Use auto-updating, natively hoverable, localized time elements (#23988)

- Added [GitHub's `relative-time` element](https://github.com/github/relative-time-element)
- Converted all formatted timestamps to use this element
- No more flashes of unstyled content around time elements
- These elements are localized using the `lang` property of the HTML file
- Relative (e.g. the activities in the dashboard) and duration (e.g.
server uptime in the admin page) time elements are auto-updated to keep
up with the current time without refreshing the page
- Code that is not needed anymore such as `formatting.js` and parts of `since.go` have been deleted

Replaces #21440
Follows #22861

## Screenshots

### Localized

![image](https://user-images.githubusercontent.com/20454870/230775041-f0af4fda-8f6b-46d3-b8e3-d340c791a50c.png)

![image](https://user-images.githubusercontent.com/20454870/230673393-931415a9-5729-4ac3-9a89-c0fb5fbeeeb7.png)

### Tooltips

#### Native for dates

![image](https://user-images.githubusercontent.com/20454870/230797525-1fa0a854-83e3-484c-9da5-9425ab6528a3.png)

#### Interactive for relative

![image](https://user-images.githubusercontent.com/115237/230796860-51e1d640-c820-4a34-ba2e-39087020626a.png)

### Auto-update

![rec](https://user-images.githubusercontent.com/20454870/230672159-37480d8f-435a-43e9-a2b0-44073351c805.gif)

---------

Signed-off-by: Yarden Shoham <git@yardenshoham.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: delvh <dev.lh@web.de>

4 files changed, 9 insertions, 228 deletions

diff --git a/modules/templates/helper.go b/modules/templates/helper.go
index 40a79d9578..f93419fe87 100644
--- a/modules/templates/helper.go
+++ b/modules/templates/helper.go
@@ -138,7 +138,7 @@ func NewFuncMap() []template.FuncMap {
 		"TimeSinceUnix": timeutil.TimeSinceUnix,
 		"Sec2Time":      util.SecToTime,
 		"DateFmtLong": func(t time.Time) string {
-			return t.Format(time.RFC1123Z)
+			return t.Format(time.RFC3339)
 		},
 		"LoadTimes": func(startTime time.Time) string {
 			return fmt.Sprint(time.Since(startTime).Nanoseconds()/1e6) + "ms"
diff --git a/modules/timeutil/since.go b/modules/timeutil/since.go
index daa5e15419..bdde54c617 100644
--- a/modules/timeutil/since.go
+++ b/modules/timeutil/since.go
@@ -6,11 +6,9 @@ package timeutil
 import (
 	"fmt"
 	"html/template"
-	"math"
 	"strings"
 	"time"
 
-	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/translation"
 )
 
@@ -24,10 +22,6 @@ const (
 	Year   = 12 * Month
 )
 
-func round(s float64) int64 {
-	return int64(math.Round(s))
-}
-
 func computeTimeDiffFloor(diff int64, lang translation.Locale) (int64, string) {
 	diffStr := ""
 	switch {
@@ -86,94 +80,6 @@ func computeTimeDiffFloor(diff int64, lang translation.Locale) (int64, string) {
 	return diff, diffStr
 }
 
