split queue package into multiple files. other minor fixes

backend/queue/emit.go

@@ -0,0 +1,82 @@
+package queue
+
+import (
+	"github.com/wailsapp/wails/v2/pkg/runtime"
+
+	"yellowjacket/backend/events"
+)
+
+// emitQueueChanged emits the full queue state to the frontend.
+func (q *Queue) emitQueueChanged() {
+	if q.ctx == nil {
+		return
+	}
+
+	state := State{
+		Tracks:           q.tracks,
+		CurrentIndex:     q.currentIndex,
+		ShuffleMode:      q.shuffleMode,
+		RepeatMode:       q.repeatMode,
+		SourcePlaylistID: q.sourcePlaylistID,
+	}
+
+	// Ensure tracks is never nil in JSON.
+	if state.Tracks == nil {
+		state.Tracks = []Track{}
+	}
+
+	runtime.EventsEmit(q.ctx, events.QueueChanged, state)
+}
+
+// emitIndexChanged emits only the current index to the frontend.
+func (q *Queue) emitIndexChanged() {
+	if q.ctx == nil {
+		return
+	}
+
+	runtime.EventsEmit(
+		q.ctx,
+		events.QueueIndexChanged,
+		IndexChanged{CurrentIndex: q.currentIndex},
+	)
+}
+
+// emitModeChanged emits only the shuffle/repeat mode to the frontend.
+func (q *Queue) emitModeChanged() {
+	if q.ctx == nil {
+		return
+	}
+
+	runtime.EventsEmit(
+		q.ctx,
+		events.QueueModeChanged,
+		ModeChanged{
+			ShuffleMode: q.shuffleMode,
+			RepeatMode:  q.repeatMode,
+		},
+	)
+}
+
+// emitTracksModified emits a delta update for track list changes.
+func (q *Queue) emitTracksModified(
+	action string,
+	tracks []Track,
+	index int,
+	positions []int,
+) {
+	if q.ctx == nil {
+		return
+	}
+
+	runtime.EventsEmit(
+		q.ctx,
+		events.QueueTracksModified,
+		TracksModified{
+			Action:       action,
+			Tracks:       tracks,
+			Index:        index,
+			Positions:    positions,
+			CurrentIndex: q.currentIndex,
+		},
+	)
+}