Move the log and crash dump lookup out of the start use case

StarterNG.Tests/SimulatorAftermathTests.cs

@@ -0,0 +1,39 @@
+using StarterNG.Application;
+using StarterNG.Tests.Fakes;
+
+namespace StarterNG.Tests;
+
+public class SimulatorAftermathTests
+{
+    private static readonly string Build =
+        Path.Combine(Path.GetTempPath(), "maszyna", "cmake-build-diag", "bin", "eu07_2026-10-04_fc195880");
+
+    [Fact]
+    public void Minidumps_of_this_run_are_found_in_the_installation_and_under_crashpad()
+    {
+        var installation = new TestInstallation(new InMemoryFileSystem()
+            .WithExecutable(Build)
+            .WithFile(TestInstallation.At("crash_2026-10-04_13-03-12.dmp"), "MDMP")
+            .WithFile(TestInstallation.At("crashdumps", "reports", "1a2b.dmp"), "MDMP"));
+        installation.Files.LastWriteTimeUtc = new DateTime(2026, 10, 4, 11, 3, 12, DateTimeKind.Utc);
+        var aftermath = new SimulatorAftermath(installation.Files, installation.Paths, installation.Log);
+
+        var thisRun = aftermath.CrashDumpsSince(new DateTime(2026, 10, 4, 11, 3, 0, DateTimeKind.Utc), Build);
+        var later = aftermath.CrashDumpsSince(new DateTime(2026, 10, 4, 12, 0, 0, DateTimeKind.Utc), Build);
+
+        Assert.Equal(2, thisRun.Count);
+        Assert.Contains(thisRun, dump => dump.EndsWith("crash_2026-10-04_13-03-12.dmp"));
+        Assert.Empty(later);
+    }
+
+    [Fact]
+    public void The_end_of_the_simulator_log_is_read_for_a_silent_crash()
+    {
+        var installation = new TestInstallation(new InMemoryFileSystem()
+            .WithFile(TestInstallation.At("log.txt"), "first\r\nsecond\r\n\r\nthird\r\n"));
+
+        var tail = new SimulatorAftermath(installation.Files, installation.Paths, installation.Log).SimulatorLogTail(2);
+
+        Assert.Equal(new[] { "second", "third" }, tail);
+    }
+}

StarterNG.Tests/StartSimulationTests.cs

@@ -68,33 +68,6 @@ public class StartSimulationTests
         Assert.False(launcher.CapturedErrors);
     }
 
-    [Fact]
-    public void Minidumps_of_this_run_are_found_in_the_installation_and_under_crashpad()
-    {
-        var (start, _, installation) = Rig(files => files
-            .WithExecutable(Build)
-            .WithFile(TestInstallation.At("crash_2026-10-04_13-03-12.dmp"), "MDMP")
-            .WithFile(TestInstallation.At("crashdumps", "reports", "1a2b.dmp"), "MDMP"));
-        installation.Files.LastWriteTimeUtc = new DateTime(2026, 10, 4, 11, 3, 12, DateTimeKind.Utc);
-
-        var thisRun = start.CrashDumpsSince(new DateTime(2026, 10, 4, 11, 3, 0, DateTimeKind.Utc), Build);
-        var later = start.CrashDumpsSince(new DateTime(2026, 10, 4, 12, 0, 0, DateTimeKind.Utc), Build);
-
-        Assert.Equal(2, thisRun.Count);
-        Assert.Contains(thisRun, dump => dump.EndsWith("crash_2026-10-04_13-03-12.dmp"));
-        Assert.Empty(later);
-    }
-
-    [Fact]
-    public void The_end_of_the_simulator_log_is_read_for_a_silent_crash()
-    {
-        var (start, _, _) = Rig(files => files
-            .WithExecutable(Build)
-            .WithFile(TestInstallation.At("log.txt"), "first\r\nsecond\r\n\r\nthird\r\n"));
-
-        Assert.Equal(new[] { "second", "third" }, start.SimulatorLogTail(2));
-    }
-
     [Fact]
     public void The_editor_opens_the_scenery_itself_not_an_export()
     {

