refactor

internal/websocket/state.go

@@ -0,0 +1,29 @@
+package websocket
+
+import "spotify-ws/internal/spotify"
+
+// PlaybackState is the client-facing data structure. It conditionally omits
+// real-time data fields from JSON based on the server's mode.
+type PlaybackState struct {
+	IsPlaying  bool               `json:"is_playing"`
+	ProgressMs int                `json:"progress_ms,omitempty"`
+	Timestamp  int64              `json:"timestamp,omitempty"`
+	Item       *spotify.TrackItem `json:"item"`
+}
+
+// newPlaybackState creates a client-facing PlaybackState from the internal Spotify data.
+// It includes progress data only if the server is in real-time mode.
+func newPlaybackState(data *spotify.CurrentlyPlaying, realtime bool) PlaybackState {
+	if data == nil {
+		return PlaybackState{IsPlaying: false}
+	}
+	state := PlaybackState{
+		IsPlaying: data.IsPlaying,
+		Item:      data.Item,
+	}
+	if realtime {
+		state.ProgressMs = data.ProgressMs
+		state.Timestamp = data.Timestamp
+	}
+	return state
+}