deduplicate connection logic

tanks-backend/TanksServer/Interactivity/ClientScreenServerConnection.cs

@@ -1,21 +1,16 @@
 using System.Buffers;
-using System.Diagnostics;
 using System.Net.WebSockets;
 using DisplayCommands;
-using DotNext.Threading;
 using TanksServer.Graphics;
 
 namespace TanksServer.Interactivity;
 
 internal sealed class ClientScreenServerConnection
-    : WebsocketServerConnection, IDisposable
+    : DroppablePackageRequestConnection<ClientScreenServerConnection.Package>
 {
     private readonly BufferPool _bufferPool;
     private readonly PlayerScreenData? _playerDataBuilder;
     private readonly Player? _player;
-    private readonly AsyncAutoResetEvent _nextPackageEvent = new(false, 1);
-    private int _runningMessageHandlers = 0;
-    private Package? _next;
 
     public ClientScreenServerConnection(
         WebSocket webSocket,
@@ -32,47 +27,11 @@ internal sealed class ClientScreenServerConnection
             : new PlayerScreenData(logger, player);
     }
 
-    protected override ValueTask HandleMessageAsync(Memory<byte> _)
-    {
-        if (Interlocked.Increment(ref _runningMessageHandlers) == 1)
-            return Core();
-
-        Interlocked.Decrement(ref _runningMessageHandlers);
-        return ValueTask.CompletedTask;
-
-        async ValueTask Core()
-        {
-            await _nextPackageEvent.WaitAsync();
-            var package = Interlocked.Exchange(ref _next, null);
-            if (package == null)
-                throw new UnreachableException("package should be set here");
-            await SendAndDisposeAsync(package);
-            Interlocked.Decrement(ref _runningMessageHandlers);
-        }
-    }
-
     public async Task OnGameTickAsync(PixelGrid pixels, GamePixelGrid gamePixelGrid)
     {
         await Task.Yield();
-
         var next = BuildNextPackage(pixels, gamePixelGrid);
-        var oldNext = Interlocked.Exchange(ref _next, next);
-
-        _nextPackageEvent.Set();
-
-        oldNext?.Dispose();
-    }
-
-    public override ValueTask RemovedAsync()
-    {
-        _player?.DecrementConnectionCount();
-        return ValueTask.CompletedTask;
-    }
-
-    public void Dispose()
-    {
-        _nextPackageEvent.Dispose();
-        Interlocked.Exchange(ref _next, null)?.Dispose();
+        SetNextPackage(next);
     }
 
     private Package BuildNextPackage(PixelGrid pixels, GamePixelGrid gamePixelGrid)
@@ -80,19 +39,17 @@ internal sealed class ClientScreenServerConnection
         var nextPixels = _bufferPool.Rent(pixels.Data.Length);
         pixels.Data.CopyTo(nextPixels.Memory);
 
-        IMemoryOwner<byte>? nextPlayerData = null;
-        if (_playerDataBuilder != null)
-        {
-            var data = _playerDataBuilder.Build(gamePixelGrid);
-            nextPlayerData = _bufferPool.Rent(data.Length);
-            data.CopyTo(nextPlayerData.Memory);
-        }
+        if (_playerDataBuilder == null)
+            return new Package(nextPixels, null);
 
-        var next = new Package(nextPixels, nextPlayerData);
-        return next;
+        var data = _playerDataBuilder.Build(gamePixelGrid);
+        var nextPlayerData = _bufferPool.Rent(data.Length);
+        data.CopyTo(nextPlayerData.Memory);
+
+        return new Package(nextPixels, nextPlayerData);
     }
 
-    private async ValueTask SendAndDisposeAsync(Package package)
+    protected override async ValueTask SendPackageAsync(Package package)
     {
         try
         {
@@ -104,13 +61,15 @@ internal sealed class ClientScreenServerConnection
         {
             Logger.LogWarning(ex, "send failed");
         }
-        finally
-        {
-            package.Dispose();
-        }
     }
 
-    private sealed record class Package(
+    public override void Dispose()
+    {
+        base.Dispose();
+        _player?.DecrementConnectionCount();
+    }
+
+    internal sealed record class Package(
         IMemoryOwner<byte> Pixels,
         IMemoryOwner<byte>? PlayerData
     ) : IDisposable