Split Settings into model, serializer, paths and store

698 lines did all of it at once. The mutable CaptureFromUi callback becomes an ISettingsCapture the settings view implements.
2026-10-16 23:49:19 +02:00 · 2026-09-04 21:13:06 +02:00
parent 8e5fe01104
commit 3c502f630d
30 changed files with 1371 additions and 779 deletions
--- a/StarterNG.Tests/ExecutableLocatorTests.cs
+++ b/StarterNG.Tests/ExecutableLocatorTests.cs
@@ -0,0 +1,82 @@
+using StarterNG.Domain.Settings;
+using StarterNG.Tests.Fakes;
+
+namespace StarterNG.Tests;
+
+public class ExecutableLocatorTests
+{
+    private const string Elf = "\u007fELF binary";
+    private const string PortableExecutable = "MZ binary";
+
+    [Fact]
+    public void The_canonical_binary_is_preferred_over_other_candidates()
+    {
+        var files = new InMemoryFileSystem()
+            .WithExecutable(TestInstallation.At("eu07-dev"), Elf)
+            .WithExecutable(TestInstallation.At("eu07"), Elf);
+        var installation = new TestInstallation(files);
+
+        string resolved = installation.Executables.Resolve(new SimulatorSettings(), out var problem);
+
+        Assert.Equal(ExeProblem.None, problem);
+        Assert.EndsWith("eu07", resolved);
+    }
+
+    [Fact]
+    public void A_binary_for_the_other_platform_is_reported_as_such()
+    {
+        var files = new InMemoryFileSystem().WithExecutable(TestInstallation.At("eu07"), PortableExecutable);
+        var installation = new TestInstallation(files);
+
+        installation.Executables.Resolve(new SimulatorSettings(), out var problem);
+
+        Assert.Equal(ExeProblem.WrongPlatform, problem);
+    }
+
+    [Fact]
+    public void A_binary_without_the_execute_bit_is_reported_as_such()
+    {
+        var files = new InMemoryFileSystem().WithFile(TestInstallation.At("eu07"), Elf);
+        var installation = new TestInstallation(files);
+
+        installation.Executables.Resolve(new SimulatorSettings(), out var problem);
+
+        Assert.Equal(ExeProblem.NotExecutable, problem);
+    }
+
+    [Fact]
+    public void An_empty_installation_reports_the_canonical_name_as_missing()
+    {
+        var installation = new TestInstallation();
+
+        string resolved = installation.Executables.Resolve(new SimulatorSettings(), out var problem);
+
+        Assert.Equal(ExeProblem.NotFound, problem);
+        Assert.Equal("eu07", resolved);
+    }
+
+    [Fact]
+    public void A_manually_chosen_path_is_used_as_given()
+    {
+        var files = new InMemoryFileSystem().WithExecutable(TestInstallation.At("eu07-custom"), Elf);
+        var installation = new TestInstallation(files);
+        var settings = new SimulatorSettings { SelectExeAutomatically = false, ExecutablePath = "eu07-custom" };
+
+        string resolved = installation.Executables.Resolve(settings, out var problem);
+
+        Assert.Equal("eu07-custom", resolved);
+        Assert.Equal(ExeProblem.None, problem);
+    }
+
+    [Fact]
+    public void Data_files_beside_the_binary_are_never_offered_as_candidates()
+    {
+        var files = new InMemoryFileSystem()
+            .WithFile(TestInstallation.At("eu07.ini"), "width 1280")
+            .WithFile(TestInstallation.At("eu07.log"), "log")
+            .WithExecutable(TestInstallation.At("eu07"), Elf);
+        var installation = new TestInstallation(files);
+
+        Assert.Equal(new[] { "eu07" }, installation.Executables.ListCandidates());
+    }
+}
--- a/StarterNG.Tests/Fakes/FakeEnvironment.cs
+++ b/StarterNG.Tests/Fakes/FakeEnvironment.cs
@@ -0,0 +1,34 @@
+using StarterNG.Application.Abstractions;
+
+namespace StarterNG.Tests.Fakes;
+
+/// <summary>A host machine described inline: platform, home folder, env vars.</summary>
+public sealed class FakeEnvironment : IEnvironment
+{
+    private readonly Dictionary<string, string> _variables = new(StringComparer.Ordinal);
+
+    public bool IsWindows { get; set; }
+
+    public bool IsLinux { get; set; } = true;
+
+    public bool IsMacOS { get; set; }
+
+    public string BaseDirectory { get; set; } = Path.Combine("game");
+
+    public string? GetVariable(string name) => _variables.TryGetValue(name, out var value) ? value : null;
+
+    public FakeEnvironment With(string name, string value)
+    {
+        _variables[name] = value;
+        return this;
+    }
+
+    /// <summary>Switches the fake to Windows, with an APPDATA folder.</summary>
+    public FakeEnvironment AsWindows(string appData = "C:/Users/kolejarz/AppData/Roaming")
+    {
+        IsWindows = true;
+        IsLinux = false;
+        IsMacOS = false;
+        return With("APPDATA", appData);
+    }
+}
--- a/StarterNG.Tests/Fakes/InMemoryFileSystem.cs
+++ b/StarterNG.Tests/Fakes/InMemoryFileSystem.cs
@@ -15,6 +15,7 @@ public sealed class InMemoryFileSystem : IFileSystem
 {
    private readonly Dictionary<string, byte[]> _files = new(StringComparer.OrdinalIgnoreCase);
    private readonly HashSet<string> _directories = new(StringComparer.OrdinalIgnoreCase);
+    private readonly HashSet<string> _executable = new(StringComparer.OrdinalIgnoreCase);

    public DateTime LastWriteTimeUtc { get; set; } = new(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc);

@@ -115,6 +116,16 @@ public sealed class InMemoryFileSystem : IFileSystem

    public DateTime GetLastWriteTimeUtc(string path) => LastWriteTimeUtc;

