import Toybox.Lang;
import Toybox.Math;
import Toybox.System;
import Toybox.Time;
import Toybox.Time.Gregorian;
import Toybox.Application;
import Toybox.ActivityMonitor;
import Toybox.Activity;
import Toybox.UserProfile;
import Toybox.SensorHistory;
import Toybox.Weather;
import Toybox.Position;
import Toybox.WatchUi;
import FieldTable;
import Settings;
import Solar;
import Owm;
import Comp;

// ============================================================================
// 数据字段
// ----------------------------------------------------------------------------
// 四个数据位能显示的全部内容，共 125 项。
//
// 字段编号沿用 https://watchface.io/docs/datafields，两边可以直接对照。
// 驱动设置项和标签文案的那张表在 tools/gen_fields.py —— 加字段要改那里，
// 然后在本文件对应分类的函数里补一个分支。
//
// 只收录**手表本机能算出来**的字段。没做的几类及原因见 README 第 7 节，简单说：
//   - 按运动分类的周/月累计：CIQ 只有按天的总计，没有分运动的历史
//   - StormGlass 潮汐、第三方 App 复杂功能：需要额外 key 或用户装了对应 App
//   - 日历、计时器：CIQ 不开放日历，表盘也拿不到触摸输入
//
// 组织方式：value() 按分类依次尝试 7 个函数，每个函数不认识编号就返回 null。
// 之所以不按编号区间派发，是因为编号是**交错**的 —— 1/2/3 是活动，8/11/12 是
// 身体，14 又回到活动。
// ============================================================================
module Fields {

    const DASH = "--";

    var mDow as Array<String>?;
    var mMon as Array<String>?;
    var mLabels as Array<String>?;
    var mMeridiem as Array<String>?;
    var mDateFmt as String = "$1$ $2$";

    function loadStrings() as Void {
        mDow = splitCsv(WatchUi.loadResource(Rez.Strings.DowNames) as String);
        mMon = splitCsv(WatchUi.loadResource(Rez.Strings.MonNames) as String);
        mLabels = splitCsv(WatchUi.loadResource(Rez.Strings.FieldLabels) as String);
        mMeridiem = splitCsv(WatchUi.loadResource(Rez.Strings.Meridiem) as String);
        mDateFmt = WatchUi.loadResource(Rez.Strings.DateFormat) as String;
    }

    function ready() as Boolean { return mDow != null; }

    // Monkey C 没有 String.split，只能自己按逗号切。
    function splitCsv(str as String) as Array<String> {
        var out = [] as Array<String>;
        var rest = str;
        var cut = rest.find(",");
        while (cut != null) {
            out.add(rest.substring(0, cut) as String);
            rest = rest.substring(cut + 1, rest.length()) as String;
            cut = rest.find(",");
        }
        out.add(rest);
        return out;
    }

    function dow(g as Gregorian.Info) as String {
        return mDow == null ? "" : mDow[g.day_of_week - 1];
    }

    function month(g as Gregorian.Info) as String {
        return mMon == null ? "" : mMon[g.month - 1];
    }

    function monthDay(g as Gregorian.Info) as String {
        return Lang.format(mDateFmt, [month(g), g.day.format("%d")]);
    }

    // 按用户填的格式串拼时间/日期。
    //
    // 用单字母占位符，因为设置项里能填的长度有限，而且这样中英文都好写：
    //     h 小时（12/24 跟随手表）   H 小时补零
    //     m 分钟补零                 s 秒补零
    //     a 上午/下午（24 小时制下为空）
    //     D 日                       M 月（数字）   N 月（名称）
    //     Y 四位年                   y 两位年       w 星期
    // 其它字符原样输出，所以 "D/M" → "10/9"，"w N D" → "周四 9月 10"。
    function applyFormat(fmt as String, g as Gregorian.Info, c as Ctx) as String {
        var out = "";
        var chars = fmt.toCharArray();
        for (var i = 0; i < chars.size(); i++) {
            var ch = chars[i];
            if (ch == 'h') {
                var hh = g.hour;
                if (!c.is24) {
                    if (hh == 0) { hh = 12; } else if (hh > 12) { hh = hh - 12; }
                }
                out += hh.format("%d");
            } else if (ch == 'H') {
                out += g.hour.format("%02d");
            } else if (ch == 'm') {
                out += g.min.format("%02d");
            } else if (ch == 's') {
                out += g.sec.format("%02d");
            } else if (ch == 'a') {
                out += c.is24 ? "" : meridiem(g);
            } else if (ch == 'D') {
                out += g.day.format("%d");
            } else if (ch == 'M') {
                out += g.month.format("%d");
            } else if (ch == 'N') {
                out += month(g);
            } else if (ch == 'Y') {
                out += g.year.format("%d");
            } else if (ch == 'y') {
                out += (g.year % 100).format("%02d");
            } else if (ch == 'w') {
                out += dow(g);
            } else {
                out += ch.toString();
            }
        }
        return out;
    }

