live player info in client

tanks-backend/TanksServer/Interactivity/PlayerInfoConnection.cs

@@ -0,0 +1,58 @@
+using System.Net.WebSockets;
+using System.Text.Json;
+
+namespace TanksServer.Interactivity;
+
+internal sealed class PlayerInfoConnection(
+    Player player,
+    ILogger logger,
+    WebSocket rawSocket
+) : WebsocketServerConnection(logger, new ByteChannelWebSocket(rawSocket, logger, 0)), IDisposable
+{
+    private readonly SemaphoreSlim _wantedFrames = new(1);
+    private readonly AppSerializerContext _context = new(new JsonSerializerOptions(JsonSerializerDefaults.Web));
+    private byte[] _lastMessage = [];
+
+    protected override ValueTask HandleMessageAsync(Memory<byte> buffer)
+    {
+        var response = GetMessageToSend();
+        if (response == null)
+        {
+            Logger.LogTrace("cannot respond directly, increasing wanted frames");
+            _wantedFrames.Release();
+            return ValueTask.CompletedTask;
+        }
+
+        Logger.LogTrace("responding directly");
+        return Socket.SendTextAsync(response);
+    }
+
+    public async Task OnGameTickAsync()
+    {
+        if (!await _wantedFrames.WaitAsync(TimeSpan.Zero))
+            return;
+
+        var response = GetMessageToSend();
+        if (response == null)
+        {
+            _wantedFrames.Release();
+            return;
+        }
+
+        Logger.LogTrace("responding indirectly");
+        await Socket.SendTextAsync(response);
+    }
+
+    private byte[]? GetMessageToSend()
+    {
+        var info = new PlayerInfo(player.Name, player.Scores, player.Controls);
+        var response = JsonSerializer.SerializeToUtf8Bytes(info, _context.PlayerInfo);
+
+        if (response.SequenceEqual(_lastMessage))
+            return null;
+
+        return _lastMessage = response;
+    }
+
+    public void Dispose() => _wantedFrames.Dispose();
+}