SimTimeManager.h

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/*
Time Manager class header file
 
Author: Alex Reynolds
*/
#ifndef SIM_TIME_MANAGER_H
#define SIM_TIME_MANAGER_H
 
#include "architecture/Time.h"
#include "architecture/TimeManager.h"
 
namespace modelspace {
 
    /// @brief This is the default simulation time
    const std::string DEFAULT_SIMULATION_TIME = "2023 September 26, 12:00:00 MDT";
 
    /// @brief This is the offset between the GPS and J2000 epochs for calculation of GPS time
    const double GPS_TO_J2000_ET_OFFSET = 630763200.0;
 
    /**
     * @brief   Class to manage time for the simulation object
     * 
     * This class uses the SPICE module to manage time within
     * the simulation. Internally it steps the sim time and the
     * spice ephemeris time (TDB time), which is used to cast UTC and 
     * JD time scales. All are published on the time manager.
     * 
     * Time representations are based on the clockwerk Time class.
     */
    class SimTimeManager : public clockwerk::TimeManager {
    public:
        /// Base constructor -- time manager should initialize to zeros and then be set
        SimTimeManager();
        ~SimTimeManager() {};
 
        /// @brief   Function to increment all times
        /// @param   step    Time object to step by
        virtual void stepTime(const clockwerk::Time& step);
 
        /// ------------------------------------------------------------------
        /// Other time functions -- These functions return other forms of time
        /// ------------------------------------------------------------------
        /// @brief Function to return the wall clock time since run start
        /// @return A time object containing the time since run start
        virtual clockwerk::Time wallClockTimer() override;
 
        /// ------------------------------------------------------------------
        /// Time converters
        /// The following functions convert time between representations
        /// ------------------------------------------------------------------
        double str2tdb(const std::string &time_input);
 
        /// ------------------------------------------------------------------
        /// Useful Time Representations
        /// The following functions return time as any one of a number of 
        /// useful representations such as UTC and GPS time
        /// ------------------------------------------------------------------
        /// @brief Function to return the TDB time as a string
        /// @return TDB time as seconds since J2000
        std::string tdbTime() {return std::to_string(tdb_time().asDouble());}
        /// @brief Function to return the TDB time as a string
        /// @return UTC time in the format 'YYYY MMM DD HH:MM:SS'
        std::string utcTime();
        /// @brief Function to return the Julian date as a string
        /// @return Julian date as a days since the JD epoch as JDUTC
        std::string jdTime();
        /// @brief Function to return the GPS time as a string
        /// @return GPS time in the format 
        std::string gpsTime();
 
        /// ------------------------------------------------------------------
        /// Methods to set time
        /// The following functions allow users to set time based on string
        /// input.
        /// ------------------------------------------------------------------
 
        /// @brief Function to set time by string input
        /// @param time_input The string input by which time will be set. 
        ///                   valid inputs are any input which is accepted
        ///                   by the SPICE function STR2ET. More info here:
        ///                   https://naif.jpl.nasa.gov/pub/naif/toolkit_docs/FORTRAN/spicelib/str2et.html
        ///                   This value defaults to 2023 September 26, 12:00:00 MDT
        void setTime(const std::string &time_input=DEFAULT_SIMULATION_TIME);
 
        /// Incrementing clocks -- these are standard clocks that begin on 
        /// start and continue incrementing as the scheduler steps forward
        /// in time. 
        /// ------------------------------------------------------------------
        // NOTE: All clocks provided by TimeManager are present in SimTimeManager as well.
 
        /** TDB time is represented as seconds relative to the J2000 epoch,
         *  which is January 1, 2000, at 12:00 TT (Terrestrial Time). 
         *  This is also known as "ephemeris time"*/
        clockwerk::DataIO<clockwerk::Time> tdb_time = clockwerk::DataIO<clockwerk::Time>(this, "tdb_time");
    protected:
        /// Pointers to our time objects
        clockwerk::Time* _tdb_ptr;
 
        // Temporary variable to make time retrieval faster
        clockwerk::Time _diff;
        struct timespec _tmp;
    };
 
}
 
#endif