StarterNG/Application/AppServices.cs

@@ -62,6 +62,7 @@ public sealed class AppServices
                                   files, clock, log, settingsPaths.UpdateCheckPath());
         StartSimulation = new StartSimulation(State, SettingsStore, Library.Vehicles, Executables, files, paths,
                                               Processes, Random, log);
+        Aftermath = new SimulatorAftermath(files, paths, log);
     }
 
     public static AppServices Current =>
@@ -139,5 +140,7 @@ public sealed class AppServices
 
     public StartSimulation StartSimulation { get; }
 
+    public SimulatorAftermath Aftermath { get; }
+
     public LocalizationService Localization { get; }
 }

StarterNG/Application/SimulatorAftermath.cs

@@ -0,0 +1,81 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using StarterNG.Application.Abstractions;
+using StarterNG.Infrastructure.Adapters;
+
+namespace StarterNG.Application;
+
+/// <summary>What a simulator that went down left behind: its log and its crash dumps.</summary>
+public sealed class SimulatorAftermath
+{
+    private readonly IFileSystem _files;
+    private readonly IGamePaths _paths;
+    private readonly IDiagnosticsLog _log;
+
+    public SimulatorAftermath(IFileSystem files, IGamePaths paths, IDiagnosticsLog log)
+    {
+        _files = files;
+        _paths = paths;
+        _log = log;
+    }
+
+    /// <summary>
+    /// Minidumps written since the simulator was started, newest first. The
+    /// simulator names them crash_*.dmp relative to its working directory - the
+    /// installation - and crashpad, where it is set up, keeps its own under
+    /// crashdumps; the folder of the binary is looked at too, for a simulator that
+    /// was once run from there.
+    /// </summary>
+    public IReadOnlyList<string> CrashDumpsSince(DateTime startedUtc, string executable)
+    {
+        var dumps = new List<string>();
+        try
+        {
+            foreach (string directory in new[] { _paths.Root, Path.GetDirectoryName(executable) ?? _paths.Root }
+                         .Distinct(StringComparer.OrdinalIgnoreCase)
+                         .Where(_files.DirectoryExists))
+                dumps.AddRange(_files.GetFiles(directory, "*.dmp"));
+
+            string crashpad = _paths.FromRoot("crashdumps");
+            if (_files.DirectoryExists(crashpad))
+                dumps.AddRange(_files.GetFilesRecursive(crashpad, "*.dmp"));
+
+            // A little slack: the start is taken just after the launch, not before it.
+            var since = startedUtc - TimeSpan.FromSeconds(5);
+            return dumps.Distinct(StringComparer.OrdinalIgnoreCase)
+                        .Where(dump => _files.GetLastWriteTimeUtc(dump) >= since)
+                        .OrderByDescending(_files.GetLastWriteTimeUtc)
+                        .ToList();
+        }
+        catch (Exception ex)
+        {
+            _log.Log("looking for crash dumps", ex);
+            return Array.Empty<string>();
+        }
+    }
+
+    /// <summary>The end of the simulator's own log, for when it died without a word on its error stream.</summary>
+    public IReadOnlyList<string> SimulatorLogTail(int count)
+    {
+        string path = _paths.FromRoot("log.txt");
+        try
+        {
+            if (!_files.FileExists(path))
+                return Array.Empty<string>();
+
+            var lines = LegacyText.Decode(_files.ReadAllBytes(path))
+                .Split('\n')
+                .Select(line => line.TrimEnd('\r'))
+                .Where(line => line.Trim().Length > 0)
+                .ToList();
+            return lines.Skip(Math.Max(0, lines.Count - count)).ToList();
+        }
+        catch (Exception ex)
+        {
+            _log.Log($"reading {path}", ex);
+            return Array.Empty<string>();
+        }
+    }
+}

