/// <summary>
/// Adjust calculated imsak, fajr, maghrib and isha prayer times to high latitude adjustment.
/// </summary>
private static PrayersInDouble AdjustAllForHighLatitude(PrayersInDouble raw, PrayerCalculationSettings settings)
{
//
// Do not apply adjustment if none option is specified.
if (settings.HighLatitudeAdjustment == HighLatitudeAdjustment.None)
{
return(raw);
}
// Copy reference.
var method = settings.HighLatitudeAdjustment;
var imsak = raw.Imsak;
var fajr = raw.Fajr;
var sunrise = raw.Sunrise;
var sunset = raw.Sunset;
var maghrib = raw.Maghrib;
var isha = raw.Isha;
var imsakParameterValue = settings.ImsakParameter.Value;
var fajrParameterValue = settings.CalculationMethod.FajrParameter.Value;
var maghribParameterValue = settings.CalculationMethod.MaghribParameter.Value;
var ishaParameterValue = settings.CalculationMethod.IshaParameter.Value;
// Compute sunrise to sunset difference.
var diff = DateTimeMath.ComputeDuration(raw.Sunrise, raw.Sunset);
// Adjust.
raw.Imsak = AdjustForHighLatitude(method, imsak, sunrise, imsakParameterValue, diff, Direction.CounterClockwise);
raw.Fajr = AdjustForHighLatitude(method, fajr, sunrise, fajrParameterValue, diff, Direction.CounterClockwise);
raw.Maghrib = AdjustForHighLatitude(method, maghrib, sunset, maghribParameterValue, diff, Direction.Clockwise);
raw.Isha = AdjustForHighLatitude(method, isha, sunset, ishaParameterValue, diff, Direction.Clockwise);
return(raw);
}
/// <summary>
/// Apply adjustments to given calculated prayer time.
/// </summary>
private static PrayersInDouble AdjustTime(PrayersInDouble raw, PrayerCalculationSettings settings, double longitude, double timeZone)
{
// Adjust imsak if minute adjustment parameter is used.
if (settings.ImsakParameter.Type == PrayerCalculationParameterType.MinutesAdjust)
{
raw.Imsak = raw.Fajr + (settings.ImsakParameter.Value / 60.0);
}
// Adjust maghrib if minute adjustment parameter is used.
// This is Sunni method which maghrib equals to sunset. As precaution, this
// library add 1 minute to the sunset time.
if (settings.CalculationMethod.MaghribParameter.Type == PrayerCalculationParameterType.MinutesAdjust)
{
raw.Maghrib = raw.Sunset + 0.016666666666666667 + (settings.CalculationMethod.MaghribParameter.Value / 60.0);
}
// Adjust isha if minute adjustment parameter is used.
if (settings.CalculationMethod.IshaParameter.Type == PrayerCalculationParameterType.MinutesAdjust)
{
raw.Isha = raw.Maghrib + (settings.CalculationMethod.IshaParameter.Value / 60.0);
}
// Adjust to time zone.
raw = AdjustAllToTimeZone(raw, longitude, timeZone);
raw = AdjustAllForHighLatitude(raw, settings);
raw = MinuteAdjustAll(raw, settings);
return(raw);
}
/// <summary>
/// Apply time zone adjustment to given calculated prayer time.
/// </summary>
private static PrayersInDouble MinuteAdjustAll(PrayersInDouble raw, PrayerCalculationSettings settings)
{
raw.Imsak = raw.Imsak + (settings.ImsakMinutesAdjustment / 60.0);
raw.Fajr = raw.Fajr + (settings.FajrMinutesAdjustment / 60.0);
raw.Sunrise = raw.Sunrise + (settings.SunriseMinutesAdjustment / 60.0);
raw.Dhuha = raw.Dhuha + (settings.DhuhaMinutesAdjustment / 60.0);
raw.Zuhr = raw.Zuhr + (settings.ZuhrMinutesAdjustment / 60.0);
raw.Asr = raw.Asr + (settings.AsrMinutesAdjustment / 60.0);
raw.Maghrib = raw.Maghrib + (settings.MaghribMinutesAdjustment / 60.0);
raw.Isha = raw.Isha + (settings.IshaMinutesAdjustment / 60.0);
return(raw);
}
/// <summary>
/// Convert <see cref="PrayersInDouble"/> into <see cref="Prayers"/>.
