Fix service pool ICE candidate collection and logging

Fixed critical timing issue where ICE candidates were generated before
the handler was attached, causing them to be lost:

- Set up onicecandidate handler BEFORE setLocalDescription()
- Collect candidates in array while waiting for offer ID
- Send all pending candidates once offer ID is available
- Add detailed logging for service pool ICE candidates
- Log candidate type (host/srflx/relay) for debugging

This ensures all ICE candidates are captured and sent to the signaling
server, and provides visibility into what types of candidates are being
generated (especially important for diagnosing TURN relay issues).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/service-pool.ts

@@ -385,6 +385,8 @@ export class ServicePool {
     try {
       // Create peer connections and generate offers
       const offerRequests = [];
+      const pendingCandidates: RTCIceCandidateInit[][] = []; // Store candidates before we have offer IDs
+
       for (let i = 0; i < batchSize; i++) {
         const pc = new RTCPeerConnection(this.options.rtcConfig || {
           iceServers: [{ urls: 'stun:stun.l.google.com:19302' }]
@@ -394,9 +396,28 @@ export class ServicePool {
         const channel = pc.createDataChannel('rondevu-service');
         dataChannels.push(channel);
 
+        // Set up temporary candidate collector BEFORE setLocalDescription
+        const candidatesForThisOffer: RTCIceCandidateInit[] = [];
+        pendingCandidates.push(candidatesForThisOffer);
+
+        pc.onicecandidate = (event) => {
+          if (event.candidate) {
+            const candidateData = event.candidate.toJSON();
+            if (candidateData.candidate && candidateData.candidate !== '') {
+              const type = candidateData.candidate.includes('typ host') ? 'host' :
+                           candidateData.candidate.includes('typ srflx') ? 'srflx' :
+                           candidateData.candidate.includes('typ relay') ? 'relay' : 'unknown';
+              console.log(`🧊 Service pool generated ${type} ICE candidate:`, candidateData.candidate);
+              candidatesForThisOffer.push(candidateData);
+            }
+          } else {
+            console.log('🧊 Service pool ICE gathering complete');
+          }
+        };
+
         // Create offer
         const offer = await pc.createOffer();
-        await pc.setLocalDescription(offer);
+        await pc.setLocalDescription(offer); // ICE gathering starts here, candidates go to collector
 
         if (!offer.sdp) {
           pc.close();
@@ -417,19 +438,37 @@ export class ServicePool {
       const createdOffers = await this.offersApi.create(offerRequests);
       offers.push(...createdOffers);
 
-      // Set up ICE candidate handlers AFTER we have offer IDs
+      // Now send all pending candidates and set up handlers for future ones
       for (let i = 0; i < peerConnections.length; i++) {
         const pc = peerConnections[i];
         const offerId = createdOffers[i].id;
+        const candidates = pendingCandidates[i];
 
+        // Send any candidates that were collected while waiting for offer ID
+        if (candidates.length > 0) {
+          console.log(`📤 Sending ${candidates.length} pending ICE candidate(s) for offer ${offerId}`);
+          try {
+            await this.offersApi.addIceCandidates(offerId, candidates);
+            console.log(`✅ Sent ${candidates.length} pending ICE candidate(s)`);
+          } catch (err) {
+            console.error('❌ Error sending pending ICE candidates:', err);
+          }
+        }
+
+        // Replace temporary handler with permanent one for any future candidates
         pc.onicecandidate = async (event) => {
           if (event.candidate) {
             const candidateData = event.candidate.toJSON();
             if (candidateData.candidate && candidateData.candidate !== '') {
+              const type = candidateData.candidate.includes('typ host') ? 'host' :
+                           candidateData.candidate.includes('typ srflx') ? 'srflx' :
+                           candidateData.candidate.includes('typ relay') ? 'relay' : 'unknown';
+              console.log(`🧊 Service pool generated late ${type} ICE candidate:`, candidateData.candidate);
               try {
                 await this.offersApi.addIceCandidates(offerId, [candidateData]);
+                console.log(`✅ Sent late ${type} ICE candidate`);
               } catch (err) {
-                console.error('Error sending ICE candidate:', err);
+                console.error(`❌ Error sending ${type} ICE candidate:`, err);
               }
             }
           }
@@ -468,9 +507,28 @@ export class ServicePool {
 
     const dataChannel = pc.createDataChannel('rondevu-service');
 
+    // Collect candidates before we have offer ID
+    const pendingCandidates: RTCIceCandidateInit[] = [];
+
+    // Set up temporary candidate collector BEFORE setLocalDescription
+    pc.onicecandidate = (event) => {
+      if (event.candidate) {
+        const candidateData = event.candidate.toJSON();
+        if (candidateData.candidate && candidateData.candidate !== '') {
+          const type = candidateData.candidate.includes('typ host') ? 'host' :
+                       candidateData.candidate.includes('typ srflx') ? 'srflx' :
+                       candidateData.candidate.includes('typ relay') ? 'relay' : 'unknown';
+          console.log(`🧊 Initial service generated ${type} ICE candidate:`, candidateData.candidate);
+          pendingCandidates.push(candidateData);
+        }
+      } else {
+        console.log('🧊 Initial service ICE gathering complete');
+      }
+    };
+
     // Create offer
     const offer = await pc.createOffer();
-    await pc.setLocalDescription(offer);
+    await pc.setLocalDescription(offer); // ICE gathering starts here
 
     if (!offer.sdp) {
       pc.close();
@@ -512,15 +570,31 @@ export class ServicePool {
 
     const data = await response.json();
 
-    // Set up ICE candidate handler now that we have the offer ID
+    // Send any pending candidates
+    if (pendingCandidates.length > 0) {
+      console.log(`📤 Sending ${pendingCandidates.length} pending ICE candidate(s) for initial service`);
+      try {
+        await this.offersApi.addIceCandidates(data.offerId, pendingCandidates);
+        console.log(`✅ Sent ${pendingCandidates.length} pending ICE candidate(s)`);
+      } catch (err) {
+        console.error('❌ Error sending pending ICE candidates:', err);
+      }
+    }
+
+    // Set up handler for any future candidates
     pc.onicecandidate = async (event) => {
       if (event.candidate) {
         const candidateData = event.candidate.toJSON();
         if (candidateData.candidate && candidateData.candidate !== '') {
+          const type = candidateData.candidate.includes('typ host') ? 'host' :
+                       candidateData.candidate.includes('typ srflx') ? 'srflx' :
+                       candidateData.candidate.includes('typ relay') ? 'relay' : 'unknown';
+          console.log(`🧊 Initial service generated late ${type} ICE candidate:`, candidateData.candidate);
           try {
             await this.offersApi.addIceCandidates(data.offerId, [candidateData]);
+            console.log(`✅ Sent late ${type} ICE candidate`);
           } catch (err) {
-            console.error('Error sending ICE candidate:', err);
+            console.error(`❌ Error sending ${type} ICE candidate:`, err);
           }
         }
       }