/*
* kollavarsham
* http://kollavarsham.org
*
* Copyright (c) 2014-2023 The Kollavarsham Team
* Licensed under the MIT license.
*/
/**
* @module calendar
*/
import { JulianDate } from './dates/julianDate';
import { MathHelper } from './mathHelper';
// TODO: Refactor this out
const samkranti = {
ahargana: -1,
Year: -1,
Month: -1,
Day: -1,
Hour: -1,
Min: -1
};
/**
*
* **INTERNAL/PRIVATE**
*
* @class Calendar
*/
export class Calendar {
constructor(celestial) {
this.celestial = celestial;
}
static get weekdays() {
return {
0: { en: 'Monday', ml: 'തിങ്കൾ' },
1: { en: 'Tuesday', ml: 'ചൊവ്വ' },
2: { en: 'Wednesday', ml: 'ബുധൻ' },
3: { en: 'Thursday', ml: 'വ്യാഴം' },
4: { en: 'Friday', ml: 'വെള്ളി' },
5: { en: 'Saturday', ml: 'ശനി' },
6: { en: 'Sunday', ml: 'ഞായർ' }
};
}
static get months() {
return {
January: 0,
February: 1,
March: 2,
April: 3,
May: 4,
June: 5,
July: 6,
August: 7,
September: 8,
October: 9,
November: 10,
December: 11
};
}
static get naksatras() {
return {
[-1]: { saka: '', enMalayalam: '', mlMalayalam: '' },
0: { saka: 'Asvini', enMalayalam: 'Ashwathi', mlMalayalam: 'അശ്വതി' },
1: { saka: 'Bharani', enMalayalam: 'Bharani', mlMalayalam: 'ഭരണി' },
2: { saka: 'Krttika', enMalayalam: 'Karthika', mlMalayalam: 'കാർത്തിക' },
3: { saka: 'Rohini', enMalayalam: 'Rohini', mlMalayalam: 'രോഹിണി' },
4: { saka: 'Mrgasira', enMalayalam: 'Makiryam', mlMalayalam: 'മകയിരം' },
5: { saka: 'Ardra', enMalayalam: 'Thiruvathira', mlMalayalam: 'തിരുവാതിര' },
6: { saka: 'Punarvasu', enMalayalam: 'Punartham', mlMalayalam: 'പുണർതം' },
7: { saka: 'Pusya', enMalayalam: 'Pooyam', mlMalayalam: 'പൂയം' },
8: { saka: 'Aslesa', enMalayalam: 'Aayilyam', mlMalayalam: 'ആയില്യം' },
9: { saka: 'Magha', enMalayalam: 'Makam', mlMalayalam: 'മകം' },
10: { saka: 'P-phalguni', enMalayalam: 'Pooram', mlMalayalam: 'പൂരം' },
11: { saka: 'U-phalguni', enMalayalam: 'Uthram', mlMalayalam: 'ഉത്രം' },
12: { saka: 'Hasta', enMalayalam: 'Atham', mlMalayalam: 'അത്തം' },
13: { saka: 'Citra', enMalayalam: 'Chithra', mlMalayalam: 'ചിത്ര' },
14: { saka: 'Svati', enMalayalam: 'Chothi', mlMalayalam: 'ചോതി' },
15: { saka: 'Visakha', enMalayalam: 'Vishakham', mlMalayalam: 'വിശാഖം' },
16: { saka: 'Anuradha', enMalayalam: 'Anizham', mlMalayalam: 'അനിഴം' },
17: { saka: 'Jyestha', enMalayalam: 'Thrikketta', mlMalayalam: 'തൃക്കേട്ട' },
18: { saka: 'Mula', enMalayalam: 'Moolam', mlMalayalam: 'മൂലം' },
19: { saka: 'P-asadha', enMalayalam: 'Pooradam', mlMalayalam: 'പൂരാടം' },
20: { saka: 'U-asadha', enMalayalam: 'Uthradam', mlMalayalam: 'ഉത്രാടം' },
21: { saka: 'Sravana', enMalayalam: 'Thiruvonam', mlMalayalam: 'തിരുവോണം' },
22: { saka: 'Dhanistha', enMalayalam: 'Avittam', mlMalayalam: 'അവിട്ടം' },
23: { saka: 'Satabhisaj', enMalayalam: 'Chathayam', mlMalayalam: 'ചതയം' },
24: { saka: 'P-bhadrapada', enMalayalam: 'Poororuttathi', mlMalayalam: 'പൂരുരുട്ടാതി' },
25: { saka: 'U-bhadrapada', enMalayalam: 'Uthrattathi', mlMalayalam: 'ഉത്രട്ടാതി' },
26: { saka: 'Revati', enMalayalam: 'Revathi', mlMalayalam: 'രേവതി' },
27: { saka: 'Asvini', enMalayalam: 'Ashwathi', mlMalayalam: 'അശ്വതി' }
};
}
static timeIntoFractionalDay(date) {
// TODO: Incorporate this into calculating the multiple-naksatra-per-day (time precision)
// The year, month and day from the passed in date is discarded and only the time is used.