+    /// <summary>Files added through <see cref="WithExecutable"/> carry the execute bit.</summary>
+    public bool IsExecutable(string path) => _executable.Contains(Normalize(path));
+
+    public InMemoryFileSystem WithExecutable(string path, string contents = "\u007fELF")
+    {
+        WithFile(path, contents);
+        _executable.Add(Normalize(path));
+        return this;
+    }
+
    private byte[] Bytes(string path) =>
        _files.TryGetValue(Normalize(path), out var bytes)
            ? bytes
--- a/StarterNG.Tests/Fakes/TestInstallation.cs
+++ b/StarterNG.Tests/Fakes/TestInstallation.cs
@@ -1,6 +1,7 @@
 using StarterNG.Application;
 using StarterNG.Infrastructure.Adapters;
 using StarterNG.Infrastructure.Sceneries;
+using StarterNG.Infrastructure.Settings;
 using StarterNG.Infrastructure.Vehicles;

 namespace StarterNG.Tests.Fakes;
@@ -28,6 +29,11 @@ public sealed class TestInstallation
        Sceneries = new SceneryRepository(Files, Paths, Log, new SceneryParser(Clock, Random));
        MissingAssets = new MissingAssetScanner(Files, Paths);
        Library = new GameLibrary(Vehicles, Sceneries, MiniTextures, Physics, Log);
+
+        Environment = new FakeEnvironment();
+        SettingsPaths = new SettingsPaths(Environment, Paths);
+        Executables = new ExecutableLocator(Files, Paths, Environment, Log);
+        SettingsStore = new SettingsStore(Files, Clock, Log, SettingsPaths, new SettingsSerializer(), Executables);
    }

    public InMemoryFileSystem Files { get; }
@@ -42,6 +48,10 @@ public sealed class TestInstallation
    public SceneryRepository Sceneries { get; }
    public MissingAssetScanner MissingAssets { get; }
    public GameLibrary Library { get; }
+    public FakeEnvironment Environment { get; }
+    public SettingsPaths SettingsPaths { get; }
+    public ExecutableLocator Executables { get; }
+    public SettingsStore SettingsStore { get; }

    /// <summary>Path of a file inside the fake installation.</summary>
    public static string At(params string[] segments) => Path.Combine(new[] { Root }.Concat(segments).ToArray());
--- a/StarterNG.Tests/InstallationCheckTests.cs
+++ b/StarterNG.Tests/InstallationCheckTests.cs
@@ -12,7 +12,7 @@ public class InstallationCheckTests
        var installation = new TestInstallation();
        var strings = installation.Strings.With("FaultNoDir", "missing {0}");
        var check = new InstallationCheck(installation.Paths, installation.Files, strings,
-                                          installation.Physics, installation.Library);
+                                          installation.Physics, installation.Library, installation.SettingsStore);

        var faults = check.Run();

@@ -35,7 +35,7 @@ public class InstallationCheckTests
        var strings = installation.Strings.With("FaultNoDir", "missing {0}");

        var faults = new InstallationCheck(installation.Paths, files, strings,
-                                           installation.Physics, installation.Library).Run();
+                                           installation.Physics, installation.Library, installation.SettingsStore).Run();

        Assert.DoesNotContain(faults, fault => fault.StartsWith("missing "));
        Assert.DoesNotContain("FaultNoWeights", faults);
--- a/StarterNG.Tests/SettingsStoreTests.cs
+++ b/StarterNG.Tests/SettingsStoreTests.cs
@@ -0,0 +1,131 @@
+using StarterNG.Domain.Settings;
+using StarterNG.Tests.Fakes;
+
+namespace StarterNG.Tests;
+
+public class SettingsStoreTests
+{
+    private const string UserIni = "/home/kolejarz/.config/MaSzyna/eu07.ini";
+
+    private static TestInstallation WithHome(InMemoryFileSystem? files = null)
+    {
+        var installation = new TestInstallation(files);
+        installation.Environment.With("HOME", "/home/kolejarz");
+        return installation;
+    }
+
+    [Fact]
+    public void Settings_are_read_from_the_users_ini()
+    {
+        var installation = WithHome(new InMemoryFileSystem()
+            .WithFile(UserIni, "width 1920\nheight 1080\nfullscreen yes\nlang pl\n"));
+
+        installation.SettingsStore.Load();
+
+        var settings = installation.SettingsStore.Settings;
+        Assert.Equal(1920, settings.Width);
+        Assert.Equal(1080, settings.Height);
+        Assert.True(settings.Fullscreen);
+        Assert.Equal("Polski", settings.Language);
+        Assert.True(settings.LanguageWasSet);
+        Assert.Equal(UserIni, installation.SettingsStore.LoadedFrom);
+    }
+
+    [Fact]
+    public void A_first_run_falls_back_to_the_ini_shipped_with_the_installation()
+    {
+        var installation = WithHome(new InMemoryFileSystem()
+            .WithFile(TestInstallation.At("eu07.ini"), "width 800\n"));
+
+        installation.SettingsStore.Load();
+
+        Assert.Equal(800, installation.SettingsStore.Settings.Width);
+        Assert.Equal(TestInstallation.At("eu07.ini"), installation.SettingsStore.LoadedFrom);
+        // Saving still goes to the user's own file, never back into the installation.
+        Assert.Equal(UserIni, installation.SettingsStore.SavePath);
+    }
+
+    [Fact]
+    public void With_no_ini_at_all_the_defaults_stand()
+    {
+        var installation = WithHome();
+
+        installation.SettingsStore.Load();
+
+        Assert.Equal(1280, installation.SettingsStore.Settings.Width);
+        Assert.False(installation.SettingsStore.Settings.LanguageWasSet);
+    }
+
+    [Fact]
+    public void A_save_round_trips_the_settings()
+    {
+        var installation = WithHome();
+        installation.SettingsStore.Load();
+        installation.SettingsStore.Settings.Width = 2560;
+        installation.SettingsStore.Settings.FieldOfView = 60;
+        installation.SettingsStore.Save();
+
+        var reopened = WithHome(installation.Files);
+        reopened.SettingsStore.Load();
+
+        Assert.Equal(2560, reopened.SettingsStore.Settings.Width);
+        Assert.Equal(60, reopened.SettingsStore.Settings.FieldOfView);
+    }
+
+    [Fact]
+    public void Keys_the_starter_does_not_manage_survive_a_round_trip()
+    {
+        var installation = WithHome(new InMemoryFileSystem()
+            .WithFile(UserIni, "width 1280\nsomethingexotic 42\n"));
+        installation.SettingsStore.Load();
+
+        installation.SettingsStore.Save();
+
+        Assert.Contains("somethingexotic 42", installation.Files.ReadAllText(UserIni));
+    }
+
+    [Fact]
+    public void A_registered_screen_is_asked_for_its_edits_before_a_save()
+    {
+        var installation = WithHome();
+        installation.SettingsStore.Load();
+        installation.SettingsStore.RegisterCapture(new WidthCapture(3840));
+
+        installation.SettingsStore.CaptureAndSave();
+
+        Assert.Equal(3840, installation.SettingsStore.Settings.Width);
+    }
+
+    [Fact]
+    public void An_ini_written_by_someone_else_is_noticed()
+    {
+        var installation = WithHome(new InMemoryFileSystem().WithFile(UserIni, "width 1280\n"));
+        installation.SettingsStore.Load();
+
+        Assert.False(installation.SettingsStore.IsConfigNewerOnDisk());
+
+        installation.Files.LastWriteTimeUtc = installation.Files.LastWriteTimeUtc.AddMinutes(5);
+
+        Assert.True(installation.SettingsStore.IsConfigNewerOnDisk());
+    }
+
+    [Fact]
+    public void On_windows_the_ini_lives_under_appdata()
+    {
+        var installation = new TestInstallation();
+        installation.Environment.AsWindows();
+
+        Assert.Equal(Path.Combine("C:/Users/kolejarz/AppData/Roaming", "MaSzyna", "eu07.ini"),
+                     installation.SettingsPaths.UserConfigPath());
+    }
+
+    /// <summary>Stands in for the settings screen holding an unsaved edit.</summary>
+    private sealed class WidthCapture : StarterNG.Application.ISettingsCapture
+    {
+        private readonly int _width;
+
+        public WidthCapture(int width) => _width = width;
+
+        public void CaptureInto(SimulatorSettings settings) => settings.Width = _width;
+    }
+}
--- a/StarterNG/App.axaml.cs
+++ b/StarterNG/App.axaml.cs
@@ -29,20 +29,20 @@ public partial class App : Avalonia.Application
    {
        AvaloniaXamlLoader.Load(this);

