package formatter

import (
	"fmt"
	"time"
)

// Relative returns a human-friendly relative time string like "3 hours ago".
func Relative(t time.Time) string {
	d := time.Since(t)

	if d < time.Minute {
		return "just now"
	}
	if d < time.Hour {
		m := int(d.Minutes())
		return pluralize(m, "minute") + " ago"
	}
	if d < 24*time.Hour {
		h := int(d.Hours())
		return pluralize(h, "hour") + " ago"
	}
	if d < 30*24*time.Hour {
		day := int(d.Hours() / 24)
		return pluralize(day, "day") + " ago"
	}
	if d < 365*24*time.Hour {
		month := int(d.Hours() / 24 / 30)
		return pluralize(month, "month") + " ago"
	}

	year := int(d.Hours() / 24 / 365)
	return pluralize(year, "year") + " ago"
}

func pluralize(n int, unit string) string {
	if n == 1 {
		return fmt.Sprintf("1 %s", unit)
	}
	return fmt.Sprintf("%d %ss", n, unit)
}