game tick service

TanksServer/ClientScreenServer.cs

@@ -7,8 +7,9 @@ namespace TanksServer;
 
 internal sealed class ClientScreenServer(
     ILogger<ClientScreenServer> logger,
-    ILoggerFactory loggerFactory
-) : IHostedLifecycleService
+    ILoggerFactory loggerFactory,
+    MapDrawer drawer
+) : IHostedLifecycleService, ITickStep
 {
     private readonly List<ClientScreenServerConnection> _connections = new();
 
@@ -16,45 +17,57 @@ internal sealed class ClientScreenServer(
     {
         logger.LogDebug("HandleClient");
         var connection =
-            new ClientScreenServerConnection(socket, loggerFactory.CreateLogger<ClientScreenServerConnection>());
+            new ClientScreenServerConnection(socket, loggerFactory.CreateLogger<ClientScreenServerConnection>(), this);
         _connections.Add(connection);
         return connection.Done;
     }
 
-    public Task Send(DisplayPixelBuffer buf)
-    {
-        logger.LogDebug("Sending buffer to {} clients", _connections.Count);
-        return Task.WhenAll(_connections.Select(c => c.Send(buf)));
-    }
-
     public Task StoppingAsync(CancellationToken cancellationToken)
     {
         logger.LogInformation("closing connections");
         return Task.WhenAll(_connections.Select(c => c.CloseAsync()));
     }
 
+    public Task TickAsync()
+    {
+        logger.LogTrace("Sending buffer to {} clients", _connections.Count);
+        return Task.WhenAll(_connections.Select(c => c.SendAsync(drawer.LastFrame)));
+    }
+
     public Task StartAsync(CancellationToken cancellationToken) => Task.CompletedTask;
     public Task StopAsync(CancellationToken cancellationToken) => Task.CompletedTask;
     public Task StartedAsync(CancellationToken cancellationToken) => Task.CompletedTask;
     public Task StartingAsync(CancellationToken cancellationToken) => Task.CompletedTask;
     public Task StoppedAsync(CancellationToken cancellationToken) => Task.CompletedTask;
-}
-
-internal sealed class ClientScreenServerConnection(WebSocket webSocket, ILogger<ClientScreenServerConnection> logger)
-    : EasyWebSocket(webSocket, logger, ArraySegment<byte>.Empty)
-{
-    private bool _wantsNewFrame = true;
-
-    public Task Send(DisplayPixelBuffer buf)
+    
+    private void Remove(ClientScreenServerConnection connection) => _connections.Remove(connection);
+    
+    private sealed class ClientScreenServerConnection(
+        WebSocket webSocket,
+        ILogger<ClientScreenServerConnection> logger,
+        ClientScreenServer server
+    ) : EasyWebSocket(webSocket, logger, ArraySegment<byte>.Empty)
     {
-        if (!_wantsNewFrame)
+        private bool _wantsNewFrame = true;
+
+        public Task SendAsync(DisplayPixelBuffer buf)
+        {
+            if (!_wantsNewFrame)
+                return Task.CompletedTask;
+            _wantsNewFrame = false;
+            return TrySendAsync(buf.Data);
+        }
+
+        protected override Task ReceiveAsync(ArraySegment<byte> buffer)
+        {
+            _wantsNewFrame = true;
             return Task.CompletedTask;
-        return SendAsync(buf.Data);
-    }
+        }
 
-    protected override Task ReceiveAsync(ArraySegment<byte> buffer)
-    {
-        _wantsNewFrame = true;
-        return Task.CompletedTask;
+        protected override Task ClosingAsync()
+        {
+            server.Remove(this);
+            return Task.CompletedTask;
+        }
     }
 }

TanksServer/EasyWebSocket.cs

@@ -12,6 +12,7 @@ internal abstract class EasyWebSocket
     private readonly WebSocket _socket;
     private readonly Task _readLoop;
     private readonly ArraySegment<byte> _buffer;
+    private int _closed;
 
     protected EasyWebSocket(WebSocket socket, ILogger logger, ArraySegment<byte> buffer)
     {
@@ -33,21 +34,38 @@ internal abstract class EasyWebSocket
 
             await ReceiveAsync(_buffer[..response.Count]);
         } while (_socket.State == WebSocketState.Open);
+
+        await CloseAsync();
     }
 
     protected abstract Task ReceiveAsync(ArraySegment<byte> buffer);
+    protected abstract Task ClosingAsync();
 
