AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

RelayClient/Resources/Raw/wwwroot/index.js

@@ -36,20 +36,10 @@ async function ensurePeerConnection() {
         iceServers: [{ urls: "stun:stun.l.google.com:19302" }]
     });
 
-    peerConnection.onicecandidate = async (event) => {
+    peerConnection.onicecandidate = (event) => {
-        if (!event.candidate || !currentChannelId || !currentUsername) return;
+        if (event.candidate) {
-
+            LogMessage("ICE candidate gathered");
-        const payload = {
+        }
-            type: "rtc_ice_candidate",
-            from: currentUsername,
-            channelId: currentChannelId,
-            candidate: event.candidate.candidate,
-            sdpMid: event.candidate.sdpMid,
-            sdpMLineIndex: event.candidate.sdpMLineIndex
-        };
-
-        LogMessage("Sending ICE candidate");
-        await window.HybridWebView.InvokeDotNet("SendRtcSignal", [JSON.stringify(payload)]);
     };
 
     peerConnection.ontrack = (event) => {
@@ -180,17 +170,13 @@ async function joinChannelCall() {
 
         LogMessage(`Joining call with media: audio=${hasAudioTrack()} video=${hasVideoTrack()}`);
 
-        const offer = await peerConnection.createOffer();
-        await peerConnection.setLocalDescription(offer);
-
         const payload = {
-            type: "rtc_offer",
+            type: "rtc_join",
             from: currentUsername,
-            channelId: currentChannelId,
+            channelId: currentChannelId
-            sdp: offer.sdp
         };
 
-        LogMessage("Sending offer to channel " + currentChannelId);
+        LogMessage("Requesting join for channel " + currentChannelId);
         await window.HybridWebView.InvokeDotNet("SendRtcSignal", [JSON.stringify(payload)]);
     } catch (err) {
         LogMessage("joinChannelCall failed: " + err);
@@ -254,6 +240,30 @@ async function handleRtcSignal(rawJson) {
 
         await ensurePeerConnection();
 
+        if (msg.type === "rtc_join_state") {
+            if (msg.isInitiator) {
+                LogMessage("No active call found. Becoming initiator.");
+
+                const offer = await peerConnection.createOffer();
+                await peerConnection.setLocalDescription(offer);
+                await waitForIceGatheringComplete(peerConnection);
+
+                const payload = {
+                    type: "rtc_offer",
+                    from: currentUsername,
+                    channelId: currentChannelId,
+                    sdp: peerConnection.localDescription.sdp
+                };
+
+                LogMessage("Sending offer to channel " + currentChannelId);
+                await window.HybridWebView.InvokeDotNet("SendRtcSignal", [JSON.stringify(payload)]);
+            } else {
+                LogMessage("Active call exists. Waiting for stored offer.");
+            }
+
+            return;
+        }
+
         if (msg.type === "rtc_offer") {
             LogMessage("Incoming channel call offer from " + msg.from);
             await ensureLocalMedia();
@@ -268,12 +278,13 @@ async function handleRtcSignal(rawJson) {
 
             const answer = await peerConnection.createAnswer();
             await peerConnection.setLocalDescription(answer);
+            await waitForIceGatheringComplete(peerConnection);
 
             const payload = {
                 type: "rtc_answer",
                 from: currentUsername,
                 channelId: msg.channelId,
-                sdp: answer.sdp
+                sdp: peerConnection.localDescription.sdp
             };
 
             LogMessage("Sending answer to channel " + msg.channelId);
@@ -360,6 +371,21 @@ async function loadDevices() {
     }
 }
 
+async function waitForIceGatheringComplete(pc) {
+    if (pc.iceGatheringState === "complete") return;
+
+    await new Promise(resolve => {
+        function checkState() {
+            if (pc.iceGatheringState === "complete") {
+                pc.removeEventListener("icegatheringstatechange", checkState);
+                resolve();
+            }
+        }
+
+        pc.addEventListener("icegatheringstatechange", checkState);
+    });
+}
+
 window.handleRtcSignal = handleRtcSignal;
 
 window.addEventListener("HybridWebViewMessageReceived", function (e) {

RelayServer/Services/ChatTest.cs

@@ -12,6 +12,8 @@ public class ChatTest : WebSocketBehavior
     public static string? ServerPrivateKey { get; set; }
     public static string? ChannelDbKey { get; set; }
     public static SurrealDb.Net.SurrealDbClient? Db { get; set; }
+    private static readonly Dictionary<string, string> ActiveRtcOffersByChannel = new();
+    private static readonly HashSet<string> ActiveRtcChannels = new();
 
     protected override void OnMessage(MessageEventArgs e)
     {
@@ -89,10 +91,8 @@ public class ChatTest : WebSocketBehavior
             return;
         }
 