-        Settings.Instance.Load();
+        AppServices.Current.SettingsStore.Load();

        KeyboardConfig.Instance.Load();

        CultureInfo ci = CultureInfo.InstalledUICulture ;

-        var langName = Settings.Instance.LanguageWasSet
-            ? Settings.Instance.Language
+        var langName = AppServices.Current.Settings.LanguageWasSet
+            ? AppServices.Current.Settings.Language
            : ci.Name switch
            {
                "pl-PL" => "Polski",
                _ => "English"
            };
-        Settings.Instance.Language = langName;
+        AppServices.Current.Settings.Language = langName;

        ApplyLanguage(langName);
    }
@@ -51,7 +51,7 @@ public partial class App : Avalonia.Application
    {

        var resolvedName = Loc.Load(langNameOrCode);
-        Settings.Instance.Language = resolvedName;
+        AppServices.Current.Settings.Language = resolvedName;
        ApplyCulture(Loc.CurrentLangCode);
    }

@@ -87,10 +87,10 @@ public partial class App : Avalonia.Application

            desktop.ShutdownRequested += (_, _) =>
            {
-                try { Settings.Instance.CaptureAndSave(); }
+                try { AppServices.Current.SettingsStore.CaptureAndSave(); }
                catch (Exception ex) { Diagnostics.Log("Settings save", ex); }

-                Settings.Instance.DumpMissingVehicleLog();
+                AppServices.Current.MissingVehicleLog.Dump();

                try
                {
--- a/StarterNG/Application/Abstractions/IEnvironment.cs
+++ b/StarterNG/Application/Abstractions/IEnvironment.cs
@@ -0,0 +1,20 @@
+namespace StarterNG.Application.Abstractions;
+
+/// <summary>
+/// The bits of the host machine the starter has to ask about: which operating
+/// system it is on, and where that system keeps per-user configuration.
+/// </summary>
+public interface IEnvironment
+{
+    bool IsWindows { get; }
+
+    bool IsLinux { get; }
+
+    bool IsMacOS { get; }
+
+    /// <summary>An environment variable, or null when it is not set.</summary>
+    string? GetVariable(string name);
+
+    /// <summary>The folder the starter's own executable lives in.</summary>
+    string BaseDirectory { get; }
+}
--- a/StarterNG/Application/Abstractions/IFileSystem.cs
+++ b/StarterNG/Application/Abstractions/IFileSystem.cs
@@ -58,4 +58,10 @@ public interface IFileSystem
    IReadOnlyList<string> GetFilesRecursive(string path, string searchPattern);

    DateTime GetLastWriteTimeUtc(string path);
+
+    /// <summary>
+    /// Whether the file carries an execute bit. Always true on Windows, where
+    /// executability is a property of the file's contents rather than its mode.
+    /// </summary>
+    bool IsExecutable(string path);
 }
--- a/StarterNG/Application/AppServices.cs
+++ b/StarterNG/Application/AppServices.cs
@@ -1,7 +1,9 @@
 using System;
 using StarterNG.Application.Abstractions;
+using StarterNG.Domain.Settings;
 using StarterNG.Infrastructure.Adapters;
 using StarterNG.Infrastructure.Sceneries;
+using StarterNG.Infrastructure.Settings;
 using StarterNG.Infrastructure.Vehicles;
 using StarterNG.Services;

@@ -27,11 +29,12 @@ public sealed class AppServices
 {
    private static AppServices? _current;

-    private AppServices(IGamePaths paths, IFileSystem files, IClock clock)
+    private AppServices(IGamePaths paths, IFileSystem files, IClock clock, IEnvironment environment)
    {
        Paths = paths;
        Files = files;
        Clock = clock;
+        Environment = environment;

        var log = new FileDiagnosticsLog(files, clock, paths);
        Log = log;
@@ -48,6 +51,12 @@ public sealed class AppServices
        LoadWeights = new LoadWeightsRepository(files, paths, log);
        Library = new GameLibrary(Vehicles, Sceneries, MiniTextures, Physics, log);
        State = new AppState();
+
+        var settingsPaths = new SettingsPaths(environment, paths);
+        Executables = new ExecutableLocator(files, paths, environment, log);
+        SettingsStore = new SettingsStore(files, clock, log, settingsPaths, new SettingsSerializer(), Executables);
+        SettingsPaths = settingsPaths;
+        MissingVehicleLog = new MissingVehicleLog(SettingsStore.Settings, MissingAssets, Library, log);
    }

    /// <summary>
@@ -60,12 +69,14 @@ public sealed class AppServices
            "AppServices.Current read before Initialize(); the composition root must be built first.");

    /// <summary>Builds the production graph. Called once, from the entry point.</summary>
-    public static AppServices Initialize(IGamePaths? paths = null, IFileSystem? files = null, IClock? clock = null)
+    public static AppServices Initialize(IGamePaths? paths = null, IFileSystem? files = null, IClock? clock = null,
+                                         IEnvironment? environment = null)
    {
        _current = new AppServices(
            paths ?? GamePaths.ForCurrentDirectory(),
            files ?? new PhysicalFileSystem(),
-            clock ?? new SystemClock());
+            clock ?? new SystemClock(),
+            environment ?? new SystemEnvironment());
        return _current;
    }

@@ -75,6 +86,8 @@ public sealed class AppServices

    public IClock Clock { get; }

+    public IEnvironment Environment { get; }
+
    public IDiagnosticsLog Log { get; }

    public IProcessLauncher Processes { get; }
@@ -103,6 +116,18 @@ public sealed class AppServices
    /// <summary>What the user currently has selected.</summary>
    public AppState State { get; }