    // 距目标日期还有几天。目标日期是设置里填的 YYYY-MM-DD 字符串。
    // 解析失败（没填/格式不对）返回 null，字段显示 "--"。
    function daysUntil(target as String, g as Gregorian.Info) as Number? {
        if (target.length() < 8) { return null; }
        var parts = splitOn(target, '-');
        if (parts.size() < 3) { return null; }
        var y = parts[0].toNumber();
        var mo = parts[1].toNumber();
        var d = parts[2].toNumber();
        if (y == null || mo == null || d == null) { return null; }
        // 都换算成「儒略日式」的绝对天数再相减，省得处理跨月跨年。
        return absDay(y, mo, d) - absDay(g.year, g.month, g.day);
    }

    function absDay(y as Number, m as Number, d as Number) as Number {
        var yy = y;
        var mm = m;
        if (mm <= 2) { yy = yy - 1; mm = mm + 12; }
        var a = yy / 100;
        var b = 2 - a + a / 4;
        return (365.25 * (yy + 4716)).toNumber() + (30.6001 * (mm + 1)).toNumber()
               + d + b - 1524;
    }

    function splitOn(str as String, sep as Char) as Array<String> {
        var out = [] as Array<String>;
        var cur = "";
        var chars = str.toCharArray();
        for (var i = 0; i < chars.size(); i++) {
            if (chars[i] == sep) { out.add(cur); cur = ""; }
            else { cur += chars[i].toString(); }
        }
        out.add(cur);
        return out;
    }

    // 英文出 "10"，中文出 "10日"。
    // 后缀带在本地化的日期格式串里，所以这里把月份传空串即可。
    function dayOnly(g as Gregorian.Info) as String {
        return Lang.format(mDateFmt, ["", g.day.format("%d")]);
    }

    function meridiem(g as Gregorian.Info) as String {
        return mMeridiem == null ? "" : mMeridiem[g.hour >= 12 ? 1 : 0];
    }

    // 底部格子数值下方的小标签。按字段编号查 FieldTable 的下标，
    // 再到本地化的标签表里取词，所以中英文会自动跟随系统语言。
    function label(id as Number) as String {
        if (mLabels == null) { return ""; }
        var i = FieldTable.indexOf(id);
        return i < mLabels.size() ? mLabels[i] : "";
    }

    // 每次绘制构造一个，传给所有数据位共用。
    // 目的是让开销大的查询（天气预报、传感器历史、用户档案）**每次绘制最多做
    // 一次，且只在真的有格子要用时才做** —— 四个格子可能都要天气，但只查一次；
    // 没有格子用到 UserProfile 时就完全不去碰它。
    class Ctx {
        var greg as Gregorian.Info;
        var is24 as Boolean = true;
        var metric as Boolean = true;
        var fahrenheit as Boolean = false;

        private var mInfo as ActivityMonitor.Info?;
        private var mStats as System.Stats?;
        private var mDs as System.DeviceSettings?;
        private var mAct as Activity.Info?;
        private var mWx as Weather.CurrentConditions?;
        private var mFc as Array<Weather.DailyForecast>?;
        private var mProf as UserProfile.Profile?;
        private var mGotAct = false;
        private var mGotWx = false;
        private var mGotFc = false;
        private var mGotProf = false;

        function initialize(ds as System.DeviceSettings?, tempUnit as Number) {
            mDs = ds;
            greg = Gregorian.info(Time.now(), Time.FORMAT_SHORT);
            if (ds != null) {
                is24 = ds.is24Hour;
                metric = (ds.distanceUnits != System.UNIT_STATUTE);
                fahrenheit = (tempUnit == 2)
                    || (tempUnit == 0 && ds.temperatureUnits == System.UNIT_STATUTE);
            }
            if (tempUnit == 1) { fahrenheit = false; }
        }

        function ds() as System.DeviceSettings? { return mDs; }

        function info() as ActivityMonitor.Info? {
            if (mInfo == null) { mInfo = ActivityMonitor.getInfo(); }
            return mInfo;
        }

        function stats() as System.Stats? {
            if (mStats == null) { mStats = System.getSystemStats(); }
            return mStats;
        }

        function act() as Activity.Info? {
            if (!mGotAct) { mAct = Activity.getActivityInfo(); mGotAct = true; }
            return mAct;
        }

        function wx() as Weather.CurrentConditions? {
            if (!mGotWx) { mWx = Weather.getCurrentConditions(); mGotWx = true; }
            return mWx;
        }

        function forecast() as Weather.DailyForecast? {
            if (!mGotFc) { mFc = Weather.getDailyForecast(); mGotFc = true; }
            if (mFc != null && mFc.size() > 0) { return mFc[0]; }
            return null;
        }

        function profile() as UserProfile.Profile? {
            if (!mGotProf) { mProf = UserProfile.getProfile(); mGotProf = true; }
            return mProf;
        }

