mal/static/js/timezone.js

// static/js/timezone.ts
(() => {
  const jstOffsetMinutes = 9 * 60;
  const parseBroadcastTime = (value) => {
    if (!value || typeof value !== "string") {
      return null;
    }
    const match = value.trim().match(/^(\d{1,2}):(\d{2})$/);
    if (!match) {
      return null;
    }
    const hour = Number.parseInt(match[1], 10);
    const minute = Number.parseInt(match[2], 10);
    if (Number.isNaN(hour) || Number.isNaN(minute) || hour < 0 || hour > 23 || minute < 0 || minute > 59) {
      return null;
    }
    return { hour, minute };
  };
  const isJstTimezone = (timezone) => {
    if (!timezone) {
      return true;
    }
    const normalized = timezone.trim().toLowerCase();
    return normalized === "asia/tokyo" || normalized === "jst";
  };
  const parseFromStructuredAttrs = (node) => {
    const day = node.getAttribute("data-broadcast-day");
    const time = node.getAttribute("data-broadcast-time");
    const timezone = node.getAttribute("data-broadcast-timezone");
    if (!day || !time || !isJstTimezone(timezone)) {
      return null;
    }
    const parsedTime = parseBroadcastTime(time);
    if (!parsedTime) {
      return null;
    }
    return { day: day.trim(), hour: parsedTime.hour, minute: parsedTime.minute };
  };
  const parseBroadcast = (text) => {
    if (!text || typeof text !== "string") {
      return null;
    }
    const match = text.match(/^(.*) at (\d{1,2}):(\d{2}) \(JST\)$/i);
    if (!match) {
      return null;
    }
    const day = match[1].trim();
    const hour = Number.parseInt(match[2], 10);
    const minute = Number.parseInt(match[3], 10);
    if (Number.isNaN(hour) || Number.isNaN(minute)) {
      return null;
    }
    if (hour < 0 || hour > 23 || minute < 0 || minute > 59) {
      return null;
    }
    return { day, hour, minute };
  };
  const normalizeDay = (day) => {
    const key = day.trim().toLowerCase().replace(/s$/, "");
    const days = {
      mon: 1,
      monday: 1,
      tue: 2,
      tues: 2,
      tuesday: 2,
      wed: 3,
      wednesday: 3,
      thu: 4,
      thur: 4,
      thurs: 4,
      thursday: 4,
      fri: 5,
      friday: 5,
      sat: 6,
      saturday: 6,
      sun: 0,
      sunday: 0
    };
    if (typeof days[key] !== "number") {
      return null;
    }
    return days[key];
  };
  const convertToLocal = (parsed, localOffsetMinutes) => {
    const sourceMinutes = parsed.hour * 60 + parsed.minute;
    const diff = jstOffsetMinutes - localOffsetMinutes;
    const localTotal = sourceMinutes - diff;
    const dayShift = Math.floor(localTotal / 1440);
    const normalizedMinutes = (localTotal % 1440 + 1440) % 1440;
    const localHour = Math.floor(normalizedMinutes / 60);
    const localMinute = normalizedMinutes % 60;
    const sourceDayIndex = normalizeDay(parsed.day);
    if (sourceDayIndex === null) {
      return null;
    }
    const localDayIndex = ((sourceDayIndex + dayShift) % 7 + 7) % 7;
    const localDay = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"][localDayIndex];
    const time = `${localHour.toString().padStart(2, "0")}:${localMinute.toString().padStart(2, "0")}`;
    return `${localDay} at ${time} (Local)`;
  };
  const nextAiringUTC = (parsed) => {
    const targetDay = normalizeDay(parsed.day);
    if (targetDay === null) {
      return null;
    }
    const now = new Date;
    const jstNow = new Date(now.getTime() + jstOffsetMinutes * 60 * 1000);
    const currentDay = jstNow.getUTCDay();
    const currentMinuteOfDay = jstNow.getUTCHours() * 60 + jstNow.getUTCMinutes();
    const targetMinuteOfDay = parsed.hour * 60 + parsed.minute;
    let dayDelta = (targetDay - currentDay + 7) % 7;
    if (dayDelta === 0 && targetMinuteOfDay <= currentMinuteOfDay) {
      dayDelta = 7;
    }
    const minuteDelta = dayDelta * 1440 + (targetMinuteOfDay - currentMinuteOfDay);
    return new Date(now.getTime() + minuteDelta * 60 * 1000);
  };
  const formatRelative = (value, unit) => {
    if (typeof Intl !== "undefined" && typeof Intl.RelativeTimeFormat === "function") {
      const formatter = new Intl.RelativeTimeFormat(undefined, { numeric: "auto" });
      return formatter.format(value, unit);
    }
    const suffix = value === 1 ? unit : `${unit}s`;
    return `in ${value} ${suffix}`;
  };
  const relativeText = (target) => {
    const diffMs = target.getTime() - Date.now();
    if (diffMs <= 0) {
      return "soon";
    }
    const minutes = Math.ceil(diffMs / 60000);
    if (minutes < 60) {
      return formatRelative(minutes, "minute");
    }
    const hours = Math.ceil(minutes / 60);
    if (hours < 36) {
      return formatRelative(hours, "hour");
    }
    const days = Math.ceil(hours / 24);
    return formatRelative(days, "day");
  };
  const localDateTimeText = (date) => {
    const formatter = new Intl.DateTimeFormat(undefined, {
      weekday: "short",
      hour: "2-digit",
      minute: "2-digit"
    });
    return formatter.format(date);
  };
  const updateNextAiring = (node, parsed) => {
    const card = node.closest(".notification-content");
    if (!card) {
      return;
    }
    const nextNode = card.querySelector("[data-next-airing]");
    if (!(nextNode instanceof HTMLElement)) {
      return;
    }
    const nextDate = nextAiringUTC(parsed);
    if (!nextDate) {
      nextNode.remove();
      return;
    }
    nextNode.textContent = `Next episode ${relativeText(nextDate)} (${localDateTimeText(nextDate)})`;
  };
  const updateNode = (node, localOffsetMinutes) => {
    const card = node.closest(".notification-content");
    const nextNode = card ? card.querySelector("[data-next-airing]") : null;
    const structured = parseFromStructuredAttrs(node);
    const source = node.getAttribute("data-jst-text");
    const parsed = structured || parseBroadcast(source);
    if (!parsed) {
      if (nextNode instanceof HTMLElement) {
        nextNode.remove();
      }
      return;
    }
    const converted = convertToLocal(parsed, localOffsetMinutes);
    if (!converted) {
      if (nextNode instanceof HTMLElement) {
        nextNode.remove();
      }
      return;
    }
    node.textContent = converted;
    updateNextAiring(node, parsed);
  };
  const updateAll = () => {
    const localOffsetMinutes = -new Date().getTimezoneOffset();
    const nodes = document.querySelectorAll("[data-jst-text]");
    nodes.forEach((node) => updateNode(node, localOffsetMinutes));
  };
  document.addEventListener("DOMContentLoaded", updateAll);
  document.body.addEventListener("htmx:afterSwap", updateAll);
})();