add mediasession info

src/lib/stores.js

@@ -1,8 +1,8 @@
-import { writable } from 'svelte/store';
+import { writable, get } from 'svelte/store';
 import { browser } from '$app/environment';
 
 export const currentStream = writable({});
-export const currentSongIndex = writable(0);
+export const currentSongIndex = writable(null);
 
 export const favoritedStreams = writable(
 	new Set(JSON.parse((browser && localStorage.getItem('favoritedStreams')) || '[]'))
@@ -12,6 +12,18 @@ if (browser) {
 	favoritedStreams.subscribe((val) => {
 		localStorage.setItem('favoritedStreams', JSON.stringify(Array.from(val)));
 	});
+
+	if ('mediaSession' in navigator) {
+		currentSongIndex.subscribe((val) => {
+			if (val != null) {
+				const song = get(currentStream).tracks[val];
+				navigator.mediaSession.metadata = new MediaMetadata({
+					artist: song[1],
+					title: song[2]
+				});
+			}
+		});
+	}
 }
 
 export const tagList = [