package cobol

import (
	"fmt"
	"time"
)

// this math isn't perfect but I don't care right now
// use time.
func FormatDuration(d time.Duration) string {
	result := ""

	// check if it's more than a year
	years := int(d.Hours()) / (24 * 365)
	if years > 0 {
		result += fmt.Sprintf("%3d Y", years)
		return result
	}

	days := int(d.Hours()) / 24
	/* was terrible
	// check if it's more than a day
	if days > 45 {
		months := int(d.Hours()) % 12
		result += fmt.Sprintf("%2d M", months)
		return result
	}
	*/

	if days > 0 {
		result += fmt.Sprintf("%3d d", days)
		return result
	}

	// check if it's more than an hour
	hours := int(d.Hours()) % 24
	if hours > 2 {
		result += fmt.Sprintf("%3d h", hours)
		return result
	}

	// check if it's more than a minute
	minutes := int(d.Minutes()) % 60
	if minutes > 2 {
		result += fmt.Sprintf("%3d m", minutes)
		return result
	}

	// check if it's more than a second
	seconds := int(d.Seconds()) % 60
	if seconds > 0 {
		result += fmt.Sprintf("%3d s", seconds)
		return result
	}

	// report in milliseconds
	ms := int(d.Milliseconds())
	if ms > 100 {
		// todo: print .3s, etc ?
	}
	if ms > 0 {
		/*
			if ms > 99 {
				result += fmt.Sprintf("%-3dm", ms)
				return result
			}
		*/
		result += fmt.Sprintf("%3dms", ms)
		return result
	}

	// report in milliseconds
	mc := int(d.Microseconds())
	if mc > 0 {
		result += fmt.Sprintf("%3dmc", mc)
		return result
	}

	ns := int(d.Nanoseconds())
	result += fmt.Sprintf("%3dns", ns)
	return result
}