/*!
 * \file rtklib_solver.cc
 * \brief PVT solver based on rtklib library functions adapted to the GNSS-SDR
 *  data flow and structures
 * \authors <ul>
 *          <li> 2017, Javier Arribas
 *          <li> 2017, Carles Fernandez
 *          <li> 2007-2013, T. Takasu
 *          </ul>
 *
 * This is a derived work from RTKLIB http://www.rtklib.com/
 * The original source code at https://github.com/tomojitakasu/RTKLIB is
 * released under the BSD 2-clause license with an additional exclusive clause
 * that does not apply here. This additional clause is reproduced below:
 *
 * " The software package includes some companion executive binaries or shared
 * libraries necessary to execute APs on Windows. These licenses succeed to the
 * original ones of these software. "
 *
 * Neither the executive binaries nor the shared libraries are required by, used
 * or included in GNSS-SDR.
 *
 * -------------------------------------------------------------------------
 * Copyright (C) 2007-2013, T. Takasu
 * Copyright (C) 2017, Javier Arribas
 * Copyright (C) 2017, Carles Fernandez
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * -----------------------------------------------------------------------*/

#include "rtklib_solver.h"
#include <glog/logging.h>
#include "rtklib_conversions.h"
#include "GPS_L1_CA.h"
#include "Galileo_E1.h"


using google::LogMessage;

rtklib_solver::rtklib_solver(int nchannels, std::string dump_filename, bool flag_dump_to_file,  rtk_t & rtk)
{
    // init empty ephemeris for all the available GNSS channels
    d_nchannels = nchannels;
    d_dump_filename = dump_filename;
    d_flag_dump_enabled = flag_dump_to_file;
    count_valid_position = 0;
    this->set_averaging_flag(false);
    rtk_ = rtk;

    pvt_sol = {{0,0}, {0,0,0,0,0,0}, {0,0,0,0,0,0}, {0,0,0,0,0,0}, '0', '0', '0', 0, 0, 0 };

    // ############# ENABLE DATA FILE LOG #################
    if (d_flag_dump_enabled == true)
        {
            if (d_dump_file.is_open() == false)
                {
                    try
                    {
                            d_dump_file.exceptions(std::ifstream::failbit | std::ifstream::badbit);
                            d_dump_file.open(d_dump_filename.c_str(), std::ios::out | std::ios::binary);
                            LOG(INFO) << "PVT lib dump enabled Log file: " << d_dump_filename.c_str();
                    }
                    catch (const std::ifstream::failure &e)
                    {
                            LOG(WARNING) << "Exception opening PVT lib dump file " << e.what();
                    }
                }
        }
}


rtklib_solver::~rtklib_solver()
{
    if (d_dump_file.is_open() == true)
        {
            try
            {
                    d_dump_file.close();
            }
            catch(const std::exception & ex)
            {
                    LOG(WARNING) << "Exception in destructor closing the dump file " << ex.what();
            }
        }
}


bool rtklib_solver::get_PVT(const std::map<int,Gnss_Synchro> & gnss_observables_map, double Rx_time, bool flag_averaging)
{
    std::map<int,Gnss_Synchro>::const_iterator gnss_observables_iter;
    std::map<int,Galileo_Ephemeris>::const_iterator galileo_ephemeris_iter;
    std::map<int,Gps_Ephemeris>::const_iterator gps_ephemeris_iter;
    std::map<int,Gps_CNAV_Ephemeris>::const_iterator gps_cnav_ephemeris_iter;

    this->set_averaging_flag(flag_averaging);

    // ********************************************************************************
    // ****** PREPARE THE DATA (SV EPHEMERIS AND OBSERVATIONS) ************************
    // ********************************************************************************
    int valid_obs = 0; //valid observations counter

    obsd_t obs_data[MAXOBS];
    eph_t eph_data[MAXOBS];

    for(gnss_observables_iter = gnss_observables_map.cbegin();
            gnss_observables_iter != gnss_observables_map.cend();
            gnss_observables_iter++)
        {
            switch(gnss_observables_iter->second.System)
            {
            case 'E':
                {
                    std::string sig_(gnss_observables_iter->second.Signal);
                    // Galileo E1
                    if(sig_.compare("1B") == 0)
                        {
                            // 1 Gal - find the ephemeris for the current GALILEO SV observation. The SV PRN ID is the map key
                            galileo_ephemeris_iter = galileo_ephemeris_map.find(gnss_observables_iter->second.PRN);
                            if (galileo_ephemeris_iter != galileo_ephemeris_map.cend())
                                {
                                    //convert ephemeris from GNSS-SDR class to RTKLIB structure
                                    eph_data[valid_obs] = eph_to_rtklib(galileo_ephemeris_iter->second);
                                    //convert observation from GNSS-SDR class to RTKLIB structure
                                    obsd_t newobs = {{0,0}, '0', '0', {}, {}, {}, {}, {}, {}};
                                    obs_data[valid_obs] = insert_obs_to_rtklib(newobs,
                                            gnss_observables_iter->second,
                                            galileo_ephemeris_iter->second.WN_5,
                                            0);
                                    valid_obs++;
                                }
                            else // the ephemeris are not available for this SV
                                {
                                    DLOG(INFO) << "No ephemeris data for SV " << gnss_observables_iter->second.PRN;
                                }