+    /// <summary>The settings the starter runs with, and their load/save lifecycle.</summary>
+    public SettingsStore SettingsStore { get; }
+
+    /// <summary>Shorthand for the settings themselves.</summary>
+    public SimulatorSettings Settings => SettingsStore.Settings;
+
+    public ExecutableLocator Executables { get; }
+
+    public SettingsPaths SettingsPaths { get; }
+
+    public MissingVehicleLog MissingVehicleLog { get; }
+
    /// <summary>
    /// Exposed as the concrete service rather than <see cref="ILocalizedStrings"/>
    /// because the XAML binds to it as a change-notifying source; code should take
--- a/StarterNG/Application/MissingVehicleLog.cs
+++ b/StarterNG/Application/MissingVehicleLog.cs
@@ -0,0 +1,49 @@
+using System;
+using StarterNG.Application.Abstractions;
+using StarterNG.Domain.Settings;
+using StarterNG.Infrastructure.Vehicles;
+
+namespace StarterNG.Application;
+
+/// <summary>
+/// Writes the "vehicle files that are not there" report into the diagnostics
+/// log, when the user has asked for it.
+/// </summary>
+/// <remarks>
+/// Was a method on the settings object, which had no business scanning the
+/// installation. The setting decides whether it runs; the scan itself belongs to
+/// the vehicle side.
+/// </remarks>
+public sealed class MissingVehicleLog
+{
+    private readonly SimulatorSettings _settings;
+    private readonly MissingAssetScanner _scanner;
+    private readonly GameLibrary _library;
+    private readonly IDiagnosticsLog _log;
+
+    public MissingVehicleLog(SimulatorSettings settings, MissingAssetScanner scanner, GameLibrary library,
+                             IDiagnosticsLog log)
+    {
+        _settings = settings;
+        _scanner = scanner;
+        _library = library;
+        _log = log;
+    }
+
+    public void Dump()
+    {
+        if (!_settings.LogMissingVehicleFiles)
+            return;
+
+        try
+        {
+            var lines = _scanner.Scan(_library.Vehicles);
+            if (lines.Count > 0)
+                _log.Log(lines);
+        }
+        catch (Exception ex)
+        {
+            _log.Log("Missing vehicle log", ex);
+        }
+    }
+}
--- a/StarterNG/Application/SettingsStore.cs
+++ b/StarterNG/Application/SettingsStore.cs
@@ -0,0 +1,191 @@
+using System;
+using System.IO;
+using System.Text;
+using StarterNG.Application.Abstractions;
+using StarterNG.Classes;
+using StarterNG.Domain.Settings;
+using StarterNG.Infrastructure.Settings;
+
+namespace StarterNG.Application;
+
+/// <summary>
+/// A screen that holds settings the user is editing and can be asked to write
+/// them back into the model before a save.
+/// </summary>
+/// <remarks>
+/// Replaces the mutable <c>Action? CaptureFromUi</c> the settings model used to
+/// expose: the dependency now points the right way, from the store to an
+/// interface the view implements.
+/// </remarks>
+public interface ISettingsCapture
+{
+    void CaptureInto(SimulatorSettings settings);
+}
+
+/// <summary>
+/// Owns the settings the starter runs with: where they were read from, when to
+/// write them back, and which executable they point at.
+/// </summary>
+public sealed class SettingsStore
+{
+    private readonly IFileSystem _files;
+    private readonly IClock _clock;
+    private readonly IDiagnosticsLog _log;
+    private readonly SettingsPaths _paths;
+    private readonly SettingsSerializer _serializer;
+    private readonly ExecutableLocator _executables;
+    private readonly Encoding _encoding;
+
+    private ConfigFile _config = new();
+    private string _savePath = string.Empty;
+    private DateTime _configAgeUtc = DateTime.MinValue;
+    private ISettingsCapture? _capture;
+
+    public SettingsStore(IFileSystem files, IClock clock, IDiagnosticsLog log, SettingsPaths paths,
+                         SettingsSerializer serializer, ExecutableLocator executables)
+    {
+        _files = files;
+        _clock = clock;
+        _log = log;
+        _paths = paths;
+        _serializer = serializer;
+        _executables = executables;
+        _encoding = LegacyEncoding();
+    }
+
+    /// <summary>The settings the application is running with.</summary>
+    public SimulatorSettings Settings { get; } = new();
+
+    /// <summary>The file the current settings were read from.</summary>
+    public string LoadedFrom { get; private set; } = string.Empty;
+
+    /// <summary>The file a save will write to.</summary>
+    public string SavePath => _savePath;
+
+    /// <summary>
+    /// Registers the screen that holds pending edits, so a save can collect them
+    /// first. Called by the settings view when it is created.
+    /// </summary>
+    public void RegisterCapture(ISettingsCapture capture) => _capture = capture;
+
+    /// <summary>
+    /// Reads the user's settings, falling back to the copy shipped with the
+    /// installation on a first run.
+    /// </summary>
+    public void Load()
+    {
+        _savePath = _paths.UserConfigPath();
+        string source = _files.FileExists(_savePath) ? _savePath : _paths.InstallationConfigPath();
+        LoadedFrom = source;
+        LoadFrom(source);
+    }
+
+    public void LoadFrom(string path)
+    {
+        try
+        {
+            _config = _files.FileExists(path)
+                ? ConfigFile.Parse(_files.ReadAllText(path, _encoding))
+                : new ConfigFile();
+        }
+        catch (Exception ex)
+        {
+            // An unreadable ini means defaults, not a failed start.
+            _log.Log($"reading {path}", ex);
+            _config = new ConfigFile();
+        }
+
+        _serializer.Read(Settings, _config);
+        TouchConfigAge();
+    }
+
+    /// <summary>Collects pending edits from the settings screen, then saves.</summary>
+    public void CaptureAndSave()
+    {
+        _capture?.CaptureInto(Settings);
+        Save();
+    }
+
+    public void Save()
+    {
+        if (string.IsNullOrEmpty(_savePath))
+            _savePath = _paths.UserConfigPath();
+
+        SaveTo(_savePath);
+    }
+
+    public void SaveTo(string path)
+    {
+        _serializer.Write(Settings, _config);
+
+        try
+        {
+            string? directory = Path.GetDirectoryName(path);