StarterNG/Application/StartSimulation.cs

@@ -63,64 +63,6 @@ public sealed class StartSimulation
         _log = log;
     }
 
-    /// <summary>
-    /// Minidumps written since the simulator was started, newest first. The
-    /// simulator names them crash_*.dmp relative to its working directory - the
-    /// installation - and crashpad, where it is set up, keeps its own under
-    /// crashdumps; the folder of the binary is looked at too, for a simulator that
-    /// was once run from there.
-    /// </summary>
-    public IReadOnlyList<string> CrashDumpsSince(DateTime startedUtc, string executable)
-    {
-        var dumps = new List<string>();
-        try
-        {
-            foreach (string directory in new[] { _paths.Root, Path.GetDirectoryName(executable) ?? _paths.Root }
-                         .Distinct(StringComparer.OrdinalIgnoreCase)
-                         .Where(_files.DirectoryExists))
-                dumps.AddRange(_files.GetFiles(directory, "*.dmp"));
-
-            string crashpad = _paths.FromRoot("crashdumps");
-            if (_files.DirectoryExists(crashpad))
-                dumps.AddRange(_files.GetFilesRecursive(crashpad, "*.dmp"));
-
-            // A little slack: the start is taken just after the launch, not before it.
-            var since = startedUtc - TimeSpan.FromSeconds(5);
-            return dumps.Distinct(StringComparer.OrdinalIgnoreCase)
-                        .Where(dump => _files.GetLastWriteTimeUtc(dump) >= since)
-                        .OrderByDescending(_files.GetLastWriteTimeUtc)
-                        .ToList();
-        }
-        catch (Exception ex)
-        {
-            _log.Log("looking for crash dumps", ex);
-            return Array.Empty<string>();
-        }
-    }
-
-    /// <summary>The end of the simulator's own log, for when it died without a word on its error stream.</summary>
-    public IReadOnlyList<string> SimulatorLogTail(int count)
-    {
-        string path = _paths.FromRoot("log.txt");
-        try
-        {
-            if (!_files.FileExists(path))
-                return Array.Empty<string>();
-
-            var lines = LegacyText.Decode(_files.ReadAllBytes(path))
-                .Split('\n')
-                .Select(line => line.TrimEnd('\r'))
-                .Where(line => line.Trim().Length > 0)
-                .ToList();
-            return lines.Skip(Math.Max(0, lines.Count - count)).ToList();
-        }
-        catch (Exception ex)
-        {
-            _log.Log($"reading {path}", ex);
-            return Array.Empty<string>();
-        }
-    }
-
     public static string? StartableVehicle(Trainset? trainset, string? preferred)
     {
         if (trainset is null || trainset.Vehicles.Count == 0)

StarterNG/MainWindow.axaml.cs

@@ -597,7 +597,7 @@ public partial class MainWindow : Window
 
         var words = exit.CleanErrors.Count > 0
             ? exit.CleanErrors
-            : AppServices.Current.StartSimulation.SimulatorLogTail(12);
+            : AppServices.Current.Aftermath.SimulatorLogTail(12);
 
         var message = new StringBuilder();
         message.AppendLine(string.Format(App.Loc["SimExitCode"], exit.DescribeCode()));
@@ -611,7 +611,7 @@ public partial class MainWindow : Window
         }
         message.AppendLine().Append(App.Loc["SimExitSeeLog"]);
 
-        string? dump = AppServices.Current.StartSimulation.CrashDumpsSince(startedUtc, executable).FirstOrDefault();
+        string? dump = AppServices.Current.Aftermath.CrashDumpsSince(startedUtc, executable).FirstOrDefault();
         if (dump is not null)
             message.AppendLine().AppendLine().AppendLine(string.Format(App.Loc["SimExitDump"], dump))
                    .Append(App.Loc["SimExitOpenDump"]);