mirror of
https://github.com/acamarata/pray-calc-dart.git
synced 2026-06-30 19:04:25 +00:00
971022734e
Replace the 1280-line bundled SPA implementation with a dependency on the nrel_spa package. SpaResult and SpaAnglesResult are now re-exported from nrel_spa for backwards compatibility. All 24 tests pass unchanged.
109 lines
3.4 KiB
Dart
109 lines
3.4 KiB
Dart
/// Core prayer times computation — PrayCalc Dynamic Method.
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///
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/// Returns all prayer times as fractional hours using the dynamic twilight
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/// angle algorithm. Times are in local time as determined by the UTC offset.
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library;
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import 'package:nrel_spa/nrel_spa.dart';
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import 'types.dart';
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import 'solar_ephemeris.dart';
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import 'angles.dart';
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import 'asr.dart';
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import 'qiyam.dart';
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/// Compute prayer times for a given date and location.
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///
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/// [date] is the observer's local date (time-of-day is ignored).
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/// [lat] is latitude in decimal degrees (−90 to 90, south = negative).
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/// [lng] is longitude in decimal degrees (−180 to 180, west = negative).
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/// [tz] is UTC offset in hours (e.g., −5 for EST).
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/// [elevation] is observer elevation in meters (default: 0).
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/// [temperature] is ambient temperature in °C (default: 15).
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/// [pressure] is atmospheric pressure in mbar/hPa (default: 1013.25).
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/// [hanafi] selects Asr convention: false = Shafi'i/Maliki/Hanbali (default),
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/// true = Hanafi.
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PrayerTimes getTimes(
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DateTime date,
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double lat,
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double lng,
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double tz, {
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double elevation = 0,
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double temperature = 15,
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double pressure = 1013.25,
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bool hanafi = false,
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}) {
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// 1. Compute dynamic twilight angles.
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final tw = getAngles(
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date,
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lat,
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lng,
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elevation: elevation,
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temperature: temperature,
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pressure: pressure,
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);
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// 2. Convert depression angles to SPA zenith angles.
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// SPA uses zenith (90° + depression) for custom altitude events.
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final fajrZenith = 90 + tw.fajrAngle;
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final ishaZenith = 90 + tw.ishaAngle;
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// 3. Run SPA for solar position + custom twilight times.
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final spaData = getSpa(
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date,
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lat,
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lng,
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tz,
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elevation: elevation,
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temperature: temperature,
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pressure: pressure,
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customAngles: [fajrZenith, ishaZenith],
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);
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final fajrTime = spaData.angles[0].sunrise;
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final sunriseTime = spaData.sunrise;
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final noonTime = spaData.solarNoon;
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final maghribTime = spaData.sunset;
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final ishaTime = spaData.angles[1].sunset;
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// Dhuhr: 2.5 minutes after solar noon.
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final dhuhrTime = noonTime + 2.5 / 60;
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// 4. Solar declination for Asr (Meeus formula, accurate to ~0.01°).
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final jd = toJulianDate(
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DateTime.utc(date.year, date.month, date.day, 12, 0, 0),
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);
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final eph = solarEphemeris(jd);
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// 5. Asr time.
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final asrTime = getAsr(noonTime, lat, eph.decl, hanafi: hanafi);
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// 6. Qiyam al-Layl (last third of the night).
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final qiyamTime = getQiyam(fajrTime, ishaTime);
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return PrayerTimes(
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qiyam: qiyamTime.isFinite ? qiyamTime : double.nan,
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fajr: fajrTime.isFinite ? fajrTime : double.nan,
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sunrise: sunriseTime.isFinite ? sunriseTime : double.nan,
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noon: noonTime.isFinite ? noonTime : double.nan,
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dhuhr: dhuhrTime.isFinite ? dhuhrTime : double.nan,
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asr: asrTime.isFinite ? asrTime : double.nan,
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maghrib: maghribTime.isFinite ? maghribTime : double.nan,
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isha: ishaTime.isFinite ? ishaTime : double.nan,
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angles: tw,
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);
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}
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/// Format fractional hours as HH:MM:SS string.
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/// Returns "N/A" if the value is non-finite or negative.
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String formatTime(double hours) {
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if (!hours.isFinite || hours < 0) return 'N/A';
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final totalSec = (hours * 3600).round();
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final h = (totalSec ~/ 3600) % 24;
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final rem = totalSec - (totalSec ~/ 3600) * 3600;
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final m = rem ~/ 60;
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final s = rem - m * 60;
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return '${h.toString().padLeft(2, '0')}:'
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'${m.toString().padLeft(2, '0')}:'
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'${s.toString().padLeft(2, '0')}';
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}
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