Added WebRTC stuff - Needs Testing.

RelayClient/MainPage.xaml.cs

@@ -15,7 +15,7 @@ public partial class MainPage : ContentPage
     private string? _currentChannelName;
 
     private readonly Dictionary<string, List<ChatMessage>> _messagesByChannel = new();
-    private readonly List<ChannelItem> _channels = new();
+    private readonly List<ChannelItem> _channels = [];
     
     public MainPage(string username)
     {
@@ -41,6 +41,11 @@ public partial class MainPage : ContentPage
         _wsc.Send("GET_SERVER_KEY");
         _wsc.Send("GET_CHANNELS");
         hybridWebView.SetInvokeJavaScriptTarget(this);
+        
+        Loaded += async (_, _) =>
+        {
+            await InitializeRtcPageAsync();
+        };
 
     }
 
@@ -66,6 +71,12 @@ public partial class MainPage : ContentPage
             Console.WriteLine("Server public key not loaded yet.");
             return;
         }
+        
+        if (string.IsNullOrWhiteSpace(_currentChannelId))
+        {
+            Console.WriteLine("No channel selected yet.");
+            return;
+        }
 
         var encrypted = E2EeHelper.EncryptForRecipient(text, _serverPublicKey);
 
@@ -152,49 +163,79 @@ public partial class MainPage : ContentPage
 
                 return;
             }
+            
+            if (type == "encrypted_rtc_signal")
+            {
+                var payload = JsonSerializer.Deserialize<SocketRtcSignalMessage>(e.Data);
+                if (payload is null)
+                    return;
+
+                if (payload.RecipientUsername != _username)
+                    return;
+
+                var privateKey = KeyStorage.LoadPrivateKey(_username);
+
+                var decryptedJson = E2EeHelper.DecryptForRecipient(
+                    new EncryptedPayload
+                    {
+                        CipherText = payload.CipherText,
+                        Nonce = payload.Nonce,
+                        Tag = payload.Tag,
+                        EncryptedKey = payload.EncryptedKey
+                    },
+                    privateKey
+                );
+
+                MainThread.BeginInvokeOnMainThread(async () =>
+                {
+                    await SendRtcSignalToJsAsync(decryptedJson);
+                });
+
+                return;
+            }
 
             if (type != "encrypted_chat")
                 return;
 
-            var payload = JsonSerializer.Deserialize<SocketEncryptedMessage>(e.Data);
-            if (payload is null)
+            var pyload = JsonSerializer.Deserialize<SocketEncryptedMessage>(e.Data);
+            if (pyload is null)
                 return;
 
-            if (payload.RecipientUsername != _username)
+            if (pyload.RecipientUsername != _username)
                 return;
 
-            Console.WriteLine($"[{_username}] received encrypted payload for {payload.RecipientUsername}");
+            Console.WriteLine($"[{_username}] received encrypted payload for {pyload.RecipientUsername}");
 
-            var privateKey = KeyStorage.LoadPrivateKey(_username);
+            var privKey = KeyStorage.LoadPrivateKey(_username);
 
             var decryptedText = E2EeHelper.DecryptForRecipient(
                 new EncryptedPayload
                 {
-                    CipherText = payload.CipherText,
-                    Nonce = payload.Nonce,
-                    Tag = payload.Tag,
-                    EncryptedKey = payload.EncryptedKey
+                    CipherText = pyload.CipherText,
+                    Nonce = pyload.Nonce,
+                    Tag = pyload.Tag,
+                    EncryptedKey = pyload.EncryptedKey
                 },
-                privateKey
+                privKey
             );
 
-            Console.WriteLine($"[{_username}] decrypted message from {payload.SenderUsername}: {decryptedText}");
+            Console.WriteLine($"[{_username}] decrypted message from {pyload.SenderUsername}: {decryptedText}");
 
             var message = new ChatMessage
             {
-                SenderUsername = payload.SenderUsername,
+                SenderUsername = pyload.SenderUsername,
                 Text = decryptedText,
                 Timestamp = DateTime.Now
             };
 