                        }
                    // Galileo E5
                    if(sig_.compare("5X") == 0)
                        {

                            // 1 Gal - find the ephemeris for the current GALILEO SV observation. The SV PRN ID is the map key
                            galileo_ephemeris_iter = galileo_ephemeris_map.find(gnss_observables_iter->second.PRN);
                            if (galileo_ephemeris_iter != galileo_ephemeris_map.cend())
                                {
                                    bool found_E1_obs=false;
                                    for (int i = 0; i < valid_obs; i++)
                                        {
                                            if (eph_data[i].sat == (static_cast<int>(gnss_observables_iter->second.PRN + NSATGPS + NSATGLO)))
                                                {
                                                    obs_data[i] = insert_obs_to_rtklib(obs_data[i],
                                                            gnss_observables_iter->second,
                                                            galileo_ephemeris_iter->second.WN_5,
                                                            2);//Band 3 (L5/E5)
                                                    found_E1_obs=true;
                                                    break;
                                                }
                                        }
                                    if (!found_E1_obs)
                                        {
                                            //insert Galileo E5 obs as new obs and also insert its ephemeris
                                            //convert ephemeris from GNSS-SDR class to RTKLIB structure
                                            eph_data[valid_obs] = eph_to_rtklib(galileo_ephemeris_iter->second);
                                            //convert observation from GNSS-SDR class to RTKLIB structure
                                            obsd_t newobs = {{0,0}, '0', '0', {}, {}, {}, {}, {}, {}};
                                            obs_data[valid_obs] = insert_obs_to_rtklib(newobs,
                                                    gnss_observables_iter->second,
                                                    galileo_ephemeris_iter->second.WN_5,
                                                    2); //Band 3 (L5/E5)
                                            valid_obs++;
                                        }
                                }
                            else // the ephemeris are not available for this SV
                                {
                                    DLOG(INFO) << "No ephemeris data for SV " << gnss_observables_iter->second.PRN;
                                }
                        }
                    break;
                }
            case 'G':
                {
                    // GPS L1
                    // 1 GPS - find the ephemeris for the current GPS SV observation. The SV PRN ID is the map key
                    std::string sig_(gnss_observables_iter->second.Signal);
                    if(sig_.compare("1C") == 0)
                        {
                            gps_ephemeris_iter = gps_ephemeris_map.find(gnss_observables_iter->second.PRN);
                            if (gps_ephemeris_iter != gps_ephemeris_map.cend())
                                {
                                    //convert ephemeris from GNSS-SDR class to RTKLIB structure
                                    eph_data[valid_obs] = eph_to_rtklib(gps_ephemeris_iter->second);
                                    //convert observation from GNSS-SDR class to RTKLIB structure
                                    obsd_t newobs = {{0,0}, '0', '0', {}, {}, {}, {}, {}, {}};
                                    obs_data[valid_obs] = insert_obs_to_rtklib(newobs,
                                            gnss_observables_iter->second,
                                            gps_ephemeris_iter->second.i_GPS_week,
                                            0);
                                    valid_obs++;
                                }
                            else // the ephemeris are not available for this SV
                                {
                                    DLOG(INFO) << "No ephemeris data for SV " << gnss_observables_iter->first;
                                }
                        }
                    //GPS L2
                    if(sig_.compare("2S") == 0)
                        {
                            gps_cnav_ephemeris_iter = gps_cnav_ephemeris_map.find(gnss_observables_iter->second.PRN);
                            if (gps_cnav_ephemeris_iter != gps_cnav_ephemeris_map.cend())
                                {
                                    // 1. Find the same satellite in GPS L1 band
                                    gps_ephemeris_iter = gps_ephemeris_map.find(gnss_observables_iter->second.PRN);
                                    if (gps_ephemeris_iter != gps_ephemeris_map.cend())
                                        {
                                            // 2. If found, replace the existing GPS L1 ephemeris with the GPS L2 ephemeris
                                            // (more precise!), and attach the L2 observation to the L1 observation in RTKLIB structure
                                            for (int i = 0; i < valid_obs; i++)
                                                {
                                                    if (eph_data[i].sat == static_cast<int>(gnss_observables_iter->second.PRN))
                                                        {
                                                            eph_data[i] = eph_to_rtklib(gps_cnav_ephemeris_iter->second);
                                                            obs_data[i] = insert_obs_to_rtklib(obs_data[i],
                                                                    gnss_observables_iter->second,
                                                                    gps_cnav_ephemeris_iter->second.i_GPS_week,
                                                                    1);//Band 2 (L2)
                                                            break;
                                                        }
                                                }
                                        }
                                    else
                                        {
                                            // 3. If not found, insert the GPS L2 ephemeris and the observation
                                            //convert ephemeris from GNSS-SDR class to RTKLIB structure
                                            eph_data[valid_obs] = eph_to_rtklib(gps_cnav_ephemeris_iter->second);
                                            //convert observation from GNSS-SDR class to RTKLIB structure
                                            obsd_t newobs = {{0,0}, '0', '0', {}, {}, {}, {}, {}, {}};
                                            obs_data[valid_obs] = insert_obs_to_rtklib(newobs,
                                                    gnss_observables_iter->second,
                                                    gps_cnav_ephemeris_iter->second.i_GPS_week,
                                                    1);//Band 2 (L2)
                                            valid_obs++;
                                        }
                                }
                            else // the ephemeris are not available for this SV
                                {
                                    DLOG(INFO) << "No ephemeris data for SV " << gnss_observables_iter->second.PRN;
                                }
                        }
                    break;
                }
            default :
                DLOG(INFO) << "Hybrid observables: Unknown GNSS";
                break;
            }
        }

