250 lines
8.3 KiB
JavaScript
250 lines
8.3 KiB
JavaScript
// Seth Calendar
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//
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// Structure:
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// - Same year numbers and Jan 1 epoch as Gregorian
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// - 10 months of 36 days (6 weeks of 6 days each)
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// - 5 holiday days at year end (6 on leap years)
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// - Total: 365 or 366 days
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//
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// Gregorian alignment (non-leap year):
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// Month 1 Day 1 = Jan 1
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// Month 10 Day 35 = Dec 25 (Christmas)
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// Month 10 Day 36 = Dec 26 (Boxing Day)
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// Holiday 1 = Dec 27
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// Holiday 5 = Dec 31 (New Year's Eve)
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//
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// Gregorian alignment (leap year):
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// Month 10 Day 35 = Dec 24 (Christmas Eve)
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// Month 10 Day 36 = Dec 25 (Christmas)
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// Holiday 1 = Dec 26 (Boxing Day)
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// Holiday 6 = Dec 31 (New Year's Eve)
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function isLeapYear(year) {
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return (year % 4 === 0 && year % 100 !== 0) || year % 400 === 0;
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}
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function toSethDate(year, dayOfYear) {
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// dayOfYear: 1-indexed (Jan 1 = 1)
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const leap = isLeapYear(year);
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// Leap Day: DOY 60 in a leap year — sits between M1 W3 D4 and M1 W3 D5
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if (leap && dayOfYear === 60) {
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return { type: "leapday", year, dayOfYear };
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}
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// After leap day, subtract 1 so the rest of the calendar stays pegged
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const idx = (leap && dayOfYear > 60 ? dayOfYear - 1 : dayOfYear) - 1;
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if (idx < 360) {
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const month = Math.floor(idx / 36); // 0..9
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const dayInM = idx % 36; // 0..35
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const week = Math.floor(dayInM / 6); // 0..5
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const dayInW = dayInM % 6; // 0..5
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return { type: "month", year, month, day: dayInM, week, weekDay: dayInW, dayOfYear };
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} else {
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const holiday = idx - 360; // 0..4 (or 0..5 leap)
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return { type: "holiday", year, holiday, leap, dayOfYear };
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}
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}
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function getDayOfYear(date, zone) {
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const fmt = new Intl.DateTimeFormat("en-US", {
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timeZone: zone,
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year: "numeric", month: "numeric", day: "numeric"
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});
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const parts = fmt.formatToParts(date).reduce((acc, p) => {
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if (p.type !== "literal") acc[p.type] = parseInt(p.value, 10);
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return acc;
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}, {});
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const { year, month, day } = parts;
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// Day of year calculation
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const cumDays = [0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334];
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const leap = isLeapYear(year);
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let doy = cumDays[month - 1] + day;
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if (leap && month > 2) doy++;
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return { year, doy };
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}
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// Notation helpers
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// short: D.M e.g. "30.1"
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// medium: D.M.YY e.g. "30.1.26"
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// log: DD.M.YYYY e.g. "30.1.2026" (DD zero-pads to 2 digits)
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// full: YYYY.M.DD e.g. "2026.1.30"
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function sethShort(sd) {
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if (sd.type === "leapday") return "Leap Day";
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if (sd.type === "holiday") return `H${sd.holiday}`;
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return `${sd.day}.${sd.month}`;
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}
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function sethMedium(sd) {
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if (sd.type === "leapday") return "Leap Day";
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if (sd.type === "holiday") return `H${sd.holiday}.${String(sd.year).slice(-2)}`;
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return `${sd.day}.${sd.month}.${String(sd.year).slice(-2)}`;
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}
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function sethLog(sd) {
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if (sd.type === "leapday") return `Leap Day ${sd.year}`;
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if (sd.type === "holiday") return `H${sd.holiday}.${sd.year}`;
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return `${String(sd.day).padStart(2,"0")}.${sd.month}.${sd.year}`;
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}
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function sethFull(sd) {
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if (sd.type === "leapday") return `${sd.year}.Leap`;
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if (sd.type === "holiday") return `${sd.year}.H${sd.holiday}`;
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return `${sd.year}.${sd.month}.${sd.day}`;
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}
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// Legacy display helpers (used by seth.html dateLine)
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function formatSethDate(sd) {
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if (sd.type === "leapday") return "Leap Day";
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if (sd.type === "holiday") {
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const total = sd.leap ? 6 : 5;
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return `Holiday ${sd.holiday} of ${total}`;
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}
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return `${sd.day}.${sd.month} (Month ${sd.month}, Day ${sd.day})`;
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}
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function formatSethLong(sd) {
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if (sd.type === "leapday") return `${sd.year} Leap Day — Feb 29`;
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if (sd.type === "holiday") {
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const lastHoliday = sd.leap ? 5 : 4;
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const isNYE = sd.holiday === lastHoliday;
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const isBoxingDay = sd.leap && sd.holiday === 0;
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let note = "";
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if (isNYE) note = " — New Year's Eve";
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else if (isBoxingDay) note = " — Boxing Day";
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return `${sd.year} Holiday ${sd.holiday}${note}`;
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}
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return `${sethLog(sd)} (${sd.year}.${sd.month}.${sd.day})`;
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}
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// --- Decimal time (same as decimal page) ---
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function getLocalParts(date, zone) {
