/* -*- 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/>.
 */

#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, "%llu\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 int f;
      char *end;
      f = strtol ((char *) buf, &end, 10);

      /* Check for various possible errors */
      if ((errno == ERANGE && (f == LONG_MAX || f == LONG_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 */