Implement basic Playlist rendering

internal/playlist/playlist.go

@@ -1,17 +1,24 @@
 package playlist
 
 import (
+	"fmt"
 	"segmento/internal/segment"
 	"time"
 )
 
 const DefaultPlaylistDuration = 20 * time.Second
 
+type PlaylistListener interface {
+	OnUpdate(p *Playlist)
+}
+
 type Playlist interface {
 	// These could be moved to an interface?
 	Duration() time.Duration
 	TargetDuration() time.Duration
 	AddSegment(s *segment.Segment) error
+	Render() string
+	//AddListener(l PlaylistListener)
 }
 
 type MediaPlaylist struct {
@@ -57,6 +64,19 @@ func (p *MediaPlaylist) durationOf(ss []*segment.Segment) time.Duration {
 	return t
 }
 
+func (p *MediaPlaylist) Render() string {
+	var r string
+	r += "#EXTM3U\n"
+	r += "#EXT-X-VERSION:3\n"
+	r += "#EXT-X-TARGETDURATION:3\n" // TODO
+	for _, s := range p.Segments {
+		r += fmt.Sprintf("#EXTINF:%.05f\n", float32(s.Duration())/float32(time.Second))
+		r += "http://www.example.com/x.mp3\n"
+	}
+	r += "#EXT-X-ENDLIST"
+	return r
+}
+
 func (p *MediaPlaylist) Run() error {
 	for {
 		// TODO block here and listen to the channel of incoming segments.
@@ -65,8 +85,3 @@ func (p *MediaPlaylist) Run() error {
 		// What would actually be a useful API and/or Go best practices?
 	}
 }
-
-type PlaylistListener interface {
-	SegmentAdded(s *segment.Segment) error
-	SegmentRemoved(s *segment.Segment) error
-}

internal/playlist/playlist_test.go

@@ -3,6 +3,7 @@ package playlist_test
 import (
 	"segmento/internal/playlist"
 	"segmento/internal/segment"
+	"strings"
 	"testing"
 	"time"
 
@@ -17,9 +18,31 @@ func TestMediaPlaylist(t *testing.T) {
 	playlist := playlist.NewMediaPlaylist()
 
 	for i := 0; i < 8; i++ {
-		s := segment.NewSegment(10*time.Second, 0)
+		s := segment.NewSegment(3*time.Second, 0)
 		s.IncrementDuration(3 * time.Second)
 		playlist.AddSegment(s)
 	}
 	require.Equal(t, 21*time.Second, playlist.Duration())
 }
+
+func TestMediaPlaylistRender(t *testing.T) {
+	playlist := playlist.NewMediaPlaylist()
+
+	s := segment.NewSegment(3*time.Second, 0)
+	s.IncrementDuration(3 * time.Second)
+	playlist.AddSegment(s)
+
+	s = segment.NewSegment(3*time.Second, 0)
+	s.IncrementDuration(2700 * time.Millisecond)
+	playlist.AddSegment(s)
+
+	lines := strings.Split(playlist.Render(), "\n")
+
+	require.Equal(t, "#EXTM3U", lines[0])
+	require.Equal(t, "#EXT-X-VERSION:3", lines[1])
+	require.Equal(t, "#EXT-X-TARGETDURATION:3", lines[2])
+	require.Equal(t, "#EXTINF:3.00000", lines[3])
+	require.Equal(t, "http://www.example.com/x.mp3", lines[4])
+	require.Equal(t, "#EXTINF:2.70000", lines[5])
+	require.Equal(t, "http://www.example.com/x.mp3", lines[6])
+}