-            if (!_messagesByChannel.ContainsKey(payload.ChannelId))
+            if (!_messagesByChannel.ContainsKey(pyload.ChannelId))
             {
-                _messagesByChannel[payload.ChannelId] = [];
+                _messagesByChannel[pyload.ChannelId] = [];
             }
 
-            _messagesByChannel[payload.ChannelId].Add(message);
+            _messagesByChannel[pyload.ChannelId].Add(message);
 
-            if (payload.ChannelId == _currentChannelId)
+            if (pyload.ChannelId == _currentChannelId)
             {
                 MainThread.BeginInvokeOnMainThread(() =>
                 {
@@ -296,14 +337,14 @@ public partial class MainPage : ContentPage
         {
             MessagesScrollView.IsVisible = true;
             RtcView.IsVisible = false;
-            ViewSwapped.Text = "Swap to Message View";
+            ViewSwapped.Text = "Swap to Web View";
 
         }
         else
         {
             MessagesScrollView.IsVisible = false;
             RtcView.IsVisible = true;
-            ViewSwapped.Text = "Swap to Web View";
+            ViewSwapped.Text = "Swap to Message View";
         }
     }
     
@@ -316,62 +357,56 @@ public partial class MainPage : ContentPage
     {
         await DisplayAlertAsync("Raw Message Received", e.Message, "OK");
     }
-
-    #region syncs
-    public async void DoSyncWork()
-    {
-        await DisplayAlertAsync("Sync Work", "Sync Work", "OK");
-    }
-
-    public async void DoSyncWorkParams(int i, string s)
-    {
-        await DisplayAlertAsync("Sync Work", $"{i}:{s}", "OK");
-    }
-
-    public string DoSyncWorkReturn()
-    {
-        return "Hello from C#!";
-    }
-
-    public SyncReturn DoSyncWorkParamsReturn(int i, string s)
-    {
-        return new SyncReturn
-        {
-            Message = $"Hello from C#!  {s}",
-            Value = i
-        };
-    }
-    #endregion
     
-    #region asyncs
-
-    public async Task DoAsyncWork()
+    public void SendRtcSignal(string json)
     {
-        await Task.Delay(1000);
-    }
-    public async Task DoAsyncWorkParams(int i, string s)
-    {
-        await DisplayAlertAsync("Sync Work", $"{i}:{s}", "OK");
-    }
-    public async Task<string> DoAsyncWorkReturn()
-    {
-        return "Hello from C#!";
-    }
-
-    public async Task<SyncReturn> DoAsyncWorkParamsReturn(int i, string s)
-    {
-        await Task.Delay(1000);
-        return new SyncReturn
+        if (string.IsNullOrWhiteSpace(_serverPublicKey))
         {
-            Message = $"Hello from C# ASync!  {s}",
-            Value = i
-        };
-    }
+            Console.WriteLine("Server public key not loaded yet.");
+            return;
+        }
 
-    #endregion
-    public class SyncReturn
+        RtcSignalMessage? rtcSignal;
+        try
+        {
+            rtcSignal = JsonSerializer.Deserialize<RtcSignalMessage>(json);
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine($"Failed to parse RTC signal from JS: {ex.Message}");
+            return;
+        }
+
+        if (rtcSignal is null)
+            return;
+
+        var encrypted = E2EeHelper.EncryptForRecipient(json, _serverPublicKey);
+
+        var payload = new SocketRtcSignalMessage
+        {
+            Type = "encrypted_rtc_signal",
+            SenderUsername = _username,
+            RecipientUsername = rtcSignal.To,
+            CipherText = encrypted.CipherText,
+            Nonce = encrypted.Nonce,
+            Tag = encrypted.Tag,
+            EncryptedKey = encrypted.EncryptedKey
+        };
+
+        _wsc.Send(JsonSerializer.Serialize(payload));
+        Console.WriteLine($"[{_username}] sent RTC signal: {rtcSignal.Type} -> {rtcSignal.To}");
+    }
+    
+    private async Task SendRtcSignalToJsAsync(string rawJson)
     {
-        public string? Message { get; set; }
-        public int Value { get; set; }
+        var jsArg = JsonSerializer.Serialize(rawJson);
+        await hybridWebView.EvaluateJavaScriptAsync($"window.handleRtcSignal({jsArg})");
+    }
+    
+    private async Task InitializeRtcPageAsync()
+    {
+        var jsArg = JsonSerializer.Serialize(_username);
+        await hybridWebView.EvaluateJavaScriptAsync($"window.currentUsername = {jsArg};");
+        Console.WriteLine($"[{_username}] RTC page initialized.");
     }
 }

