Now lastPlayedCache's initial capacity is not hardcoded to 10. And it will be filled slowly, instead of initial read of last N songs from a playlist.log.

internal/radio/icecast.go

@@ -22,7 +22,7 @@ const (
 )
 
 var (
-	lastPlayedCache      []Song = make([]Song, 10)
+	lastPlayedCache      []Song
 	lastPlayedCacheMutex sync.Mutex
 )
 
@@ -204,8 +204,15 @@ func (pw *PlaylistLogWatcher) Watch(playlistPath string, n int) (err error) {
 			case mask := <-pw.changed:
 				if mask&syscall.IN_MODIFY > 0 {
 					lastPlayedCacheMutex.Lock()
-					if songs, err := icecastLastPlayedSongs(playlistPath, n); err == nil {
+					if lastPlayedCache == nil {
-						lastPlayedCache = songs
+						lastPlayedCache = make([]Song, n)
+					}
+					if songs, err := icecastLastPlayedSongs(playlistPath, 1); err == nil && len(songs) > 0 {
+						if len(lastPlayedCache) == n {
+							lastPlayedCache = append(lastPlayedCache[1:], songs...)
+						} else {
+							lastPlayedCache = append(lastPlayedCache, songs...)
+						}
 					}
 					lastPlayedCacheMutex.Unlock()
 				} else if mask&syscall.IN_IGNORED > 0 {