package com.wd.common.utils;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

/**
 * <b>描述</b>: 日历转换工具类：阴历和阳历日期互换(阴历日期范围19000101~20491229)<br>
 * @author liu 2015-1-5
 */
public class CalendarUtil {
    //	private static final Logger logger = LoggerFactory.getLogger(CalendarUtil.class);
    // 计算阴历日期参照1900年到2049年
    private final static int[] LUNAR_INFO = {
            0x04bd8,0x04ae0,0x0a570,0x054d5,0x0d260,0x0d950,0x16554,0x056a0,0x09ad0,0x055d2,
            0x04ae0,0x0a5b6,0x0a4d0,0x0d250,0x1d255,0x0b540,0x0d6a0,0x0ada2,0x095b0,0x14977,
            0x04970,0x0a4b0,0x0b4b5,0x06a50,0x06d40,0x1ab54,0x02b60,0x09570,0x052f2,0x04970,
            0x06566,0x0d4a0,0x0ea50,0x06e95,0x05ad0,0x02b60,0x186e3,0x092e0,0x1c8d7,0x0c950,
            0x0d4a0,0x1d8a6,0x0b550,0x056a0,0x1a5b4,0x025d0,0x092d0,0x0d2b2,0x0a950,0x0b557,
            0x06ca0,0x0b550,0x15355,0x04da0,0x0a5d0,0x14573,0x052d0,0x0a9a8,0x0e950,0x06aa0,
            0x0aea6,0x0ab50,0x04b60,0x0aae4,0x0a570,0x05260,0x0f263,0x0d950,0x05b57,0x056a0,
            0x096d0,0x04dd5,0x04ad0,0x0a4d0,0x0d4d4,0x0d250,0x0d558,0x0b540,0x0b5a0,0x195a6,
            0x095b0,0x049b0,0x0a974,0x0a4b0,0x0b27a,0x06a50,0x06d40,0x0af46,0x0ab60,0x09570,
            0x04af5,0x04970,0x064b0,0x074a3,0x0ea50,0x06b58,0x055c0,0x0ab60,0x096d5,0x092e0,
            0x0c960,0x0d954,0x0d4a0,0x0da50,0x07552,0x056a0,0x0abb7,0x025d0,0x092d0,0x0cab5,
            0x0a950,0x0b4a0,0x0baa4,0x0ad50,0x055d9,0x04ba0,0x0a5b0,0x15176,0x052b0,0x0a930,
            0x07954,0x06aa0,0x0ad50,0x05b52,0x04b60,0x0a6e6,0x0a4e0,0x0d260,0x0ea65,0x0d530,
            0x05aa0,0x076a3,0x096d0,0x04bd7,0x04ad0,0x0a4d0,0x1d0b6,0x0d250,0x0d520,0x0dd45,
            0x0b5a0,0x056d0,0x055b2,0x049b0,0x0a577,0x0a4b0,0x0aa50,0x1b255,0x06d20,0x0ada0
    };

    // 允许输入的最小年份
    private final static int MIN_YEAR = 1900;
    // 允许输入的最大年份
    private final static int MAX_YEAR = 2049;
    // 当年是否有闰月
    private static boolean isLeapYear;
    // 阳历日期计算起点
    private final static String START_DATE = "19000130";


    /**
     * 计算阴历 {@code year}年闰哪个月 1-12 , 没闰传回 0
     * @param year 阴历年
     * @return (int)月份
     * @author liu 2015-1-5
     */
    private static int getLeapMonth(int year) {
        return (int) (LUNAR_INFO[year - 1900] & 0xf);
    }

    /**
     * 计算阴历{@code year}年闰月多少天
     * @param year 阴历年
     * @return (int)天数
     * @author liu 2015-1-5
     */
    private static int getLeapMonthDays(int year) {
        if(getLeapMonth(year)!=0){
            if((LUNAR_INFO[year - 1900] & 0xf0000)==0){
                return 29;
            }else {
                return 30;
            }
        }else{
            return 0;
        }
    }