RelayClient/Models/RtcSignalMessage.cs

@@ -0,0 +1,13 @@
+namespace RelayClient.Models;
+
+public class RtcSignalMessage
+{
+    public required string Type { get; set; } // rtc_offer / rtc_answer / rtc_ice_candidate / rtc_call_request / rtc_call_accept / rtc_call_reject
+    public required string From { get; set; }
+    public required string To { get; set; }
+
+    public string? Sdp { get; set; }
+    public string? Candidate { get; set; }
+    public string? SdpMid { get; set; }
+    public int? SdpMLineIndex { get; set; }
+}

RelayClient/Models/SocketRtcSignalMessage.cs

@@ -0,0 +1,13 @@
+namespace RelayClient.Models;
+
+public class SocketRtcSignalMessage
+{
+    public required string Type { get; set; } // encrypted_rtc_signal
+    public required string SenderUsername { get; set; }
+    public required string RecipientUsername { get; set; }
+
+    public required string CipherText { get; set; }
+    public required string Nonce { get; set; }
+    public required string Tag { get; set; }
+    public required string EncryptedKey { get; set; }
+}

RelayClient/Resources/Raw/wwwroot/index.html

@@ -9,116 +9,190 @@
     <link rel="stylesheet" href="index.css">
     <script src="_framework/hybridwebview.js"></script>
     <script>
+        let peerConnection = null;
+        let localStream = null;
+        let currentTarget = null;
+        let currentUsername = null;
+
         function LogMessage(msg) {
-            var messageLog = document.getElementById("messageLog");
+            const messageLog = document.getElementById("messageLog");
             messageLog.value += '\r\n' + msg;
         }
 
-        window.addEventListener(
-            "HybridWebViewMessageReceived",
-            function (e) {
-                LogMessage("Raw message: " + e.detail.message);
+        async function ensurePeerConnection() {
+            if (peerConnection) return;
+
+            peerConnection = new RTCPeerConnection({
+                iceServers: [{ urls: "stun:stun.l.google.com:19302" }]
             });
 
-        function AddNumbers(a, b) {
-            var result = {
-                "result": a + b,
-                "operationName": "Addition"
+            peerConnection.onicecandidate = async (event) => {
+                if (!event.candidate || !currentTarget || !currentUsername) return;
+
+                const payload = {
+                    type: "rtc_ice_candidate",
+                    from: currentUsername,
+                    to: currentTarget,
+                    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) => {
+                LogMessage("Remote track received");
+                const remoteVideo = document.getElementById("remoteVideo");
+                remoteVideo.srcObject = event.streams[0];
+            };
+
+            peerConnection.onconnectionstatechange = () => {
+                LogMessage("Connection state: " + peerConnection.connectionState);
+            };
+
+            peerConnection.oniceconnectionstatechange = () => {
+                LogMessage("ICE connection state: " + peerConnection.iceConnectionState);
+            };
+
+            peerConnection.onicegatheringstatechange = () => {
+                LogMessage("ICE gathering state: " + peerConnection.iceGatheringState);
             };
-            return result;
         }
 
-        var count = 0;
+        async function ensureLocalMedia() {
+            if (localStream) return;
 
