package lingtao.net.util;

import java.util.Arrays;
import java.util.Date;
import java.util.GregorianCalendar;

/**
 * 工具类，实现阴阳历互转
 */
public class LunarCalendarUtil {
	/**
	 * 支持转换的最小农历年份
	 */
	public static final int MIN_YEAR = 1900;

	/**
	 * 支持转换的最大农历年份
	 */
	public static final int MAX_YEAR = 2099;

	/**
	 * 公历每月前的天数
	 */
	private static final int[] DAYS_BEFORE_MONTH = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
	/**
	 * 用来表示1900年到2099年间农历年份的相关信息，共24位bit的16进制表示，其中： 1. 前4位表示该年闰哪个月； 2.
	 * 5-17位表示农历年份13个月的大小月分布，0表示小，1表示大； 3. 最后7位表示农历年首（正月初一）对应的公历日期。
	 * 以2014年的数据0x955ABF为例说明： 1001 0101 0101 1010 1011 1111 闰九月 农历正月初一对应公历1月31号
	 */
	private static final int[] LUNAR_INFO = {
			/* 1900 */
			0x84B6BF,
			/* 1901-1910 */
			0x04AE53, 0x0A5748, 0x5526BD, 0x0D2650, 0x0D9544, 0x46AAB9, 0x056A4D, 0x09AD42, 0x24AEB6, 0x04AE4A,
			/* 1911-1920 */
			0x6A4DBE, 0x0A4D52, 0x0D2546, 0x5D52BA, 0x0B544E, 0x0D6A43, 0x296D37, 0x095B4B, 0x749BC1, 0x049754,
			/* 1921-1930 */
			0x0A4B48, 0x5B25BC, 0x06A550, 0x06D445, 0x4ADAB8, 0x02B64D, 0x095742, 0x2497B7, 0x04974A, 0x664B3E,
			/* 1931-1940 */
			0x0D4A51, 0x0EA546, 0x56D4BA, 0x05AD4E, 0x02B644, 0x393738, 0x092E4B, 0x7C96BF, 0x0C9553, 0x0D4A48,
			/* 1941-1950 */
			0x6DA53B, 0x0B554F, 0x056A45, 0x4AADB9, 0x025D4D, 0x092D42, 0x2C95B6, 0x0A954A, 0x7B4ABD, 0x06CA51,
			/* 1951-1960 */
			0x0B5546, 0x555ABB, 0x04DA4E, 0x0A5B43, 0x352BB8, 0x052B4C, 0x8A953F, 0x0E9552, 0x06AA48, 0x6AD53C,
			/* 1961-1970 */
			0x0AB54F, 0x04B645, 0x4A5739, 0x0A574D, 0x052642, 0x3E9335, 0x0D9549, 0x75AABE, 0x056A51, 0x096D46,
			/* 1971-1980 */
			0x54AEBB, 0x04AD4F, 0x0A4D43, 0x4D26B7, 0x0D254B, 0x8D52BF, 0x0B5452, 0x0B6A47, 0x696D3C, 0x095B50,
			/* 1981-1990 */
			0x049B45, 0x4A4BB9, 0x0A4B4D, 0xAB25C2, 0x06A554, 0x06D449, 0x6ADA3D, 0x0AB651, 0x095746, 0x5497BB,
			/* 1991-2000 */
			0x04974F, 0x064B44, 0x36A537, 0x0EA54A, 0x86B2BF, 0x05AC53, 0x0AB647, 0x5936BC, 0x092E50, 0x0C9645,
			/* 2001-2010 */
			0x4D4AB8, 0x0D4A4C, 0x0DA541, 0x25AAB6, 0x056A49, 0x7AADBD, 0x025D52, 0x092D47, 0x5C95BA, 0x0A954E,
			/* 2011-2020 */
			0x0B4A43, 0x4B5537, 0x0AD54A, 0x955ABF, 0x04BA53, 0x0A5B48, 0x652BBC, 0x052B50, 0x0A9345, 0x474AB9,
			/* 2021-2030 */
			0x06AA4C, 0x0AD541, 0x24DAB6, 0x04B64A, 0x6a573D, 0x0A4E51, 0x0D2646, 0x5E933A, 0x0D534D, 0x05AA43,
			/* 2031-2040 */
			0x36B537, 0x096D4B, 0xB4AEBF, 0x04AD53, 0x0A4D48, 0x6D25BC, 0x0D254F, 0x0D5244, 0x5DAA38, 0x0B5A4C,
			/* 2041-2050 */
			0x056D41, 0x24ADB6, 0x049B4A, 0x7A4BBE, 0x0A4B51, 0x0AA546, 0x5B52BA, 0x06D24E, 0x0ADA42, 0x355B37,
			/* 2051-2060 */
			0x09374B, 0x8497C1, 0x049753, 0x064B48, 0x66A53C, 0x0EA54F, 0x06AA44, 0x4AB638, 0x0AAE4C, 0x092E42,
			/* 2061-2070 */
			0x3C9735, 0x0C9649, 0x7D4ABD, 0x0D4A51, 0x0DA545, 0x55AABA, 0x056A4E, 0x0A6D43, 0x452EB7, 0x052D4B,
			/* 2071-2080 */
			0x8A95BF, 0x0A9553, 0x0B4A47, 0x6B553B, 0x0AD54F, 0x055A45, 0x4A5D38, 0x0A5B4C, 0x052B42, 0x3A93B6,
			/* 2081-2090 */
			0x069349, 0x7729BD, 0x06AA51, 0x0AD546, 0x54DABA, 0x04B64E, 0x0A5743, 0x452738, 0x0D264A, 0x8E933E,
			/* 2091-2099 */
			0x0D5252, 0x0DAA47, 0x66B53B, 0x056D4F, 0x04AE45, 0x4A4EB9, 0x0A4D4C, 0x0D1541, 0x2D92B5 };

