using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace HotelPms.Share.Windows.Util
{
    public class JapaneseDateTime
    {
        private int year, month, dayOfMonth;
        private bool isLeap;
        private DateTime time;
        //System.Globalization.ChineseLunisolarCalendar cc;
        System.Globalization.JapaneseLunisolarCalendar cc;
        private static string[] RokuyouList = new string[] { "大安", "赤口", "先勝", "友引", "先負", "仏滅" };

        /// <summary>
        /// 旧暦年
        /// </summary>
        public int Year
        {
            get { return year; }
        }

        /// <summary>
        /// 旧暦月
        /// </summary>
        public int Month
        {
            get { return month; }
        }

        /// <summary>
        /// 新暦時間
        /// </summary>
        public DateTime NewTime
        {
            get { return time; }
        }

        /// <summary>
        /// 旧暦時間
        /// </summary>
        public DateTime OldTime
        {
            get { return new DateTime(year, month, dayOfMonth); }
        }

        /// <summary>
        /// 旧暦日
        /// </summary>
        public int DayOfMonth
        {
            get { return dayOfMonth; }
        }

        /// <summary>
        /// 閏月かどうか
        /// </summary>
        public bool IsLeap
        {
            get { return isLeap; }
        }

        /// <summary>
        /// 指定日付で旧暦を変換する
        /// </summary>
        /// <param name="time"></param>
        public JapaneseDateTime(DateTime time)
        {
            //cc = new System.Globalization.ChineseLunisolarCalendar();
            cc = new System.Globalization.JapaneseLunisolarCalendar();

            if (time > cc.MaxSupportedDateTime || time < cc.MinSupportedDateTime)
                throw new Exception("Out Of Range ：" + cc.MinSupportedDateTime.ToShortDateString() + "～" + cc.MaxSupportedDateTime.ToShortDateString());
            year = cc.GetYear(time);
            month = cc.GetMonth(time);
            dayOfMonth = cc.GetDayOfMonth(time);
            isLeap = cc.IsLeapMonth(year, month);
            if (cc.IsLeapYear(year) && month >= cc.GetLeapMonth(year)) { month -= 1; }
            this.time = time;
        }

        public static JapaneseDateTime Now
        {
            get { return new JapaneseDateTime(DateTime.Now); }
        }

        public JapaneseDateTime(int Year, int Month, int DayOfMonth, bool IsLeap)
        {
            if (Year >= cc.MaxSupportedDateTime.Year || Year <= cc.MinSupportedDateTime.Year)
                throw new Exception("Out Of Range ：：" + cc.MinSupportedDateTime.ToShortDateString() + "～" + cc.MaxSupportedDateTime.ToShortDateString());

            if (Month < 1 || Month > 12)
                throw new Exception("日付が不正です。");
            //cc = new System.Globalization.ChineseLunisolarCalendar();
            cc = new System.Globalization.JapaneseLunisolarCalendar();

            if (cc.GetLeapMonth(Year) != Month && IsLeap)
                throw new Exception("GetLeapMonth Error");
            if (cc.GetDaysInMonth(Year, IsLeap ? Month + 1 : Month) < DayOfMonth || DayOfMonth < 1)
                throw new Exception("Day Error");
            year = Year;
            month = Month;
            dayOfMonth = DayOfMonth;
            isLeap = IsLeap;
            time = DateTime.Now;
        }

        /// <summary>
        /// 旧暦⇒新暦
        /// </summary>
        /// <returns></returns>
        public DateTime ToDateTime()
        {
            return cc.ToDateTime(year, isLeap ? month + 1 : month, dayOfMonth, time.Hour, time.Minute, time.Second, time.Millisecond);
        }

        /// <summary>
        /// 旧暦⇒新暦
        /// </summary>
        /// <returns></returns>
        public static DateTime ToDateTime(JapaneseDateTime CnTime)
        {
            return CnTime.ToDateTime();
        }

        /// <summary>
        /// 新暦⇒旧暦
        /// </summary>
        /// <returns></returns>
        public static JapaneseDateTime ToJapaneseDateTime(DateTime Time)
        {
            return new JapaneseDateTime(Time);
        }

        /// <summary>
        /// 新暦⇒旧暦
        /// </summary>
        /// <returns></returns>
        public static string ToJapaneseDateString(DateTime Time)
        {
            return ToJapaneseDateString(Time, "yyyy/MM/dd");
        }

        /// <summary>
        /// 新暦⇒旧暦
        /// </summary>
        /// <returns></returns>
        public static string ToJapaneseDateString(DateTime Time, string format)
        {
            try
            {
                JapaneseDateTime jpDate = new JapaneseDateTime(Time);
                return jpDate.OldTime.ToString(format);
            }
            catch
            {
                return string.Empty;
            }
        }

        /// <summary>
        /// 新暦⇒六曜
        /// </summary>
        /// <returns></returns>
        public static string ToRokuyou(DateTime Time)
        {
            try
            {
                JapaneseDateTime jpDate = new JapaneseDateTime(Time);
                int index = (jpDate.Month + jpDate.DayOfMonth) % 6;
                return RokuyouList[index];
            }
            catch
            {
                return string.Empty;
            }
        }
    }
}