Merge pull request #90 from kumackey/jp-holidays

Add Japanese holidays

v2/jp/jp_holidays.go

@@ -0,0 +1,354 @@
+// (c) Rick Arnold. Licensed under the BSD license (see LICENSE).
+
+// Package jp provides holiday definitions for Japan.
+package jp
+
+import (
+	"github.com/rickar/cal/v2"
+	"github.com/rickar/cal/v2/aa"
+	"math"
+	"time"
+)
+
+var (
+	// Standard Japan weekend substitution rules: Sundays move to Monday
+	weekendAlt = []cal.AltDay{
+		{Day: time.Sunday, Offset: 1},
+	}
+
+	// NewYear represents New Year's Day on 1-Jan
+	NewYear = aa.NewYear.Clone(&cal.Holiday{Type: cal.ObservancePublic, Observed: weekendAlt})
+
+	// ComingOfAgeDay represents Coming of Age Day on the 2nd Monday in January
+	ComingOfAgeDay = &cal.Holiday{
+		Name:    "Coming of Age Day",
+		Type:    cal.ObservancePublic,
+		Month:   time.January,
+		Weekday: time.Monday,
+		Offset:  2,
+		Func:    cal.CalcWeekdayOffset,
+	}
+
+	// NationalFoundationDay represents National Foundation Day on 11-February
+	NationalFoundationDay = &cal.Holiday{
+		Name:     "National Foundation Day",
+		Type:     cal.ObservancePublic,
+		Month:    time.February,
+		Day:      11,
+		Observed: weekendAlt,
+		Func:     cal.CalcDayOfMonth,
+	}
+
+	// TheEmperorsBirthday represents The Emperor's Birthday on 23-February
+	TheEmperorsBirthday = &cal.Holiday{
+		Name:     "The Emperor's Birthday",
+		Type:     cal.ObservancePublic,
+		Month:    time.February,
+		Day:      23,
+		Observed: weekendAlt,
+		Func: func(h *cal.Holiday, year int) time.Time {
+			if year <= 2019 {
+				// Emperor Akihito abdicated in 2019.
+				holiday := *h
+				holiday.Month = time.December
+				holiday.Day = 23
+
+				return cal.CalcDayOfMonth(&holiday, year)
+			}
+
+			return cal.CalcDayOfMonth(h, year)
+		},
+	}
+
+	// VernalEquinoxDay represents Vernal Equinox Day on Around 20-March
+	VernalEquinoxDay = &cal.Holiday{
+		Name:     "Vernal Equinox Day",
+		Type:     cal.ObservancePublic,
+		Month:    time.March,
+		Observed: weekendAlt,
+		Func: func(h *cal.Holiday, year int) time.Time {
+			holiday := h
+			holiday.Day = calcVernalEquinoxDate(year)
+
+			return cal.CalcDayOfMonth(holiday, year)
+		},
+	}
+
+	// ShowaDay represents Showa Day on 29-April
+	ShowaDay = &cal.Holiday{
+		Name:     "Showa Day",
+		Type:     cal.ObservancePublic,
+		Month:    time.April,
+		Day:      29,
+		Observed: weekendAlt,
+		Func:     cal.CalcDayOfMonth,
+	}
+
+	// ConstitutionMemorialDay represents Constitution Memorial Day on 3-May
+	ConstitutionMemorialDay = &cal.Holiday{
+		Name:  "Constitution Memorial Day",
+		Type:  cal.ObservancePublic,
+		Month: time.May,
+		Day:   3,
+		Observed: []cal.AltDay{
+			{Day: time.Sunday, Offset: 3},
+		},
+		Func: cal.CalcDayOfMonth,
+	}
+
+	// GreeneryDay represents Greenery Day on 4-May
+	GreeneryDay = &cal.Holiday{
+		Name:  "Greenery Day",
+		Type:  cal.ObservancePublic,
+		Month: time.May,
+		Day:   4,
+		Observed: []cal.AltDay{
+			{Day: time.Sunday, Offset: 2},
+		},
+		Func: cal.CalcDayOfMonth,
+	}
+
+	// ChildrensDay represents Children's Day on 5-May
+	ChildrensDay = &cal.Holiday{
+		Name:     "Children's Day",
+		Type:     cal.ObservancePublic,
+		Month:    time.May,
+		Day:      5,
+		Observed: weekendAlt,
+		Func:     cal.CalcDayOfMonth,
+	}
+
+	// MarineDay represents Marine Day on the 3rd Monday in July
+	MarineDay = &cal.Holiday{
+		Name:    "Marine Day",
+		Type:    cal.ObservancePublic,
+		Month:   time.July,