// And even from the time information only the hour and minute is used and seconds, milliseconds etc. is discarded
if (!(date instanceof Date)) {
throw new Error('Invalid parameter. \'date\' should be an instance of \'Date\'');
}
const hour = date.getHours();
const minute = date.getMinutes();
return (hour * 60 + minute) / (24 * 60);
}
static gregorianDateToJulianDay(date) {
// TODO:
// Annotate all the magic numbers below !
// There is some explanation here - http://quasar.as.utexas.edu/BillInfo/JulianDatesG.html
let year = date.getFullYear();
let month = date.getMonth() + 1;
const day = date.getDate();
if (month < 3) {
year -= 1;
month += 12;
}
let julianDay = MathHelper.truncate(365.25 * year) + MathHelper.truncate(30.59 * (month - 2)) + day + 1721086.5;
if (year < 0) {
julianDay -= 1;
if (year % 4 === 0 && month > 3) {
julianDay += 1;
}
}
if (julianDay >= 2299160) {
julianDay += MathHelper.truncate(year / 400) - MathHelper.truncate(year / 100) + 2;
}
return julianDay;
}
static julianDayToJulianDate(julianDay) {
const j = MathHelper.truncate(julianDay) + 1402;
const k = MathHelper.truncate((j - 1) / 1461);
const l = j - 1461 * k;
const n = MathHelper.truncate((l - 1) / 365) - MathHelper.truncate(l / 1461);
const i = l - 365 * n + 30;
const J = MathHelper.truncate(80 * i / 2447);
const I = MathHelper.truncate(J / 11);
const day = i - MathHelper.truncate(2447 * J / 80);
const month = J + 2 - 12 * I;
const year = 4 * k + n + I - 4716;
return new JulianDate(year, month, day);
}
static julianDayToGregorianDate(julianDay) {
const a = julianDay + 68569;
const b = MathHelper.truncate(a / 36524.25);
const c = a - MathHelper.truncate(36524.25 * b + 0.75);
const e = MathHelper.truncate((c + 1) / 365.2425);
const f = c - MathHelper.truncate(365.25 * e) + 31;
const g = MathHelper.truncate(f / 30.59);
const h = MathHelper.truncate(g / 11);
const day = MathHelper.truncate(f - MathHelper.truncate(30.59 * g) + (julianDay - MathHelper.truncate(julianDay)));
const month = MathHelper.truncate(g - 12 * h + 2);
const year = MathHelper.truncate(100 * (b - 49) + e + h);
const result = new Date(year, month - 1, day);
if (year > 0 && year <= 99) {
result.setFullYear(year);
}
return result;
}
static julianDayToModernDate(julianDay) {
// Will return JulianDate object for any date before 1st January 1583 AD and Date objects for later dates
return julianDay < 2299239 ? Calendar.julianDayToJulianDate(julianDay) : Calendar.julianDayToGregorianDate(julianDay);
}
static julianDayToAhargana(julianDay) {
return julianDay - 588465.50;
}
static aharganaToJulianDay(ahargana) {
return 588465.50 + ahargana;
}
static kaliToSaka(yearKali) {
return yearKali - 3179;
}
static sakaToKali(yearSaka) {
return yearSaka + 3179;
}
static julianDayToWeekday(julianDay) {
return Calendar.weekdays[MathHelper.truncate(julianDay + 0.5) % 7];
}
static getAdhimasa(lastConjunctionLongitude, nextConjunctionLongitude) {
const n1 = MathHelper.truncate(lastConjunctionLongitude / 30);
const n2 = MathHelper.truncate(nextConjunctionLongitude / 30);
return Math.abs(n1 - n2) < MathHelper.epsilon ? 'Adhika-' : '';
}
static getMasaNum(trueSolarLongitude, lastConjunctionLongitude) {
let masaNum = MathHelper.truncate(trueSolarLongitude / 30) % 12;
if (masaNum === MathHelper.truncate(lastConjunctionLongitude / 30) % 12) {
masaNum += 1;
}
masaNum = (masaNum + 12) % 12;
return masaNum;
}
static getNaksatra(trueLunarLongitude) {
return Calendar.naksatras[MathHelper.truncate(trueLunarLongitude * 27 / 360)];
}
nextDate(date) {
// TODO: This looks like a concern of the calling library - But could be exposed as a static utility method (0 usages other than tests)
date.setUTCDate(date.getUTCDate() + 1);
return date;
}
julianInEngland(julianDay) {
// TODO: This might be exposed as a static utility method (0 usages other than tests)
// Gregorian calendar was first introduced in most of Europe in 1582,