-func computeTimeDiff(diff int64, lang translation.Locale) (int64, string) {
-	diffStr := ""
-	switch {
-	case diff <= 0:
-		diff = 0
-		diffStr = lang.Tr("tool.now")
-	case diff < 2:
-		diff = 0
-		diffStr = lang.Tr("tool.1s")
-	case diff < 1*Minute:
-		diffStr = lang.Tr("tool.seconds", diff)
-		diff = 0
-
-	case diff < Minute+Minute/2:
-		diff -= 1 * Minute
-		diffStr = lang.Tr("tool.1m")
-	case diff < 1*Hour:
-		minutes := round(float64(diff) / Minute)
-		if minutes > 1 {
-			diffStr = lang.Tr("tool.minutes", minutes)
-		} else {
-			diffStr = lang.Tr("tool.1m")
-		}
-		diff -= diff / Minute * Minute
-
-	case diff < Hour+Hour/2:
-		diff -= 1 * Hour
-		diffStr = lang.Tr("tool.1h")
-	case diff < 1*Day:
-		hours := round(float64(diff) / Hour)
-		if hours > 1 {
-			diffStr = lang.Tr("tool.hours", hours)
-		} else {
-			diffStr = lang.Tr("tool.1h")
-		}
-		diff -= diff / Hour * Hour
-
-	case diff < Day+Day/2:
-		diff -= 1 * Day
-		diffStr = lang.Tr("tool.1d")
-	case diff < 1*Week:
-		days := round(float64(diff) / Day)
-		if days > 1 {
-			diffStr = lang.Tr("tool.days", days)
-		} else {
-			diffStr = lang.Tr("tool.1d")
-		}
-		diff -= diff / Day * Day
-
-	case diff < Week+Week/2:
-		diff -= 1 * Week
-		diffStr = lang.Tr("tool.1w")
-	case diff < 1*Month:
-		weeks := round(float64(diff) / Week)
-		if weeks > 1 {
-			diffStr = lang.Tr("tool.weeks", weeks)
-		} else {
-			diffStr = lang.Tr("tool.1w")
-		}
-		diff -= diff / Week * Week
-
-	case diff < 1*Month+Month/2:
-		diff -= 1 * Month
-		diffStr = lang.Tr("tool.1mon")
-	case diff < 1*Year:
-		months := round(float64(diff) / Month)
-		if months > 1 {
-			diffStr = lang.Tr("tool.months", months)
-		} else {
-			diffStr = lang.Tr("tool.1mon")
-		}
-		diff -= diff / Month * Month
-
-	case diff < Year+Year/2:
-		diff -= 1 * Year
-		diffStr = lang.Tr("tool.1y")
-	default:
-		years := round(float64(diff) / Year)
-		if years > 1 {
-			diffStr = lang.Tr("tool.years", years)
-		} else {
-			diffStr = lang.Tr("tool.1y")
-		}
-		diff -= (diff / Year) * Year
-	}
-	return diff, diffStr
-}
-
 // MinutesToFriendly returns a user friendly string with number of minutes
 // converted to hours and minutes.
 func MinutesToFriendly(minutes int, lang translation.Locale) string {
@@ -208,43 +114,14 @@ func timeSincePro(then, now time.Time, lang translation.Locale) string {
 	return strings.TrimPrefix(timeStr, ", ")
 }
 
-func timeSince(then, now time.Time, lang translation.Locale) string {
-	return timeSinceUnix(then.Unix(), now.Unix(), lang)
-}
-
-func timeSinceUnix(then, now int64, lang translation.Locale) string {
-	lbl := "tool.ago"
-	diff := now - then
-	if then > now {
-		lbl = "tool.from_now"
-		diff = then - now
-	}
-	if diff <= 0 {
-		return lang.Tr("tool.now")
-	}
-
-	_, diffStr := computeTimeDiff(diff, lang)
-	return lang.Tr(lbl, diffStr)
-}
-
-// TimeSince calculates the time interval and generate user-friendly string.
+// TimeSince renders relative time HTML given a time.Time
 func TimeSince(then time.Time, lang translation.Locale) template.HTML {
-	return htmlTimeSince(then, time.Now(), lang)
+	timestamp := then.UTC().Format(time.RFC3339)
+	// declare data-tooltip-content attribute to switch from "title" tooltip to "tippy" tooltip
+	return template.HTML(fmt.Sprintf(`<relative-time class="time-since" prefix="%s" datetime="%s" data-tooltip-content data-tooltip-interactive="true">%s</relative-time>`, lang.Tr("on_date"), timestamp, timestamp))
 }
 
