1package humanize
2
3import (
4 "fmt"
5 "math"
6 "sort"
7 "time"
8)
9
10// Seconds-based time units
11const (
12 Day = 24 * time.Hour
13 Week = 7 * Day
14 Month = 30 * Day
15 Year = 12 * Month
16 LongTime = 37 * Year
17)
18
19// Time formats a time into a relative string.
20//
21// Time(someT) -> "3 weeks ago"
22func Time(then time.Time) string {
23 return RelTime(then, time.Now(), "ago", "from now")
24}
25
26// A RelTimeMagnitude struct contains a relative time point at which
27// the relative format of time will switch to a new format string. A
28// slice of these in ascending order by their "D" field is passed to
29// CustomRelTime to format durations.
30//
31// The Format field is a string that may contain a "%s" which will be
32// replaced with the appropriate signed label (e.g. "ago" or "from
33// now") and a "%d" that will be replaced by the quantity.
34//
35// The DivBy field is the amount of time the time difference must be
36// divided by in order to display correctly.
37//
38// e.g. if D is 2*time.Minute and you want to display "%d minutes %s"
39// DivBy should be time.Minute so whatever the duration is will be
40// expressed in minutes.
41type RelTimeMagnitude struct {
42 D time.Duration
43 Format string
44 DivBy time.Duration
45}
46
47var defaultMagnitudes = []RelTimeMagnitude{
48 {time.Second, "now", time.Second},
49 {2 * time.Second, "1 second %s", 1},
50 {time.Minute, "%d seconds %s", time.Second},
51 {2 * time.Minute, "1 minute %s", 1},
52 {time.Hour, "%d minutes %s", time.Minute},
53 {2 * time.Hour, "1 hour %s", 1},
54 {Day, "%d hours %s", time.Hour},
55 {2 * Day, "1 day %s", 1},
56 {Week, "%d days %s", Day},
57 {2 * Week, "1 week %s", 1},
58 {Month, "%d weeks %s", Week},
59 {2 * Month, "1 month %s", 1},
60 {Year, "%d months %s", Month},
61 {18 * Month, "1 year %s", 1},
62 {2 * Year, "2 years %s", 1},
63 {LongTime, "%d years %s", Year},
64 {math.MaxInt64, "a long while %s", 1},
65}
66
67// RelTime formats a time into a relative string.
68//
69// It takes two times and two labels. In addition to the generic time
70// delta string (e.g. 5 minutes), the labels are used applied so that
71// the label corresponding to the smaller time is applied.
72//
73// RelTime(timeInPast, timeInFuture, "earlier", "later") -> "3 weeks earlier"
74func RelTime(a, b time.Time, albl, blbl string) string {
75 return CustomRelTime(a, b, albl, blbl, defaultMagnitudes)
76}
77
78// CustomRelTime formats a time into a relative string.
79//
80// It takes two times two labels and a table of relative time formats.
81// In addition to the generic time delta string (e.g. 5 minutes), the
82// labels are used applied so that the label corresponding to the
83// smaller time is applied.
84func CustomRelTime(a, b time.Time, albl, blbl string, magnitudes []RelTimeMagnitude) string {
85 lbl := albl
86 diff := b.Sub(a)
87
88 if a.After(b) {
89 lbl = blbl
90 diff = a.Sub(b)
91 }
92
93 n := sort.Search(len(magnitudes), func(i int) bool {
94 return magnitudes[i].D > diff
95 })
96
97 if n >= len(magnitudes) {
98 n = len(magnitudes) - 1
99 }
100 mag := magnitudes[n]
101 args := []interface{}{}
102 escaped := false
103 for _, ch := range mag.Format {
104 if escaped {
105 switch ch {
106 case 's':
107 args = append(args, lbl)
108 case 'd':
109 args = append(args, diff/mag.DivBy)
110 }
111 escaped = false
112 } else {
113 escaped = ch == '%'
114 }
115 }
116 return fmt.Sprintf(mag.Format, args...)
117}