// but it wasn't adopted in England (and so in US and Canada) until 1752
//
// - http://www.timeanddate.com/calendar/julian-gregorian-switch.html
//
// This returns true between
// October 14th, 1582 and September 14th, 1752, both dates exclusive
return julianDay >= 2299160 && julianDay <= 2361221;
}
aharganaToKali(ahargana) {
return MathHelper.truncate(ahargana * this.celestial.planets.sun.YugaRotation / this.celestial.yuga.CivilDays);
}
kaliToAhargana(yearKali, masaNum, tithiDay) {
const sauraMasas = yearKali * 12 + masaNum; // expired saura masas
const adhiMasas = MathHelper.truncate(sauraMasas * this.celestial.yuga.Adhimasa / (12 * this.celestial.planets.sun.YugaRotation)); // expired adhimasas
const candraMasas = sauraMasas + adhiMasas; // expired candra masas
const tithis = 30 * candraMasas + tithiDay - 1; // expired tithis
const avamas = MathHelper.truncate(tithis * this.celestial.yuga.Ksayadina / this.celestial.yuga.Tithi); // expired avamas
return tithis - avamas;
}
findSamkranti(leftAhargana, rightAhargana) {
const width = (rightAhargana - leftAhargana) / 2;
const centreAhargana = (rightAhargana + leftAhargana) / 2;
if (width < MathHelper.epsilon) {
return centreAhargana;
}
else {
let centreTslong = this.celestial.getTrueSolarLongitude(centreAhargana);
centreTslong -= MathHelper.truncate(centreTslong / 30) * 30;
if (centreTslong < 5) {
return this.findSamkranti(leftAhargana, centreAhargana);
}
else {
return this.findSamkranti(centreAhargana, rightAhargana);
}
}
}
calculateSamkranti(ahargana, desantara) {
samkranti.ahargana = this.findSamkranti(ahargana, ahargana + 1) + desantara;
// below line is the fix that Yano-san worked in for Kerala dates - #20140223 cf. try_calculations
const roundedSamkranti = MathHelper.truncate(samkranti.ahargana) + 0.5;
const samkrantiModernDate = Calendar.julianDayToModernDate(Calendar.aharganaToJulianDay(roundedSamkranti));
if (JulianDate.prototype.isPrototypeOf(samkrantiModernDate)) { // eslint-disable-line no-prototype-builtins
const samkrantiDate = samkrantiModernDate;
samkranti.Year = samkrantiDate.year;
samkranti.Month = samkrantiDate.month;
samkranti.Day = samkrantiDate.date;
}
else {
const samkrantiDate = samkrantiModernDate;
samkranti.Year = samkrantiDate.getFullYear();
samkranti.Month = samkrantiDate.getMonth() + 1;
samkranti.Day = samkrantiDate.getDate();
}
const fractionalDay = MathHelper.fractional(samkranti.ahargana) * 24;
samkranti.Hour = MathHelper.truncate(fractionalDay);
samkranti.Min = MathHelper.truncate(60 * MathHelper.fractional(fractionalDay));
}
isTodaySauraMasaFirst(ahargana, desantara) {
/*
// Definition of the first day
// samkranti is between today's 0:00 and 24:00
// ==
// at 0:00 before 30x, at 24:00 after 30x
*/
let trueSolarLongitudeToday = this.celestial.getTrueSolarLongitude(ahargana - desantara);
let trueSolarLongitudeTomorrow = this.celestial.getTrueSolarLongitude(ahargana - desantara + 1);
trueSolarLongitudeToday -= MathHelper.truncate(trueSolarLongitudeToday / 30) * 30;
trueSolarLongitudeTomorrow -= MathHelper.truncate(trueSolarLongitudeTomorrow / 30) * 30;
if (25 < trueSolarLongitudeToday && trueSolarLongitudeTomorrow < 5) { // eslint-disable-line yoda
this.calculateSamkranti(ahargana, desantara);
return true;
}
return false;
}
getSauraMasaAndSauraDivasa(ahargana, desantara) {
// If today is the first day then 1
// Otherwise yesterday's + 1
let month;
let day;
ahargana = MathHelper.truncate(ahargana);
if (this.isTodaySauraMasaFirst(ahargana, desantara)) {
day = 1;
const tsLongTomorrow = this.celestial.getTrueSolarLongitude(ahargana + 1);
month = MathHelper.truncate(tsLongTomorrow / 30) % 12;
month = (month + 12) % 12;
}
else {
const { sauraMasa, sauraDivasa } = this.getSauraMasaAndSauraDivasa(ahargana - 1, desantara);
month = sauraMasa;
day = sauraDivasa + 1;
}
return { sauraMasa: month, sauraDivasa: day };
}
}