Add TcpRpc server and client and split crypto code into multiple classes

Networking/TcpRpcServer.cs

@@ -0,0 +1,94 @@
+using System.Collections.Concurrent;
+using System.Diagnostics.CodeAnalysis;
+using System.Net;
+using System.Net.Sockets;
+using System.Text.Json;
+
+namespace RemSox.Networking;
+
+public class TcpRpcServer(IPacketCrypto? crypto = null) : TcpRpcBase(crypto)
+{
+    // Fix: Using ConcurrentDictionary to prevent collection errors during structural additions/prunings
+    private readonly ConcurrentDictionary<TcpConnection, byte> connections = new();
+    private TcpListener? listener;
+    private CancellationTokenSource? cts;
+
+    public async Task StartAsync(int port, CancellationToken token = default)
+    {
+        cts = CancellationTokenSource.CreateLinkedTokenSource(token);
+
+        listener = new TcpListener(IPAddress.Any, port);
+        listener.Start();
+
+        try
+        {
+            while (!cts.IsCancellationRequested)
+            {
+                TcpClient client = await listener.AcceptTcpClientAsync(cts.Token);
+
+                TcpConnection conn = new(client);
+                _ = connections.TryAdd(conn, 0);
+
+                _ = HandleConnection(conn, cts.Token);
+            }
+        }
+        catch (OperationCanceledException)
+        {
+            // Expected shutdown scenario
+        }
+    }
+
+    public void Stop()
+    {
+        cts?.Cancel();
+        listener?.Stop();
+
+        foreach (TcpConnection c in connections.Keys)
+        {
+            c.Dispose();
+        }
+
+        connections.Clear();
+    }
+
+    [UnconditionalSuppressMessage("Trimming", "IL2026", Justification = "Handled via library constraints")]
+    public void RespondTo<TReq, TRes>(string type, Func<TReq, Task<TRes>> handler)
+    {
+        handlers[type] = async (conn, msg) =>
+        {
+            TReq req = JsonSerializer.Deserialize<TReq>(msg.Payload)!;
+            TRes res = await handler(req);
+
+            await SendRaw(conn, new TcpMessage
+            {
+                Type = type,
+                RequestId = msg.RequestId,
+                Payload = JsonSerializer.SerializeToUtf8Bytes(res)
+            });
+        };
+    }
+
+    [UnconditionalSuppressMessage("Trimming", "IL2026", Justification = "Handled via library constraints")]
+    public Task SendToAll<T>(string type, T data)
+    {
+        byte[] payloadBytes = JsonSerializer.SerializeToUtf8Bytes(data);
+        List<Task> sendTasks = [];
+
+        foreach (TcpConnection conn in connections.Keys)
+        {
+            sendTasks.Add(SendRaw(conn, new TcpMessage
+            {
+                Type = type,
+                RequestId = Guid.NewGuid().ToString(),
+                Payload = payloadBytes
+            }));
+        }
+
+        return Task.WhenAll(sendTasks);
+    }
+
+    protected override void OnConnectionClosed(TcpConnection conn)
+    {
+        _ = connections.TryRemove(conn, out _);
+    }
+}