to compare
         * the in-equality against 0.0.
         */
        if (freq != 0.0) {
          reported_freq = freq;
          message_port_pub(pmt::mp("freq"), pmt::from_double(freq));
          error_code = 0;
        }
        else {
          error_code = -11;
        }
        /* Send the report code */
        send_report_code(sock, error_code);
        break;
      case 'f':
        send_freq(sock, reported_freq);
        break;
      /* Terminate the connection and exit */
      case 'q':
        send_report_code(sock, 0);
        d_running = false;
        break;
      default:
        LOG_WARN("Unsupported rigctl command");
        send_report_code(sock, -11);
      }
    }
    shutdown(sock, SHUT_RDWR);
    close(sock);
  }
  shutdown(listen_sock, SHUT_RDWR);
  close(listen_sock);
  delete[] buf;
  exit(EXIT_SUCCESS);
}

/**
 * Parses the string in the \p buf trying to extract a frequency reading
 * until the newline character
 * @param buf the buffer containing a line with the target frequency
 * @return the frequency converted into double
 */
double
tcp_rigctl_msg_source_impl::get_freq_from_buf(const uint8_t *buf)
{
  long long int f;
  char *end;
  f = strtoll((char *) buf, &end, 10);

  /* Check for various possible errors */
  if ((errno == ERANGE && (f == LLONG_MAX || f == LLONG_MIN))
      || (errno != 0 && f == 0)) {
    LOG_WARN("Invalid rigctl command");
    f = 0;
  }

  if ((char *) buf == end) {
    LOG_WARN("Invalid rigctl command");
    f = 0;
  }

  return (double) f;
}

/*
 * Our virtual destructor.
 */
tcp_rigctl_msg_source_impl::~tcp_rigctl_msg_source_impl()
{
  d_running = false;
  d_thread->join();
}

} /* namespace satnogs */
} /* namespace gr */