Initial commit

app/astro-calcs.js

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+(function () {
+  const DAY_IN_MS = 24 * 60 * 60 * 1000;
+  const START = ["sol", "luna", "mars", "mercury", "jupiter", "venus", "saturn"];
+  const CHALDEAN = ["saturn", "jupiter", "mars", "sol", "venus", "mercury", "luna"];
+
+  function toTitleCase(value) {
+    if (!value) return "";
+    return value.charAt(0).toUpperCase() + value.slice(1);
+  }
+
+  function getDateKey(date) {
+    const year = date.getFullYear();
+    const month = String(date.getMonth() + 1).padStart(2, "0");
+    const day = String(date.getDate()).padStart(2, "0");
+    return `${year}-${month}-${day}`;
+  }
+
+  function getCenteredWeekStartDay(date) {
+    return (date.getDay() + 4) % 7;
+  }
+
+  function minutesBetween(a, b) {
+    return (a.getTime() - b.getTime()) / 60000;
+  }
+
+  function getMoonPhaseName(phase) {
+    if (phase < 0.03 || phase > 0.97) return "New Moon";
+    if (phase < 0.22) return "Waxing Crescent";
+    if (phase < 0.28) return "First Quarter";
+    if (phase < 0.47) return "Waxing Gibbous";
+    if (phase < 0.53) return "Full Moon";
+    if (phase < 0.72) return "Waning Gibbous";
+    if (phase < 0.78) return "Last Quarter";
+    return "Waning Crescent";
+  }
+
+  function parseMonthDay(monthDay) {
+    const [month, day] = monthDay.split("-").map(Number);
+    return { month, day };
+  }
+
+  function isDateInSign(date, sign) {
+    const { month: startMonth, day: startDay } = parseMonthDay(sign.start);
+    const { month: endMonth, day: endDay } = parseMonthDay(sign.end);
+    const month = date.getMonth() + 1;
+    const day = date.getDate();
+    const wrapsYear = startMonth > endMonth;
+
+    if (!wrapsYear) {
+      const afterStart = month > startMonth || (month === startMonth && day >= startDay);
+      const beforeEnd = month < endMonth || (month === endMonth && day <= endDay);
+      return afterStart && beforeEnd;
+    }
+
+    const afterStart = month > startMonth || (month === startMonth && day >= startDay);
+    const beforeEnd = month < endMonth || (month === endMonth && day <= endDay);
+    return afterStart || beforeEnd;
+  }
+
+  function getSignStartDate(date, sign) {
+    const { month: startMonth, day: startDay } = parseMonthDay(sign.start);
+    const month = date.getMonth() + 1;
+    const day = date.getDate();
+    const wrapsYear = startMonth > parseMonthDay(sign.end).month;
+
+    let year = date.getFullYear();
+    if (wrapsYear && (month < startMonth || (month === startMonth && day < startDay))) {
+      year -= 1;
+    }
+
+    return new Date(year, startMonth - 1, startDay);
+  }
+
+  function getSignForDate(date, signs) {
+    return signs.find((sign) => isDateInSign(date, sign)) || null;
+  }
+
+  function groupDecansBySign(decans) {
+    const map = {};
+    for (const decan of decans) {
+      if (!map[decan.signId]) {
+        map[decan.signId] = [];
+      }
+      map[decan.signId].push(decan);
+    }
+
+    for (const signId of Object.keys(map)) {
+      map[signId].sort((a, b) => a.index - b.index);
+    }
+    return map;
+  }
+
+  function getDecanForDate(date, signs, decansBySign) {
+    const sign = getSignForDate(date, signs);
+    if (!sign) return null;
+
+    const signDecans = decansBySign[sign.id] || [];
+    if (!signDecans.length) {
+      return { sign, decan: null };
+    }
+
+    const signStartDate = getSignStartDate(date, sign);
+    const daysSinceSignStart = Math.floor((date.getTime() - signStartDate.getTime()) / DAY_IN_MS);
+    let index = Math.floor(daysSinceSignStart / 10) + 1;
+    if (index < 1) index = 1;
+    if (index > 3) index = 3;
+
+    const decan = signDecans.find((entry) => entry.index === index) || signDecans[0];
+    return { sign, decan };
+  }
+
+  function calcPlanetaryHoursForDayAndLocation(date, geo) {
+    const sunCalc = window.SunCalc;
+    if (!sunCalc) {
+      throw new Error("SunCalc library is not loaded.");
+    }
+
+    const solar = sunCalc.getTimes(date, geo.latitude, geo.longitude);
+    const nextDay = new Date(date.getTime() + DAY_IN_MS);
+    const solarNext = sunCalc.getTimes(nextDay, geo.latitude, geo.longitude);
+    const dayOfWeek = date.getDay();
+    const chaldeanStartPos = CHALDEAN.indexOf(START[dayOfWeek]);
+
+    const dayHourInMinutes = minutesBetween(solar.sunset, solar.sunrise) / 12;
+    const nightHourInMinutes = minutesBetween(solarNext.sunrise, solar.sunset) / 12;
+
+    const hours = [];
+    for (let hour = 0; hour < 12; hour += 1) {
+      const start = new Date(solar.sunrise.getTime() + dayHourInMinutes * hour * 60_000);
+      const end = new Date(start.getTime() + dayHourInMinutes * 60_000);
+      hours.push({
+        start,
+        end,
+        planetId: CHALDEAN[(chaldeanStartPos + hour) % 7],
+        isDaylight: true
+      });
+    }
+
+    for (let hour = 12; hour < 24; hour += 1) {
+      const start = new Date(solar.sunset.getTime() + nightHourInMinutes * (hour - 12) * 60_000);
+      const end = new Date(start.getTime() + nightHourInMinutes * 60_000);
+      hours.push({
+        start,
+        end,
+        planetId: CHALDEAN[(chaldeanStartPos + hour) % 7],
+        isDaylight: false
+      });
+    }
+
+    return hours;
+  }
+
+  window.TarotCalc = {
+    DAY_IN_MS,
+    toTitleCase,
+    getDateKey,
+    getCenteredWeekStartDay,
+    getMoonPhaseName,
+    groupDecansBySign,
+    getDecanForDate,
+    calcPlanetaryHoursForDayAndLocation
+  };
+})();