ChineseDateTime.cs

ChineseDateTime

/*
copy from: https://www.jianshu.com/p/de33e6d9d880
*/

using System;
using System.Globalization;
using System.Linq;
using System.Linq.Expressions;
using System.Text;

/// <summary>
/// ChineseDateTime
/// 一日有十二时辰，一时辰有四刻，一刻有三盏茶，一盏茶有两柱香
/// 一柱香有五分，一分有六弹指，一弹指有十刹那，一刹那为一念
/// </summary>
public class ChineseDateTime
{
    #region ====== 内部常量 ======
    private readonly ChineseLunisolarCalendar _chineseDateTime;
    private readonly DateTime _dateTime;
    private readonly int _serialMonth;

    private static readonly string[] 中文数字 = { "〇", "一", "二", "三", "四", "五", "六", "七", "八", "九" };
    private static readonly string[] 中文月份 =
    {
        "正", "二", "三", "四", "五", "六", "七", "八", "九", "十", "冬", "腊"
    };
    private static readonly string[] 中文日期 =
    {
        "初一", "初二", "初三", "初四", "初五", "初六", "初七", "初八", "初九", "初十",
        "十一", "十二", "十三", "十四", "十五", "十六", "十七", "十八", "十九", "二十",
        "廿一", "廿二", "廿三", "廿四", "廿五", "廿六", "廿七", "廿八", "廿九", "三十"
    };
    private static readonly string[] _chineseWeek =
    {
        "星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"
    };

    private static readonly string[] 天干 = { "甲", "乙", "丙", "丁", "戊", "己", "庚", "辛", "壬", "癸" };
    private static readonly string[] 地支 = { "子", "丑", "寅", "卯", "辰", "巳", "午", "未", "申", "酉", "戌", "亥" };
    private static readonly string[] 属相 = { "鼠", "牛", "虎", "免", "龙", "蛇", "马", "羊", "猴", "鸡", "狗", "猪" };

    private static readonly string[] 节气 =
    {
        "小寒", "大寒", "立春", "雨水", "惊蛰", "春分",
        "清明", "谷雨", "立夏", "小满", "芒种", "夏至",
        "小暑", "大暑", "立秋", "处暑", "白露", "秋分",
        "寒露", "霜降", "立冬", "小雪", "大雪", "冬至"
    };

    /// <summary>
    /// 当前节气距离小寒的时间（分钟）
    /// </summary>
    private static readonly int[] _solarTermInfo = {
        0,      21208,   42467,  63836,  85337, 107014,
        128867, 150921, 173149, 195551, 218072, 240693,
        263343, 285989, 308563, 331033, 353350, 375494,
        397447, 419210, 440795, 462224, 483532, 504758
    };
    #endregion

    #region ======= 构建日期 ======

    public ChineseDateTime(DateTime dateTime)
    {
        _chineseDateTime = new ChineseLunisolarCalendar();
        if (dateTime < _chineseDateTime.MinSupportedDateTime || dateTime > _chineseDateTime.MaxSupportedDateTime)
        {
            throw new ArgumentOutOfRangeException(
                $"参数日期不在有效的范围内：只支持{_chineseDateTime.MinSupportedDateTime.ToShortTimeString()}到{_chineseDateTime.MaxSupportedDateTime}");
        }

        Year = _chineseDateTime.GetYear(dateTime);
        Month = _chineseDateTime.GetMonth(dateTime);
        Day = _chineseDateTime.GetDayOfMonth(dateTime);
        IsLeep = _chineseDateTime.IsLeapMonth(Year, Month);
        _dateTime = dateTime;
        _serialMonth = Month;
        var leepMonth = _chineseDateTime.GetLeapMonth(Year);
        if (leepMonth > 0 && leepMonth <= Month) Month--;
    }

