fix #58: add jitter to suggested commiter date

Author: kamilsk

internal/command/github/view/suggest.go

@@ -2,6 +2,7 @@ package view
 
 import (
 	"fmt"
+	"math/rand"
 	"strconv"
 	"time"
 
@@ -21,6 +22,11 @@ type SuggestOption struct {
 // TODO:refactoring combine with Lookup, use HeatMap as input
 // TODO:refactoring extract "table builder", compare with others views
 
+func jitter(duration time.Duration) time.Duration {
+	r := rand.New(rand.NewSource(time.Now().UnixNano()))
+	return time.Duration(r.Int63n(int64(duration)))
+}
+
 func Suggest(
 	printer interface{ Println(...interface{}) },
 
@@ -29,23 +35,22 @@ func Suggest(
 
 	option SuggestOption,
 ) error {
-	now := time.Now().UTC()
+	now := time.Now()
+	day := option.Suggest.Day.Add(jitter(time.Hour)).In(time.Local)
 
 	var suggestion string
 	if option.Delta {
-		suggestion = fmt.Sprintf("%dd", option.Suggest.Day.Sub(now)/xtime.Day)
+		days := day.Sub(now) / xtime.Day
+		tail := -day.Sub(now) % xtime.Day
+		suggestion = fmt.Sprintf("%dd%s", days, tail)
 	} else {
-		day := xtime.CopyClock(now, option.Suggest.Day).In(time.Local)
 		suggestion = day.Format(time.RFC3339)
 	}
 	if option.Short {
 		printer.Println(suggestion)
 		return nil
 	} else if option.Delta {
-		suggestion = fmt.Sprintf("%s: %s",
-			option.Suggest.Day.Format(xtime.RFC3339Day),
-			suggestion,
-		)
+		suggestion = fmt.Sprintf("%s: %s", day.Format(time.RFC3339), suggestion)
 	}
 
 	data := convert(scope, histogram)