uhd

//

// Copyright 2010-2011 Ettus Research LLC

//

// 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/>.

//

#include <uhd/usrp/gps_ctrl.hpp>

#include <uhd/utils/msg.hpp>

#include <uhd/exception.hpp>

#include <uhd/types/sensors.hpp>

#include <boost/algorithm/string.hpp>

#include <boost/assign/list_of.hpp>

#include <boost/cstdint.hpp>

#include <boost/date_time/posix_time/posix_time.hpp>

#include <boost/thread/thread.hpp>

#include <boost/tokenizer.hpp>

#include <boost/format.hpp>

using namespace uhd;

using namespace boost::gregorian;

using namespace boost::posix_time;

using namespace boost::algorithm;

using namespace boost::this_thread;

/*!

 * A GPS control for Jackson Labs devices (and other NMEA compatible GPS's)

 */

class gps_ctrl_impl : public gps_ctrl{

public:

  gps_ctrl_impl(uart_iface::sptr uart){

    _uart = uart;

    std::string reply;

    bool i_heard_some_nmea = false, i_heard_something_weird = false;

    gps_type = GPS_TYPE_NONE;

    //first we look for a Jackson Labs Firefly (since that's what we provide...)

    _flush(); //get whatever junk is in the rx buffer right now, and throw it away

    _send("HAAAY GUYYYYS\n"); //to elicit a response from the Firefly

    //wait for _send(...) to return

    sleep(milliseconds(FIREFLY_STUPID_DELAY_MS));

    //then we loop until we either timeout, or until we get a response that indicates we're a JL device

    const boost::system_time comm_timeout = boost::get_system_time() + milliseconds(GPS_COMM_TIMEOUT_MS);

    while(boost::get_system_time() < comm_timeout) {

      reply = _recv();

      if(reply.find("Command Error") != std::string::npos) {

        gps_type = GPS_TYPE_JACKSON_LABS;

        break;

      } 

      else if(reply.substr(0, 3) == "$GP") i_heard_some_nmea = true; //but keep looking for that "Command Error" response

      else if(reply.length() != 0) i_heard_something_weird = true; //probably wrong baud rate

      sleep(milliseconds(GPS_TIMEOUT_DELAY_MS));

    }

    if((i_heard_some_nmea) && (gps_type != GPS_TYPE_JACKSON_LABS)) gps_type = GPS_TYPE_GENERIC_NMEA;

    if((gps_type == GPS_TYPE_NONE) && i_heard_something_weird) {

      UHD_MSG(error) << "GPS invalid reply \"" << reply << "\", assuming none available" << std::endl;

    }

    switch(gps_type) {

    case GPS_TYPE_JACKSON_LABS:

      UHD_MSG(status) << "Found a Jackson Labs GPS" << std::endl;

      init_firefly();

      break;

    case GPS_TYPE_GENERIC_NMEA:

      if(gps_type == GPS_TYPE_GENERIC_NMEA) UHD_MSG(status) << "Found a generic NMEA GPS device" << std::endl;

      break;

    case GPS_TYPE_NONE:

    default:

      break;

    }

  }

  ~gps_ctrl_impl(void){

    /* NOP */

  }

  //return a list of supported sensors

  std::vector<std::string> get_sensors(void) {

    std::vector<std::string> ret = boost::assign::list_of

        ("gps_gpgga")

        ("gps_gprmc")

        ("gps_gpgsa")

        ("gps_time")

        ("gps_locked");

    return ret;

  }

  uhd::sensor_value_t get_sensor(std::string key) {

    if(key == "gps_gpgga"

    or key == "gps_gprmc"

    or key == "gps_gpgsa") {

        return sensor_value_t(

                 boost::to_upper_copy(key),

                 get_nmea(boost::to_upper_copy(key.substr(4,8))),

                 "");

    }

    else if(key == "gps_time") {

        return sensor_value_t("GPS epoch time", int(get_epoch_time()), "seconds");

    }

    else if(key == "gps_locked") {

        return sensor_value_t("GPS lock status", locked(), "locked", "unlocked");

    }

    else {

        throw uhd::value_error("gps ctrl get_sensor unknown key: " + key);

    }

  }

private:

  void init_firefly(void) {

    //issue some setup stuff so it spits out the appropriate data

    //none of these should issue replies so we don't bother looking for them

    //we have to sleep between commands because the JL device, despite not acking, takes considerable time to process each command.

     sleep(milliseconds(FIREFLY_STUPID_DELAY_MS));

    _send("SYST:COMM:SER:ECHO OFF\n");

     sleep(milliseconds(FIREFLY_STUPID_DELAY_MS));

    _send("SYST:COMM:SER:PRO OFF\n");

     sleep(milliseconds(FIREFLY_STUPID_DELAY_MS));