        // 日出/日落/晨昏蒙影都要位置，而两个实时来源都会间歇性为空：
        //   - 天气在同步之前没有观测点坐标
        //   - currentLocation 要有东西刚定过位才有值
        // 所以每次拿到位置就缓存进 Storage，两个来源都空时用缓存兜底，
        // 免得这些字段一会儿有一会儿变 "--"。
        function where() as Position.Location? {
            var w = wx();
            if (w != null && (w has :observationLocationPosition)
                    && w.observationLocationPosition != null) {
                return remember(w.observationLocationPosition);
            }
            var a = act();
            if (a != null && a.currentLocation != null) {
                return remember(a.currentLocation);
            }
            var lat = Application.Storage.getValue("lastLat");
            var lon = Application.Storage.getValue("lastLon");
            if (lat != null && lon != null) {
                return new Position.Location({:latitude => lat as Double,
                                              :longitude => lon as Double,
                                              :format => :degrees});
            }
            return null;
        }

        function remember(loc as Position.Location) as Position.Location {
            var d = loc.toDegrees();
            Application.Storage.setValue("lastLat", d[0]);
            Application.Storage.setValue("lastLon", d[1]);
            return loc;
        }
    }

    // ------------------------------- 格式化工具 ----------------------------
    function num(v as Numeric?) as String {
        return v == null ? DASH : v.format("%d");
    }

    function one(v as Float?) as String {
        return v == null ? DASH : v.format("%.1f");
    }

    function clock(m as Time.Moment?, c as Ctx) as String {
        if (m == null) { return DASH; }
        return clockInfo(Gregorian.info(m, Time.FORMAT_SHORT), c);
    }

    function clockInfo(g as Gregorian.Info, c as Ctx) as String {
        var h = g.hour;
        if (!c.is24) {
            if (h == 0) { h = 12; } else if (h > 12) { h = h - 12; }
        }
        return h.format("%d") + ":" + g.min.format("%02d");
    }

    function offsetClock(minutes as Number, c as Ctx) as String {
        var m = Time.now().add(new Time.Duration(minutes * 60));
        return clock(m, c);
    }

    function temp(celsius as Numeric?, c as Ctx) as String {
        if (celsius == null) { return DASH; }
        var t = celsius.toFloat();
        if (c.fahrenheit) { t = t * 9.0 / 5.0 + 32.0; }
        return t.format("%d") + "°";
    }

    // ActivityMonitor 的距离单位是**厘米**，先换算成公里再按单位制转换。
    function dist(cm as Numeric?, c as Ctx) as String {
        if (cm == null) { return DASH; }
        var km = cm.toFloat() / 100000.0;
        return (c.metric ? km : km * 0.621371).format("%.1f");
    }

    function metres(m as Numeric?, c as Ctx) as String {
        if (m == null) { return DASH; }
        var v = m.toFloat();
        return (c.metric ? v : v * 3.28084).format("%d");
    }

    function rounded(v as Numeric?) as String {
        if (v == null) { return DASH; }
        var n = v.toNumber();
        if (n < 1000) { return n.format("%d"); }
        return (n / 1000.0).format("%.1f") + "k";
    }

    // 从 SensorHistory 迭代器里取最新一条读数；没有则 null。
    function latest(iter) as Numeric? {
        if (iter == null) { return null; }
        var s = iter.next();
        if (s == null) { return null; }
        return s.data;
    }

    // 历史累计。
    // ActivityMonitor.getHistory() 返回过去若干天（最新在前），**不含今天**。
    // 把它加起来是本机唯一能做出「本周累计 / 近 7 天累计」的路子；
    // 按运动项目细分的那些仍然做不到，那需要手机侧与 Garmin Connect 的集成。
    //
    // which：0 步数 / 1 卡路里 / 2 距离(厘米) / 3 楼层 / 4 活动分钟
    // days ：往前折算几天，今天总是算在内
    function sumHistory(c as Ctx, which as Number, days as Number) as Numeric? {
        var today = todayValue(c, which);
        if (today == null) { return null; }
        var total = today;
        if (days <= 0) { return total; }
        var hist = ActivityMonitor.getHistory();
        if (hist == null) { return total; }
        var n = days < hist.size() ? days : hist.size();
        for (var k = 0; k < n; k++) {
            var v = sampleValue(hist[k], which);
            if (v != null) { total = total + v; }
        }
        return total;
    }

    function todayValue(c as Ctx, which as Number) as Numeric? {
        var i = c.info();
        if (i == null) { return null; }
        return sampleValue(i, which);
    }

    function sampleValue(d, which as Number) as Numeric? {
        if (which == 0) { return (d has :steps) ? d.steps : null; }
        if (which == 1) { return (d has :calories) ? d.calories : null; }
        if (which == 2) { return (d has :distance) ? d.distance : null; }
        if (which == 3) { return (d has :floorsClimbed) ? d.floorsClimbed : null; }
        if (which == 4) {
            if (!(d has :activeMinutesDay) || d.activeMinutesDay == null) { return null; }
            return d.activeMinutesDay.total;
        }
        return null;
    }

    // 距本周一过了几天，本周累计据此决定往前取多少天。
    // day_of_week 是 1=周日，所以周日要特判成 6。
    function daysIntoWeek(g as Gregorian.Info) as Number {
        var dow = g.day_of_week;              // 1 = Sunday
        return dow == 1 ? 6 : dow - 2;
    }

    function dayOfYear(g as Gregorian.Info) as Number {
        var cum = [0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334];
        var d = cum[g.month - 1] + g.day;
        var y = g.year;
        var leap = (y % 4 == 0 && y % 100 != 0) || (y % 400 == 0);
        if (leap && g.month > 2) { d = d + 1; }
        return d;
    }