    // **********************************************************************
    // ****** SOLVE PVT******************************************************
    // **********************************************************************

    this->set_valid_position(false);
    if (valid_obs > 0)
        {
            int result = 0;
            nav_t nav_data;
            nav_data.eph = eph_data;
            nav_data.n = valid_obs;
            for (int i = 0; i < MAXSAT; i++)
                {
                    nav_data.lam[i][0] = SPEED_OF_LIGHT / FREQ1; /* L1/E1 */
                    nav_data.lam[i][1] = SPEED_OF_LIGHT / FREQ2; /* L2 */
                    nav_data.lam[i][2] = SPEED_OF_LIGHT / FREQ5; /* L5/E5 */
                }

            result = rtkpos(&rtk_, obs_data, valid_obs, &nav_data);
            if(result == 0)
                {
                    LOG(INFO) << "RTKLIB rtkpos error message: " << rtk_.errbuf;
                    this->set_time_offset_s(0.0); //reset rx time estimation
                    this->set_num_valid_observations(0);
                }
            else
                {
                    this->set_num_valid_observations(rtk_.sol.ns); //record the number of valid satellites used by the PVT solver
                    pvt_sol = rtk_.sol;
                    this->set_valid_position(true);
                    arma::vec rx_position_and_time(4);
                    rx_position_and_time(0) = pvt_sol.rr[0];
                    rx_position_and_time(1) = pvt_sol.rr[1];
                    rx_position_and_time(2) = pvt_sol.rr[2];
                    rx_position_and_time(3) = pvt_sol.dtr[0];
                    this->set_rx_pos(rx_position_and_time.rows(0, 2)); // save ECEF position for the next iteration
                    double offset_s = this->get_time_offset_s();
                    this->set_time_offset_s(offset_s + (rx_position_and_time(3) / GPS_C_m_s)); // accumulate the rx time error for the next iteration [meters]->[seconds]
                    DLOG(INFO) << "RTKLIB Position at TOW=" << Rx_time << " in ECEF (X,Y,Z,t[meters]) = " << rx_position_and_time;

                    boost::posix_time::ptime p_time;
                    gtime_t rtklib_utc_time = gpst2utc(pvt_sol.time);
                    p_time = boost::posix_time::from_time_t(rtklib_utc_time.time);
                    p_time += boost::posix_time::microseconds(round(rtklib_utc_time.sec * 1e6));
                    this->set_position_UTC_time(p_time);
                    cart2geo(static_cast<double>(rx_position_and_time(0)), static_cast<double>(rx_position_and_time(1)), static_cast<double>(rx_position_and_time(2)), 4);

                    DLOG(INFO) << "RTKLIB Position at " << boost::posix_time::to_simple_string(p_time)
                               << " is Lat = " << this->get_latitude() << " [deg], Long = " << this->get_longitude()
                               << " [deg], Height= " << this->get_height() << " [m]" << " RX time offset= " << this->get_time_offset_s() << " [s]";

                    // ######## LOG FILE #########
                    if(d_flag_dump_enabled == true)
                        {
                            // MULTIPLEXED FILE RECORDING - Record results to file
                            try
                            {
                                    double tmp_double;
                                    //  PVT GPS time
                                    tmp_double = Rx_time;
                                    d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
                                    // ECEF User Position East [m]
                                    tmp_double = rx_position_and_time(0);
                                    d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
                                    // ECEF User Position North [m]
                                    tmp_double = rx_position_and_time(1);
                                    d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
                                    // ECEF User Position Up [m]
                                    tmp_double = rx_position_and_time(2);
                                    d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
                                    // User clock offset [s]
                                    tmp_double = rx_position_and_time(3);
                                    d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
                                    // GEO user position Latitude [deg]
                                    tmp_double = this->get_latitude();
                                    d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
                                    // GEO user position Longitude [deg]
                                    tmp_double = this->get_longitude();
                                    d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
                                    // GEO user position Height [m]
                                    tmp_double = this->get_height();
                                    d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
                            }
                            catch (const std::ifstream::failure& e)
                            {
                                    LOG(WARNING) << "Exception writing PVT LS dump file " << e.what();
                            }
                        }
                }
        }
    return this->is_valid_position();
}