    /**
     * 计算阴历{@code lunarYeay}年{@code month}月的天数
     * @param lunarYeay 阴历年
     * @param month 阴历月
     * @return (int)该月天数
     * @throws Exception
     * @author liu 2015-1-5
     */
    private static int getMonthDays(int lunarYeay, int month) throws Exception {
        if ((month > 31) || (month < 0)) {
            throw(new Exception("月份有错！"));
        }
        // 0X0FFFF[0000 {1111 1111 1111} 1111]中间12位代表12个月，1为大月，0为小月
        int bit = 1 << (16-month);
        if(((LUNAR_INFO[lunarYeay - 1900] & 0x0FFFF)&bit)==0){
            return 29;
        }else {
            return 30;
        }
    }

    /**
     * 计算阴历{@code year}年的总天数
     * @param year 阴历年
     * @return (int)总天数
     * @author liu 2015-1-5
     */
    private static int getYearDays(int year) {
        int sum = 29*12;
        for(int i=0x8000;i>=0x8;i>>=1){
            if((LUNAR_INFO[year-1900]&0xfff0&i)!=0){
                sum++;
            }
        }
        return sum+getLeapMonthDays(year);
    }

    /**
     * 计算两个阳历日期相差的天数。计算不准确，已经废弃
     * @param startDate 开始时间
     * @param endDate 截至时间
     * @return (int)天数
     * @author liu 2015-1-5
     */
    @Deprecated
    private static int daysBetween2(Date startDate, Date endDate) {
        long between_days=(endDate.getTime()-startDate.getTime())/(1000*3600*24);

        return Integer.parseInt(String.valueOf(between_days));
    }

    /**
     * 计算两个阳历日期相差的天数。
     * @param startDate 开始时间
     * @param endDate 截至时间
     * @return (int)天数
     * @author liu 2017-3-2
     */
    private static int daysBetween(Date startDate, Date endDate) {
        int days = 0;
        //将转换的两个时间对象转换成Calendar对象
        Calendar can1 = Calendar.getInstance();
        can1.setTime(startDate);
        Calendar can2 = Calendar.getInstance();
        can2.setTime(endDate);
        //拿出两个年份
        int year1 = can1.get(Calendar.YEAR);
        int year2 = can2.get(Calendar.YEAR);
        //天数

        Calendar can = null;
        //如果can1 < can2
        //减去小的时间在这一年已经过了的天数
        //加上大的时间已过的天数
        if(can1.before(can2)){
            days -= can1.get(Calendar.DAY_OF_YEAR);
            days += can2.get(Calendar.DAY_OF_YEAR);
            can = can1;
        }else{
            days -= can2.get(Calendar.DAY_OF_YEAR);
            days += can1.get(Calendar.DAY_OF_YEAR);
            can = can2;
        }
        for (int i = 0; i < Math.abs(year2-year1); i++) {
            //获取小的时间当前年的总天数
            days += can.getActualMaximum(Calendar.DAY_OF_YEAR);
            //再计算下一年。
            can.add(Calendar.YEAR, 1);
        }
        return days;
    }

    /**
     * 检查阴历日期是否合法
     * @param lunarYear 阴历年
     * @param lunarMonth 阴历月
     * @param lunarDay 阴历日
     * @param leapMonthFlag 闰月标志
     * @throws Exception
     */
    private static void checkLunarDate(int lunarYear, int lunarMonth, int lunarDay, boolean leapMonthFlag) throws Exception {
        if ((lunarYear < MIN_YEAR) || (lunarYear > MAX_YEAR)) {
            throw(new Exception("非法农历年份！"));
        }
        if ((lunarMonth < 1) || (lunarMonth > 12)) {
            throw(new Exception("非法农历月份！"));
        }
        if ((lunarDay < 1) || (lunarDay > 30)) { // 中国的月最多30天
            throw(new Exception("非法农历天数！"));
        }

        int leap = getLeapMonth(lunarYear);// 计算该年应该闰哪个月
        if ((leapMonthFlag == true) && (lunarMonth != leap)) {
            throw(new Exception("非法闰月！"));
        }
    }

    /**
     * 阴历转换为阳历
     * @param lunarDate 阴历日期,格式YYYYMMDD
     * @param leapMonthFlag 是否为闰月
     * @return 阳历日期,格式：YYYYMMDD
     * @throws Exception
     * @author liu 2015-1-5
     */
    public static String lunarToSolar(String lunarDate, boolean leapMonthFlag) throws Exception{
        int lunarYear = Integer.parseInt(lunarDate.substring(0, 4));
        int lunarMonth = Integer.parseInt(lunarDate.substring(4, 6));
        int lunarDay = Integer.parseInt(lunarDate.substring(6, 8));

        checkLunarDate(lunarYear, lunarMonth, lunarDay, leapMonthFlag);

        int offset = 0;

        for (int i = MIN_YEAR; i < lunarYear; i++) {
            int yearDaysCount = getYearDays(i); // 求阴历某年天数
            offset += yearDaysCount;
        }
        //计算该年闰几月
        int leapMonth = getLeapMonth(lunarYear);

        if(leapMonthFlag & leapMonth != lunarMonth){
            throw(new Exception("您输入的闰月标志有误！"));
        }