	/**
	 * 将农历日期转换为公历日期
	 * 
	 * @param year        农历年份
	 * @param month       农历月
	 * @param monthDay    农历日
	 * @param isLeapMonth 该月是否是闰月(该参数可以根据本类中leapMonth()方法，先判断一下要查询的年份是否有闰月，并且闰的几月)
	 * @return 返回农历日期对应的公历日期，year0, month1, day2.
	 */
	public static final int[] lunarToSolar(int year, int month, int monthDay, boolean isLeapMonth) {
		int dayOffset;
		int leapMonth;
		int i;
		if (year < MIN_YEAR || year > MAX_YEAR || month < 1 || month > 12 || monthDay < 1 || monthDay > 30) {
			throw new IllegalArgumentException("Illegal lunar date, must be like that:\n\t" + "year : 1900~2099\n\t"
					+ "month : 1~12\n\t" + "day : 1~30");
		}
		dayOffset = (LUNAR_INFO[year - MIN_YEAR] & 0x001F) - 1;
		if (((LUNAR_INFO[year - MIN_YEAR] & 0x0060) >> 5) == 2) {
			dayOffset += 31;
		}
		for (i = 1; i < month; i++) {
			if ((LUNAR_INFO[year - MIN_YEAR] & (0x80000 >> (i - 1))) == 0) {
				dayOffset += 29;
			} else {
				dayOffset += 30;
			}
		}
		dayOffset += monthDay;
		leapMonth = (LUNAR_INFO[year - MIN_YEAR] & 0xf00000) >> 20;
		// 这一年有闰月
		if (leapMonth != 0) {
			if (month > leapMonth || (month == leapMonth && isLeapMonth)) {
				if ((LUNAR_INFO[year - MIN_YEAR] & (0x80000 >> (month - 1))) == 0) {
					dayOffset += 29;
				} else {
					dayOffset += 30;
				}
			}
		}
		if (dayOffset > 366 || (year % 4 != 0 && dayOffset > 365)) {
			year += 1;
			if (year % 4 == 1) {
				dayOffset -= 366;
			} else {
				dayOffset -= 365;
			}
		}
		int[] solarInfo = new int[3];
		for (i = 1; i < 13; i++) {
			int iPos = DAYS_BEFORE_MONTH[i];
			if (year % 4 == 0 && i > 2) {
				iPos += 1;
			}
			if (year % 4 == 0 && i == 2 && iPos + 1 == dayOffset) {
				solarInfo[1] = i;
				solarInfo[2] = dayOffset - 31;
				break;
			}
			if (iPos >= dayOffset) {
				solarInfo[1] = i;
				iPos = DAYS_BEFORE_MONTH[i - 1];
				if (year % 4 == 0 && i > 2) {
					iPos += 1;
				}
				if (dayOffset > iPos) {
					solarInfo[2] = dayOffset - iPos;
				} else if (dayOffset == iPos) {
					if (year % 4 == 0 && i == 2) {
						solarInfo[2] = DAYS_BEFORE_MONTH[i] - DAYS_BEFORE_MONTH[i - 1] + 1;
					} else {
						solarInfo[2] = DAYS_BEFORE_MONTH[i] - DAYS_BEFORE_MONTH[i - 1];
					}
				} else {
					solarInfo[2] = dayOffset;
				}
				break;
			}
		}
		solarInfo[0] = year;
		return solarInfo;
	}