    // ISO 8601 周数：周一为一周之始，含当年第一个周四的那周为第 1 周。
    function isoWeek(g as Gregorian.Info) as Number {
        var dow = g.day_of_week - 1;          // 0 = Sunday
        var iso = dow == 0 ? 7 : dow;         // 1 = Monday .. 7 = Sunday
        var w = (dayOfYear(g) - iso + 10) / 7;
        if (w < 1) { return 52; }
        if (w > 52) { return 1; }
        return w;
    }

    // 月龄：距 2000-01-06 那次新月的天数，对朔望月（29.530588853 天）取余。
    function moonAge(g as Gregorian.Info) as Float {
        var y = g.year;
        var m = g.month;
        if (m <= 2) { y = y - 1; m = m + 12; }
        var a = y / 100;
        var b = 2 - a + a / 4;
        var jd = (365.25 * (y + 4716)).toNumber() + (30.6001 * (m + 1)).toNumber()
                 + g.day + b - 1524.5 + g.hour / 24.0;
        // ⚠️ Monkey C 的 % 不支持浮点，只能手写取余。
        var syn = 29.530588853;
        var x = jd - 2451550.1;
        var age = x - (x / syn).toNumber() * syn;
        if (age < 0) { age = age + syn; }
        return age.toFloat();
    }

    function windDir(bearingDeg as Numeric?) as String {
        if (bearingDeg == null) { return DASH; }
        var pts = ["N", "NNE", "NE", "ENE", "E", "ESE", "SE", "SSE",
                   "S", "SSW", "SW", "WSW", "W", "WNW", "NW", "NNW"];
        var b = bearingDeg.toFloat();
        while (b < 0) { b = b + 360.0; }
        var i = ((b + 11.25) / 22.5).toNumber() % 16;
        return pts[i];
    }

    // ------------------------------- 分类取值 ------------------------------
    // ---- 日期时间类 ----
    // 不属于本类的编号返回 null，交给 value() 试下一个分类。
    function dateTime(id as Number, c as Ctx) as String? {
        if (id == 860) { return clockInfo(c.greg, c); }                   // 时间
        if (id == 880) {                                                  // UTC 时间
            var utc = Gregorian.utcInfo(Time.now(), Time.FORMAT_SHORT);
            return clockInfo(utc, c);
        }
        // 第二时区 1
        if (id == 864) { return offsetClock(Settings.number("AltOffset1", 0), c); }
        // 第二时区 2
        if (id == 865) { return offsetClock(Settings.number("AltOffset2", 0), c); }
        if (id == 855) { return c.greg.day.format("%d"); }                // 日
        if (id == 868) { return c.greg.month.format("%d"); }              // 月份数字
        if (id == 859) { return isoWeek(c.greg).format("%d"); }           // 周数 (ISO)
        // 周数
        if (id == 873) { return ((dayOfYear(c.greg) + 6) / 7).format("%d"); }
        // 秒数要动起来依赖设备支持 onPartialUpdate；
        // view 只在有格子选了秒时才去请求那个回调。
        if (id == 850) { return c.greg.sec.format("%d"); }                // 秒
        if (id == 869) { return c.greg.sec.format("%02d"); }              // 秒 (前导零)
        // 自定义格式：格式串来自设置，占位符说明见 applyFormat
        if (id == 861) { return applyFormat(Settings.text("TimeFmt"), c.greg, c); }
        if (id == 862) { return applyFormat(Settings.text("DateFmt1"), c.greg, c); }
        if (id == 863) { return applyFormat(Settings.text("DateFmt2"), c.greg, c); }
        if (id == 735) {                                                  // 事件倒计时
            var left = daysUntil(Settings.text("CountdownDate"), c.greg);
            if (left == null) { return DASH; }
            return left.format("%d");
        }              // 秒 (前导零)
        if (id == 870) { return dow(c.greg); }                            // 星期简写
        if (id == 856) { return dow(c.greg); }                            // 星期全称
        if (id == 853) { return month(c.greg); }                          // 月份
        if (id == 852) { return monthDay(c.greg); }                       // 月 日
        if (id == 872) { return dow(c.greg) + " " + dayOnly(c.greg); }    // 星期 日
        if (id == 851) { return dow(c.greg) + " " + monthDay(c.greg); }   // 星期 月 日
        if (id == 858) { return meridiem(c.greg); }                       // 上午/下午

