more consistent tick pacing

TanksServer/GameTickWorker.cs

@@ -0,0 +1,56 @@
+using System.Diagnostics;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+using TanksServer.TickSteps;
+
+namespace TanksServer;
+
+internal sealed class GameTickWorker(
+    IEnumerable<ITickStep> steps, IHostApplicationLifetime lifetime, ILogger<GameTickWorker> logger
+) : IHostedService, IDisposable
+{
+    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()
+    {
+        try
+        {
+            var sw = new Stopwatch();
+            while (!_cancellation.IsCancellationRequested)
+            {
+                logger.LogTrace("since last frame: {}", sw.Elapsed);
+                sw.Restart();
+
+                foreach (var step in _steps)
+                    await step.TickAsync();
+                
+                await Task.Delay(TimeSpan.FromMilliseconds(1000 / 25) - sw.Elapsed);
+            }
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "game tick service crashed");
+            lifetime.StopApplication();
+        }
+    }
+
+    public async Task StopAsync(CancellationToken cancellationToken)
+    {
+        await _cancellation.CancelAsync();
+        if (_run != null) await _run;
+    }
+
+    public void Dispose()
+    {
+        _cancellation.Dispose();
+        _run?.Dispose();
+    }
+}

TanksServer/Program.cs

@@ -88,7 +88,7 @@ internal static class Program
         builder.Services.AddSingleton<LastFinishedFrameProvider>();
         builder.Services.AddSingleton<SpawnQueueProvider>();
 
-        builder.Services.AddHostedService<GameTickService>();
+        builder.Services.AddHostedService<GameTickWorker>();
         builder.Services.AddHostedService(sp => sp.GetRequiredService<ControlsServer>());
         builder.Services.AddHostedService(sp => sp.GetRequiredService<ClientScreenServer>());