Add discoverable rooms to desktop lobby

server.ts

@@ -8,8 +8,9 @@ interface FileInfo {
   duration: number;
 }
 
-interface RoomState {
-  code: string;
+interface RoomState {
+  code: string;
+  listed: boolean;
   fileInfo: FileInfo;
   playing: boolean;
   position: number;
@@ -133,7 +134,17 @@ const server = Bun.serve<WSData>({
   port: Number(process.env.PORT) || 3000,
 
   fetch(req, server) {
-    const url = new URL(req.url);
+    const url = new URL(req.url);
+
+    if (url.pathname === "/api/rooms" && req.method === "GET") {
+      const activeRooms = Array.from(rooms.values()).flatMap(room => {
+        const users = Array.from(room.users).filter(([, ws]) => ws.readyState === 1)
+          .map(([name]) => name);
+        return room.listed && users.length ? [{ code: room.code, fileInfo: room.fileInfo,
+          users, playing: room.playing, position: getCurrentPosition(room) }] : [];
+      });
+      return Response.json({ rooms: activeRooms }, { headers: { "Cache-Control": "no-store" } });
+    }
 
     // WebSocket upgrade
     if (url.pathname === "/ws") {
@@ -179,8 +190,9 @@ const server = Bun.serve<WSData>({
           }
 
           const code = generateRoomCode();
-          const room: RoomState = {
-            code,
+          const room: RoomState = {
+            code,
+            listed: msg.listed !== false,
             fileInfo: {
               name: msg.fileInfo.name,
               size: msg.fileInfo.size,