        return null;
    }

    // ---- 活动类 ----
    // 步数、卡路里、距离、楼层、活动分钟，以及它们的本周/近 7 天累计。
    function activity(id as Number, c as Ctx) as String? {
        var i = c.info();
        if (id == 1)   { return i == null ? DASH : num(i.steps); }        // 步数
        if (id == 14)  { return i == null ? DASH : rounded(i.steps); }    // 步数 (取整)
        if (id == 707) {                                                  // 剩余步数
            if (i == null || i.steps == null || i.stepGoal == null) { return DASH; }
            var left = i.stepGoal - i.steps;
            return left > 0 ? left.format("%d") : "0";
        }
        if (id == 2)   { return i == null ? DASH : num(i.calories); }     // 卡路里
        if (id == 603) {                                                  // 活动卡路里
            if (i == null || i.calories == null) { return DASH; }
            var p = c.profile();
            if (p == null || p.weight == null || p.height == null) { return num(i.calories); }
            return num(i.calories);          // device reports total only
        }
        if (id == 150 || id == 152 || id == 154) {                        // 活动分钟 / 中强度分钟 / 高强度分钟
            if (i == null || !(i has :activeMinutesDay) || i.activeMinutesDay == null) {
                return DASH;
            }
            var am = i.activeMinutesDay;
            if (id == 152) { return num(am.moderate); }                   // 中强度分钟
            if (id == 154) { return num(am.vigorous); }                   // 高强度分钟
            return num(am.total);
        }
        if (id == 151) {                                                  // 本周活动分钟
            if (i == null || !(i has :activeMinutesWeek) || i.activeMinutesWeek == null) {
                return DASH;
            }
            return num(i.activeMinutesWeek.total);
        }
        // 距离
        if (id == 3)   { return i == null ? DASH : dist(i.distance, c); }
        // 上楼层数
        if (id == 4)   { return i == null ? DASH : num(i.floorsClimbed); }
        // ⚠️ ActivityMonitor.Info 上有些成员**在所有设备上都能编译通过，但只有
        // 部分设备/固件运行时才真的有**。轮椅计数器就是典型：在 fenix 8 上直接抛
        // "Symbol Not Found"，用户一选这个字段表盘就崩。
        // 所以凡是非通用成员，用之前一律先 has 检查。
        if (id == 5) {                                                    // 下楼层数
            return (i == null || !(i has :floorsDescended)) ? DASH
                : num(i.floorsDescended);
        }
        if (id == 6) {                                                    // 爬升高度
            return (i == null || !(i has :metersClimbed)) ? DASH
                : metres(i.metersClimbed, c);
        }
        if (id == 9) {                                                    // 推行距离
            return (i == null || !(i has :pushDistance)) ? DASH
                : dist(i.pushDistance, c);
        }
        if (id == 10) {                                                   // 推行次数
            return (i == null || !(i has :pushes)) ? DASH : num(i.pushes);
        }
        if (id == 219 || id == 211 || id == 213 || id == 203) {           // 本周步数 / 本周卡路里 / 本周距离 / 本周楼层
            var which = (id == 219) ? 0 : ((id == 211) ? 1 : ((id == 213) ? 2 : 3));
            var back = daysIntoWeek(c.greg);
            var v = sumHistory(c, which, back);
            if (v == null) { return DASH; }
            return (id == 213) ? dist(v, c) : rounded(v);
        }
        // 近 7 天步数 / 近 7 天卡路里 / 近 7 天距离 / 近 7 天楼层 / 近 7 天活动分钟
        if (id == 828 || id == 832 || id == 836 || id == 840) {
            // 近 28 天。getHistory 能返回多少天由固件决定，sumHistory 内部会按
            // 实际条数截断，所以拿不到 28 天时是「有多少算多少」而不是报错。
            var w28 = (id == 828) ? 0 : ((id == 832) ? 1 : ((id == 836) ? 2 : 3));
            var v28 = sumHistory(c, w28, 27);
            if (v28 == null) { return DASH; }
            return (id == 836) ? dist(v28, c) : rounded(v28);
        }
        if (id == 220 || id == 212 || id == 214 || id == 204 || id == 200) {
            var which = (id == 220) ? 0 : ((id == 212) ? 1
                      : ((id == 214) ? 2 : ((id == 204) ? 3 : 4)));
            var v = sumHistory(c, which, 6);
            if (v == null) { return DASH; }
            return (id == 214) ? dist(v, c) : rounded(v);
        }
        if (id == 8 || id == 15) {                                        // 活动条 / 活动条 (反向)
            if (i == null || i.moveBarLevel == null) { return DASH; }
            var lvl = i.moveBarLevel;
            // 活动条 (反向)
            if (id == 15) { lvl = ActivityMonitor.MOVE_BAR_LEVEL_MAX - lvl; }
            return lvl.format("%d");
        }
        if (id == 13) {                                                   // 恢复时间
            return (i == null || !(i has :timeToRecovery)) ? DASH
                : num(i.timeToRecovery);
        }
        if (id == 11) {                                                   // 呼吸频率
            return (i == null || !(i has :respirationRate)) ? DASH
                : num(i.respirationRate);
        }
        if (id == 12) {                                                   // 压力指数
            return (i == null || !(i has :stressScore)) ? DASH : num(i.stressScore);
        }