+            if (!string.IsNullOrEmpty(directory))
+                _files.CreateDirectory(directory);
+
+            _files.WriteAllText(path, _config.ToText(), _encoding);
+            TouchConfigAge();
+        }
+        catch (Exception ex)
+        {
+            _log.Log($"saving {path}", ex);
+        }
+    }
+
+    /// <summary>Records the ini's timestamp, so an outside edit can be noticed.</summary>
+    public void TouchConfigAge()
+    {
+        string path = string.IsNullOrEmpty(_savePath) ? _paths.UserConfigPath() : _savePath;
+        try
+        {
+            _configAgeUtc = _files.FileExists(path) ? _files.GetLastWriteTimeUtc(path) : _clock.UtcNow;
+        }
+        catch (Exception)
+        {
+            _configAgeUtc = _clock.UtcNow;
+        }
+    }
+
+    /// <summary>
+    /// True when something else has written the ini since we last touched it -
+    /// the simulator itself, usually, which the starter must not clobber.
+    /// </summary>
+    public bool IsConfigNewerOnDisk()
+    {
+        string path = string.IsNullOrEmpty(_savePath) ? _paths.UserConfigPath() : _savePath;
+        try
+        {
+            if (!_files.FileExists(path) || _configAgeUtc == DateTime.MinValue)
+                return false;
+
+            // A second of slack: writing our own file must not count as an edit.
+            return _files.GetLastWriteTimeUtc(path) > _configAgeUtc + TimeSpan.FromSeconds(1);
+        }
+        catch (Exception)
+        {
+            return false;
+        }
+    }
+
+    public string ResolveExecutable() => _executables.Resolve(Settings, out _);
+
+    public string ResolveExecutable(out ExeProblem problem) => _executables.Resolve(Settings, out problem);
+
+    /// <summary>
+    /// The .ini keeps its own code page. UTF-8 is a safe fallback if the code
+    /// page provider is unavailable.
+    /// </summary>
+    private static Encoding LegacyEncoding()
+    {
+        try
+        {
+            Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
+            return Encoding.GetEncoding(1250);
+        }
+        catch (Exception)
+        {
+            return Encoding.UTF8;
+        }
+    }
+}
--- a/StarterNG/Classes/Settings.cs
+++ b/StarterNG/Classes/Settings.cs
@@ -1,699 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Globalization;
-using System.IO;
-using System.Linq;
-using System.Text;
-using StarterNG.Application;
-
-namespace StarterNG.Classes;
-
-public enum BatteryDefault { Default = 0, AlwaysOff = 1, AlwaysOn = 2 }
-
-public enum ExeProblem { None, NotFound, NotExecutable, WrongPlatform }
-
-public sealed class Settings
-{
-    public static Settings Instance { get; } = new();
-
-    public Action? CaptureFromUi { get; set; }
-
-    public bool LanguageWasSet { get; private set; }
-
-    public string Language = "English";
-    public bool Fullscreen;
-    public bool PauseWhenInactive = true;
-    public bool PauseOnStart;
-    public int CursorSensitivity = 2;
-    public bool InvertMouseHorizontal;
-    public bool InvertMouseVertical;
-
-    public bool IgnoreGamepad;
-    public int FeedbackMode = 1;
-    public int FeedbackPort = 888;
-    public bool UartEnabled;
-    public string UartPort = "";
-    public string UartTune = "";
-    public bool UartDebug;
-    public bool UartMain, UartScnd, UartTrain, UartLocal, UartRadioVolume, UartRadioChannel;
-
-    public bool SelectExeAutomatically = true;
-    public string ExecutablePath = "eu07.exe";
-    public bool DebugMode;
-    public bool VirtualShunting = true;
-    public bool LogMissingVehicleFiles;
-
-    public int RenderEngine;
-    public int Width = 1280;
-    public int Height = 720;
-    public int BufferScalePercent = 100;
-    public int MaxTextureSize = 4096;
-    public int MaxCabTextureSize = 4096;
-    public int TextureFiltering = 8;
-    public int Multisampling = 2;
-    public int DynamicLights = 7;
-    public double DrawRangeFactor = 3.0;
-    public bool VSync;
-    public bool Smoke = true;
-    public int SmokeFidelity = 1;
-    public bool ChromaticAberration = true;
-    public bool MotionBlur = true;
-    public bool ExtraEffects = true;
-    public bool EnvMap = true;
-    public bool UseVbo = true;
-    public bool RenderShadows = true;
-    public int ReflectionsFramerate = 60;
-    public int ShadowMapResolution = 2048;
-    public int ShadowProjectionRange = 250;
-    public int CabShadowsRange;
-    public int ShadowRankCutoff = 3;
-    public int ReflectionsFidelity;
-    public int FieldOfView = 45;
-    public bool PythonScreens = true;
-    public bool PythonThreadedUpload = true;
-    public bool FpsLimitEnabled;
-    public int FpsLimit = 30;
-    public double ShadowAngleLimit = 0.2;
-    public bool FullscreenWindowed;
-    public bool RenderAngleVulkan;
-
-    public int SplineFidelity = 1;
-    public bool FullPhysics = true;
-    public bool EnableTraction = true;
-    public bool LiveTraction = true;
-    public bool PhysicsLog;
-    public bool DebugLog = true;
-    public bool MultipleLogs;
-    public bool DisplaySimulation = true;
-    public bool CrashDamage = true;
-    public double Friction = 1.0;
-    public double BrakeStep = 1.0;
-    public double BrakeSpeed = 3.0;
-
-    public bool SoundEnabled = true;
-    public int Volume = 50;
-    public int RadioVolume = 75;
-    public int VehiclesVolume = 100;
-    public int PositionalVolume = 100;
-    public int AmbientVolume = 100;
-    public bool SkipPipeline;
-    public int PythonScreenUpdateRate = 200;
-    public bool DebugLogVisible;
-    private int _debugLogExtraBits;
-
-    public bool CompressTextures = true;
-    public bool ScaleSpeculars = true;
-    public bool UseGLES;
-    public bool ShaderGamma;
-    public bool ScreenMipmaps = true;
-    public bool ExtendedModelConversion;
-    public bool GfxResourceMove;
-    public bool GfxResourceSweep = true;
-    public int TrainPhysicsThreads;
-    public bool IgnoreIrrelevantTrains;
-
-    public bool AutoCloseStarter;
-    public bool LargeThumbnails;
-    public bool AutoExpandSceneryTree;
-    public BatteryDefault BatteryDefault = BatteryDefault.Default;
-
-    public bool ShowAiVehicles = true;
