fix ice candidates

public/app.js

@@ -625,12 +625,19 @@ function handleSignal(msg) {
       toast(`Joined ${msg.room}`, 'ok');
       break;
     }
-    case 'joined':
-      S.peers.set(msg.peer.id, makePeerRecord(msg.peer));
+    case 'joined': {
+      // If candidates for this peer arrived before its description (orphan
+      // record from the candidate handler), carry the buffer over instead of
+      // dropping it with the old record.
+      const prev = S.peers.get(msg.peer.id);
+      const peer = makePeerRecord(msg.peer);
+      if (prev?.pendingCandidates?.length) peer.pendingCandidates = prev.pendingCandidates;
+      S.peers.set(msg.peer.id, peer);
       playRetroCue('join');
       renderAll();
       toast(`${msg.peer.name} joined`, 'ok');
       break;
+    }
     case 'left': {
       const peer = S.peers.get(msg.id);
       if (peer) {
@@ -662,8 +669,13 @@ function handleSignal(msg) {
       break;
     }
     case 'candidate': {
-      const peer = S.peers.get(msg.from);
-      if (!peer || !peer.pc) return; // candidates only after description path created pc
+      // A candidate can legitimately arrive before its description is
+      // applied: during a join storm the offer may still be inside
+      // createOffer(), and after a 'reset' the pc is briefly null mid-rebuild.
+      // Dropping those loses srflx/relay candidates the pair may have no
+      // alternative for, so buffer them — onDescription() flushes
+      // peer.pendingCandidates once the remote description lands.
+      const peer = S.peers.get(msg.from) || createOrphanPeer(msg.from);
       onCandidate(peer, msg.candidate).catch((e) => {
         console.error('candidate failed', e);
         captureRumIssue('WebRTC ICE candidate failed', 'WARNING', { peerId: peer.id, error: e?.message || String(e) });
@@ -674,9 +686,11 @@ function handleSignal(msg) {
       // The other side's connection to us failed and it's rebuilding from
       // scratch — tear down our half so a fresh offer lands on a clean
       // RTCPeerConnection instead of an already-established (and now
-      // mismatched) DTLS transport. See recreatePeerConnection().
+      // mismatched) DTLS transport, and count the failure toward the relay
+      // fallback so both halves force TURN on the retry.
+      // See recreatePeerConnection().
       const peer = S.peers.get(msg.from);
-      if (peer) recreatePeerConnection(peer, { announce: false });
+      if (peer) recreatePeerConnection(peer, { announce: false, remote: true });
       break;
     }
     default:
@@ -864,7 +878,7 @@ const RESET_MAX_ATTEMPTS = 3;
 // failure first, whichever side detects it also tells the other to rebuild via
 // a 'reset' signal — otherwise the other side keeps its old, now-mismatched
 // transport and the fresh offer we send will fail against it too.
-function recreatePeerConnection(peer, { announce }) {
+function recreatePeerConnection(peer, { announce, remote = false }) {
   if (announce) {
     peer.resetAttempts++;
     if (peer.resetAttempts > RESET_MAX_ATTEMPTS) {
@@ -876,6 +890,16 @@ function recreatePeerConnection(peer, { announce }) {
       return;
     }
     send({ type: 'reset', to: peer.id });
+  } else if (remote) {
+    // The far side detected 'failed' against us and is rebuilding. Count the
+    // failure here too so our half ALSO recreates with
+    // iceTransportPolicy:'relay' — before, only the detecting side forced
+    // relay, so the other side kept retrying the same direct path that just
+    // died and the pair burned rebuild rounds before converging.
+    peer.resetAttempts++;
+    if (peer.resetAttempts === RESET_MAX_ATTEMPTS + 1) {
+      toast(`Connection to ${peer.name} keeps failing — TURN relay may be down`, 'error');
+    }
   }
   if (peer.pc) { try { peer.pc.close(); } catch {} }
   if (peer.qualityTimer) { clearInterval(peer.qualityTimer); peer.qualityTimer = null; }
@@ -915,7 +939,7 @@ async function onDescription(peer, desc) {
 
 async function onCandidate(peer, candidate) {
   if (peer.ignoreOffer) return;
-  if (!peer.pc.remoteDescription) {
+  if (!peer.pc || !peer.pc.remoteDescription) { // no pc yet: orphan peer mid-join or mid-rebuild
     peer.pendingCandidates.push(candidate);
     return;
   }