Add adaptive packet loss handling

src/VoiceCat.Core/VoiceCatClient.cs

@@ -39,6 +39,8 @@ public sealed partial class VoiceCatClient : IAsyncDisposable
     private long nextRequest;
     private AuthResult? authentication;
     private ServerHello? hello;
+    private uint adaptiveLossChannel;
+    private int adaptiveLossPercent = -1;
     private ClientConnectionState state;
 
     public event Action<ClientConnectionState>? ConnectionStateChanged;
@@ -47,6 +49,7 @@ public sealed partial class VoiceCatClient : IAsyncDisposable
     public Task Completion => reader;
     public AuthResult? Authentication { get { lock (stateGate) return authentication?.Clone(); } }
     public ServerHello? ServerHello { get { lock (stateGate) return hello?.Clone(); } }
+    public bool SupportsAdaptivePacketLoss { get { lock (stateGate) return hello?.Features.Contains(ProtocolFeatures.AdaptivePacketLoss) == true; } }
     public IReadOnlyList<Channel> Channels { get { lock (stateGate) return channels.Values.Select(c => c.Clone()).ToArray(); } }
     public IReadOnlyList<User> Users { get { lock (stateGate) return users.Values.Select(u => u.Clone()).ToArray(); } }
     public bool TryReadEvent(out Envelope? envelope) => events.Reader.TryRead(out envelope);
@@ -94,7 +97,9 @@ public sealed partial class VoiceCatClient : IAsyncDisposable
                 pins.Pin(host, port, certificatePin);
             }
             reader = ReadAsync(control, connectionLifetime.Token);
-            Envelope response = await RequestAsync(new() { ClientHello = new() { ProtoVersion = 2, ClientName = clientName, ClientVersion = clientVersion } }, token).ConfigureAwait(false);
+            var clientHello = new ClientHello { ProtoVersion = 2, ClientName = clientName, ClientVersion = clientVersion };
+            clientHello.Features.Add(ProtocolFeatures.AdaptivePacketLoss);
+            Envelope response = await RequestAsync(new() { ClientHello = clientHello }, token).ConfigureAwait(false);
             if (response.ServerHello?.ProtoVersion != 2) throw new IOException("Unsupported server protocol.");
             lock (stateGate) hello = response.ServerHello.Clone();
             keepalive = KeepaliveAsync(connectionLifetime.Token);
@@ -147,7 +152,14 @@ public sealed partial class VoiceCatClient : IAsyncDisposable
         var info = new StreamInfo { StreamId = response.StreamId, Ssrc = response.Ssrc, Kind = kind, Audio = response.EffectiveAudio.Clone(), Label = label };
         try
         {
-            lock (stateGate) { if (State != ClientConnectionState.Connected) throw new InvalidOperationException("Client disconnected during stream negotiation."); Audio.AddLocalStream(info, captureChannels); localStreams[info.StreamId] = info; }
+            lock (stateGate)
+            {
+                if (State != ClientConnectionState.Connected) throw new InvalidOperationException("Client disconnected during stream negotiation.");
+                Audio.AddLocalStream(info, captureChannels); localStreams[info.StreamId] = info;
+                User? self = authentication is null ? null : users.GetValueOrDefault(authentication.Self.Id, authentication.Self);
+                if (self is not null && self.ChannelId == adaptiveLossChannel && adaptiveLossPercent >= 0)
+                    Audio.SetExpectedPacketLoss(adaptiveLossPercent);
+            }
             return info.Clone();
         }
         catch { if (State == ClientConnectionState.Connected) Send(new() { StreamStop = new() { StreamId = info.StreamId } }); throw; }
@@ -226,13 +238,31 @@ public sealed partial class VoiceCatClient : IAsyncDisposable
             if (message.ChannelEvent is not null)
             {
                 if (message.ChannelEvent.Kind == ChannelEvent.Types.Kind.Deleted) channels.Remove(message.ChannelEvent.DeletedId);
-                else if (message.ChannelEvent.Channel is not null) channels[message.ChannelEvent.Channel.Id] = message.ChannelEvent.Channel.Clone();
+                else if (message.ChannelEvent.Channel is not null)
+                {
+                    PacketLossMode previousMode = channels.GetValueOrDefault(message.ChannelEvent.Channel.Id)?.Audio.PacketLossMode
+                        ?? PacketLossMode.PacketLossManual;
+                    channels[message.ChannelEvent.Channel.Id] = message.ChannelEvent.Channel.Clone();
+                    User? self = authentication is null ? null : users.GetValueOrDefault(authentication.Self.Id, authentication.Self);
+                    if (self?.ChannelId == message.ChannelEvent.Channel.Id && previousMode != message.ChannelEvent.Channel.Audio.PacketLossMode)
+                    { adaptiveLossChannel = 0; adaptiveLossPercent = -1; }
+                }
             }
             if (message.UserEvent is not null)
             {
                 if (message.UserEvent.Kind == UserEvent.Types.Kind.Left) users.Remove(message.UserEvent.LeftId);
                 else if (message.UserEvent.User is not null) users[message.UserEvent.User.Id] = message.UserEvent.User.Clone();
             }
+            if (message.PacketLossUpdate is not null && authentication is not null)
+            {
+                User self = users.GetValueOrDefault(authentication.Self.Id, authentication.Self);
+                if (self.ChannelId == message.PacketLossUpdate.ChannelId)
+                {
+                    adaptiveLossChannel = self.ChannelId;
+                    adaptiveLossPercent = checked((int)message.PacketLossUpdate.AppliedPercent);
+                    Audio.SetExpectedPacketLoss(checked((int)message.PacketLossUpdate.AppliedPercent));
+                }
+            }
             if (authentication is not null && (message.ServerState is not null || message.UserEvent is not null))
             {
                 User self = users.GetValueOrDefault(authentication.Self.Id, authentication.Self);
@@ -273,7 +303,7 @@ public sealed partial class VoiceCatClient : IAsyncDisposable
                 media = null;
                 mediaCrypto?.Dispose(); mediaCrypto = null;
                 connectionLifetime?.Dispose(); connectionLifetime = null;
-                lock (stateGate) { authentication = null; hello = null; channels.Clear(); users.Clear(); }
+                lock (stateGate) { authentication = null; hello = null; channels.Clear(); users.Clear(); adaptiveLossChannel = 0; adaptiveLossPercent = -1; }
                 lock (stateGate)
                 {
                     foreach (var id in localStreams.Keys) Audio.RemoveLocalStream(id);