-func htmlTimeSince(then, now time.Time, lang translation.Locale) template.HTML {
-	return template.HTML(fmt.Sprintf(`<span class="time-since" data-tooltip-content="%s" data-tooltip-interactive="true">%s</span>`,
-		then.In(setting.DefaultUILocation).Format(GetTimeFormat(lang.Language())),
-		timeSince(then, now, lang)))
-}
-
-// TimeSinceUnix calculates the time interval and generate user-friendly string.
+// TimeSinceUnix renders relative time HTML given a TimeStamp
 func TimeSinceUnix(then TimeStamp, lang translation.Locale) template.HTML {
-	return htmlTimeSinceUnix(then, TimeStamp(time.Now().Unix()), lang)
-}
-
-func htmlTimeSinceUnix(then, now TimeStamp, lang translation.Locale) template.HTML {
-	return template.HTML(fmt.Sprintf(`<span class="time-since" data-tooltip-content="%s" data-tooltip-interactive="true">%s</span>`,
-		then.FormatInLocation(GetTimeFormat(lang.Language()), setting.DefaultUILocation),
-		timeSinceUnix(int64(then), int64(now), lang)))
+	return TimeSince(then.AsLocalTime(), lang)
 }
diff --git a/modules/timeutil/since_test.go b/modules/timeutil/since_test.go
index 9a037c7bd0..40fefe8700 100644
--- a/modules/timeutil/since_test.go
+++ b/modules/timeutil/since_test.go
@@ -5,7 +5,6 @@ package timeutil
 
 import (
 	"context"
-	"fmt"
 	"os"
 	"testing"
 	"time"
@@ -40,46 +39,6 @@ func TestMain(m *testing.M) {
 	os.Exit(retVal)
 }
 
-func TestTimeSince(t *testing.T) {
-	assert.Equal(t, "now", timeSince(BaseDate, BaseDate, translation.NewLocale("en-US")))
-
-	// test that each diff in `diffs` yields the expected string
-	test := func(expected string, diffs ...time.Duration) {
-		t.Run(expected, func(t *testing.T) {
-			for _, diff := range diffs {
-				actual := timeSince(BaseDate, BaseDate.Add(diff), translation.NewLocale("en-US"))
-				assert.Equal(t, translation.NewLocale("en-US").Tr("tool.ago", expected), actual)
-				actual = timeSince(BaseDate.Add(diff), BaseDate, translation.NewLocale("en-US"))
-				assert.Equal(t, translation.NewLocale("en-US").Tr("tool.from_now", expected), actual)
-			}
-		})
-	}
-	test("1 second", time.Second, time.Second+50*time.Millisecond)
-	test("2 seconds", 2*time.Second, 2*time.Second+50*time.Millisecond)
-	test("1 minute", time.Minute, time.Minute+29*time.Second)
-	test("2 minutes", 2*time.Minute, time.Minute+30*time.Second)
-	test("2 minutes", 2*time.Minute, 2*time.Minute+29*time.Second)
-	test("1 hour", time.Hour, time.Hour+29*time.Minute)
-	test("2 hours", 2*time.Hour, time.Hour+30*time.Minute)
-	test("2 hours", 2*time.Hour, 2*time.Hour+29*time.Minute)
-	test("3 hours", 3*time.Hour, 2*time.Hour+30*time.Minute)
-	test("1 day", DayDur, DayDur+11*time.Hour)
-	test("2 days", 2*DayDur, DayDur+12*time.Hour)
-	test("2 days", 2*DayDur, 2*DayDur+11*time.Hour)
-	test("3 days", 3*DayDur, 2*DayDur+12*time.Hour)
-	test("1 week", WeekDur, WeekDur+3*DayDur)
-	test("2 weeks", 2*WeekDur, WeekDur+4*DayDur)
-	test("2 weeks", 2*WeekDur, 2*WeekDur+3*DayDur)
-	test("3 weeks", 3*WeekDur, 2*WeekDur+4*DayDur)
-	test("1 month", MonthDur, MonthDur+14*DayDur)
-	test("2 months", 2*MonthDur, MonthDur+15*DayDur)
-	test("2 months", 2*MonthDur, 2*MonthDur+14*DayDur)
-	test("1 year", YearDur, YearDur+5*MonthDur)
-	test("2 years", 2*YearDur, YearDur+6*MonthDur)
-	test("2 years", 2*YearDur, 2*YearDur+5*MonthDur)
-	test("3 years", 3*YearDur, 2*YearDur+6*MonthDur)
-}
-
 func TestTimeSincePro(t *testing.T) {
 	assert.Equal(t, "now", timeSincePro(BaseDate, BaseDate, translation.NewLocale("en-US")))
 
