/*!
 * \file glonass_gnav_ephemeris.h
 * \brief  Interface of a GLONASS EPHEMERIS storage
 * \note Code added as part of GSoC 2017 program
 * \author Damian Miralles, 2017. dmiralles2009(at)gmail.com
 * \see <a href="http://russianspacesystems.ru/wp-content/uploads/2016/08/ICD_GLONASS_eng_v5.1.pdf">GLONASS ICD</a>
 *
 * -----------------------------------------------------------------------------
 *
 * GNSS-SDR is a Global Navigation Satellite System software-defined receiver.
 * This file is part of GNSS-SDR.
 *
 * Copyright (C) 2010-2020  (see AUTHORS file for a list of contributors)
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 * -----------------------------------------------------------------------------
 */


#ifndef GNSS_SDR_GLONASS_GNAV_EPHEMERIS_H
#define GNSS_SDR_GLONASS_GNAV_EPHEMERIS_H


#include "glonass_gnav_utc_model.h"
#include <boost/date_time/posix_time/ptime.hpp>  // for ptime
#include <boost/serialization/nvp.hpp>
#include <cstdint>

/** \addtogroup Core
 * \{ */
/** \addtogroup System_Parameters
 * \{ */


/*!
 * \brief This class is a storage and orbital model functions for the GLONASS SV ephemeris data as described in GLONASS ICD (Edition 5.1)
 * \note Code added as part of GSoC 2017 program
 * \see <a href="http://russianspacesystems.ru/wp-content/uploads/2016/08/ICD_GLONASS_eng_v5.1.pdf">GLONASS ICD</a>
 */
class Glonass_Gnav_Ephemeris
{
public:
    /*!
     * Default constructor
     */
    Glonass_Gnav_Ephemeris() = default;

    double d_m{};            //!< String number within frame [dimensionless]
    double d_t_k{};          //!< GLONASS Time (UTC(SU) + 3 h) referenced to the beginning of the frame within the current day [s]
    double d_t_b{};          //!< Reference ephemeris relative time in GLONASS Time (UTC(SU) + 3 h). Index of a time interval within current day according to UTC(SU) + 03 hours 00 min. [s]
    double d_M{};            //!< Type of satellite transmitting navigation signal [dimensionless]
    double d_gamma_n{};      //!< Relative deviation of predicted carrier frequency value of n- satellite from nominal value at the instant tb [dimensionless]
    double d_tau_n{};        //!< Correction to the nth satellite time (tn) relative to GLONASS time (te),
    double d_Xn{};           //!< Earth-fixed coordinate x of the satellite in PZ-90.02 coordinate system [km].
    double d_Yn{};           //!< Earth-fixed coordinate y of the satellite in PZ-90.02 coordinate system [km]
    double d_Zn{};           //!< Earth-fixed coordinate z of the satellite in PZ-90.02 coordinate system [km]
    double d_VXn{};          //!< Earth-fixed velocity coordinate x of the satellite in PZ-90.02 coordinate system [km/s]
    double d_VYn{};          //!< Earth-fixed velocity coordinate y of the satellite in PZ-90.02 coordinate system [km/s]
    double d_VZn{};          //!< Earth-fixed velocity coordinate z of the satellite in PZ-90.02 coordinate system [km/s]
    double d_AXn{};          //!< Earth-fixed acceleration coordinate x of the satellite in PZ-90.02 coordinate system [km/s^2]
    double d_AYn{};          //!< Earth-fixed acceleration coordinate y of the satellite in PZ-90.02 coordinate system [km/s^2]
    double d_AZn{};          //!< Earth-fixed acceleration coordinate z of the satellite in PZ-90.02 coordinate system [km/s^2]
    double d_B_n{};          //!< Health flag [dimensionless]
    double d_P{};            //!< Technological parameter of control segment, indication the satellite operation mode in respect of time parameters [dimensionless]
    double d_N_T{};          //!< Current date, calendar number of day within four-year interval starting from the 1-st of January in a leap year [days]
    double d_F_T{};          //!< Parameter that provides the predicted satellite user range accuracy at time tb [dimensionless]
    double d_n{};            //!< Index of the satellite transmitting given navigation signal. It corresponds to a slot number within GLONASS constellation
    double d_Delta_tau_n{};  //!< Time difference between navigation RF signal transmitted in L2 sub- band and aviation RF signal transmitted in L1 sub-band by nth satellite. [dimensionless]
    double d_E_n{};          //!< Characterises "age" of a current information [days]
    double d_P_1{};          //!< Flag of the immediate data updating [minutes]
    bool d_P_2{};            //!< Flag of oddness ("1") or evenness ("0") of the value of (tb) [dimensionless]
    bool d_P_3{};            //!< Flag indicating a number of satellites for which almanac is transmitted within given frame: "1" corresponds to 5 satellites and "0" corresponds to 4 satellites [dimensionless]
    bool d_P_4{};            //!< Flag to show that ephemeris parameters are present. "1" indicates that updated ephemeris or frequency/time parameters have been uploaded by the control segment [dimensionless]
    bool d_l3rd_n{};         //!< Health flag for nth satellite; ln = 0 indicates the n-th satellite is healthy, ln = 1 indicates malfunction of this nth satellite [dimensionless]
    bool d_l5th_n{};         //!< Health flag for nth satellite; ln = 0 indicates the n-th satellite is healthy, ln = 1 indicates malfunction of this nth satellite [dimensionless]