-    public bool DrivableOnly = true;
-    public bool ShowArchivalSceneries = true;
-    public bool HideArchivalVehicles = true;
-    public string LastScenery = "";
-
-    /// <summary>
-    /// Starter's own window state, the way the old one kept WindowMaximized in
-    /// starter.ini. Only the maximised flag is remembered - a normal window
-    /// always opens at its design size, centred on the screen.
-    /// </summary>
-    public bool WindowMaximized;
-
-    public static readonly string[] RenderEngines =
-        { "full", "legacy", "simpleshader", "simple", "off", "experimental" };
-
-    public static readonly int[] AnisotropySteps = { 1, 2, 4, 8, 16 };
-
-    private double _mouseScaleYMagnitude = 0.2;
-    private string[] _shadowTuneExtra = { "400", "300" };
-
-    private ConfigFile _config = new();
-    private string _savePath = string.Empty;
-    private DateTime _configAgeUtc = DateTime.MinValue;
-
-    public string LoadedFrom { get; private set; } = string.Empty;
-
-    public string SavePath => _savePath;
-
-    public static string UserConfigPath()
-    {
-        if (OperatingSystem.IsWindows())
-        {
-            string? appData = Environment.GetEnvironmentVariable("APPDATA");
-            if (!string.IsNullOrEmpty(appData))
-                return Path.Combine(appData, "MaSzyna", "eu07.ini");
-        }
-        else if (OperatingSystem.IsMacOS())
-        {
-            string? home = Environment.GetEnvironmentVariable("HOME");
-            if (!string.IsNullOrEmpty(home))
-                return Path.Combine(home, "Library", "Application Support", "MaSzyna", "eu07.ini");
-        }
-        else
-        {
-            string? home = Environment.GetEnvironmentVariable("HOME");
-            if (!string.IsNullOrEmpty(home))
-                return Path.Combine(home, ".config", "MaSzyna", "eu07.ini");
-        }
-
-        return Path.Combine(AppContext.BaseDirectory, "eu07.ini");
-    }
-
-    private static string DefaultConfigPath() =>
-        Path.Combine(Directory.GetCurrentDirectory(), "eu07.ini");
-
-    public static string UserConfigDirectory() =>
-        Path.GetDirectoryName(UserConfigPath()) ?? AppContext.BaseDirectory;
-
-    public string ResolveExecutable() => ResolveExecutable(out _);
-
-    public string ResolveExecutable(out ExeProblem problem)
-    {
-        if (!SelectExeAutomatically && !string.IsNullOrWhiteSpace(ExecutablePath))
-        {
-            problem = ValidateExecutable(FullPath(ExecutablePath));
-            return ExecutablePath;
-        }
-
-        string canonical = OperatingSystem.IsWindows() ? "eu07.exe" : "eu07";
-        string? fallback = null;
-        try
-        {
-            var candidates = Directory.GetFiles(Directory.GetCurrentDirectory(), "eu07*")
-                .Where(IsExecutableCandidate)
-                .OrderBy(p => string.Equals(Path.GetFileName(p), canonical, StringComparison.OrdinalIgnoreCase) ? 0 : 1)
-                .ThenBy(p => Path.GetFileName(p)!.Length);
-
-            foreach (string path in candidates)
-            {
-                if (ValidateExecutable(path) == ExeProblem.None)
-                {
-                    problem = ExeProblem.None;
-                    return path;
-                }
-                fallback ??= path;
-            }
-        }
-        catch (Exception ex)
-        {
-            StarterNG.Infrastructure.Diagnostics.Log("looking for the simulator executable", ex);
-        }
-
-        if (fallback != null)
-        {
-            problem = ValidateExecutable(fallback);
-            return fallback;
-        }
-
-        problem = ExeProblem.NotFound;
-        return canonical;
-    }
-
-    private static string FullPath(string path) =>
-        Path.IsPathRooted(path) ? path : Path.Combine(Directory.GetCurrentDirectory(), path);
-
-    public static ExeProblem ValidateExecutable(string path)
-    {
-        try
-        {
-            if (!File.Exists(path))
-                return ExeProblem.NotFound;
-
-            if (!OperatingSystem.IsWindows())
-            {
-                const UnixFileMode anyExecute =
-                    UnixFileMode.UserExecute | UnixFileMode.GroupExecute | UnixFileMode.OtherExecute;
-                if ((File.GetUnixFileMode(path) & anyExecute) == 0)
-                    return ExeProblem.NotExecutable;
-            }
-
-            byte[] head = new byte[4];
-            using (var fs = File.OpenRead(path))
-            {
-                if (fs.Read(head, 0, 4) == 4)
-                {
-                    bool pe = head[0] == 0x4D && head[1] == 0x5A;
-                    bool elf = head[0] == 0x7F && head[1] == 0x45 && head[2] == 0x4C && head[3] == 0x46;
-                    if (OperatingSystem.IsWindows() && elf)
-                        return ExeProblem.WrongPlatform;
-                    if (OperatingSystem.IsLinux() && pe)
-                        return ExeProblem.WrongPlatform;
-                }
-            }
-
-            return ExeProblem.None;
-        }
-        catch
-        {
-            return ExeProblem.NotFound;
-        }
-    }
-
-    public static List<string> ListCandidateExecutables(string? directory = null)
-    {
-        directory ??= Directory.GetCurrentDirectory();
-        try
-        {
-            return Directory.GetFiles(directory, "eu07*")
-                .Where(IsExecutableCandidate)
-                .OrderByDescending(File.GetLastWriteTimeUtc)
-                .Select(Path.GetFileName)
-                .ToList()!;
-        }
-        catch { return new List<string>(); }
-    }
-
-    private static bool IsExecutableCandidate(string path)
-    {
-        string ext = Path.GetExtension(path).ToLowerInvariant();
-        if (ext is ".ini" or ".log" or ".txt" or ".cfg" or ".config" or ".json"
-                or ".dll" or ".so" or ".dat" or ".bak" or ".csv" or ".xml")
-            return false;
-        if (OperatingSystem.IsWindows())
-            return ext == ".exe";
-        if (OperatingSystem.IsLinux())
-            return ext.Length == 0 || ext is ".x86_64" or ".run" or ".appimage";
-
-        return ext.Length == 0 || ext is ".exe" or ".x86_64" or ".run" or ".appimage";
-    }
