return waitGroup and comments

main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"log"
 	"time"
 
@@ -10,14 +11,13 @@ import (
 )
 
 var (
-	count time.Duration = 15 * time.Second
 	str string = ""
 	p   *widgets.Paragraph
 )
 
 const (
 	playSound = true
-	timer     = 15 * time.Second
+	timer     = 5 * time.Second
 )
 
 func prepareScreen() {
@@ -37,9 +37,14 @@ func updateScreen() {
 }
 
 func main() {
+	fmt.Println("Playing only sound for 5s")
+	rofl := roflcopter.NewRoflcopter(timer, &str, updateScreen)
+	wg := rofl.OnlySound()
+	wg.Wait()
+	time.Sleep(500 * time.Millisecond)
 	prepareScreen()
-	rofl := roflcopter.NewRoflcopter(timer, &str, playSound, updateScreen)
+	wg = rofl.Start(playSound)
-	rofl.Start()
+	wg.Wait()
-	time.Sleep(timer + 500*time.Millisecond)
+	time.Sleep(500 * time.Millisecond)
 	ui.Close()
 }

roflcopter/roflcopter.go

@@ -18,7 +18,7 @@ var swah []byte
 var (
 	work     bool = true
 	duration time.Duration
-	wg       sync.WaitGroup
+	inWork   *sync.WaitGroup
 )
 
 const (
@@ -27,16 +27,16 @@ const (
 )
 
 type Roflcopter struct {
-	output bool
 	work   bool
 	count  time.Duration
 	str    *string
 	runner func()
 }
 
-func NewRoflcopter(amount time.Duration, outStr *string, out bool, funcrunner func()) *Roflcopter {
+// NewRoflcopter creates a new instance of roflcopter. amount sets duration, outStr is used to output frames, funcrunner will be called after frame change
+func NewRoflcopter(amount time.Duration, outStr *string, funcrunner func()) *Roflcopter {
+	inWork = new(sync.WaitGroup)
 	return &Roflcopter{
-		output: out,
 		work:   true,
 		str:    outStr,
 		count:  amount,
@@ -44,31 +44,54 @@ func NewRoflcopter(amount time.Duration, outStr *string, out bool, funcrunner fu
 	}
 }
 
-func (b *Roflcopter) Start() {
+// Start starts frame changing. Soundplaying can be set by true or false. Returns WaitGroup to know when it has finished work.
+func (b *Roflcopter) Start(playSound bool) *sync.WaitGroup {
+	var wg *sync.WaitGroup = new(sync.WaitGroup)
+	inWork.Add(1)
 	*b.str = frame1 + b.count.String()
 	work = b.work
 	duration = b.count
-	if b.output {
+	if playSound {
-		go b.player()
+		go b.player(wg)
 	}
-	go b.timecounter(500 * time.Millisecond)
+	go b.timeCounter(500 * time.Millisecond)
 	go b.frameChanger(125 * time.Millisecond)
+	return inWork
 }
 
-func (b *Roflcopter) timecounter(step time.Duration) {
+// OnlySound only plays sound. Frames are not changing. Returns WaitGroup to know when it has finished work
-	for b.count >= 0 {
+func (b *Roflcopter) OnlySound() *sync.WaitGroup {
-		b.count -= step
+	var wg *sync.WaitGroup = new(sync.WaitGroup)
+	inWork.Add(1)
+	work = b.work
+	duration = b.count
+	go b.player(wg)
+	go b.timeCounter(500 * time.Millisecond)
+	return inWork
+}
+
+// timeCounter counts time and stops other work when time ends
+func (b *Roflcopter) timeCounter(step time.Duration) {
+	for duration > 0 {
+		duration -= step
 		time.Sleep(step)
 	}
 	work = false
+	time.Sleep(100 * time.Millisecond)
 }
 
-func (b *Roflcopter) player() {
+//player is a loop to start sound play
-	b.sound()
+func (b *Roflcopter) player(wg *sync.WaitGroup) {
+	b.sound(wg)
 	wg.Wait()
-	b.player()
+	if work {
+		b.player(wg)
+	} else {
+		inWork.Done()
+	}
 }
 
+//frameChanger is a loop to change frames
 func (b *Roflcopter) frameChanger(delay time.Duration) {
 	nextframe := 2
 
@@ -76,23 +99,25 @@ func (b *Roflcopter) frameChanger(delay time.Duration) {
 		switch nextframe {
 		case 1:
 			{
-				*b.str = frame1 + "Ends in " + b.count.String()
+				*b.str = frame1 + "Ends in " + duration.String()
 				time.Sleep(delay)
 				nextframe = 2
 			}
 
 		case 2:
 			{
-				*b.str = frame2 + "Ends in " + b.count.String()
+				*b.str = frame2 + "Ends in " + duration.String()
 				time.Sleep(delay)
 				nextframe = 1
 			}
 		}
 		b.runner()
 	}
+	inWork.Done()
 }
 
-func (b *Roflcopter) sound() {
+//sound plays sound
+func (b *Roflcopter) sound(wg *sync.WaitGroup) {
 	wg.Add(1)
 	t := 1*time.Second + 380*time.Millisecond
 	streamer, format, err := mp3.Decode(io.NopCloser(bytes.NewReader(swah)))