    /// <summary>
    /// 参数为农历的年月日及是否润月
    /// </summary>
    /// <param name="year"></param>
    /// <param name="month"></param>
    /// <param name="day"></param>
    /// <param name="isLeap"></param>
    public ChineseDateTime(int year, int month, int day, bool isLeap = false)
        : this(year, month, day, 0, 0, 0, isLeap)
    {

    }

    public ChineseDateTime(int year, int month, int day, int hour, int minute, int second, bool isLeap = false)
        : this(year, month, day, hour, minute, second, 0, isLeap)
    {

    }

    public ChineseDateTime(int year, int month, int day, int hour, int minute, int second, int millisecond, bool isLeap = false)
    {
        _chineseDateTime = new ChineseLunisolarCalendar();
        if (year < _chineseDateTime.MinSupportedDateTime.Year || year >= _chineseDateTime.MaxSupportedDateTime.Year)
        {
            throw new ArgumentOutOfRangeException(
                $"参数年份不在有效的范围内，只支持{_chineseDateTime.MinSupportedDateTime.Year}到{_chineseDateTime.MaxSupportedDateTime.Year - 1}");
        }

        if (month < 1 || month > 12) throw new ArgumentOutOfRangeException($"月份只支持1-12");
        IsLeep = isLeap;
        var leepMonth = _chineseDateTime.GetLeapMonth(year);
        if (leepMonth - 1 != month)
            IsLeep = false;
        _serialMonth = month;
        if (leepMonth > 0 && (month == leepMonth - 1 && isLeap || month > leepMonth - 1))
            _serialMonth = month + 1;

        if (_chineseDateTime.GetDaysInMonth(year, _serialMonth) < day || day < 1)
            throw new ArgumentOutOfRangeException($"指定的月份天数，不在有效的范围内");

        Year = year;
        Month = month;
        Day = day;
        _dateTime = _chineseDateTime.ToDateTime(Year, _serialMonth, Day, hour, minute, second, millisecond);
    }

    public static ChineseDateTime Now => new ChineseDateTime(DateTime.Now);

    #endregion

    #region ====== 年月日润属性 ======
    public int Year { get; }
    public int Month { get; }
    public int Day { get; }

    /// <summary>
    /// 是否为润月
    /// </summary>
    public bool IsLeep { get; }
    #endregion

    #region ====== 输出常规日期 ======
    /// <summary>
    /// 转换为公历
    /// </summary>
    /// <returns></returns>
    public DateTime ToDateTime()
    {
        return _chineseDateTime.ToDateTime(Year, _serialMonth, Day, _dateTime.Hour,
            _dateTime.Minute,
            _dateTime.Second, _dateTime.Millisecond);
    }

    /// <summary>
    /// 短日期（农历）
    /// </summary>
    /// <returns></returns>
    public string ToShortDateString()
    {
        return $"{Year}-{GetLeap(false)}{Month}-{Day}";
    }

    /// <summary>
    /// 长日期（农历）
    /// </summary>
    /// <returns></returns>
    public string ToLongDateString()
    {
        return $"{Year}年{GetLeap()}{Month}月-{Day}日";
    }

    public new string ToString()
    {
        return $"{Year}-{GetLeap(false)}{Month}-{Day} {_dateTime.Hour}:{_dateTime.Minute}:{_dateTime.Second}";
    }
    #endregion

    #region ====== 输出中文日期及星期 ======
    public string ToChineseString()
    {
        return ToChineseString("yMd");
    }

    public string ToChineseString(string format)
    {
        var year = GetYear();
        var month = GetMonth();
        var day = GetDay();

        var date = new StringBuilder();
        foreach (var item in format.ToCharArray())
        {
            switch (item)
            {
                case 'y':
                    date.Append($"{year}年");
                    break;
                case 'M':
                    date.Append($"{month}月");
                    break;
                case 'd':
                    date.Append($"{day}");
                    break;
                default:
                    date.Append(item);
                    break;
            }
        }
        var def = $"{year}年{month}月{day}";
        var result = date.ToString();
        return string.IsNullOrEmpty(result) ? def : result;
    }

    public string ChineseWeek => _chineseWeek[(int)_dateTime.DayOfWeek];
    #endregion