-
-    private static readonly Encoding FileEncoding = ResolveEncoding();
-
-    private static Encoding ResolveEncoding()
-    {
-
-        try
-        {
-            Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
-            return Encoding.GetEncoding(1250);
-        }
-        catch
-        {
-            return Encoding.UTF8;
-        }
-    }
-
-    public void Load()
-    {
-        _savePath = UserConfigPath();
-        string source = File.Exists(_savePath) ? _savePath : DefaultConfigPath();
-        LoadedFrom = source;
-        LoadFrom(source);
-    }
-
-    public void CaptureAndSave()
-    {
-        CaptureFromUi?.Invoke();
-        Save();
-    }
-
-    public void LoadFrom(string path)
-    {
-        try
-        {
-            _config = File.Exists(path)
-                ? ConfigFile.Parse(File.ReadAllText(path, FileEncoding))
-                : new ConfigFile();
-        }
-        catch
-        {
-            _config = new ConfigFile();
-        }
-
-        ReadFromConfig();
-        TouchConfigAge();
-    }
-
-    public void Save()
-    {
-        if (string.IsNullOrEmpty(_savePath))
-            _savePath = UserConfigPath();
-
-        SaveTo(_savePath);
-    }
-
-    public void SaveTo(string path)
-    {
-        WriteToConfig();
-
-        try
-        {
-            string? dir = Path.GetDirectoryName(path);
-            if (!string.IsNullOrEmpty(dir))
-                Directory.CreateDirectory(dir);
-            File.WriteAllText(path, _config.ToText(), FileEncoding);
-            TouchConfigAge();
-        }
-        catch (Exception ex)
-        {
-            StarterNG.Infrastructure.Diagnostics.Log($"saving {path}", ex);
-        }
-    }
-
-    public void TouchConfigAge()
-    {
-        string path = string.IsNullOrEmpty(_savePath) ? UserConfigPath() : _savePath;
-        try
-        {
-            _configAgeUtc = File.Exists(path)
-                ? File.GetLastWriteTimeUtc(path)
-                : DateTime.UtcNow;
-        }
-        catch
-        {
-            _configAgeUtc = DateTime.UtcNow;
-        }
-    }
-
-    public bool IsConfigNewerOnDisk()
-    {
-        string path = string.IsNullOrEmpty(_savePath) ? UserConfigPath() : _savePath;
-        try
-        {
-            if (!File.Exists(path) || _configAgeUtc == DateTime.MinValue)
-                return false;
-            return File.GetLastWriteTimeUtc(path) > _configAgeUtc + TimeSpan.FromSeconds(1);
-        }
-        catch
-        {
-            return false;
-        }
-    }
-
-    public void DumpMissingVehicleLog()
-    {
-        if (!LogMissingVehicleFiles) return;
-        try
-        {
-            var lines = AppServices.Current.MissingAssets.Scan(AppServices.Current.Library.Vehicles);
-            if (lines.Count == 0) return;
-            Infrastructure.Diagnostics.Log(lines);
-        }
-        catch (Exception ex)
-        {
-            Infrastructure.Diagnostics.Log("Missing vehicle log", ex);
-        }
-    }
-
-    private void ReadFromConfig()
-    {
-        var c = _config;
-
-        LanguageWasSet = c.Has("lang");
-        Language = c.GetString("lang", "en").ToLowerInvariant() == "pl" ? "Polski" : "English";
-        Fullscreen = c.GetBool("fullscreen", false);
-        PauseWhenInactive = c.GetBool("inactivepause", true);
-        PauseOnStart = c.GetBool("pause", false);
-
-        var mouse = c.GetTokens("mousescale");
-        if (mouse.Length >= 1 && double.TryParse(mouse[0], NumberStyles.Float, CultureInfo.InvariantCulture, out double mx))
-        {
-            InvertMouseHorizontal = mx < 0;
-            CursorSensitivity = Clamp((int)Math.Round(Math.Abs(mx)), 1, 5);
-        }
-        if (mouse.Length >= 2 && double.TryParse(mouse[1], NumberStyles.Float, CultureInfo.InvariantCulture, out double my))
-        {
-            InvertMouseVertical = my < 0;
-            _mouseScaleYMagnitude = Math.Abs(my);
-        }
-
-        IgnoreGamepad = !c.GetBool("input.gamepad", true);
-        FeedbackMode = Clamp(c.GetInt("feedbackmode", 1), 0, 5);
-        FeedbackPort = c.GetInt("feedbackport", 888);
-        UartEnabled = c.Has("uart");
-        UartPort = c.GetString("uart", "");
-        UartTune = c.GetString("uarttune", "");
-        UartDebug = c.GetBool("uartdebug", false);
-        if (c.Has("uartfeature"))
-        {
-            var uartTokens = (c.GetRaw("uartfeature") ?? "").Split('|', StringSplitOptions.RemoveEmptyEntries);
-            var uf = new HashSet<string>(uartTokens, StringComparer.OrdinalIgnoreCase);
-            UartMain = uf.Contains("main"); UartScnd = uf.Contains("scnd"); UartTrain = uf.Contains("train");
-            UartLocal = uf.Contains("local"); UartRadioVolume = uf.Contains("radiovolume"); UartRadioChannel = uf.Contains("radiochannel");
-        }
-        else
-        {
-            UartMain = UartScnd = UartTrain = UartLocal = true;
-            UartRadioVolume = UartRadioChannel = false;
-        }
-
-        SelectExeAutomatically = c.GetBool("starter.exe.auto", true);
-        ExecutablePath = c.GetString("starter.exe.path", "eu07.exe");
-        DebugMode = c.GetBool("debugmode", false);
-        VirtualShunting = c.GetBool("ai.trainman", true);
-        LogMissingVehicleFiles = c.GetBool("starter.logmissingvehicles", false);
-
-        RenderEngine = IndexOf(RenderEngines, c.GetString("gfxrenderer", "full"), 0);
-        Width = c.GetInt("width", 1280);
-        Height = c.GetInt("height", 720);
-        BufferScalePercent = Clamp(c.GetInt("starter.bufferscale", 100), 50, 200);
-        MaxTextureSize = c.GetInt("maxtexturesize", 4096);
-        MaxCabTextureSize = c.GetInt("maxcabtexturesize", 4096);
-        TextureFiltering = c.GetInt("anisotropicfiltering", 8);
-        Multisampling = Clamp(c.GetInt("multisampling", 2), 0, 3);
-        DynamicLights = Clamp(c.GetInt("dynamiclights", 7), 0, 7);
-        DrawRangeFactor = c.GetDouble("gfx.drawrange.factor.max", 3.0);
-        VSync = c.GetBool("vsync", false);
-        Smoke = c.GetBool("gfx.smoke", true);
-        SmokeFidelity = Clamp(c.GetInt("gfx.smoke.fidelity", 1), 1, 4);
-        ChromaticAberration = c.GetBool("gfx.postfx.chromaticaberration.enabled", true);