+		Weekday: time.Monday,
+		Offset:  3,
+		Func: func(h *cal.Holiday, year int) time.Time {
+			if year == 2020 || year == 2021 {
+				// As special arrangement for the 2020 Summer Olympics, the 2020 and 2021 date for Marine Day was moved
+				holiday := *h
+				holiday.Weekday = time.Thursday
+				holiday.Offset = 4
+
+				return cal.CalcWeekdayOffset(&holiday, year)
+			}
+
+			return cal.CalcWeekdayOffset(h, year)
+		},
+	}
+
+	// MountainDay represents Mountain Day on 11-August
+	MountainDay = &cal.Holiday{
+		Name:      "Mountain Day",
+		Type:      cal.ObservancePublic,
+		Month:     time.August,
+		Day:       11,
+		Observed:  weekendAlt,
+		Func:      cal.CalcDayOfMonth,
+		StartYear: 2016,
+	}
+
+	// RespectForTheAgedDay represents Respect for the Aged Day on the 3rd Monday in September
+	RespectForTheAgedDay = &cal.Holiday{
+		Name:    "Respect for the Aged Day",
+		Type:    cal.ObservancePublic,
+		Month:   time.September,
+		Weekday: time.Monday,
+		Offset:  3,
+		Func:    cal.CalcWeekdayOffset,
+	}
+
+	// AutumnalEquinoxDay represents Autumnal Equinox Day on Around 23-September
+	AutumnalEquinoxDay = &cal.Holiday{
+		Name:     "Autumnal Equinox Day",
+		Type:     cal.ObservancePublic,
+		Month:    time.September,
+		Observed: weekendAlt,
+		Func: func(h *cal.Holiday, year int) time.Time {
+			holiday := *h
+			holiday.Day = calcAutumnalEquinoxDate(year)
+
+			return cal.CalcDayOfMonth(&holiday, year)
+		},
+	}
+
+	// SportsDay represents Sports Day on the 2nd Monday in October
+	SportsDay = &cal.Holiday{
+		Name:    "Sports Day",
+		Type:    cal.ObservancePublic,
+		Month:   time.October,
+		Weekday: time.Monday,
+		Offset:  2,
+		Func: func(h *cal.Holiday, year int) time.Time {
+			if year == 2020 || year == 2021 {
+				// As special arrangement for the 2020 Summer Olympics, the 2020 and 2021 date for Sports Day was moved
+				holiday := *h
+				holiday.Month = time.July
+				holiday.Weekday = time.Friday
+				holiday.Offset = 4
+
+				return cal.CalcWeekdayOffset(&holiday, year)
+			}
+
+			return cal.CalcWeekdayOffset(h, year)
+		},
+	}
+
+	// CultureDay represents Culture Day on 3-November
+	CultureDay = &cal.Holiday{
+		Name:     "Culture Day",
+		Type:     cal.ObservancePublic,
+		Month:    time.November,
+		Day:      3,
+		Observed: weekendAlt,
+		Func:     cal.CalcDayOfMonth,
+	}
+
+	// LaborThanksgivingDay represents Labor Thanksgiving Day on 23-November
+	LaborThanksgivingDay = &cal.Holiday{
+		Name:     "Labor Thanksgiving Day",
+		Type:     cal.ObservancePublic,
+		Month:    time.November,
+		Day:      23,
+		Observed: weekendAlt,
+		Func:     cal.CalcDayOfMonth,
+	}
+
+	// NationalHolidayBetweenRespectForTheAgedDayAndAutumnalEquinoxDay represents National holiday between Respect for the Aged Day and Autumnal Equinox Day in September
+	NationalHolidayBetweenRespectForTheAgedDayAndAutumnalEquinoxDay = &cal.Holiday{
+		Name:  "National holiday between Respect for the Aged Day and Autumnal Equinox Day",
+		Type:  cal.ObservancePublic,
+		Month: time.September,
+		Func: func(h *cal.Holiday, year int) time.Time {
+			switch year {
+			// only dates in September 2009 - 2032 are supported
+			case 2009:
+				return time.Date(year, h.Month, 22, 0, 0, 0, 0, cal.DefaultLoc)
+			case 2015:
+				return time.Date(year, h.Month, 22, 0, 0, 0, 0, cal.DefaultLoc)
+			case 2026:
+				return time.Date(year, h.Month, 22, 0, 0, 0, 0, cal.DefaultLoc)
+			case 2032:
+				return time.Date(year, h.Month, 21, 0, 0, 0, 0, cal.DefaultLoc)
+			default:
+				return time.Time{}
+			}
+		},
+	}
+
+	// NationalHolidayBetweenShowaDayAndNewEmperorEnthronementDay represents
+	// National Holiday Between Showa Day And New Emperor Enthronement Day on 30-April 2019
+	NationalHolidayBetweenShowaDayAndNewEmperorEnthronementDay = &cal.Holiday{
+		Name:      "National Holiday Between Showa Day And New Emperor Enthronement Day",
+		Type:      cal.ObservancePublic,
+		Month:     time.April,
+		Day:       30,
+		Func:      cal.CalcDayOfMonth,
+		StartYear: 2019,
+		EndYear:   2019,
+	}
+
+	// TheNewEmperorEnthronementDay represents The New Emperor Enthronement Day on 1-May 2019
+	TheNewEmperorEnthronementDay = &cal.Holiday{
+		Name:      "New Emperor Enthronement Day",
+		Type:      cal.ObservancePublic,
+		Month:     time.May,
+		Day:       1,
+		Func:      cal.CalcDayOfMonth,
+		StartYear: 2019,
+		EndYear:   2019,
+	}
+
+	// NationalHolidayBetweenTheNewEmperorEnthronementDayAndConstitutionMemorialDay represents
+	// National holiday between The New Emperor Enthronement Day and Constitution Memorial Day on 2-May 2019
+	NationalHolidayBetweenTheNewEmperorEnthronementDayAndConstitutionMemorialDay = &cal.Holiday{
+		Name:      "National holiday between New Emperor Enthronement Day and Constitution Memorial Day",
+		Type:      cal.ObservancePublic,
+		Month:     time.May,
+		Day:       2,
+		Func:      cal.CalcDayOfMonth,
+		StartYear: 2019,
+		EndYear:   2019,
+	}
+
+	// TheNewEmperorEnthronementCeremony represents The New Emperor Enthronement Day on 22-October 2019
+	TheNewEmperorEnthronementCeremony = &cal.Holiday{
+		Name:      "The New Emperor Enthronement Ceremony",
+		Type:      cal.ObservancePublic,
+		Month:     time.October,
+		Day:       22,
+		Func:      cal.CalcDayOfMonth,
+		StartYear: 2019,
+		EndYear:   2019,
+	}
+
+	exceptionalNationalHolidays = []*cal.Holiday{
+		NationalHolidayBetweenRespectForTheAgedDayAndAutumnalEquinoxDay,
+		NationalHolidayBetweenShowaDayAndNewEmperorEnthronementDay,
+		TheNewEmperorEnthronementDay,
+		NationalHolidayBetweenTheNewEmperorEnthronementDayAndConstitutionMemorialDay,
+		TheNewEmperorEnthronementCeremony,
+	}
+
+	Holidays = append(
+		[]*cal.Holiday{
+			NewYear,
+			ComingOfAgeDay,
+			NationalFoundationDay,
+			TheEmperorsBirthday,
+			VernalEquinoxDay,
+			ShowaDay,
+			ConstitutionMemorialDay,
+			GreeneryDay,
+			ChildrensDay,
+			MarineDay,
+			MountainDay,
+			RespectForTheAgedDay,
+			AutumnalEquinoxDay,
+			SportsDay,
+			CultureDay,
+			LaborThanksgivingDay,
+		},
+		exceptionalNationalHolidays...,
+	)
+)
+
+func calcVernalEquinoxDate(year int) int {
+	val := calcEquinoxBase(year)
+
+	switch {
+	case 1851 <= year && year <= 1899:
+		val += 19.8277
+	case 1900 <= year && year <= 1979:
+		val += 20.8357
+	case 1980 <= year && year <= 2099:
+		val += 20.8431
+	case 2100 <= year && year <= 2150:
+		val += 21.8510
+	}
+
+	return int(math.Floor(val))
+}
+
+func calcAutumnalEquinoxDate(year int) int {
+	val := calcEquinoxBase(year)
+
+	switch {
+	case 1851 <= year && year <= 1899:
+		val += 22.2588
+	case 1900 <= year && year <= 1979:
+		val += 23.2588
+	case 1980 <= year && year <= 2099:
+		val += 23.2488
+	case 2100 <= year && year <= 2150:
+		val += 24.2488
+	}
+
+	return int(math.Floor(val))
+}
+
+func calcEquinoxBase(year int) float64 {
+	return 0.242194*float64(year-1980) - math.Floor(float64(year-1980)/4.0)
+}