/// </summary>
private static Prayers ConvertFromFloatingPointFormat(PrayersInDouble prayers, int year, int month, int day, double timeZone)
{
var local = new DateTimeOffset(year, month, day, 0, 0, 0, TimeSpan.FromHours(timeZone));
var instant = Instant.FromDateTimeOffset(local);
return(new Prayers(instant + Duration.FromHours(prayers.Imsak),
instant + Duration.FromHours(prayers.Fajr),
instant + Duration.FromHours(prayers.Sunrise),
instant + Duration.FromHours(prayers.Dhuha),
instant + Duration.FromHours(prayers.Zuhr),
instant + Duration.FromHours(prayers.Asr),
instant + Duration.FromHours(prayers.Sunset),
instant + Duration.FromHours(prayers.Maghrib),
instant + Duration.FromHours(prayers.Isha),
instant + Duration.FromHours(prayers.Midnight)));
}
/// <summary>
/// Apply time zone adjustment to given calculated prayer time.
/// </summary>
private static PrayersInDouble AdjustAllToTimeZone(PrayersInDouble raw, double longitude, double timeZone)
{
var adjustment = timeZone - (longitude / 15.0);
raw.Imsak = raw.Imsak + adjustment;
raw.Fajr = raw.Fajr + adjustment;
raw.Sunrise = raw.Sunrise + adjustment;
raw.Dhuha = raw.Dhuha + adjustment;
raw.Zuhr = raw.Zuhr + adjustment;
raw.Asr = raw.Asr + adjustment;
raw.Sunset = raw.Sunset + adjustment;
raw.Maghrib = raw.Maghrib + adjustment;
raw.Isha = raw.Isha + adjustment;
return(raw);
}
/// <summary>
/// Compute all prayer times at given Julian Date and return the raw results.
/// </summary>
private static PrayersInDouble ComputeRaw(double jd, PrayerCalculationSettings settings, double latitude, double altitude)
{
var raw = new PrayersInDouble();
// Compute imsak.
if (settings.ImsakParameter.Type == PrayerCalculationParameterType.Angle)
{
// raw.imsak = _computeImsakTime(jd, settings.imsakParameter.value, latitude);
// NOTE: Do imsak time can be calculated using angle parameter?
throw new PrayerCalculationException("Imsak calculation parameter type must be the type of minute adjust.");
}
// Check fajr parameter type.
if (settings.CalculationMethod.FajrParameter.Type == PrayerCalculationParameterType.MinutesAdjust)
{
throw new PrayerCalculationException("Fajr calculation parameter type must be the type of angle.");
}
// Compute fajr, sunrise, dhuha, zuhr, asr and sunset.
raw.Fajr = ComputeFajrTime(jd, settings.CalculationMethod.FajrParameter.Value, latitude);
raw.Sunrise = ComputeSunriseTime(jd, latitude, altitude);
raw.Dhuha = ComputeDhuhaTime(raw.Fajr, raw.Sunrise);
raw.Zuhr = ComputeZuhrTime(jd);
raw.Asr = ComputeAsrTime(jd, settings.JuristicMethod.TimeOfShadow, latitude);
raw.Sunset = ComputeSunsetTime(jd, latitude, altitude);
// Compute maghrib.
if (settings.CalculationMethod.MaghribParameter.Type == PrayerCalculationParameterType.Angle)
{
raw.Maghrib = ComputeMaghribTime(jd, settings.CalculationMethod.MaghribParameter.Value, latitude);
}
// Compute isha.
if (settings.CalculationMethod.IshaParameter.Type == PrayerCalculationParameterType.Angle)
{
raw.Isha = ComputeIshaTime(jd, settings.CalculationMethod.IshaParameter.Value, latitude);
}
return(raw);
}
