using System;

namespace Rextester{

    public class Program

{

    public static void Main(string[] args)

    {

        var vanatime = new VanadielTime(DateTimeOffset.Now.ToUnixTimeMilliseconds());

        Console.WriteLine(vanatime.ToString());

        Console.WriteLine(vanatime.SeasonOfYear);

    }

}

​

    public enum Day : int

    {

        Firesday,

        Earthsday,

        Watersday,

        Windsday,

        Iceday,

        Lightningday,

        Lightsday,

        Darksday

    }

    public enum Season : int

    {

        Winter,

        Spring,

        Summer,

        Autumn

    }

    public enum Moon : int

    {

        NewMoon,

        WaxingCrescent,

        WaxingCrescent2,

        FirstQuarterMoon,

        WaxingGibbous,

        WaxingGibbous2,

        FullMoon,

        WaningGibbous,

        WaningGibbous2,

        LastQuarterMoon,

        WaningCrescent,

        WaningCrescent2

    }

​

    public struct VanadielTime

    {

        // Vana'diel time scale is 1/25 Earth time

        // https://ffxiclopedia.fandom.com/wiki/Time

        private const long VanadielYearMilliseconds     = 1244160000;       // VanadielDay * 360

        private const long VanadielSeasonMilliseconds   = 311040000;        // VanadielDay * 90

        private const long VanadielMoonMilliseconds     = 290304000;        // VanadielDay * 84

        private const long VanadielMonthMilliseconds    = 103680000;        // VanadielDay * 30

        private const long VanadielWeekMilliseconds     = 27648000;         // VanadielDay * 8

        private const long VanadielDayMilliseconds      = 3456000;          // VanadielHour * 24

        private const long VanadielHourMilliseconds     = 144000;           // VanadielMinute * 60

        private const long VanadielMinuteMilliseconds   = 2400;             // 1 VanadielMinute = 2.4 Earth seconds

        private const long VanadielSecondMilliseconds   = 40;               // 1 VanadielSecond = 0.04 Earth seconds

​

        // Adjust this timestamp to change when the Age of Adventurers during Crystal Era started

        private const long VanadielTimeMilliseconds     = 1102325760000;    // 1/1/886, Firesday, 00:00

        // Adjust this Unix timestamp for when the physical server started

        private const long EarthTimeMilliseconds        = 1009810800000;    // 2002-01-01T00:00:00+09:00

​

        private int m_year;         // years since 0

        private int m_month;        // months since January - [0, 11]

        private int m_dayOfMonth;   // day of the month - [0, 29]

        private int m_hour;         // hours since midnight - [0, 23]

        private int m_minute;       // minutes after the hour - [0, 59]

        private int m_second;       // seconds after the minute - [0, 59]

        private int m_dayOfWeek;    // days since Firesday - [0, 7]

        private int m_dayOfYear;    // days since January 1 - [0, 359]

        private int m_season;

​

        private long m_time;

​

        public VanadielTime(long time)

        {

            if (time < 0)

                throw new ArgumentOutOfRangeException(nameof(time));

​

            m_time = VanadielTimeMilliseconds;

            m_year = (int)(m_time / VanadielYearMilliseconds);

            m_month = (int)(m_time % VanadielYearMilliseconds / VanadielMonthMilliseconds);

            m_dayOfMonth = (int)(m_time % VanadielMonthMilliseconds / VanadielDayMilliseconds);

            m_hour = (int)(m_time % VanadielDayMilliseconds / VanadielHourMilliseconds);

            m_minute = (int)(m_time % VanadielHourMilliseconds / VanadielMinuteMilliseconds);

            m_second = (int)(m_time % VanadielMinuteMilliseconds / VanadielSecondMilliseconds);

            m_dayOfWeek = (int)(m_time % VanadielWeekMilliseconds / VanadielDayMilliseconds);

            m_dayOfYear = m_month * 30 + m_dayOfMonth;

            m_season = (int)(m_time % VanadielYearMilliseconds / VanadielSeasonMilliseconds);

            int test = (int)(m_time / VanadielDayMilliseconds);

            int percent = 200 * (test % 84) / 84;

            int diff = 38 - percent;

            if (diff <= -100)

                diff += 200;

            Console.WriteLine(Math.Abs(diff));

        }

​

        public int Year => m_year;

        public int Month => m_month + 1;

        public int DayOfMonth => m_dayOfMonth + 1;

        public Day DayOfWeek => (Day)m_dayOfWeek;

        public int Hour => m_hour;

        public int Minute => m_minute;

        public int Second => m_second;

        public int DayOfYear => m_dayOfYear + 1;

        public Season SeasonOfYear => (Season)m_season;

​

        public bool IsFiresday => DayOfWeek == Day.Firesday;

        public bool IsEarthsday => DayOfWeek == Day.Earthsday;

        public bool IsWatersday => DayOfWeek == Day.Watersday;

        public bool IsWindsday => DayOfWeek == Day.Windsday;

        public bool IsIceday => DayOfWeek == Day.Iceday;

        public bool IsLightningday => DayOfWeek == Day.Lightningday;

        public bool IsLightsday => DayOfWeek == Day.Lightsday;

        public bool IsDarksday => DayOfWeek == Day.Darksday;

​

        public override string ToString() => $"{Month}/{DayOfMonth}/{Year}, {DayOfWeek}, {Hour.ToString("D2")}:{Minute.ToString("D2")}";

    }

}

​

​

​