AuroraRuntime/Include/Aurora/Time/Clock.hpp

/***
    Copyright (C) 2021 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: Clock.hpp
    Date: 2021-6-10
    Author: Reece
***/
#pragma once

#include "ETimezoneShift.hpp"
#include "TM.hpp"

namespace Aurora::Time
{
    /**
        Converts milliseconds from the Aurora epoch to a civil timestamp structure
         similar to or of std::tm
    */
    AUKN_SYM tm ToCivilTime(AuInt64 time, bool UTC = true);

    /**
        Converts civil time to milliseconds from the Aurora epoch
    */
    AUKN_SYM AuInt64  FromCivilTime(const tm &time, bool UTC = true);


    /**
        Normalizes a civil data structure with respect to UTC, given the two input parameters 'in' civil and 'shiftFrom' timezone hint
    */
    AUKN_SYM tm NormalizeCivilTimezone(const tm &in, ETimezoneShift shiftFrom = ETimezoneShift::eUTC);

    /**
        Translates the Aurora epoch to the standard unix epoch
    */
    AUKN_SYM AuInt64 ConvertAuroraToUnixMS(AuInt64 in);

    /**
        Translates the Aurora epoch to the standard unix epoch
    */
    AUKN_SYM AuInt64 ConvertAuroraToUnixNS(AuInt64 in);

    /**
        Translates a standard unix epoch to the Aurora epoch
    */
    AUKN_SYM AuInt64 ConvertUnixToAuroraMS(AuInt64 in);

    /**
        Translates a standard unix epoch to the Aurora epoch
    */
    AUKN_SYM AuInt64 ConvertUnixToAuroraNS(AuInt64 in);

    /**
        Retrieves wall clock in milliseconds from the Aurora epoch
    */
    AUKN_SYM AuInt64 CurrentClockMS();

    /**
        Retrieves wall clock in nanoseconds from the Aurora epoch
    */
    AUKN_SYM AuInt64 CurrentClockNS();

    /**
     * @brief Steady clock in jiffies
     * @return 
    */
    AUKN_SYM AuUInt64 SteadyClock();

    /**
        Returns a steady system clock of SteadyClockJiffies() with an undefined epoch.

        These values should be used to drive thread primitives, IO time, and tick delta.
        On a modern plaform, these should be affected by the users' calendar or NTP. 
        On stinkier platforms, who cares if we can run mostly bug free with an assumed-sane wall-clock, right?
    */
    AUKN_SYM AuUInt64 SteadyClockMS();

    /**
     * @brief 
     * @return 
    */
    AUKN_SYM AuUInt64 SteadyClockNS();

    /**
        Retrieves the freqency of jiffies per second
    */
    AUKN_SYM AuUInt64 SteadyClockJiffies();


    /**
        Returns a high resolution count of jiffies with an undefined epoch from a
         high resolution clock.

        These values should be used to drive benchmarks.
        These values should not nor can be accurately converted meaningfully
    */
    AUKN_SYM AuUInt64 HighResClock();
    AUKN_SYM AuUInt64 HighResClockMS();
    AUKN_SYM AuUInt64 HighResClockNS();

    /**
        Retrieves the freqency of jiffies per second
    */
    AUKN_SYM AuUInt64 HighResClockJiffies();

    /**
        Let's say you're fucked and you need a ball park figure.
        Enjoy...
    */
    AUKN_SYM AuUInt64 ConvertInternalToAuroraEpochMS(AuUInt64 in);
    AUKN_SYM AuUInt64 ConvertInternalToAuroraEpochNS(AuUInt64 in);
    
    /**
        Converts seconds from the Aurora epoch to time_t
    */
    AUKN_SYM time_t   SToCTime(AuInt64 time);

    /**
        Converts nanoseconds from the Aurora epoch to time_t
    */
    AUKN_SYM time_t   NSToCTime(AuInt64 time);

    /**
        Converts milliseconds from the Aurora epoch to time_t
    */
    AUKN_SYM time_t   MSToCTime(AuInt64 time);

    AUKN_SYM AuInt64  CTimeToMS(time_t time);

    /**
        Retrieves the freqency as a fraction of: jiffies per second / 1 * nanoseconds in a second
    */
    AUKN_SYM double   CPUFrequencyDeltaNS();

    /**
        Retrieves the freqency as a fraction of: jiffies per second / 1 * milliseconds in a second
    */
    AUKN_SYM double   CPUFrequencyDeltaMS();

}