        return null;
    }

    // ---- 身体类 ----
    // 心率、压力、血氧、身体电量，以及从用户档案推出来的体重/BMI/VO2max。
    function body(id as Number, c as Ctx) as String? {
        if (id == 618) {                                                  // 心率
            var a = c.act();
            if (a != null && a.currentHeartRate != null) { return num(a.currentHeartRate); }
            var h = ActivityMonitor.getHeartRateHistory(1, true);
            if (h != null) {
                var s = h.next();
                if (s != null && s.heartRate != null
                        && s.heartRate != ActivityMonitor.INVALID_HR_SAMPLE) {
                    return num(s.heartRate);
                }
            }
            return DASH;
        }
        if (id == 276) {                                                  // 静息心率
            var p = c.profile();
            return (p == null || !(p has :restingHeartRate)) ? DASH
                : num(p.restingHeartRate);
        }
        if (id == 635) {                                                  // 血氧
            if (!(SensorHistory has :getOxygenSaturationHistory)) { return DASH; }
            return num(latest(SensorHistory.getOxygenSaturationHistory({:period => 1})));
        }
        if (id == 623) {                                                  // 身体电量
            if (!(SensorHistory has :getBodyBatteryHistory)) { return DASH; }
            return num(latest(SensorHistory.getBodyBatteryHistory({:period => 1})));
        }
        if (id == 281 || id == 742) {                                     // 体重 / BMI
            var p = c.profile();
            if (p == null || !(p has :weight) || p.weight == null) { return DASH; }
            var kg = p.weight.toFloat() / 1000.0;
            if (id == 281) {                                              // 体重
                return (c.metric ? kg : kg * 2.20462).format("%.1f");
            }
            if (!(p has :height) || p.height == null || p.height <= 0) { return DASH; }
            var m = p.height.toFloat() / 100.0;
            return (kg / (m * m)).format("%.1f");
        }
        if (id == 277 || id == 278) {                                     // 最大摄氧量 (骑) / 最大摄氧量 (跑)
            var p = c.profile();
            if (p == null) { return DASH; }
            if (id == 278) {                                              // 最大摄氧量 (跑)
                return (p has :vo2maxRunning) ? num(p.vo2maxRunning) : DASH;
            }
            return (p has :vo2maxCycling) ? num(p.vo2maxCycling) : DASH;
        }

        return null;
    }

    // ---- 系统类 ----
    // 电量、闹钟、通知、勿扰、蓝牙、太阳能强度。
    function system(id as Number, c as Ctx) as String? {
        var st = c.stats();
        if (id == 250) {                                                  // 电量
            return st == null || st.battery == null ? DASH
                : st.battery.format("%d") + "%";
        }
        if (id == 251) {                                                  // 剩余天数
            if (st == null || !(st has :batteryInDays) || st.batteryInDays == null) {
                return DASH;
            }
            return st.batteryInDays.format("%d") + "d";
        }
        if (id == 257) {                                                  // 电量 / 天数
            var pct = (st == null || st.battery == null) ? DASH : st.battery.format("%d");
            var d = (st == null || !(st has :batteryInDays) || st.batteryInDays == null)
                ? DASH : st.batteryInDays.format("%d");
            return pct + "/" + d;
        }
        if (id == 252) {                                                  // 太阳能强度
            if (st == null || !(st has :solarIntensity) || st.solarIntensity == null) {
                return DASH;
            }
            return st.solarIntensity.format("%d") + "%";
        }
        var ds = c.ds();
        // 闹钟
        if (id == 253) { return ds == null ? DASH : num(ds.alarmCount); }
        // 通知
        if (id == 255) { return ds == null ? DASH : num(ds.notificationCount); }
        if (id == 254) {                                                  // 勿扰模式
            return ds == null ? DASH : (ds.doNotDisturb ? "ON" : "OFF");
        }
        if (id == 256) {                                                  // 蓝牙
            return ds == null ? DASH : (ds.phoneConnected ? "ON" : "OFF");
        }

        return null;
    }

    // ---- 环境类 ----
    // 海拔、气压、各类太阳事件（含晨昏蒙影与黄金/蓝调时刻）、月相。
    function environment(id as Number, c as Ctx) as String? {
        if (id == 615) {                                                  // 海拔
            var a = c.act();
            return (a == null || !(a has :altitude)) ? DASH : metres(a.altitude, c);
        }
        if (id == 616 || id == 733) {                                     // 海平面气压 / 环境气压
            var a = c.act();
            if (a == null) { return DASH; }
            var pa = null;
            if (id == 616 && (a has :meanSeaLevelPressure)) {             // 海平面气压
                pa = a.meanSeaLevelPressure;
            } else if (id == 733 && (a has :ambientPressure)) {           // 环境气压
                pa = a.ambientPressure;
            }
            if (pa == null) { return DASH; }
            return (pa.toFloat() / 100.0).format("%d");
        }
        if (id == 712 || id == 717 || id == 700 || id == 731) {           // 日出 / 日落 / 下一太阳事件 / 距太阳事件
            var loc = c.where();
            if (loc == null) { return DASH; }
            var now = Time.now();
            var rise = Weather.getSunrise(loc, now);
            var set = Weather.getSunset(loc, now);
            if (id == 712) { return clock(rise, c); }                     // 日出
            if (id == 717) { return clock(set, c); }                      // 日落
            if (rise == null || set == null) { return DASH; }
            var next = (now.compare(rise) < 0) ? rise
                     : ((now.compare(set) < 0) ? set : rise);
            if (id == 700) { return clock(next, c); }                     // 下一太阳事件
            var secs = next.compare(now);
            if (secs < 0) { secs = secs + 86400; }
            return (secs / 3600).format("%d") + "h" + ((secs % 3600) / 60).format("%02d");
        }
        if (Solar.owns(id)) {
            return clock(Solar.byId(id, c.where()), c);
        }
        if (id == 706) { return moonAge(c.greg).format("%.1f"); }         // 月龄
        if (id == 732) {                                                  // 月球照明
            var age = moonAge(c.greg);
            var lit = (1.0 - Math.cos(2.0 * Math.PI * age / 29.530588853)) / 2.0;
            return (lit * 100.0).format("%d") + "%";
        }

