/* Copyright (c) 2025-2026 马建军. All rights reserved.
 * 公历 ↔ 农历（1900–2100，与国务院公布历法一致的数据表）
 */
(function (global) {
    var 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, 0x05ac0, 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, 0x04afb, 0x04ad0, 0x0a4d0, 0x1d0b6, 0x0d250, 0x0d520, 0x0dd45,
        0x0b5a0, 0x056d0, 0x055b2, 0x049b0, 0x0a577, 0x0a4b0, 0x0aa50, 0x1b255, 0x06d20, 0x0ada0,
        0x14b63, 0x09370, 0x049f8, 0x04970, 0x064b0, 0x168a6, 0x0ea50, 0x06aa0, 0x1a6c4, 0x0aae0,
        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, 0x04b60, 0x0a570, 0x054e4, 0x0d160,
        0x0e968, 0x0d520, 0x0daa0, 0x16aa6, 0x056d0, 0x04ae0, 0x0a9d4, 0x0a2d0, 0x0d150, 0x0f252,
        0x0d520,
    ];

    var TIAN_GAN = '甲乙丙丁戊己庚辛壬癸';
    var DI_ZHI = '子丑寅卯辰巳午未申酉戌亥';
    var LUNAR_MONTHS = '正二三四五六七八九十冬腊';
    var LUNAR_DAYS = [
        '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',
    ];

    function leapMonth(y) {
        return LUNAR_INFO[y - 1900] & 0xf;
    }

    function leapDays(y) {
        if (leapMonth(y)) {
            return (LUNAR_INFO[y - 1900] & 0x10000) ? 30 : 29;
        }
        return 0;
    }

    function monthDays(y, m) {
        return (LUNAR_INFO[y - 1900] & (0x10000 >> m)) ? 30 : 29;
    }

    function lYearDays(y) {
        var sum = 348;
        var i;
        for (i = 0x8000; i > 0x8; i >>= 1) {
            sum += (LUNAR_INFO[y - 1900] & i) ? 1 : 0;
        }
        return sum + leapDays(y);
    }

    function solarToDate(y, m, d) {
        return new Date(y, m - 1, d);
    }

    function solarToLunar(y, m, d) {
        var base = new Date(1900, 0, 31);
        var obj = solarToDate(y, m, d);
        var offset = Math.floor((obj - base) / 86400000);
        var i;
        var temp = 0;
        var lunarYear = 1900;

        for (i = 1900; i < 2101 && offset > 0; i++) {
            temp = lYearDays(i);
            offset -= temp;
            lunarYear++;
        }
        if (offset < 0) {
            offset += temp;
            lunarYear--;
        }

        var leap = leapMonth(lunarYear);
        var isLeap = false;
        var lunarMonth = 1;

        for (i = 1; i < 13 && offset > 0; i++) {
            if (leap > 0 && i === leap + 1 && !isLeap) {
                i--;
                isLeap = true;
                temp = leapDays(lunarYear);
            } else {
                temp = monthDays(lunarYear, i);
            }
            if (isLeap && i === leap + 1) isLeap = false;
            offset -= temp;
            if (!isLeap) lunarMonth++;
        }
        if (offset === 0 && leap > 0 && lunarMonth === leap + 1) {
            if (isLeap) {
                isLeap = false;
            } else {
                isLeap = true;
                lunarMonth--;
            }
        }
        if (offset < 0) {
            offset += temp;
            lunarMonth--;
        }

        return {
            year: lunarYear,
            month: lunarMonth,
            day: offset + 1,
            isLeap: isLeap,
        };
    }

    function lunarMonthName(month, isLeap) {
        var idx = month - 1;
        if (idx < 0 || idx >= LUNAR_MONTHS.length) return String(month) + '月';
        var name = LUNAR_MONTHS.charAt(idx);
        if (name === '冬') name = '十一';
        if (name === '腊') name = '十二';
        return (isLeap ? '闰' : '') + name + '月';
    }

    function lunarDayName(day) {
        return LUNAR_DAYS[day - 1] || String(day);
    }

    function ganZhiYear(y) {
        return TIAN_GAN.charAt((y - 4) % 10) + DI_ZHI.charAt((y - 4) % 12);
    }

    function parseIso(iso) {
        var p = iso.split('-');
        return { y: parseInt(p[0], 10), m: parseInt(p[1], 10), d: parseInt(p[2], 10) };
    }

    function fromIso(iso) {
        var p = parseIso(iso);
        var lunar = solarToLunar(p.y, p.m, p.d);
        return {
            solar: iso,
            lunarYear: lunar.year,
            lunarMonth: lunar.month,
            lunarDay: lunar.day,
            isLeap: lunar.isLeap,
            lunarMonthText: lunarMonthName(lunar.month, lunar.isLeap),
            lunarDayText: lunarDayName(lunar.day),
            lunarFull: lunarMonthName(lunar.month, lunar.isLeap) + lunarDayName(lunar.day),
            ganZhi: ganZhiYear(lunar.year),
        };
    }

    /** 单元格内农历：初一显示月份，其余显示日名 */
    function cellLunarText(iso) {
        var info = fromIso(iso);
        if (info.lunarDay === 1) {
            return info.lunarMonthText;
        }
        return info.lunarDayText;
    }

    /** 标题：公历 YYYY年M月 · 农历干支年M月 */
    function monthTitle(solarYear, solarMonth) {
        var mid = fromIso(solarYear + '-' + pad(solarMonth) + '-15');
        return (
            '公历 ' + solarYear + '年' + solarMonth + '月 · 农历 ' +
            mid.ganZhi + '年' + mid.lunarMonthText
        );
    }

    function pad(n) {
        return n < 10 ? '0' + n : String(n);
    }

    /** 详情标题后缀 */
    function daySubtitle(iso) {
        var info = fromIso(iso);
        return '农历' + info.ganZhi + '年' + info.lunarFull;
    }

    global.qihuoLunar = {
        fromIso: fromIso,
        cellLunarText: cellLunarText,
        monthTitle: monthTitle,
        daySubtitle: daySubtitle,
        lunarMonthName: lunarMonthName,
        lunarDayName: lunarDayName,
    };
}(typeof window !== 'undefined' ? window : this));