-        async function EvaluateMeWithParamsAndAsyncReturn(s1, s2) {
-            const response = await fetch("/asyncdata.txt");
-            if (!response.ok) {
-                throw new Error(`HTTP error: ${response.status}`);
+            try {
+                localStream = await navigator.mediaDevices.getUserMedia({
+                    video: true,
+                    audio: true
+                });
+
+                const localVideo = document.getElementById("localVideo");
+                localVideo.srcObject = localStream;
+
+                for (const track of localStream.getTracks()) {
+                    peerConnection.addTrack(track, localStream);
+                }
+
+                LogMessage("Local media initialized");
+            } catch (err) {
+                LogMessage("getUserMedia failed: " + err);
+                throw err;
             }
-            var jsonData = await response.json();
-
-            jsonData[s1] = s2;
-
-            const msg = 'JSON data is available: ' + JSON.stringify(jsonData);
-            window.HybridWebView.SendRawMessage(msg)
-
-            return jsonData;
         }
 
-        async function InvokeDoSyncWork() {
-            LogMessage("Invoking DoSyncWork");
-            await window.HybridWebView.InvokeDotNet('DoSyncWork');
-            LogMessage("Invoked DoSyncWork");
+        async function startCall() {
+            try {
+                currentTarget = document.getElementById("targetUser").value;
+
+                if (!currentTarget) {
+                    LogMessage("No target user set.");
+                    return;
+                }
+
+                await ensurePeerConnection();
+                await ensureLocalMedia();
+
+                const offer = await peerConnection.createOffer();
+                await peerConnection.setLocalDescription(offer);
+
+                const payload = {
+                    type: "rtc_offer",
+                    from: currentUsername,
+                    to: currentTarget,
+                    sdp: offer.sdp
+                };
+
+                LogMessage("Sending offer to " + currentTarget);
+                await window.HybridWebView.InvokeDotNet("SendRtcSignal", [JSON.stringify(payload)]);
+            } catch (err) {
+                LogMessage("startCall failed: " + err);
+            }
         }
 
-        async function InvokeDoSyncWorkParams() {
-            LogMessage("Invoking DoSyncWorkParams");
-            await window.HybridWebView.InvokeDotNet('DoSyncWorkParams', [123, 'hello']);
-            LogMessage("Invoked DoSyncWorkParams");
+        async function handleRtcSignal(rawJson) {
+            try {
+                const msg = typeof rawJson === "string" ? JSON.parse(rawJson) : rawJson;
+
+                LogMessage("Received signal: " + msg.type + " from " + msg.from);
+
+                await ensurePeerConnection();
+
+                if (msg.type === "rtc_offer") {
+                    currentTarget = msg.from;
+                    LogMessage("Incoming call from " + msg.from);
+                    await ensureLocalMedia();
+
+                    await peerConnection.setRemoteDescription({
+                        type: "offer",
+                        sdp: msg.sdp
+                    });
+
+                    const answer = await peerConnection.createAnswer();
+                    await peerConnection.setLocalDescription(answer);
+
+                    const payload = {
+                        type: "rtc_answer",
+                        from: currentUsername,
+                        to: msg.from,
+                        sdp: answer.sdp
+                    };
+
+                    LogMessage("Sending answer to " + msg.from);
+                    await window.HybridWebView.InvokeDotNet("SendRtcSignal", [JSON.stringify(payload)]);
+                    return;
+                }
+
+                if (msg.type === "rtc_answer") {
+                    await peerConnection.setRemoteDescription({
+                        type: "answer",
+                        sdp: msg.sdp
+                    });
+                    LogMessage("Remote answer applied");
+                    return;
+                }
+
+                if (msg.type === "rtc_ice_candidate") {
+                    await peerConnection.addIceCandidate({
+                        candidate: msg.candidate,
+                        sdpMid: msg.sdpMid,
+                        sdpMLineIndex: msg.sdpMLineIndex
+                    });
+                    LogMessage("Remote ICE candidate applied");
+                }
+            } catch (err) {
+                LogMessage("handleRtcSignal failed: " + err);
+            }
         }
 