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const fmt = new Intl.DateTimeFormat("en-US", {
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timeZone: zone,
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hour12: false,
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year: "numeric", month: "2-digit", day: "2-digit",
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hour: "2-digit", minute: "2-digit", second: "2-digit"
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});
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return fmt.formatToParts(date).reduce((acc, p) => {
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if (p.type !== "literal") acc[p.type] = parseInt(p.value, 10);
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return acc;
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}, {});
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}
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function toDecimalTime(date, zone) {
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const p = getLocalParts(date, zone);
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const msIntoDay =
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p.hour * 3_600_000 +
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p.minute * 60_000 +
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p.second * 1_000 +
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date.getMilliseconds();
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const dayFraction = msIntoDay / 86_400_000;
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const totalDecimalSeconds = dayFraction * 100_000;
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const dHour = Math.floor(totalDecimalSeconds / 10_000);
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const rem1 = totalDecimalSeconds % 10_000;
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const dMin = Math.floor(rem1 / 100);
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const dSec = rem1 % 100;
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const dCenti = Math.floor((dSec % 1) * 100);
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const dSecInt = Math.floor(dSec);
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return `\u00a0${dHour}:${String(dMin).padStart(2,"0")}:${String(dSecInt).padStart(2,"0")}.${String(dCenti).padStart(2,"0")}`;
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}
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// --- DOM & sync ---
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const zoneSelect = document.getElementById("zoneSelect");
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const zoneLabel = document.getElementById("zoneLabel");
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const offsetLabel = document.getElementById("offsetLabel");
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const decimalTime = document.getElementById("decimalTime");
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const gregorianTime = document.getElementById("gregorianTime");
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const dayOfYear = document.getElementById("dayOfYear");
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const weekOfYear = document.getElementById("weekOfYear");
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const utcLabel = document.getElementById("utcLabel");
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const dateLine = document.getElementById("dateLine");
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const digital = document.getElementById("digital");
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const zones = [
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"America/New_York",
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"America/Chicago",
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"America/Denver",
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"America/Los_Angeles",
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"America/Anchorage",
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"Pacific/Honolulu",
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"UTC"
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];
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let selectedZone = Intl.DateTimeFormat().resolvedOptions().timeZone || "America/New_York";
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if (!zones.includes(selectedZone)) selectedZone = "America/New_York";
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for (const zone of zones) {
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const option = document.createElement("option");
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option.value = zone;
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option.textContent = zone;
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if (zone === selectedZone) option.selected = true;
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zoneSelect.appendChild(option);
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}
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zoneSelect.addEventListener("change", () => {
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selectedZone = zoneSelect.value;
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zoneLabel.textContent = selectedZone;
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});
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let serverOffsetMs = 0;
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async function syncWithServer() {
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const start = Date.now();
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try {
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const response = await fetch(`/api/time?ts=${start}`, { cache: "no-store" });
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const end = Date.now();
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const data = await response.json();
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const rtt = end - start;
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serverOffsetMs = (data.epoch_ms + rtt / 2) - end;
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offsetLabel.textContent = `Synchronized (${serverOffsetMs >= 0 ? "+" : ""}${serverOffsetMs.toFixed(0)} ms, RTT ${rtt} ms)`;
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} catch (_) {
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offsetLabel.textContent = "Sync failed";
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}
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}
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function toGregorianTime(date, zone) {
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const p = getLocalParts(date, zone);
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// Format as HH:MM:SS.cc to match decimal time width
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const cs = String(Math.floor(date.getMilliseconds() / 10)).padStart(2, "0");
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return `${String(p.hour).padStart(2,"0")}:${String(p.minute).padStart(2,"0")}:${String(p.second).padStart(2,"0")}.${cs}`;
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}
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function render() {
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const now = new Date(Date.now() + serverOffsetMs);
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const { year, doy } = getDayOfYear(now, selectedZone);
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const sd = toSethDate(year, doy);
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const dt = toDecimalTime(now, selectedZone);
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const gt = toGregorianTime(now, selectedZone);
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dateLine.textContent = formatSethLong(sd);
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digital.textContent = dt;
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decimalTime.textContent = dt;
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gregorianTime.textContent = gt;
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dayOfYear.textContent = `${doy} of ${isLeapYear(year) ? 366 : 365}`;
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const totalWeeks = 60; // 10 months × 6 weeks
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const woy = sd.type === "month" ? sd.month * 6 + sd.week : "—";
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const woyTotal = sd.type === "month" ? `${woy} of ${totalWeeks}`
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: sd.type === "leapday" ? "— (leap day)"
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: `— (holiday days)`;
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weekOfYear.textContent = woyTotal;
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zoneLabel.textContent = selectedZone;
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utcLabel.textContent = now.toISOString().replace("T", " ").replace("Z", " UTC");
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requestAnimationFrame(render);
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}
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syncWithServer();
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setInterval(syncWithServer, 20_000);
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render();
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