birthdaybot/model/birthdays.go

package model

import (
	"fmt"
	"strconv"
	"strings"
	"time"
)

type Birthday struct {
	Name         string
	Email        string
	Phone        string
	YearOfBirth  int
	MonthOfBirth int
	DayOfBirth   int
}

func (b *Birthday) Filename() string {
	return fmt.Sprintf("%d_%d_%d_%s.png", b.YearOfBirth, b.MonthOfBirth, b.DayOfBirth, b.Phone)
}

func (b *Birthday) Time() time.Time {
	return time.Date(b.YearOfBirth, time.Month(b.MonthOfBirth), b.DayOfBirth, 0, 0, 0, 0, time.Now().Location())
}

func NewBirthdayFromRecord(record []string) (*Birthday, error) {
	if len(record) != 4 {
		return nil, fmt.Errorf("invalid length %d for record", len(record))
	}

	dateComponents := strings.Split(strings.TrimSpace(record[3]), "/")
	if len(dateComponents) != 3 {
		return nil, fmt.Errorf("invalid date format in %q", strings.TrimSpace(record[3]))
	}

	dayOfBirth, err := strconv.Atoi(dateComponents[0])
	if err != nil {
		return nil, fmt.Errorf("error parsing day of birth from %q: %w", dateComponents[0], err)
	}

	monthOfBirth, err := strconv.Atoi(dateComponents[1])
	if err != nil {
		return nil, fmt.Errorf("error parsing month of birth from %q: %w", dateComponents[1], err)
	}

	yearOfBirth, err := strconv.Atoi(dateComponents[2])
	if err != nil {
		return nil, fmt.Errorf("error parsing year of birth from %q: %w", dateComponents[2], err)
	}

	b := &Birthday{
		Name:         strings.TrimSpace(record[0]),
		Email:        strings.TrimSpace(record[1]),
		Phone:        strings.TrimSpace(record[2]),
		YearOfBirth:  yearOfBirth,
		MonthOfBirth: monthOfBirth,
		DayOfBirth:   dayOfBirth,
	}

	return b, nil
}

func FilterByYear(birthdays []*Birthday, year int) []*Birthday {
	filteredBirthdays := []*Birthday{}
	for _, birthday := range birthdays {
		if birthday.YearOfBirth == year {
			filteredBirthdays = append(filteredBirthdays, birthday)
		}
	}
	return filteredBirthdays
}

func FilterByMonth(birthdays []*Birthday, month int) []*Birthday {
	filteredBirthdays := []*Birthday{}
	for _, birthday := range birthdays {
		if birthday.MonthOfBirth == month {
			filteredBirthdays = append(filteredBirthdays, birthday)
		}
	}
	return filteredBirthdays
}

func FilterByDay(birthdays []*Birthday, day int) []*Birthday {
	filteredBirthdays := []*Birthday{}
	for _, birthday := range birthdays {
		if birthday.DayOfBirth == day {
			filteredBirthdays = append(filteredBirthdays, birthday)
		}
	}
	return filteredBirthdays
}

func FilterByDate(birthdays []*Birthday, day, month, year int) []*Birthday {
	filteredBirthdays := []*Birthday{}
	for _, birthday := range birthdays {
		if birthday.DayOfBirth == day &&
			birthday.MonthOfBirth == month &&
			birthday.YearOfBirth == year {
			filteredBirthdays = append(filteredBirthdays, birthday)
		}
	}
	return filteredBirthdays
}

func NextBirthdayDate(birthdays []*Birthday, now time.Time) (int, int, int) {
	nowRounded := now.Round(24 * time.Hour)

	var nextBirthday *Birthday
	for _, birthday := range birthdays {
		if nextBirthday == nil {
			nextBirthday = birthday
			continue
		}

		birthdayTime := birthday.Time()
		nextBirthdayTime := nextBirthday.Time()

		if nextBirthdayTime.Before(nowRounded) && birthdayTime.After(nowRounded) {
			nextBirthday = birthday
			continue
		}

		if birthdayTime.Before(nextBirthdayTime) {
			if birthdayTime.After(nowRounded) || nextBirthdayTime.Before(nowRounded) {
				nextBirthday = birthday
			}
		}
	}

	return nextBirthday.DayOfBirth, nextBirthday.MonthOfBirth, nextBirthday.YearOfBirth
}

func NextBirthdays(birthdays []*Birthday, now time.Time) []*Birthday {
	day, month, year := NextBirthdayDate(birthdays, now)
	return FilterByDate(birthdays, day, month, year)
}