// Package meetup is for meetup date handling.
package meetup
import (
	"time"
)
// WeekSchedule represents a schedulding type.
type WeekSchedule int
const (
	// First in the month
	First WeekSchedule = iota
	// Second in the month
	Second
	// Third in the month
	Third
	// Fourth int the month
	Fourth
	// Last in the month
	Last
	// Teenth in the month (monteenth, tuesteenth...)
	Teenth
)
// Day returns the meeting day based on input.
func Day(ws WeekSchedule, day time.Weekday, month time.Month, year int) int {
	var occurance int
	for t := time.Date(year, month, 1, 0, 0, 0, 0, time.UTC); ; t = t.AddDate(0, 0, 1) {
		if t.Weekday() == day {
			if ws == Teenth && t.Day() > 12 {
				return t.Day()
			}
			if ws == Last {
				if t.AddDate(0, 0, 7).Month() != t.Month() {
					return t.Day()
				}
			}
			if int(ws) == occurance {
				return t.Day()
			}
			occurance++
		}
	}
}