-        async function InvokeDoSyncWorkReturn() {
-            LogMessage("Invoking DoSyncWorkReturn");
-            const retValue = await window.HybridWebView.InvokeDotNet('DoSyncWorkReturn');
-            LogMessage("Invoked DoSyncWorkReturn, return value: " + retValue);
-        }
-
-        async function InvokeDoSyncWorkParamsReturn() {
-            LogMessage("Invoking DoSyncWorkParamsReturn");
-            const retValue = await window.HybridWebView.InvokeDotNet('DoSyncWorkParamsReturn', [123, 'hello']);
-            LogMessage("Invoked DoSyncWorkParamsReturn, return value: message=" + retValue.Message + ", value=" + retValue.Value);
-        }
-
-        async function InvokeDoAsyncWork() {
-            LogMessage("Invoking DoAsyncWork");
-            await window.HybridWebView.InvokeDotNet('DoAsyncWork');
-            LogMessage("Invoked DoAsyncWork");
-        }
-
-        async function InvokeDoAsyncWorkParams() {
-            LogMessage("Invoking DoAsyncWorkParams");
-            await window.HybridWebView.InvokeDotNet('DoAsyncWorkParams', [123, 'hello']);
-            LogMessage("Invoked DoAsyncWorkParams");
-        }
-
-        async function InvokeDoAsyncWorkReturn() {
-            LogMessage("Invoking DoAsyncWorkReturn");
-            const retValue = await window.HybridWebView.InvokeDotNet('DoAsyncWorkReturn');
-            LogMessage("Invoked DoAsyncWorkReturn, return value: " + retValue);
-        }
-
-        async function InvokeDoAsyncWorkParamsReturn() {
-            LogMessage("Invoking DoAsyncWorkParamsReturn");
-            const retValue = await window.HybridWebView.InvokeDotNet('DoAsyncWorkParamsReturn', [123, 'hello']);
-            LogMessage("Invoked DoAsyncWorkParamsReturn, return value: message=" + retValue.Message + ", value=" + retValue.Value);
-        }
+        window.handleRtcSignal = handleRtcSignal;
 
+        window.addEventListener("HybridWebViewMessageReceived", function (e) {
+            LogMessage("Raw message: " + e.detail.message);
+        });
     </script>
 </head>
-<body>
-<div>
-    Hybrid sample!
-</div>
-<div>
-    <button onclick="window.HybridWebView.SendRawMessage('Message from JS! ' + (count++))">Send message to C#</button>
-</div>
-<div>
-    <button onclick="InvokeDoSyncWork()">Call C# sync method (no params)</button>
-    <button onclick="InvokeDoSyncWorkParams()">Call C# sync method (params)</button>
-    <button onclick="InvokeDoSyncWorkReturn()">Call C# method (no params) and get simple return value</button>
-    <button onclick="InvokeDoSyncWorkParamsReturn()">Call C# method (params) and get complex return value</button>
-</div>
-<div>
-    <button onclick="InvokeDoAsyncWork()">Call C# async method (no params)</button>
-    <button onclick="InvokeDoAsyncWorkParams()">Call C# async method (params)</button>
-    <button onclick="InvokeDoAsyncWorkReturn()">Call C# async method (no params) and get simple return value</button>
-    <button onclick="InvokeDoAsyncWorkParamsReturn()">Call C# async method (params) and get complex return value</button>
-</div>
-<div>
-    Log: <textarea readonly id="messageLog" style="width: 80%; height: 10em;"></textarea>
-</div>
-<div>
-    Consider checking out this PDF: <a href="docs/sample.pdf">sample.pdf</a>
-</div>
-</body>
+    <body>
+        <div>
+            <h3>Relay RTC Test</h3>
+        </div>
+        
+        <div>
+            <label for="targetUser">Target User:</label>
+            <input id="targetUser" type="text" value="Ru_Kira" />
+            <button onclick="startCall()">Start Call</button>
+        </div>
+        
+        <div style="margin-top: 10px;">
+            <video id="localVideo" autoplay playsinline muted style="width: 320px; height: 240px; background: #111;"></video>
+            <video id="remoteVideo" autoplay playsinline style="width: 320px; height: 240px; background: #111;"></video>
+        </div>
+        
+        <div style="margin-top: 10px;">
+            <textarea readonly id="messageLog" style="width: 90%; height: 12em;"></textarea>
+        </div>
+    </body>
 </html>