Add TimeSince

modules/base/tool.go

@@ -7,6 +7,8 @@ package base
 import (
 	"crypto/md5"
 	"encoding/hex"
+	"fmt"
+	"time"
 )
 
 // Encode string to md5 hex value
@@ -15,3 +17,64 @@ func EncodeMd5(str string) string {
 	m.Write([]byte(str))
 	return hex.EncodeToString(m.Sum(nil))
 }
+
+// Seconds-based time units
+const (
+	Minute = 60
+	Hour   = 60 * Minute
+	Day    = 24 * Hour
+	Week   = 7 * Day
+	Month  = 30 * Day
+	Year   = 12 * Month
+)
+
+// TimeSince calculates the time interval and generate user-friendly string.
+func TimeSince(then time.Time) string {
+	now := time.Now()
+
+	lbl := "ago"
+	diff := now.Unix() - then.Unix()
+	if then.After(now) {
+		lbl = "from now"
+		diff = then.Unix() - now.Unix()
+	}
+
+	switch {
+
+	case diff <= 0:
+		return "now"
+	case diff <= 2:
+		return fmt.Sprintf("1 second %s", lbl)
+	case diff < 1*Minute:
+		return fmt.Sprintf("%d seconds %s", diff, lbl)
+
+	case diff < 2*Minute:
+		return fmt.Sprintf("1 minute %s", lbl)
+	case diff < 1*Hour:
+		return fmt.Sprintf("%d minutes %s", diff/Minute, lbl)
+
+	case diff < 2*Hour:
+		return fmt.Sprintf("1 hour %s", lbl)
+	case diff < 1*Day:
+		return fmt.Sprintf("%d hours %s", diff/Hour, lbl)
+
+	case diff < 2*Day:
+		return fmt.Sprintf("1 day %s", lbl)
+	case diff < 1*Week:
+		return fmt.Sprintf("%d days %s", diff/Day, lbl)
+
+	case diff < 2*Week:
+		return fmt.Sprintf("1 week %s", lbl)
+	case diff < 1*Month:
+		return fmt.Sprintf("%d weeks %s", diff/Week, lbl)
+
+	case diff < 2*Month:
+		return fmt.Sprintf("1 month %s", lbl)
+	case diff < 1*Year:
+		return fmt.Sprintf("%d months %s", diff/Month, lbl)
+
+	case diff < 18*Month:
+		return fmt.Sprintf("1 year %s", lbl)
+	}
+	return then.String()
+}