    #region ====== 输出天干地支生肖 ======

    public string ToChineseEraString()
    {
        return ToChineseEraString("yMdHm");
    }

    public string ToChineseEraString(string format)
    {
        var year = GetEraYear();
        var month = GetEraMonth();
        var day = GetEraDay();
        var hour = GetEraHour();
        var minute = GetEraMinute();

        var date = new StringBuilder();
        foreach (var item in format.ToCharArray())
        {
            switch (item)
            {
                case 'y':
                    date.Append($"{year}年");
                    break;
                case 'M':
                    date.Append($"{month}月");
                    break;
                case 'd':
                    date.Append($"{day}日");
                    break;
                case 'H':
                    date.Append($"{hour}时");
                    break;
                case 'm':
                    date.Append($"{minute}刻");
                    break;
                default:
                    date.Append(item);
                    break;
            }
        }
        var def = $"{year}年{month}月{day}日{hour}时";
        var result = date.ToString();
        return string.IsNullOrEmpty(result) ? def : result;
    }

    public string ChineseZodiac => 属相[(Year - 4) % 12];
    #endregion

    #region ====== 辅助方法(Chinese) ======
    private string GetYear()
    {
        var yearArray = Array.ConvertAll(Year.ToString().ToCharArray(), x => int.Parse(x.ToString()));
        var year = new StringBuilder();
        foreach (var item in yearArray)
            year.Append(中文数字[item]);
        return year.ToString();
    }

    private string GetMonth()
    {
        return $"{GetLeap()}{中文月份[Month - 1]}";
    }

    private string GetDay()
    {
        return 中文日期[Day - 1];
    }

    private string GetLeap(bool isChinese = true)
    {
        return IsLeep ? isChinese ? "润" : "L" : "";
    }
    #endregion

    #region ====== 输助方法（天干地支）======
    //年采用的头尾法，月采用的是节令法，主流日历基本上都这种结合，如百度的日历  

    private string GetEraYear()
    {
        var sexagenaryYear = _chineseDateTime.GetSexagenaryYear(_dateTime);
        var stemIndex = _chineseDateTime.GetCelestialStem(sexagenaryYear) - 1;
        var branchIndex = _chineseDateTime.GetTerrestrialBranch(sexagenaryYear) - 1;
        return $"{天干[stemIndex]}{地支[branchIndex]}";
    }

    private string GetEraMonth()
    {
        #region ====== 节令法 ======
        var solarIndex = SolarTermFunc(SolarTermEnum.Current | SolarTermEnum.Prev, out var dt);
        solarIndex = solarIndex == -1 ? 23 : solarIndex;
        var currentIndex = (int)Math.Floor(solarIndex / (decimal)2);

        //天干         
        var solarMonth = currentIndex == 0 ? 11 : currentIndex - 1; //计算天干序(月份)
        var sexagenaryYear = _chineseDateTime.GetSexagenaryYear(_dateTime);
        var stemYear = _chineseDateTime.GetCelestialStem(sexagenaryYear) - 1;
        if (solarMonth == 0) //立春时，春节前后的不同处理
        {
            var year = _chineseDateTime.GetYear(dt);
            var month = _chineseDateTime.GetMonth(dt);
            stemYear = year == Year && month != 1 ? stemYear + 1 : stemYear;
        }
        if (solarMonth == 11) //立春在春节后，对前一节气春节前后不同处理
        {
            var year = _chineseDateTime.GetYear(dt);
            stemYear = year != Year ? stemYear - 1 : stemYear;
        }
        int stemIndex;
        switch (stemYear)
        {
            case 0:
            case 5:
                stemIndex = 3;
                break;
            case 1:
            case 6:
                stemIndex = 5;
                break;
            case 2:
            case 7:
                stemIndex = 7;
                break;
            case 3:
            case 8:
                stemIndex = 9;
                break;
            default:
                stemIndex = 1;
                break;
        }
        //天干序
        stemIndex = (stemIndex - 1 + solarMonth) % 10;