    // Immediate deliverables of ephemeris information
    // Satellite Identification Information
    int32_t i_satellite_freq_channel{};  //!< SV Frequency Channel Number
    uint32_t PRN{};                      //!< SV PRN Number, equivalent to slot number for compatibility with GPS
    uint32_t i_satellite_slot_number{};  //!< SV Slot Number
    double d_yr = 1972.0;                //!< Current year
    double d_satClkDrift{};              //!< GLONASS clock error
    double d_dtr{};                      //!< relativistic clock correction term
    double d_iode{};                     //!< Issue of data, ephemeris (Bit 0-6 of tb)
    double d_tau_c{};                    //!< GLONASST 2 UTC correction (todo) may be eliminated
    double d_TOW{};                      //!< GLONASST IN GPST seconds of week
    int32_t d_WN{};                      //!< GLONASST IN GPST week number of the start of frame
    double d_tod{};                      //!< Time of Day since ephemeris where decoded

    /*!
     * \brief Sets (\a d_satClkDrift)and returns the clock drift in seconds according to the User Algorithm for SV Clock Correction
     */
    double sv_clock_drift(double transmitTime, double timeCorrUTC);

    /*!
     *  \brief Computes the GLONASS System Time and returns a boost::posix_time::ptime object
     * \ param offset_time Is the start of day offset to compute the time
     */
    boost::posix_time::ptime compute_GLONASS_time(double offset_time) const;

    /*!
     * \brief Converts from GLONASST to UTC
     * \details The function simply adjust for the 6 hrs offset between GLONASST and UTC
     * \param[in] offset_time Is the start of day offset
     * \param[in] glot2utc_corr Correction from GLONASST to UTC
     * \returns UTC time as a boost::posix_time::ptime object
     */
    boost::posix_time::ptime glot_to_utc(double offset_time, double glot2utc_corr) const;

    /*!
     * \brief Converts from GLONASST to GPST
     * \details Converts from GLONASST to GPST in time of week (TOW) and week number (WN) format
     * \param[in] tod_offset Is the start of day offset
     * \param[in] glot2utc_corr Correction from GLONASST to UTC
     * \param[in] glot2gpst_corr Correction from GLONASST to GPST
     * \param[out] WN Week Number, not in mod(1024) format
     * \param[out] TOW Time of Week in seconds of week
     */
    void glot_to_gpst(double tod_offset, double glot2utc_corr, double glot2gpst_corr, int32_t* WN, double* TOW) const;

    template <class Archive>

    /*!
     * \brief Serialize is a boost standard method to be called by the boost XML
     * serialization. Here is used to save the ephemeris data on disk file.
     */
    void serialize(Archive& archive, const uint32_t version)
    {
        if (version)
            {
            };