@@ -113,60 +72,6 @@ func TestTimeSincePro(t *testing.T) {
 			12*time.Minute+17*time.Second)
 }
 
-func TestHtmlTimeSince(t *testing.T) {
-	setting.TimeFormat = time.UnixDate
-	setting.DefaultUILocation = time.UTC
-	// test that `diff` yields a result containing `expected`
-	test := func(expected string, diff time.Duration) {
-		actual := htmlTimeSince(BaseDate, BaseDate.Add(diff), translation.NewLocale("en-US"))
-		assert.Contains(t, actual, `data-tooltip-content="Sat Jan  1 00:00:00 UTC 2000"`)
-		assert.Contains(t, actual, expected)
-	}
-	test("1 second", time.Second)
-	test("3 minutes", 3*time.Minute+5*time.Second)
-	test("1 day", DayDur+11*time.Hour)
-	test("1 week", WeekDur+3*DayDur)
-	test("3 months", 3*MonthDur+2*WeekDur)
-	test("2 years", 2*YearDur)
-	test("3 years", 2*YearDur+11*MonthDur+4*WeekDur)
-}
-
-func TestComputeTimeDiff(t *testing.T) {
-	// test that for each offset in offsets,
-	// computeTimeDiff(base + offset) == (offset, str)
-	test := func(base int64, str string, offsets ...int64) {
-		for _, offset := range offsets {
-			t.Run(fmt.Sprintf("%s:%d", str, offset), func(t *testing.T) {
-				diff, diffStr := computeTimeDiff(base+offset, translation.NewLocale("en-US"))
-				assert.Equal(t, offset, diff)
-				assert.Equal(t, str, diffStr)
-			})
-		}
-	}
-	test(0, "now", 0)
-	test(1, "1 second", 0)
-	test(2, "2 seconds", 0)
-	test(Minute, "1 minute", 0, 1, 29)
-	test(Minute, "2 minutes", 30, Minute-1)
-	test(2*Minute, "2 minutes", 0, 29)
-	test(2*Minute, "3 minutes", 30, Minute-1)
-	test(Hour, "1 hour", 0, 1, 29*Minute)
-	test(Hour, "2 hours", 30*Minute, Hour-1)
-	test(5*Hour, "5 hours", 0, 29*Minute)
-	test(Day, "1 day", 0, 1, 11*Hour)
-	test(Day, "2 days", 12*Hour, Day-1)
-	test(5*Day, "5 days", 0, 11*Hour)
-	test(Week, "1 week", 0, 1, 3*Day)
-	test(Week, "2 weeks", 4*Day, Week-1)
-	test(3*Week, "3 weeks", 0, 3*Day)
-	test(Month, "1 month", 0, 1)
-	test(Month, "2 months", 16*Day, Month-1)
-	test(10*Month, "10 months", 0, 13*Day)
-	test(Year, "1 year", 0, 179*Day)
-	test(Year, "2 years", 180*Day, Year-1)
-	test(3*Year, "3 years", 0, 179*Day)
-}
-
 func TestMinutesToFriendly(t *testing.T) {
 	// test that a number of minutes yields the expected string
 	test := func(expected string, minutes int) {
diff --git a/modules/timeutil/timestamp.go b/modules/timeutil/timestamp.go
index c8e0d4bdc1..c60d287fae 100644
--- a/modules/timeutil/timestamp.go
+++ b/modules/timeutil/timestamp.go
@@ -64,9 +64,8 @@ func (ts TimeStamp) AsLocalTime() time.Time {
 }
 
 // AsTimeInLocation convert timestamp as time.Time in Local locale
-func (ts TimeStamp) AsTimeInLocation(loc *time.Location) (tm time.Time) {
-	tm = time.Unix(int64(ts), 0).In(loc)
-	return tm
+func (ts TimeStamp) AsTimeInLocation(loc *time.Location) time.Time {
+	return time.Unix(int64(ts), 0).In(loc)
 }
 
 // AsTimePtr convert timestamp as *time.Time in Local locale