From cd78a16c6637ee1e45d0a11e1b106b6ae9e301ad Mon Sep 17 00:00:00 2001
From: Bas van den Aakster <bvdaakster@gmail.com>
Date: Fri, 14 Nov 2025 19:01:49 +0100
Subject: [PATCH] Improve trickle ICE with early candidate buffering
MIME-Version: 1.0
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- Buffer ICE candidates generated before offerId is set
- Flush buffered candidates immediately after offerId is set
- Continue sending candidates as they arrive (true trickle ICE)
- Prevents losing early ICE candidates during setup

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

Co-Authored-By: Claude <noreply@anthropic.com>
---
 src/connection.ts | 39 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 34 insertions(+), 5 deletions(-)

diff --git a/src/connection.ts b/src/connection.ts
index a47ebae..79cfbe7 100644
--- a/src/connection.ts
+++ b/src/connection.ts
@@ -60,6 +60,7 @@ export class RondevuConnection {
   private lastIceTimestamp: number = Date.now();
   private eventListeners: Map<keyof RondevuConnectionEvents, Set<Function>> = new Map();
   private dataChannel?: RTCDataChannel;
+  private pendingIceCandidates: string[] = [];
 
   /**
    * Current connection state
@@ -101,11 +102,19 @@ export class RondevuConnection {
    */
   private setupPeerConnection(): void {
     this.pc.onicecandidate = async (event) => {
-      if (event.candidate && this.offerId) {
-        try {
-          await this.offersApi.addIceCandidates(this.offerId, [event.candidate.candidate]);
-        } catch (err) {
-          console.error('Error sending ICE candidate:', err);
+      if (event.candidate) {
+        const candidateString = event.candidate.candidate;
+
+        if (this.offerId) {
+          // offerId is set, send immediately (trickle ICE)
+          try {
+            await this.offersApi.addIceCandidates(this.offerId, [candidateString]);
+          } catch (err) {
+            console.error('Error sending ICE candidate:', err);
+          }
+        } else {
+          // offerId not set yet, buffer the candidate
+          this.pendingIceCandidates.push(candidateString);
         }
       }
     };
@@ -141,6 +150,20 @@ export class RondevuConnection {
     };
   }
 
+  /**
+   * Flush buffered ICE candidates (trickle ICE support)
+   */
+  private async flushPendingIceCandidates(): Promise<void> {
+    if (this.pendingIceCandidates.length > 0 && this.offerId) {
+      try {
+        await this.offersApi.addIceCandidates(this.offerId, this.pendingIceCandidates);
+        this.pendingIceCandidates = [];
+      } catch (err) {
+        console.error('Error flushing pending ICE candidates:', err);
+      }
+    }
+  }
+
   /**
    * Create an offer and advertise on topics
    */
@@ -168,6 +191,9 @@ export class RondevuConnection {
 
     this.offerId = offers[0].id;
 
+    // Flush any ICE candidates that were generated during offer creation
+    await this.flushPendingIceCandidates();
+
     // Start polling for answers
     this.startAnswerPolling();
 
@@ -198,6 +224,9 @@ export class RondevuConnection {
     // This prevents a race condition where ICE candidates arrive before answer is registered
     this.offerId = offerId;
 
+    // Flush any ICE candidates that were generated during answer creation
+    await this.flushPendingIceCandidates();
+
     // Start polling for ICE candidates
     this.startIcePolling();
   }