package util

import (
	"math"
	"strconv"
	"strings"
	"time"
)

func FormatDuration(d time.Duration) string {
	sb := strings.Builder{}

	hours := int64(d.Hours())
	minutes := int64(math.Mod(d.Minutes(), 60))
	seconds := int64(math.Mod(d.Seconds(), 60))

	if hours == 1 {
		sb.WriteString("1 hour")
	} else if hours != 0 {
		sb.WriteString(strconv.FormatInt(hours, 10))
		sb.WriteString(" hours")
	}

	if hours != 0 && (seconds != 0 || minutes != 0) {
		sb.WriteString(", ")
	}

	if minutes == 1 {
		sb.WriteString("1 minute")
	} else if minutes != 0 {
		sb.WriteString(strconv.FormatInt(minutes, 10))
		sb.WriteString(" minutes")
	}

	if minutes != 0 && (seconds != 0) {
		sb.WriteString(", ")
	}

	if seconds == 1 {
		sb.WriteString("1 second")
	} else if seconds != 0 || (hours == 0 && minutes == 0) {
		sb.WriteString(strconv.FormatInt(seconds, 10))
		sb.WriteString(" seconds")
	}

	return sb.String()
}