package home

import (
	"time"
)

var shichenNames = [12]string{"子", "丑", "寅", "卯", "辰", "巳", "午", "未", "申", "酉", "戌", "亥"}

// ShichenWindow is the current Chinese double-hour window.
type ShichenWindow struct {
	Index int
	Name  string
	Start time.Time
	End   time.Time
}

// CurrentShichen returns the 十二时辰 window for now (子时 23:00–01:00 …).
func CurrentShichen(now time.Time) ShichenWindow {
	h := now.Hour()
	idx := ((h + 1) % 24) / 2
	startHour := (idx*2 + 23) % 24
	start := time.Date(now.Year(), now.Month(), now.Day(), startHour, 0, 0, 0, now.Location())
	if start.After(now) {
		start = start.Add(-24 * time.Hour)
	}
	return ShichenWindow{
		Index: idx,
		Name:  shichenNames[idx],
		Start: start,
		End:   start.Add(2 * time.Hour),
	}
}