    _send("GPS:GPGGA 1\n");

     sleep(milliseconds(FIREFLY_STUPID_DELAY_MS));

    _send("GPS:GGAST 0\n");

     sleep(milliseconds(FIREFLY_STUPID_DELAY_MS));

    _send("GPS:GPRMC 1\n");

     sleep(milliseconds(FIREFLY_STUPID_DELAY_MS));

    _send("GPS:GPGSA 1\n");

     sleep(milliseconds(FIREFLY_STUPID_DELAY_MS));

  }

  //retrieve a raw NMEA sentence

  std::string get_nmea(std::string msgtype) {

    msgtype.insert(0, "$");

    std::string reply;

    if(not gps_detected()) {

        UHD_MSG(error) << "get_nmea(): unsupported GPS or no GPS detected";

        return std::string();

    }

    _flush(); //flush all input before waiting for a message

    const boost::system_time comm_timeout = boost::get_system_time() + milliseconds(GPS_COMM_TIMEOUT_MS);

    while(boost::get_system_time() < comm_timeout) {

        reply = _recv();

        if(reply.substr(0, 6) == msgtype)

          return reply;

        boost::this_thread::sleep(milliseconds(GPS_TIMEOUT_DELAY_MS));

    }

    throw uhd::value_error(str(boost::format("get_nmea(): no %s message found") % msgtype));

    return std::string();

  }

  //helper function to retrieve a field from an NMEA sentence

  std::string get_token(std::string sentence, size_t offset) {

    boost::tokenizer<boost::escaped_list_separator<char> > tok(sentence);

    std::vector<std::string> toked;

    tok.assign(sentence); //this can throw

    toked.assign(tok.begin(), tok.end());

    if(toked.size() <= offset) {

        throw uhd::value_error(str(boost::format("Invalid response \"%s\"") % sentence));

    }

    return toked[offset];

  }

  ptime get_time(void) {

    int error_cnt = 0;

    ptime gps_time;

    while(error_cnt < 3) {

        try {

            std::string reply = get_nmea("GPRMC");

            std::string datestr = get_token(reply, 9);

            std::string timestr = get_token(reply, 1);

            if(datestr.size() == 0 or timestr.size() == 0) {

                throw uhd::value_error(str(boost::format("Invalid response \"%s\"") % reply));

            }

            //just trust me on this one

            gps_time = ptime( date( 

                             greg_year(boost::lexical_cast<int>(datestr.substr(4, 2)) + 2000),

                             greg_month(boost::lexical_cast<int>(datestr.substr(2, 2))), 

                             greg_day(boost::lexical_cast<int>(datestr.substr(0, 2))) 

                           ),

                          hours(  boost::lexical_cast<int>(timestr.substr(0, 2)))

                        + minutes(boost::lexical_cast<int>(timestr.substr(2, 2)))

                        + seconds(boost::lexical_cast<int>(timestr.substr(4, 2)))

                     );

            return gps_time;

        } catch(std::exception &e) {

            UHD_MSG(warning) << "get_time: " << e.what();

            error_cnt++;

        }

    }

    throw uhd::value_error("Timeout after no valid message found");

    return gps_time; //keep gcc from complaining

  }

  time_t get_epoch_time(void) {

      return (get_time() - from_time_t(0)).total_seconds();

  }

  bool gps_detected(void) {

    return (gps_type != GPS_TYPE_NONE);

  }

  bool locked(void) {

    int error_cnt = 0;

    while(error_cnt < 3) {

        try {

            std::string reply = get_nmea("GPGGA");

            if(reply.size() <= 1) return false;

            return (get_token(reply, 6) != "0");

        } catch(std::exception &e) {

            UHD_MSG(warning) << "locked: " << e.what();

            error_cnt++;

        }

    }

    throw uhd::value_error("Timeout after no valid message found");

    return false;

  }

  uart_iface::sptr _uart;

  void _flush(void){

    while (not _uart->read_uart(0.0).empty()){

        //NOP

    }

  }

  std::string _recv(void){

      return _uart->read_uart(GPS_TIMEOUT_DELAY_MS/1000.);

  }

  void _send(const std::string &buf){

      return _uart->write_uart(buf);

  }

  enum {

    GPS_TYPE_JACKSON_LABS,

    GPS_TYPE_GENERIC_NMEA,

    GPS_TYPE_NONE

  } gps_type;

  static const int GPS_COMM_TIMEOUT_MS = 1500;

  static const int GPS_TIMEOUT_DELAY_MS = 200;

  static const int FIREFLY_STUPID_DELAY_MS = 200;

};

/***********************************************************************

 * Public make function for the GPS control

 **********************************************************************/

gps_ctrl::sptr gps_ctrl::make(uart_iface::sptr uart){

    return sptr(new gps_ctrl_impl(uart));

}