        return null;
    }

    // ---- Garmin 原生天气 ----
    // 手表同步下来的当前天气与今日预报。与 OWM 那套完全独立。
    function weather(id as Number, c as Ctx) as String? {
        var w = c.wx();
        // 气温
        if (id == 306) { return w == null ? DASH : temp(w.temperature, c); }
        if (id == 300) {                                                  // 体感温度
            return (w == null || !(w has :feelsLikeTemperature)) ? DASH
                : temp(w.feelsLikeTemperature, c);
        }
        if (id == 305) {                                                  // 湿度
            return (w == null || !(w has :relativeHumidity)) ? DASH
                : num(w.relativeHumidity) + "%";
        }
        if (id == 304) {                                                  // 降水概率
            if (w == null || !(w has :precipitationChance)) { return DASH; }
            return num(w.precipitationChance) + "%";
        }
        if (id == 308) {                                                  // 风速
            if (w == null || !(w has :windSpeed) || w.windSpeed == null) { return DASH; }
            var kmh = w.windSpeed.toFloat() * 3.6;
            return (c.metric ? kmh : kmh * 0.621371).format("%d");
        }
        if (id == 307) {                                                  // 风向角
            return (w == null || !(w has :windBearing)) ? DASH : num(w.windBearing);
        }
        if (id == 310) {                                                  // 风向
            return (w == null || !(w has :windBearing)) ? DASH : windDir(w.windBearing);
        }
        if (id == 309) {                                                  // 天气更新时间
            if (w == null || !(w has :observationTime) || w.observationTime == null) {
                return DASH;
            }
            return clock(w.observationTime, c);
        }
        if (id == 312) {                                                  // 海平面气压
            if (w == null || !(w has :pressure) || w.pressure == null) { return DASH; }
            return (w.pressure.toFloat() / 100.0).format("%d");
        }
        if (id == 313) {                                                  // 紫外线指数
            return (w == null || !(w has :uvIndex)) ? DASH : num(w.uvIndex);
        }
        if (id == 314) {                                                  // 能见度
            if (w == null || !(w has :visibility) || w.visibility == null) { return DASH; }
            var km = w.visibility.toFloat() / 1000.0;
            return (c.metric ? km : km * 0.621371).format("%.1f");
        }
        if (id == 315) {                                                  // 露点
            // CIQ 没有露点字段，用 Magnus 公式从温度和湿度反推，
            // 误差在零点几度以内，够用。
            if (w == null || w.temperature == null
                    || !(w has :relativeHumidity) || w.relativeHumidity == null) {
                return DASH;
            }
            var t = w.temperature.toFloat();
            var rh = w.relativeHumidity.toFloat();
            if (rh <= 0.0) { return DASH; }
            var g2 = (17.62 * t) / (243.12 + t) + Math.ln(rh / 100.0);
            return temp(243.12 * g2 / (17.62 - g2), c);
        }
        if (id == 301 || id == 302 || id == 639) {                        // 最高气温 / 最低气温 / 最高/最低气温
            var f = c.forecast();
            if (f == null) { return DASH; }
            var hi = (f has :highTemperature) ? f.highTemperature : null;
            var lo = (f has :lowTemperature) ? f.lowTemperature : null;
            if (id == 301) { return temp(hi, c); }                        // 最高气温
            if (id == 302) { return temp(lo, c); }                        // 最低气温
            return temp(hi, c) + "/" + temp(lo, c);
        }