-    protected Task SendAsync(byte[] data)
+    protected async Task TrySendAsync(byte[] data)
     {
+        if (_socket.State != WebSocketState.Open)
+            await CloseAsync();
+        
         _logger.LogTrace("sending {} bytes of data", _buffer.Count);
-        return _socket.SendAsync(data, WebSocketMessageType.Binary, true, CancellationToken.None);
+
+        try
+        {
+            await _socket.SendAsync(data, WebSocketMessageType.Binary, true, CancellationToken.None);
+        }
+        catch (WebSocketException wsEx)
+        {
+            _logger.LogDebug(wsEx, "send failed");
+        }
     }
 
     public async Task CloseAsync()
     {
+        if (Interlocked.Exchange(ref _closed, 1) == 1)
+            return;
         _logger.LogDebug("closing socket");
         await _socket.CloseAsync(WebSocketCloseStatus.NormalClosure, null, CancellationToken.None);
         await _readLoop;
+        await ClosingAsync();
         _completionSource.SetResult();
     }
 }

TanksServer/GameTickService.cs

@@ -0,0 +1,38 @@
+using System.Threading;
+using Microsoft.Extensions.Hosting;
+
+namespace TanksServer;
+
+public class GameTickService(IEnumerable<ITickStep> steps) : IHostedService
+{
+    private readonly CancellationTokenSource _cancellation = new();
+    private readonly List<ITickStep> _steps = steps.ToList();
+    private Task? _run;
+
+    public Task StartAsync(CancellationToken cancellationToken)
+    {
+        _run = RunAsync();
+        return Task.CompletedTask;
+    }
+
+    private async Task RunAsync()
+    {
+        while (!_cancellation.IsCancellationRequested)
+        {
+            foreach (var step in _steps)
+                await step.TickAsync();
+            await Task.Delay(1000 / 250);
+        }
+    }
+
+    public async Task StopAsync(CancellationToken cancellationToken)
+    {
+        await _cancellation.CancelAsync();
+        if (_run != null) await _run;
+    }
+}
+
+public interface ITickStep
+{
+    Task TickAsync();
+}

TanksServer/MapDrawer.cs

@@ -1,10 +1,10 @@
 namespace TanksServer;
 
-internal class MapDrawer(MapService map)
+internal class MapDrawer(MapService map):ITickStep
 {
     private const uint GameFieldPixelCount = MapService.PixelsPerRow * MapService.PixelsPerColumn;
 
-    public void DrawInto(DisplayPixelBuffer buf)
+    private void DrawInto(DisplayPixelBuffer buf)
     {
         for (var tileY = 0; tileY < MapService.TilesPerColumn; tileY++)
         for (var tileX = 0; tileX < MapService.TilesPerRow; tileX++)
@@ -23,7 +23,7 @@ internal class MapDrawer(MapService map)
         }
     }
 
-    public DisplayPixelBuffer CreateGameFieldPixelBuffer()
+    private DisplayPixelBuffer CreateGameFieldPixelBuffer()
     {
         var data = new byte[10 + GameFieldPixelCount / 8];
         var result = new DisplayPixelBuffer(data)
@@ -37,4 +37,20 @@ internal class MapDrawer(MapService map)
         };
         return result;
     }
+
+    private DisplayPixelBuffer? _lastFrame;
+
+    public DisplayPixelBuffer LastFrame
+    {
+        get => _lastFrame ?? throw new InvalidOperationException("first frame not yet drawn");
+        private set => _lastFrame = value;
+    }
+
+    public Task TickAsync()
+    {
+        var buffer = CreateGameFieldPixelBuffer();
+        DrawInto(buffer);
+        LastFrame = buffer;
+        return Task.CompletedTask;
+    }
 }

TanksServer/Program.cs

@@ -12,14 +12,8 @@ internal static class Program
     {
         var app = Configure(args);
 
-        var display = app.Services.GetRequiredService<ServicePointDisplay>();
-        var mapDrawer = app.Services.GetRequiredService<MapDrawer>();
         var clientScreenServer = app.Services.GetRequiredService<ClientScreenServer>();
 
-        var buffer = mapDrawer.CreateGameFieldPixelBuffer();
-        mapDrawer.DrawInto(buffer);
-        await display.Send(buffer);
-
         var clientFileProvider = new PhysicalFileProvider(Path.Combine(app.Environment.ContentRootPath, "client"));
         app.UseDefaultFiles(new DefaultFilesOptions { FileProvider = clientFileProvider });
         app.UseStaticFiles(new StaticFileOptions { FileProvider = clientFileProvider });
@@ -46,10 +40,16 @@ internal static class Program
 
         builder.Services.AddSingleton<ServicePointDisplay>();
         builder.Services.AddSingleton<MapService>();
+        
         builder.Services.AddSingleton<MapDrawer>();
+        builder.Services.AddSingleton<ITickStep, MapDrawer>(sp => sp.GetRequiredService<MapDrawer>());
+        
         builder.Services.AddSingleton<ClientScreenServer>();
         builder.Services.AddHostedService<ClientScreenServer>(sp => sp.GetRequiredService<ClientScreenServer>());
+        builder.Services.AddSingleton<ITickStep, ClientScreenServer>(sp => sp.GetRequiredService<ClientScreenServer>());
 
+        builder.Services.AddHostedService<GameTickService>();
+        
         return builder.Build();
     }
 }