Attempt to handle false "ended" events with mkv files in Chrome due to blob bug

server.ts

@@ -27,6 +27,7 @@ interface ChatMessage {
 
 // --- Room Management ---
 const rooms = new Map<string, RoomState>();
+const pendingDisconnects = new Map<string, ReturnType<typeof setTimeout>>(); // key: "roomCode:username"
 
 function generateRoomCode(): string {
   const chars = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789"; // no ambiguous chars
@@ -348,6 +349,64 @@ const server = Bun.serve<WSData>({
           );
           break;
         }
+
+        case "rejoin_room": {
+          const username = (msg.username || "").trim();
+          const code = (msg.code || "").trim().toUpperCase();
+          if (!username || !code) {
+            ws.send(JSON.stringify({ type: "error", message: "Username and room code required" }));
+            return;
+          }
+
+          const room = rooms.get(code);
+          if (!room) {
+            ws.send(JSON.stringify({ type: "error", message: "Room no longer exists" }));
+            return;
+          }
+
+          // Cancel any pending disconnect timer for this user
+          const disconnectKey = `${code}:${username}`;
+          const pendingTimer = pendingDisconnects.get(disconnectKey);
+          if (pendingTimer) {
+            clearTimeout(pendingTimer);
+            pendingDisconnects.delete(disconnectKey);
+            console.log(`[Room ${code}] ${username} reconnected (cancelled disconnect timer)`);
+          }
+
+          // Swap in the new WebSocket
+          ws.data.username = username;
+          ws.data.roomCode = code;
+          room.users.set(username, ws as unknown as WebSocket);
+
+          // Send full current state to the reconnected client
+          ws.send(
+            JSON.stringify({
+              type: "room_rejoined",
+              code,
+              fileInfo: room.fileInfo,
+              users: getUserList(room),
+              state: {
+                playing: room.playing,
+                position: getCurrentPosition(room),
+                speed: room.speed,
+              },
+              chatHistory: room.chatHistory.slice(-50),
+            })
+          );
+
+          // Notify others that user is back
+          broadcastToRoom(
+            room,
+            {
+              type: "user_rejoined",
+              username,
+              users: getUserList(room),
+            },
+            ws as unknown as WebSocket
+          );
+          console.log(`[Room ${code}] ${username} rejoined`);
+          break;
+        }
       }
     },
 
@@ -358,19 +417,35 @@ const server = Bun.serve<WSData>({
       const room = rooms.get(roomCode);
       if (!room) return;
 
-      room.users.delete(username);
-      console.log(`[Room ${roomCode}] ${username} left`);
+      // Don't remove immediately — give a 30s grace period for reconnection
+      const disconnectKey = `${roomCode}:${username}`;
+      console.log(`[Room ${roomCode}] ${username} disconnected (waiting 30s for reconnect)`);
 
-      if (room.users.size === 0) {
-        rooms.delete(roomCode);
-        console.log(`[Room ${roomCode}] Deleted (empty)`);
-      } else {
-        broadcastToRoom(room, {
-          type: "user_left",
-          username,
-          users: getUserList(room),
-        });
-      }
+      const timer = setTimeout(() => {
+        pendingDisconnects.delete(disconnectKey);
+        const currentRoom = rooms.get(roomCode);
+        if (!currentRoom) return;
+
+        // Only remove if the stored WS is still the old one (not swapped by rejoin)
+        const currentWs = currentRoom.users.get(username);
+        if (currentWs === (ws as unknown as WebSocket)) {
+          currentRoom.users.delete(username);
+          console.log(`[Room ${roomCode}] ${username} removed (grace period expired)`);
+
+          if (currentRoom.users.size === 0) {
+            rooms.delete(roomCode);
+            console.log(`[Room ${roomCode}] Deleted (empty)`);
+          } else {
+            broadcastToRoom(currentRoom, {
+              type: "user_left",
+              username,
+              users: getUserList(currentRoom),
+            });
+          }
+        }
+      }, 30_000);
+
+      pendingDisconnects.set(disconnectKey, timer);
     },
   },
 });