        archive& BOOST_SERIALIZATION_NVP(i_satellite_freq_channel);  //!< SV PRN frequency channel number
        archive& BOOST_SERIALIZATION_NVP(PRN);
        archive& BOOST_SERIALIZATION_NVP(i_satellite_slot_number);
        archive& BOOST_SERIALIZATION_NVP(d_m);            //!< String number within frame [dimensionless]
        archive& BOOST_SERIALIZATION_NVP(d_t_k);          //!< Time referenced to the beginning of the frame within the current day [hours, minutes, seconds]
        archive& BOOST_SERIALIZATION_NVP(d_t_b);          //!< Index of a time interval within current day according to UTC(SU) + 03 hours 00 min. [minutes]
        archive& BOOST_SERIALIZATION_NVP(d_M);            //!< Type of satellite transmitting navigation signal [dimensionless]
        archive& BOOST_SERIALIZATION_NVP(d_gamma_n);      //!< Relative deviation of predicted carrier frequency value of n- satellite from nominal value at the instant tb [dimensionless]
        archive& BOOST_SERIALIZATION_NVP(d_tau_n);        //!< Correction to the nth satellite time (tn) relative to GLONASS time (te)
        archive& BOOST_SERIALIZATION_NVP(d_Xn);           //!< Earth-fixed coordinate x of the satellite in PZ-90.02 coordinate system [km].
        archive& BOOST_SERIALIZATION_NVP(d_Yn);           //!< Earth-fixed coordinate y of the satellite in PZ-90.02 coordinate system [km]
        archive& BOOST_SERIALIZATION_NVP(d_Zn);           //!< Earth-fixed coordinate z of the satellite in PZ-90.02 coordinate system [km]
        archive& BOOST_SERIALIZATION_NVP(d_VXn);          //!< Earth-fixed velocity coordinate x of the satellite in PZ-90.02 coordinate system [km/s]
        archive& BOOST_SERIALIZATION_NVP(d_VYn);          //!< Earth-fixed velocity coordinate y of the satellite in PZ-90.02 coordinate system [km/s]
        archive& BOOST_SERIALIZATION_NVP(d_VZn);          //!< Earth-fixed velocity coordinate z of the satellite in PZ-90.02 coordinate system [km/s]
        archive& BOOST_SERIALIZATION_NVP(d_AXn);          //!< Earth-fixed acceleration coordinate x of the satellite in PZ-90.02 coordinate system [km/s^2]
        archive& BOOST_SERIALIZATION_NVP(d_AYn);          //!< Earth-fixed acceleration coordinate y of the satellite in PZ-90.02 coordinate system [km/s^2]
        archive& BOOST_SERIALIZATION_NVP(d_AZn);          //!< Earth-fixed acceleration coordinate z of the satellite in PZ-90.02 coordinate system [km/s^2]
        archive& BOOST_SERIALIZATION_NVP(d_B_n);          //!< Health flag [dimensionless]
        archive& BOOST_SERIALIZATION_NVP(d_P);            //!< Technological parameter of control segment, indication the satellite operation mode in respect of time parameters [dimensionless]
        archive& BOOST_SERIALIZATION_NVP(d_N_T);          //!< Current date, calendar number of day within four-year interval starting from the 1-st of January in a leap year [days]
        archive& BOOST_SERIALIZATION_NVP(d_F_T);          //!< Parameter that provides the predicted satellite user range accuracy at time tb [dimensionless]
        archive& BOOST_SERIALIZATION_NVP(d_n);            //!< Index of the satellite transmitting given navigation signal. It corresponds to a slot number within GLONASS constellation
        archive& BOOST_SERIALIZATION_NVP(d_Delta_tau_n);  //!< Time difference between navigation RF signal transmitted in L2 sub- band and aviation RF signal transmitted in L1 sub-band by nth satellite. [dimensionless]
        archive& BOOST_SERIALIZATION_NVP(d_E_n);          //!< Characterises "age" of a current information [days]
        archive& BOOST_SERIALIZATION_NVP(d_P_1);          //!< Flag of the immediate data updating.
        archive& BOOST_SERIALIZATION_NVP(d_P_2);          //!< Flag of oddness ("1") or evenness ("0") of the value of (tb) [dimensionless]
        archive& BOOST_SERIALIZATION_NVP(d_P_3);          //!< Flag indicating a number of satellites for which almanac is transmitted within given frame: "1" corresponds to 5 satellites and "0" corresponds to 4 satellites [dimensionless]
        archive& BOOST_SERIALIZATION_NVP(d_P_4);          //!< Flag to show that ephemeris parameters are present. "1" indicates that updated ephemeris or frequency/time parameters have been uploaded by the control segment [dimensionless]
        archive& BOOST_SERIALIZATION_NVP(d_l3rd_n);       //!< Health flag for nth satellite; ln = 0 indicates the n-th satellite is helthy, ln = 1 indicates malfunction of this nth satellite [dimensionless]
        archive& BOOST_SERIALIZATION_NVP(d_l5th_n);       //!< Health flag for nth satellite; ln = 0 indicates the n-th satellite is helthy, ln = 1 indicates malfunction of this nth satellite [dimensionless]
    }

private:
    /*
     * Accounts for the beginning or end of week crossover
     *
     * \param[in]  -  time in seconds
     * \param[out] -  corrected time, in seconds
     */
    double check_t(double time);
};


/** \} */
/** \} */
#endif  // GNSS_SDR_GLONASS_GNAV_EPHEMERIS_H