added the shuffle command (#61)

* added the shuffle command

pkg/bot/bot.go

@@ -105,6 +105,7 @@ func (bot *MusicBot) registerCommands() {
 	bot.registerCommand(currentCommand)
 	bot.registerCommand(queueCommand)
 	bot.registerCommand(flushCommand)
+	bot.registerCommand(shuffleCommand)
 	bot.registerCommand(whiteListCommand)
 	bot.registerCommand(volCommand)
 	bot.registerCommand(aboutCommand)

pkg/bot/commands.go

@@ -197,6 +197,19 @@ var flushCommand = &Command{
 	},
 }
 
+var shuffleCommand = &Command{
+	Name: "shuffle",
+	Function: func(bot *MusicBot, message Message) {
+		bot.musicPlayer.GetQueue().Shuffle()
+
+		if message.IsPrivate {
+			bot.BroadcastMessage(fmt.Sprintf("%s shuffled the queue", message.Sender.NickName))
+		}
+
+		bot.ReplyToMessage(message, "Queue shuffled")
+	},
+}
+
 var whiteListCommand = &Command{
 	Name:       "whitelist",
 	MasterOnly: true,

pkg/music/queue.go

@@ -2,6 +2,7 @@ package music
 
 import (
 	"log"
+	"math/rand"
 	"sync"
 
 	"errors"
@@ -16,8 +17,9 @@ const (
 // Queue holds an array of songs
 type Queue struct {
 	*eventemitter.Emitter
-	songs []*Song
-	lock  sync.Mutex
+	songs      []*Song
+	lock       sync.Mutex
+	randSource *rand.Rand
 }
 
 func (queue *Queue) Append(songs ...*Song) {
@@ -88,6 +90,16 @@ func (queue *Queue) GetNextN(limit int) ([]Song, error) {
 	return result, nil
 }
 
+func (queue *Queue) Shuffle() {
+	queue.lock.Lock()
+	defer queue.lock.Unlock()
+
+	// Shuffle numbers, swapping corresponding entries in letters at the same time.
+	queue.randSource.Shuffle(len(queue.songs), func(i, j int) {
+		queue.songs[i], queue.songs[j] = queue.songs[j], queue.songs[i]
+	})
+}
+
 func (queue *Queue) Flush() {
 	queue.lock.Lock()
 	defer queue.lock.Unlock()
@@ -115,7 +127,8 @@ func (queue *Queue) WaitForNext() *Song {
 // NewQueue creates a new instance of Queue
 func NewQueue() *Queue {
 	return &Queue{
-		songs:   make([]*Song, 0),
-		Emitter: eventemitter.NewEmitter(true),
+		songs:      make([]*Song, 0),
+		Emitter:    eventemitter.NewEmitter(true),
+		randSource: rand.New(rand.NewSource(time.Now().UTC().UnixNano())),
 	}
 }

pkg/music/queue_test.go

@@ -2,6 +2,7 @@ package music
 
 import (
 	"github.com/stretchr/testify/assert"
+	"math/rand"
 	"testing"
 	"time"
 )
@@ -124,6 +125,22 @@ func TestQueue_GetTotalDuration(t *testing.T) {
 	assert.Equal(t, 2*time.Minute, queue.GetTotalDuration())
 }
 
+func TestQueue_Shuffle(t *testing.T) {
+	queue, _, _ := getTestQueue()
+
+	queue.Append(&Song{
+		Duration: time.Minute,
+		Name:     "song3",
+	})
+
+	queue.randSource = rand.New(rand.NewSource(1))
+	original := append([]*Song(nil), queue.songs...)
+
+	queue.Shuffle()
+
+	assert.NotEqual(t, original, queue.songs)
+}
+
 func TestQueue_WaitForNext(t *testing.T) {
 	t.Parallel()