-        Task.Run(async () =>
+        Task.Run(async () => { await ClientKeyService.RegisterOrUpdateKeyAsync(username, publicKey); }).GetAwaiter()
-        {
+            .GetResult();
-            await ClientKeyService.RegisterOrUpdateKeyAsync(username, publicKey);
-        }).GetAwaiter().GetResult();
 
         Send($"SERVER:REGISTERED_KEY:{username}");
     }
@@ -384,10 +384,91 @@ public class ChatTest : WebSocketBehavior
             return;
         }
 
+        RtcSignalMessage? rtcSignal;
+
+        try
+        {
+            rtcSignal = JsonSerializer.Deserialize<RtcSignalMessage>(plainJson);
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine($"Failed to parse decrypted RTC signal JSON: {ex.Message}");
+            return;
+        }
+
+        if (rtcSignal is null)
+            return;
+
         var allKeys = Task.Run(async () => await ClientKeyService.GetAllAsync())
             .GetAwaiter()
             .GetResult();
 
+        if (rtcSignal.Type == "rtc_join")
+        {
+            var joinState = new
+            {
+                type = "rtc_join_state",
+                from = "server",
+                channelId = rtcSignal.ChannelId,
+                isInitiator = !ActiveRtcOffersByChannel.ContainsKey(rtcSignal.ChannelId)
+            };
+
+            var senderClient = allKeys.FirstOrDefault(x => x.Username == clientPayload.SenderUsername);
+            if (senderClient is null)
+            {
+                Console.WriteLine($"No client key found for RTC join sender {clientPayload.SenderUsername}");
+                return;
+            }
+
+            var joinStateJson = JsonSerializer.Serialize(joinState);
+            var encryptedJoinState = E2EeHelper.EncryptForRecipient(joinStateJson, senderClient.PublicKey);
+
+            var joinStateOutbound = new SocketRtcSignalMessage
+            {
+                Type = "encrypted_rtc_signal",
+                SenderUsername = "server",
+                ChannelId = clientPayload.ChannelId,
+                CipherText = encryptedJoinState.CipherText,
+                Nonce = encryptedJoinState.Nonce,
+                Tag = encryptedJoinState.Tag,
+                EncryptedKey = encryptedJoinState.EncryptedKey
+            };
+
+            Send(JsonSerializer.Serialize(joinStateOutbound));
+
+            if (ActiveRtcOffersByChannel.TryGetValue(rtcSignal.ChannelId, out var storedOfferJson))
+            {
+                var encryptedStoredOffer = E2EeHelper.EncryptForRecipient(storedOfferJson, senderClient.PublicKey);
+
+                var storedOfferOutbound = new SocketRtcSignalMessage
+                {
+                    Type = "encrypted_rtc_signal",
+                    SenderUsername = "server",
+                    ChannelId = clientPayload.ChannelId,
+                    CipherText = encryptedStoredOffer.CipherText,
+                    Nonce = encryptedStoredOffer.Nonce,
+                    Tag = encryptedStoredOffer.Tag,
+                    EncryptedKey = encryptedStoredOffer.EncryptedKey
+                };
+
+                Send(JsonSerializer.Serialize(storedOfferOutbound));
+            }
+
+            return;
+        }
+
+        if (rtcSignal.Type == "rtc_offer")
+        {
+            ActiveRtcOffersByChannel[rtcSignal.ChannelId] = plainJson;
+            ActiveRtcChannels.Add(rtcSignal.ChannelId);
+        }
+
+        if (rtcSignal.Type == "rtc_leave")
+        {
+            ActiveRtcOffersByChannel.Remove(rtcSignal.ChannelId);
+            ActiveRtcChannels.Remove(rtcSignal.ChannelId);
+        }
+
         foreach (var client in allKeys)
         {
             if (client.Username == clientPayload.SenderUsername)