        //地支序
        var branchIndex = currentIndex >= 11 ? currentIndex - 11 : currentIndex + 1;

        return $"{天干[stemIndex]}{地支[branchIndex]}";

        #endregion

        #region ====== 头尾法 ======
        //这里算法要容易些，原理和节令法一样，只需取农历整年整月即可。未贴上来
        #endregion
    }

    private string GetEraDay()
    {
        var ts = _dateTime - new DateTime(1901, 2, 15);
        var offset = ts.Days;
        var sexagenaryDay = offset % 60;
        return $"{天干[sexagenaryDay % 10]}{地支[sexagenaryDay % 12]}";
    }

    private string GetEraHour()
    {
        var hourIndex = (int)Math.Floor((_dateTime.Hour + 1) / (decimal)2);
        hourIndex = hourIndex == 12 ? 0 : hourIndex;
        return 地支[hourIndex];
    }

    private string GetEraMinute()
    {
        var realMinute = (_dateTime.Hour % 2 == 0 ? 60 : 0) + _dateTime.Minute;
        return $"{中文数字[(int)Math.Floor(realMinute / (decimal)30) + 1]}";
    }
    #endregion

    #region ====== 24节气 ======
    private enum SolarTermEnum
    {
        Current,
        Prev,
        Next
    }
    /// <summary>
    /// 当前节气，没有则返回空
    /// </summary>
    public string SolarTerm
    {
        get
        {
            var i = SolarTermFunc(SolarTermEnum.Current, out var dt);
            return i == -1 ? "" : 节气[i];
        }
    }

    /// <summary>
    /// 上一个节气
    /// </summary>
    public string SolarTermPrev
    {
        get
        {
            var i = SolarTermFunc(SolarTermEnum.Prev, out var dt);
            return i == -1 ? "" : 节气[i];
        }
    }

    /// <summary>
    /// 下一个节气
    /// </summary>
    public string SolarTermNext
    {
        get
        {
            var i = SolarTermFunc(SolarTermEnum.Next, out var dt);
            return i == -1 ? "" : $"{节气[i]}";
        }
    }

    /// <summary>
    /// 节气计算（当前年），返回指定条件的节气序及日期（公历）
    /// </summary>
    /// <param name="func"></param>
    /// <param name="dateTime"></param>
    /// <returns>-1时即没找到</returns>
    private int SolarTermFunc(SolarTermEnum solarTermEnum, out DateTime dateTime)
    {
        var baseDateAndTime = new DateTime(1900, 1, 6, 2, 5, 0); //#1/6/1900 2:05:00 AM#
        var year = _dateTime.Year;
        int[] solar = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 };

        if (solarTermEnum == SolarTermEnum.Prev)
        {
            solar = solar.OrderByDescending(x => x).ToArray();
        }
        foreach (var item in solar)
        {
            // there are 525948.76 minutes per year
            var num = 525948.76 * (year - 1900) + _solarTermInfo[item - 1];
            var newDate = baseDateAndTime.AddMinutes(num); //按分钟计算
            var flag = false;
            if (solarTermEnum == SolarTermEnum.Current)
            {
                flag = flag || newDate.DayOfYear == _dateTime.DayOfYear;
            }
            if (solarTermEnum == SolarTermEnum.Prev)
            {
                flag = flag || newDate.DayOfYear < _dateTime.DayOfYear;
            }
            if (solarTermEnum == SolarTermEnum.Next)
            {
                flag = flag || newDate.DayOfYear > _dateTime.DayOfYear;
            }
            if (flag)
            {
                dateTime = newDate;
                return item - 1;
            }
        }
        dateTime = _chineseDateTime.MinSupportedDateTime;
        return -1;
    }
    #endregion
}