        return null;
    }

    // ---- OpenWeatherMap ----
    // 读后台服务上次存下来的数据（本函数不联网，见 Owm.mc / Fenix8V3Background.mc）。
    // 后台一律用公制请求，单位换算和其他字段一样在这里做。
    function owm(id as Number, c as Ctx) as String? {
        if (!Owm.owns(id)) { return null; }
        if (!Owm.enabled()) { return DASH; }
        if (id == 500) { return temp(Owm.get("temp"), c); }               // OWM 气温
        if (id == 503) { return temp(Owm.get("feels"), c); }              // OWM 体感温度
        if (id == 504) { return temp(Owm.get("tmax"), c); }               // OWM 最高温
        if (id == 505) { return temp(Owm.get("tmin"), c); }               // OWM 最低温
        if (id == 515) {                                                  // OWM 最高/最低
            return temp(Owm.get("tmax"), c) + "/" + temp(Owm.get("tmin"), c);
        }
        if (id == 507) { return str(Owm.get("short")); }                  // OWM 天气
        if (id == 502) { return str(Owm.get("long")); }                   // OWM 天气详述
        if (id == 501) {                                                  // OWM 湿度
            var h = Owm.get("humidity");
            return h == null ? DASH : num(h) + "%";
        }
        if (id == 506) { return num(Owm.get("pressure")); }               // OWM 气压
        if (id == 509) {                                                  // OWM 能见度
            var v = Owm.get("visibility");
            if (v == null) { return DASH; }
            var km = v.toFloat() / 1000.0;
            return (c.metric ? km : km * 0.621371).format("%.1f");
        }
        if (id == 510 || id == 512) {                                     // OWM 风速 / OWM 阵风
            var w = Owm.get(id == 510 ? "wind" : "gust");
            if (w == null) { return DASH; }
            var kmh = w.toFloat() * 3.6;
            return (c.metric ? kmh : kmh * 0.621371).format("%d");
        }
        if (id == 511) { return num(Owm.get("winddeg")); }                // OWM 风向角
        if (id == 518) { return windDir(Owm.get("winddeg")); }            // OWM 风向
        if (id == 513) {                                                  // OWM 1h 降雨
            var r = Owm.get("rain");
            return r == null ? "0" : r.toFloat().format("%.1f");
        }
        if (id == 532) {                                                  // OWM 1h 降雪
            var sn = Owm.get("snow");
            return sn == null ? "0" : sn.toFloat().format("%.1f");
        }
        if (id == 536) {                                                  // OWM 云量
            var cl = Owm.get("clouds");
            return cl == null ? DASH : num(cl) + "%";
        }
        if (id == 537) {                                                  // OWM 降水概率
            var pop = Owm.get("pop");
            return pop == null ? DASH : (pop.toFloat() * 100.0).format("%d") + "%";
        }
        if (id == 530) {                                                  // OWM 露点
            // OWM 免费接口不返回露点，同样用 Magnus 公式从温湿度算。
            var t = Owm.get("temp");
            var rh = Owm.get("humidity");
            if (t == null || rh == null || rh.toFloat() <= 0.0) { return DASH; }
            var tf = t.toFloat();
            var gg = (17.62 * tf) / (243.12 + tf) + Math.ln(rh.toFloat() / 100.0);
            return temp(243.12 * gg / (17.62 - gg), c);
        }
        if (id == 534) { return temp(Owm.get("hi1"), c); }                // OWM 明日气温
        if (id == 535) { return temp(Owm.get("hi2"), c); }                // OWM 后日气温
        if (id == 522) {                                                  // OWM 明日高低温
            return temp(Owm.get("hi1"), c) + "/" + temp(Owm.get("lo1"), c);
        }
        if (id == 523) {                                                  // OWM 后日高低温
            return temp(Owm.get("hi2"), c) + "/" + temp(Owm.get("lo2"), c);
        }
        if (id == 538 || id == 539) {                                     // 空气质量指数 / 描述
            var aqi = Owm.get("aqi");
            if (aqi == null) { return DASH; }
            if (id == 538) { return num(aqi); }
            // OWM 的 AQI 是 1..5 的等级，不是欧美常见的 0..500 数值。
            var names = ["", "优", "良", "中", "差", "很差"];
            var k = aqi.toNumber();
            return (k >= 1 && k <= 5) ? names[k] : DASH;
        }
        if (id == 540) { return oneDp(Owm.get("pm2_5")); }                 // PM2.5
        if (id == 541) { return oneDp(Owm.get("pm10")); }                  // PM10
        if (id == 542) { return oneDp(Owm.get("co")); }                    // 一氧化碳
        if (id == 516) { return str(Owm.get("city")); }                   // OWM 城市
        if (id == 517) {                                                  // OWM 更新时间
            var dt = Owm.get("dt");
            return dt == null ? DASH : clock(new Time.Moment(dt as Number), c);
        }
        return DASH;
    }

    function oneDp(v) as String {
        return v == null ? DASH : v.toFloat().format("%.1f");
    }

    function str(v) as String {
        return v == null ? DASH : v.toString();
    }

    // ---- 系统 Complication ----
    // 日历、训练状态、完赛/配速预测、按运动的周距离、以及第三方 App 发布的
    // 复杂功能。全部由 Comp.mc 经 Toybox.Complications 取得。
    function complication(id as Number, c as Ctx) as String? {
        return Comp.value(id);
    }

    // ---- 自定义文字 ----
    // 用户在设置里自己填的三段文字。
    function custom(id as Number, c as Ctx) as String? {
        if (id == 703) { return Settings.text("Custom1"); }               // 自定义文字 1
        if (id == 704) { return Settings.text("Custom2"); }               // 自定义文字 2
        if (id == 705) { return Settings.text("Custom3"); }               // 自定义文字 3
        return null;
    }

    // 取某个字段的显示文本。
    // 按分类依次尝试，而不是按编号区间派发 —— 编号是交错的（1/2/3 活动、
    // 8/11/12 身体、14 又是活动），区间派发行不通。
    function value(id as Number, c as Ctx) as String {
        var v = dateTime(id, c);
        if (v == null) { v = activity(id, c); }
        if (v == null) { v = body(id, c); }
        if (v == null) { v = system(id, c); }
        if (v == null) { v = environment(id, c); }
        if (v == null) { v = weather(id, c); }
        if (v == null) { v = complication(id, c); }
        if (v == null) { v = owm(id, c); }
        if (v == null) { v = custom(id, c); }
        return v == null ? "" : v;
    }
}