mirror of
https://github.com/AvengeMedia/DankMaterialShell.git
synced 2026-01-26 06:22:50 -05:00
123 lines
3.6 KiB
Go
123 lines
3.6 KiB
Go
package wayland
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import (
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"math"
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"time"
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)
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const (
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degToRad = math.Pi / 180.0
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radToDeg = 180.0 / math.Pi
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)
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type SunCondition int
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const (
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SunNormal SunCondition = iota
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SunMidnightSun
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SunPolarNight
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)
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type SunTimes struct {
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Dawn time.Time
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Sunrise time.Time
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Sunset time.Time
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Night time.Time
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}
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func daysInYear(year int) int {
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if (year%4 == 0 && year%100 != 0) || year%400 == 0 {
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return 366
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}
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return 365
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}
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func dateOrbitAngle(t time.Time) float64 {
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return 2 * math.Pi / float64(daysInYear(t.Year())) * float64(t.YearDay()-1)
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}
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func equationOfTime(orbitAngle float64) float64 {
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return 4 * (0.000075 +
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0.001868*math.Cos(orbitAngle) -
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0.032077*math.Sin(orbitAngle) -
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0.014615*math.Cos(2*orbitAngle) -
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0.040849*math.Sin(2*orbitAngle))
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}
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func sunDeclination(orbitAngle float64) float64 {
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return 0.006918 -
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0.399912*math.Cos(orbitAngle) +
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0.070257*math.Sin(orbitAngle) -
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0.006758*math.Cos(2*orbitAngle) +
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0.000907*math.Sin(2*orbitAngle) -
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0.002697*math.Cos(3*orbitAngle) +
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0.00148*math.Sin(3*orbitAngle)
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}
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func sunHourAngle(latRad, declination, targetSunRad float64) float64 {
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return math.Acos(math.Cos(targetSunRad)/
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math.Cos(latRad)*math.Cos(declination) -
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math.Tan(latRad)*math.Tan(declination))
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}
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func hourAngleToSeconds(hourAngle, eqtime float64) float64 {
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return radToDeg * (4.0*math.Pi - 4*hourAngle - eqtime) * 60
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}
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func sunCondition(latRad, declination float64) SunCondition {
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signLat := latRad >= 0
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signDecl := declination >= 0
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if signLat == signDecl {
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return SunMidnightSun
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}
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return SunPolarNight
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}
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func CalculateSunTimesWithTwilight(lat, lon float64, date time.Time, elevTwilight, elevDaylight float64) (SunTimes, SunCondition) {
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latRad := lat * degToRad
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elevTwilightRad := (90.833 - elevTwilight) * degToRad
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elevDaylightRad := (90.833 - elevDaylight) * degToRad
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utc := date.UTC()
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orbitAngle := dateOrbitAngle(utc)
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decl := sunDeclination(orbitAngle)
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eqtime := equationOfTime(orbitAngle)
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haTwilight := sunHourAngle(latRad, decl, elevTwilightRad)
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haDaylight := sunHourAngle(latRad, decl, elevDaylightRad)
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if math.IsNaN(haTwilight) || math.IsNaN(haDaylight) {
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cond := sunCondition(latRad, decl)
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return SunTimes{}, cond
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}
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dayStart := time.Date(utc.Year(), utc.Month(), utc.Day(), 0, 0, 0, 0, time.UTC)
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lonOffset := time.Duration(-lon*4) * time.Minute
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dawnSecs := hourAngleToSeconds(math.Abs(haTwilight), eqtime)
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sunriseSecs := hourAngleToSeconds(math.Abs(haDaylight), eqtime)
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sunsetSecs := hourAngleToSeconds(-math.Abs(haDaylight), eqtime)
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nightSecs := hourAngleToSeconds(-math.Abs(haTwilight), eqtime)
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return SunTimes{
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Dawn: dayStart.Add(time.Duration(dawnSecs)*time.Second + lonOffset).In(date.Location()),
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Sunrise: dayStart.Add(time.Duration(sunriseSecs)*time.Second + lonOffset).In(date.Location()),
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Sunset: dayStart.Add(time.Duration(sunsetSecs)*time.Second + lonOffset).In(date.Location()),
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Night: dayStart.Add(time.Duration(nightSecs)*time.Second + lonOffset).In(date.Location()),
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}, SunNormal
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}
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func CalculateSunTimes(lat, lon float64, date time.Time) SunTimes {
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times, cond := CalculateSunTimesWithTwilight(lat, lon, date, -6.0, 3.0)
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switch cond {
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case SunMidnightSun:
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dayStart := time.Date(date.Year(), date.Month(), date.Day(), 0, 0, 0, 0, date.Location())
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dayEnd := dayStart.Add(24*time.Hour - time.Second)
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return SunTimes{Dawn: dayStart, Sunrise: dayStart, Sunset: dayEnd, Night: dayEnd}
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case SunPolarNight:
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dayStart := time.Date(date.Year(), date.Month(), date.Day(), 0, 0, 0, 0, date.Location())
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return SunTimes{Dawn: dayStart, Sunrise: dayStart, Sunset: dayStart, Night: dayStart}
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}
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return times
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}
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