package calendar;

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

public class Lunar {
    private int year;
    private int month;
    private int day;
    private boolean leap;
    final static String chineseNumber[] = {"一", "二", "三", "四", "五", "六", "七",
            "八", "九", "十", "十一", "十二"};
    static SimpleDateFormat chineseDateFormat = new SimpleDateFormat(
            "yyyy年MM月dd日");

    final static long[] lunarInfo = new long[] {
                                    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,
                                    0x14b63, 0x1937f, 0x049f8, 0x04970, 0x064b0,
                                    0x168a6, 0x0ea5f, 0x06b20, 0x1a6c4, 0x1aaef,
                                    0x092e0, 0x0d2e3, 0x0c960, 0x0d557, 0x0d4a0,
                                    0x0da50, 0x05d55, 0x056a0, 0x0a6d0, 0x055d4,
                                    0x052d0, 0x0a9b8, 0x0a950, 0x0b4a0, 0x0b6a6,
                                    0x0ad50, 0x055a0, 0x0aba4, 0x0a5b0, 0x052b0,
                                    0x0b273, 0x06930, 0x07337, 0x06aa0, 0x0ad50,
                                    0x14b55, 0x04b6f, 0x0a570, 0x054e4, 0x0d260,
                                    0x0e968, 0x0d520, 0x0daa0, 0x16aa6, 0x056df,
                                    0x04ae0, 0x0a9d4, 0x0a4d0, 0x0d150, 0x0f252,
    };

    final private static int yearDays(int y) {
        int i, sum = 348;
        for (i = 0x8000; i > 0x8; i >>= 1) {
            if ((lunarInfo[y - 1900] & i) != 0)
                sum += 1;
        }
        return (sum + leapDays(y));
    }

    final private static int leapDays(int y) {
        if (leapMonth(y) != 0) {
            if ((lunarInfo[y - 1900] & 0x10000) != 0)
                return 30;
            else
                return 29;
        } else
            return 0;
    }

    final private static int leapMonth(int y) {
        long lm = 0;
        lm = lunarInfo[y - 1900] & 0xf;
        if (lm == 0xf)
            return 0;
        else
            return (int) lm;
    }

    final private static int monthDays(int y, int m) {
        if ((lunarInfo[y - 1900] & (0x10000 >> m)) == 0)
            return 29;
        else
            return 30;
    }


    public Lunar(Calendar cal) {
        int[] nongDate = new int[3]; //
        int leapMonth = 0;
        Date baseDate = null;
        try {
            baseDate = chineseDateFormat.parse("1900年1月31日");
        } catch (ParseException e) {
            e.printStackTrace();
        } finally {

        }
        int offset = (int) ((cal.getTime().getTime() - baseDate.getTime()) /
                            86400000L);
        nongDate[2] = offset + 40;
        nongDate[1] = 14;

        int iYear, daysOfYear = 0;
        for (iYear = 1900; iYear < 2099 && offset > 0; iYear++) {
            daysOfYear = yearDays(iYear);
            offset = offset - daysOfYear;
            nongDate[1] = nongDate[1] + 12;
        }
        if (offset < 0) {
            offset = offset + daysOfYear;
            iYear--;
            nongDate[1] = nongDate[1] - 12;
        }

        year = iYear;

        nongDate[0] = iYear - 1900;
        leapMonth = leapMonth(iYear);
        leap = false;

        int iMonth, daysOfMonth = 0;
        for (iMonth = 1; iMonth < 13 && offset > 0; iMonth++) {

            if (leapMonth > 0 && iMonth == (leapMonth + 1) && !leap) {
                --iMonth;
                leap = true;
                daysOfMonth = leapDays(year);
            } else
                daysOfMonth = monthDays(year, iMonth);

            offset = offset - daysOfMonth;

            if (leap && iMonth == (leapMonth + 1))
                leap = false;
            if (!leap)
                nongDate[1]++;
        }

        if (offset == 0 && leapMonth > 0 && iMonth == leapMonth + 1) {
            if (leap) {
                leap = false;
            } else {
                leap = true;
                --iMonth;
                --nongDate[1];
            }
        }

        if (offset < 0) {
            offset = offset + daysOfMonth;
            --iMonth;
            --nongDate[1];
        }
        month = iMonth;
        day = offset + 1;
    }

    public static String getChinaDayString(int day) {
        String chineseTen[] = {"初", "十", "廿", "卅"};
        int n = day % 10 == 0 ? 9 : day % 10 - 1;
        if (day > 30)
            return "";
        if (day == 10)
            return "初十";
        else
            return chineseTen[day / 10] + chineseNumber[n];
    }

    public String toString() {
        return year + "年" + (leap ? "閏" : "") + chineseNumber[month - 1] + "月" +
                getChinaDayString(day);
    }


    public static void main(String[] args) throws ParseException {
        Calendar today = Calendar.getInstance();
        today.setTime(chineseDateFormat.parse("1900年01月30日"));
        Lunar lunar = new Lunar(today);
        System.out.println("北京時間：" + chineseDateFormat.format(today.getTime()) +
                           "　農歷" + lunar);
    }
}