fullerene.go

package fullerene

import (
	"time"
)

type Fullerene struct {
	t time.Time
}

func Now() Fullerene {
	return Fullerene{
		t: time.Now(),
	}
}

func (fr Fullerene) Date() (year int, month time.Month, day int) {
	return fr.t.Date()
}

func (fr Fullerene) After(u Fullerene) bool {
	return fr.t.After(u.t)
}

func (fr Fullerene) Before(u Fullerene) bool {
	return fr.t.Before(u.t)
}

func (fr Fullerene) Equal(u Fullerene) bool {
	return fr.t.Equal(u.t)
}

func (fr Fullerene) IsZero() bool {
	return fr.t.IsZero()
}

func Date(year int, month time.Month, day, hour, min, sec, nsec int, loc *time.Location) Fullerene {
	return Fullerene{t: time.Date(year, month, day, hour, min, sec, nsec, loc)}
}

func (fr Fullerene) Year() int {
	return fr.t.Year()
}

func (fr Fullerene) Month() time.Month {
	return fr.t.Month()
}

func (fr Fullerene) Day() int {
	return fr.t.Day()
}

func (fr Fullerene) AddDate(years int, months int, days int) Fullerene {
	return Fullerene{t: fr.t.AddDate(years, months, days)}
}

func (fr Fullerene) IsLeapYear() bool {
	y := fr.Year()
	return (y%4 == 0 && (y%100 != 0 || y%400 == 0))
}

func (fr Fullerene) IsLeapDay() bool {
	_, m, d := fr.Date()
	return (m == 2 && d == 29)
}

func (fr Fullerene) IsBirthday(targetTime Fullerene, beforeDayIfLeap bool) bool {
	_, m, d := fr.Date()           // birthday
	_, mm, dd := targetTime.Date() // check if it is birthday.
	if m == mm && d == dd && !fr.IsLeapDay() {
		// consider leap year.
		return true
	}

	// there are countries which a person get old at the day before leap day, and the day after in a leap year.
	return fr.isBirthdayEx(targetTime, beforeDayIfLeap)
}

func (fr Fullerene) isBirthdayEx(targetTime Fullerene, beforeDayIfLeap bool) bool {
	_, m, d := targetTime.Date()
	if targetTime.IsLeapYear() {
		return false
	}
	if beforeDayIfLeap && m == 2 && d == 28 {
		return true
	}
	if !beforeDayIfLeap && m == 3 && d == 1 {
		return true
	}
	return false
}

func (fr Fullerene) Age(targetTime Fullerene) int {
	y, m, d := targetTime.Date()
	age := y - fr.Year()
	if m < fr.Month() {
		return age - 1
	}
	if m > fr.Month() {
		return age
	}
	// month of targetTime is equal to birthday.
	if d <= fr.Day() {
		return age
	}
	if d > fr.Day() {
		return age - 1
	}
	return age
}

func (fr Fullerene) CurrentAge() int {
	return fr.Age(Now())
}

func (fr Fullerene) IsHoliday() bool {
	if fr.t.Location() == loc && fr.IsJapanesePublicHoliday() {
		return true
	}
	switch fr.t.Weekday() {
	case time.Sunday, time.Saturday:
		return true
	default:
		return false
	}
}

func (fr Fullerene) IsJapanesePublicHoliday() bool {
	y1, m1, d1 := fr.Date()
	for _, d := range JapanesePublicHolidays {
		y2, m2, d2 := d.Date()
		if y1 == y2 && m1 == m2 && d1 == d2 {
			return true
		}
	}
	return false
}

func (fr Fullerene) IsWeekday() bool {
	return !fr.IsHoliday()
}

func (fr *Fullerene) String() string {
	return fr.t.String()
}

func (fr *Fullerene) Format(layout string) string {
	return fr.t.Format(layout)
}