        //当年没有闰月或月份早于闰月或和闰月同名的月份
        if(leapMonth==0|| (lunarMonth < leapMonth) || (lunarMonth==leapMonth && !leapMonthFlag)){
            for (int i = 1; i < lunarMonth; i++) {
                int tempMonthDaysCount = getMonthDays(lunarYear, i);
                offset += tempMonthDaysCount;
            }

            // 检查日期是否大于最大天
            if (lunarDay > getMonthDays(lunarYear, lunarMonth)) {
                throw(new Exception("不合法的农历日期！"));
            }
            offset += lunarDay; // 加上当月的天数
        }else{//当年有闰月，且月份晚于或等于闰月
            for (int i = 1; i < lunarMonth; i++) {
                int tempMonthDaysCount = getMonthDays(lunarYear, i);
                offset += tempMonthDaysCount;
            }
            if (lunarMonth>leapMonth) {
                int temp = getLeapMonthDays(lunarYear); // 计算闰月天数
                offset += temp; // 加上闰月天数

                if (lunarDay > getMonthDays(lunarYear, lunarMonth)) {
                    throw(new Exception("不合法的农历日期！"));
                }
                offset += lunarDay;
            }else {	// 如果需要计算的是闰月，则应首先加上与闰月对应的普通月的天数
                // 计算月为闰月
                int temp = getMonthDays(lunarYear, lunarMonth); // 计算非闰月天数
                offset += temp;

                if (lunarDay > getLeapMonthDays(lunarYear)) {
                    throw(new Exception("不合法的农历日期！"));
                }
                offset += lunarDay;
            }
        }

        SimpleDateFormat formatter = new SimpleDateFormat("yyyyMMdd");
        Date myDate = null;
        myDate = formatter.parse(START_DATE);
        Calendar c = Calendar.getInstance();
        c.setTime(myDate);
        c.add(Calendar.DATE, offset);
        myDate = c.getTime();

        return formatter.format(myDate);
    }

    /**
     * 阳历日期转换为阴历日期
     * @param solarDate 阳历日期,格式YYYYMMDD
     * @return 阴历日期
     * @throws Exception
     * @author liu 2015-1-5
     */
    public static int[] solarToLunar(String solarDate) throws Exception{
        int i;
        int temp = 0;
        int lunarYear;
        int lunarMonth; //农历月份
        int lunarDay; //农历当月第几天
        boolean leapMonthFlag =false;

        SimpleDateFormat formatter = new SimpleDateFormat("yyyyMMdd");
        Date myDate = null;
        Date startDate = null;
        try {
            myDate = formatter.parse(solarDate);
            startDate = formatter.parse(START_DATE);
        } catch (ParseException e) {
            e.printStackTrace();
        }

        int offset = daysBetween(startDate,myDate);

        for (i = MIN_YEAR; i <= MAX_YEAR; i++){
            temp = getYearDays(i);  //求当年农历年天数
            if (offset - temp < 1){
                break;
            }else{
                offset -= temp;
            }
        }
        lunarYear = i;

        int leapMonth = getLeapMonth(lunarYear);//计算该年闰哪个月
        //设定当年是否有闰月
        if (leapMonth > 0){
            isLeapYear = true;
        }else{
            isLeapYear = false;
        }

        for (i = 1;  i<=12; i++) {
            if(i==leapMonth+1 && isLeapYear){
                temp = getLeapMonthDays(lunarYear);
                isLeapYear = false;
                leapMonthFlag = true;
                i--;
            }else{
                temp = getMonthDays(lunarYear, i);
            }
            offset -= temp;
            if(offset<=0){
                break;
            }
        }

        offset += temp;
        lunarMonth = i;
        lunarDay = offset;

        int[] date = new int[]{lunarYear,lunarMonth,lunarDay};
        return date;
    }

}