	/**
	 * 将公历日期转换为农历日期，且标识是否是闰月 (如果当年有闰月，被闰的阴历月份所对应的阳历日期计算出来不对，后期自己根据本方法leap3
	 * 返回值判断如果为1，给月份+1，如果为0就是正确的，不用在操作，阴历闰月对应的阳历日期计算出来的阴历闰月日期正确，leap3为0)
	 * 
	 * @param year
	 * @param month    传入需要为单数如 08 为8
	 * @param monthDay
	 * @return 返回公历日期对应的农历日期，year0，month1，day2，leap3(0 为计算正常 1 月份会比正确少一个月，需要月份+1)
	 */
	public static final int[] solarToLunar(int year, int month, int monthDay) {
		int[] lunarDate = new int[4];
		Date baseDate = new GregorianCalendar(1900, 0, 31).getTime();
		Date objDate = new GregorianCalendar(year, month - 1, monthDay).getTime();
		int offset = (int) ((objDate.getTime() - baseDate.getTime()) / 86400000L);
		// 用offset减去每农历年的天数计算当天是农历第几天
		// iYear最终结果是农历的年份, offset是当年的第几天
		int iYear, daysOfYear = 0;
		for (iYear = MIN_YEAR; iYear <= MAX_YEAR && offset > 0; iYear++) {
			daysOfYear = daysInLunarYear(iYear);
			offset -= daysOfYear;
		}
		if (offset < 0) {
			offset += daysOfYear;
			iYear--;
		}
		// 农历年份
		lunarDate[0] = iYear;
		int leapMonth = leapMonth(iYear);
		// 闰哪个月,1-12
		boolean isLeap = false;
		// 用当年的天数offset,逐个减去每月（农历）的天数，求出当天是本月的第几天
		int iMonth, daysOfMonth = 0;
		for (iMonth = 1; iMonth <= 13 && offset > 0; iMonth++) {
			daysOfMonth = daysInLunarMonth(iYear, iMonth);
			offset -= daysOfMonth;
		}
		// 当前月超过闰月，要校正
		if (leapMonth != 0 && iMonth > leapMonth) {
			--iMonth;
			if (iMonth == leapMonth) {
				isLeap = true;
			}
		}
		// offset小于0时，也要校正
		if (offset < 0) {
			offset += daysOfMonth;
			--iMonth;
		}
		lunarDate[1] = iMonth;
		lunarDate[2] = offset + 1;
		lunarDate[3] = isLeap ? 1 : 0;
		return lunarDate;
	}

	/**
	 * 传回农历year年month月的总天数
	 *
	 * @param year  要计算的年份
	 * @param month 要计算的月
	 * @return 传回天数
	 */
	final public static int daysInMonth(int year, int month) {
		return daysInMonth(year, month, false);
	}

	/**
	 * 传回农历year年month月的总天数
	 *
	 * @param year  要计算的年份
	 * @param month 要计算的月
	 * @param leap  当月是否是闰月
	 * @return 传回天数，如果闰月是错误的，返回0.
	 */
	public static final int daysInMonth(int year, int month, boolean leap) {
		int leapMonth = leapMonth(year);
		int offset = 0;
		// 如果本年有闰月且month大于闰月时，需要校正
		if (leapMonth != 0 && month > leapMonth) {
			offset = 1;
		}
		// 不考虑闰月
		if (!leap) {
			return daysInLunarMonth(year, month + offset);
		} else {
			// 传入的闰月是正确的月份
			if (leapMonth != 0 && leapMonth == month) {
				return daysInLunarMonth(year, month + 1);
			}
		}
		return 0;
	}

	/**
	 * 传回农历 year年的总天数
	 *
	 * @param year 将要计算的年份
	 * @return 返回传入年份的总天数
	 */
	private static int daysInLunarYear(int year) {
		int i, sum = 348;
		if (leapMonth(year) != 0) {
			sum = 377;
		}
		int monthInfo = LUNAR_INFO[year - MIN_YEAR] & 0x0FFF80;
		for (i = 0x80000; i > 0x7; i >>= 1) {
			if ((monthInfo & i) != 0) {
				sum += 1;
			}
		}
		return sum;
	}

	/**
	 * 传回农历 year年month月的总天数，总共有13个月包括闰月
	 *
	 * @param year  将要计算的年份
	 * @param month 将要计算的月份
	 * @return 传回农历 year年month月的总天数
	 */
	private static int daysInLunarMonth(int year, int month) {
		if ((LUNAR_INFO[year - MIN_YEAR] & (0x100000 >> month)) == 0) {
			return 29;
		} else {
			return 30;
		}
	}

	/**
	 * 传回农历 year年闰哪个月 1-12 , 没闰传回 0
	 * 
	 * @param year 将要计算的年份
	 * @return 传回农历 year年闰哪个月1-12, 没闰传回 0
	 */
	public static int leapMonth(int year) {
		return ((LUNAR_INFO[year - MIN_YEAR] & 0xF00000)) >> 20;
	}

	public static void main(String[] args) {
		// 计算录入年份是否有闰月
		System.out.println(leapMonth(2020));
		// 传回农历 year年month月的总天数，总共有13个月包括闰月
		System.out.println(daysInLunarMonth(2017, 6));
		// 传回农历year年month月的总天数
		System.out.println(daysInMonth(2017, 6, false));
		// 阳历转阴历 9.25 10.23 有问题
		System.out.println(Arrays.toString(solarToLunar(2020, 3, 2)));
		// 阴历转阳历
		System.out.println(Arrays.toString(lunarToSolar(2020, 2, 9, true)));
	}
}