1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 7
8. 8
9. 9
10. 10
11. 11
12. 12
13. 13
14. 14
15. 15
16. 16
17. 17
18. 18
19. 19
20. 20
21. 21
22. 22
23. 23
24. 24
25. 25
26. 26
27. 27
28. 28
29. 29
30. 30
31. 31
32. 32
33. 33
34. 34
35. 35
36. 36
37. 37
38. 38
39. 39
40. 40
41. 41
42. 42
43. 43
44. 44
45. 45
46. 46
47. 47
48. 48
49. 49
50. 50
51. 51
52. 52
53. 53
54. 54
55. 55
56. 56
57. 57
58. 58
59. 59
60. 60
61. 61
62. 62
63. 63
64. 64
65. 65
66. 66
67. 67
68. 68
69. 69
70. 70
71. 71
72. 72
73. 73
74. 74
75. 75
76. 76
77. 77
78. 78
79. 79
80. 80
81. 81
82. 82
83. 83
84. 84
85. 85
86. 86
87. 87
88. 88
89. 89
90. 90
91. 91
92. 92
93. 93
94. 94
95. 95
96. 96
97. 97
98. 98
99. 99
100. 100
101. 101
102. 102
103. 103
104. 104
105. 105
106. 106
107. 107
108. 108
109. 109
110. 110
111. 111
112. 112
113. 113
114. 114
115. 115
116. 116
117. 117

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...)
}