package humanize
import (
"fmt"
"math"
"sort"
"time"
)
// Seconds-based time units
const (
Day = 24 * time.Hour
Week = 7 * Day
Month = 30 * Day
Year = 12 * Month
LongTime = 37 * Year
)
// Time formats a time into a relative string.
//
// Time(someT) -> "3 weeks ago"
func Time(then time.Time) string {
return RelTime(then, time.Now(), "ago", "from now")
}
// A RelTimeMagnitude struct contains a relative time point at which
// the relative format of time will switch to a new format string. A
// slice of these in ascending order by their "D" field is passed to
// CustomRelTime to format durations.
//
// The Format field is a string that may contain a "%s" which will be
// replaced with the appropriate signed label (e.g. "ago" or "from
// now") and a "%d" that will be replaced by the quantity.
//
// The DivBy field is the amount of time the time difference must be
// divided by in order to display correctly.
//
// e.g. if D is 2*time.Minute and you want to display "%d minutes %s"
// DivBy should be time.Minute so whatever the duration is will be
// expressed in minutes.
type RelTimeMagnitude struct {
D time.Duration
Format string
DivBy time.Duration
}
var defaultMagnitudes = []RelTimeMagnitude{
{time.Second, "now", time.Second},
{2 * time.Second, "1 second %s", 1},
{time.Minute, "%d seconds %s", time.Second},
{2 * time.Minute, "1 minute %s", 1},
{time.Hour, "%d minutes %s", time.Minute},
{2 * time.Hour, "1 hour %s", 1},
{Day, "%d hours %s", time.Hour},
{2 * Day, "1 day %s", 1},
{Week, "%d days %s", Day},
{2 * Week, "1 week %s", 1},
{Month, "%d weeks %s", Week},
{2 * Month, "1 month %s", 1},
{Year, "%d months %s", Month},
{18 * Month, "1 year %s", 1},
{2 * Year, "2 years %s", 1},
{LongTime, "%d years %s", Year},
{math.MaxInt64, "a long while %s", 1},
}
// RelTime formats a time into a relative string.
//
// It takes two times and two labels. In addition to the generic time
// delta string (e.g. 5 minutes), the labels are used applied so that
// the label corresponding to the smaller time is applied.
//
// RelTime(timeInPast, timeInFuture, "earlier", "later") -> "3 weeks earlier"
func RelTime(a, b time.Time, albl, blbl string) string {
return CustomRelTime(a, b, albl, blbl, defaultMagnitudes)
}
// CustomRelTime formats a time into a relative string.
//
// It takes two times two labels and a table of relative time formats.
// In addition to the generic time delta string (e.g. 5 minutes), the
// labels are used applied so that the label corresponding to the
// smaller time is applied.
func CustomRelTime(a, b time.Time, albl, blbl string, magnitudes []RelTimeMagnitude) string {
lbl := albl
diff := b.Sub(a)
if a.After(b) {
lbl = blbl
diff = a.Sub(b)
}
n := sort.Search(len(magnitudes), func(i int) bool {
return magnitudes[i].D > diff
})
if n >= len(magnitudes) {
n = len(magnitudes) - 1
}
mag := magnitudes[n]
args := []interface{}{}
escaped := false
for _, ch := range mag.Format {
if escaped {
switch ch {
case 's':
args = append(args, lbl)
case 'd':
args = append(args, diff/mag.DivBy)
}
escaped = false
} else {
escaped = ch == '%'
}
}
return fmt.Sprintf(mag.Format, args...)
}