-        MotionBlur = c.GetBool("gfx.postfx.motionblur.enabled", true);
-        ExtraEffects = c.GetBool("gfx.extraeffects", true);
-        EnvMap = c.GetBool("gfx.envmap.enabled", true);
-        UseVbo = c.GetBool("usevbo", true);
-        RenderShadows = c.GetBool("shadows", true);
-        ReflectionsFramerate = c.GetInt("gfx.reflections.framerate", 60);
-
-        var shadowTune = c.GetTokens("shadowtune");
-        if (shadowTune.Length >= 1) ShadowMapResolution = ParseInt(shadowTune[0], 2048);
-        if (shadowTune.Length >= 2) ShadowProjectionRange = ParseInt(shadowTune[1], 250);
-        if (shadowTune.Length >= 4) _shadowTuneExtra = new[] { shadowTune[2], shadowTune[3] };
-
-        CabShadowsRange = (int)Math.Round(c.GetDouble("gfx.shadows.cab.range", 0));
-        ShadowRankCutoff = c.GetInt("gfx.shadow.rank.cutoff", 3);
-        ReflectionsFidelity = Clamp(c.GetInt("gfx.reflections.fidelity", 0), 0, 2);
-        FieldOfView = Clamp((int)Math.Round(c.GetDouble("fieldofview", 45)), 15, 75);
-        PythonScreens = c.GetBool("python.enabled", true);
-        PythonThreadedUpload = c.GetBool("python.threadedupload", true);
-        FpsLimitEnabled = c.Has("fpslimit");
-        FpsLimit = Clamp(c.GetInt("fpslimit", 30), 1, 100);
-        ShadowAngleLimit = c.GetDouble("gfx.shadow.angle.min", 0.2);
-        FullscreenWindowed = c.GetBool("fullscreenwindowed", false);
-        RenderAngleVulkan = string.Equals(c.GetString("gfx.angleplatform", ""), "vulkan", StringComparison.OrdinalIgnoreCase);
-
-        SplineFidelity = Clamp(c.GetInt("splinefidelity", 1), 1, 4);
-        FullPhysics = c.GetBool("fullphysics", true);
-        EnableTraction = c.GetBool("enabletraction", true);
-        LiveTraction = c.GetBool("livetraction", true);
-        PhysicsLog = c.GetBool("physicslog", false);
-        int debugLog = c.GetInt("debuglog", 3);
-        DebugLog = (debugLog & 1) != 0;
-        DebugLogVisible = (debugLog & 2) != 0;
-        _debugLogExtraBits = debugLog & ~3;
-        MultipleLogs = c.GetBool("multiplelogs", false);
-        DisplaySimulation = !c.GetBool("gfx.skiprendering", false);
-        CrashDamage = c.GetBool("crashdamage", true);
-        Friction = c.GetDouble("friction", 1.0);
-        BrakeStep = c.GetDouble("brakestep", 1.0);
-        BrakeSpeed = c.GetDouble("brakespeed", 3.0);
-
-        SoundEnabled = c.GetBool("soundenabled", true);
-        Volume = Clamp((int)Math.Round(c.GetDouble("sound.volume", 1.0) * 50), 1, 100);
-        RadioVolume = Clamp((int)Math.Round(c.GetDouble("sound.volume.radio", 0.75) * 100), 1, 100);
-        VehiclesVolume = Clamp((int)Math.Round(c.GetDouble("sound.volume.vehicle", 1.0) * 100), 1, 100);
-        PositionalVolume = Clamp((int)Math.Round(c.GetDouble("sound.volume.positional", 1.0) * 100), 1, 100);
-        AmbientVolume = Clamp((int)Math.Round(c.GetDouble("sound.volume.ambient", 1.0) * 100), 1, 100);
-        SkipPipeline = c.GetBool("gfx.skippipeline", false);
-        PythonScreenUpdateRate = c.Has("python.updatetime")
-            ? Clamp(c.GetInt("python.updatetime", 200), 0, 10000)
-            : MapOldPyScreenPriority(c.GetString("pyscreenrendererpriority", "normal"));
-
-        CompressTextures = c.GetBool("compresstex", true);
-        ScaleSpeculars = c.GetBool("scalespeculars", true);
-        UseGLES = c.GetBool("gfx.usegles", false);
-        ShaderGamma = c.GetBool("gfx.shadergamma", false);
-        ScreenMipmaps = c.GetBool("python.mipmaps", true);
-        ExtendedModelConversion = c.GetInt("convertmodels", 0) != 0;
-        GfxResourceMove = c.GetBool("gfx.resource.move", false);
-        GfxResourceSweep = c.GetBool("gfx.resource.sweep", true);
-        TrainPhysicsThreads = Clamp(c.GetInt("async.trainThreads", 0), 0, Environment.ProcessorCount);
-        IgnoreIrrelevantTrains = c.GetBool("starter.ignoreirrelevant", false);
-
-        AutoCloseStarter = c.GetBool("starter.autoclose", false);
-        LargeThumbnails = c.GetBool("starter.largethumbnails", false);
-        AutoExpandSceneryTree = c.GetBool("starter.expandtree", false);
-        BatteryDefault = (BatteryDefault)Clamp(c.GetInt("starter.batterydefault", 0), 0, 2);
-        ShowAiVehicles = c.GetBool("starter.show.ai", true);
-        DrivableOnly = c.GetBool("starter.drivableonly", true);
-        ShowArchivalSceneries = c.GetBool("starter.show.archival", true);
-        HideArchivalVehicles = c.GetBool("starter.hide.archivalvehicles", true);
-        LastScenery = c.GetString("starter.last.scenery", "");
-        WindowMaximized = c.GetBool("starter.window.maximized", false);
-    }
-
-    private static readonly string[] ObsoleteKeys =
-    {
-        "gfx.postfx.tonemapping",
-    };
-
-    private void WriteToConfig()
-    {
-        var c = _config;
-
-        foreach (string key in ObsoleteKeys)
-            c.Remove(key);
-
-        c.Set("lang", Language == "Polski" ? "pl" : "en");
-        c.SetBool("fullscreen", Fullscreen);
-        c.SetBool("inactivepause", PauseWhenInactive);
-        c.SetBool("pause", PauseOnStart);
-
-        double mx = CursorSensitivity * (InvertMouseHorizontal ? -1 : 1);
-        double my = _mouseScaleYMagnitude * (InvertMouseVertical ? -1 : 1);
-        c.Set("mousescale",
-            $"{mx.ToString("0.###", CultureInfo.InvariantCulture)} " +
-            $"{my.ToString("0.###", CultureInfo.InvariantCulture)}");
-
-        c.SetBool("input.gamepad", !IgnoreGamepad);
-        c.SetInt("feedbackmode", FeedbackMode);
-        c.SetInt("feedbackport", FeedbackPort);
-        if (UartEnabled && !string.IsNullOrWhiteSpace(UartPort)) c.Set("uart", UartPort); else c.Remove("uart");
-        c.Set("uarttune", UartTune);
-        c.SetBool("uartdebug", UartDebug);
-        var sb = new StringBuilder();
-        if (UartMain) sb.Append("main|");
-        if (UartScnd) sb.Append("scnd|");
-        if (UartTrain) sb.Append("train|");
-        if (UartLocal) sb.Append("local|");
-        if (UartRadioVolume) sb.Append("radiovolume|");
-        if (UartRadioChannel) sb.Append("radiochannel|");
-        c.Set("uartfeature", sb.ToString());
-
-        c.SetBool("starter.exe.auto", SelectExeAutomatically);
-        c.Set("starter.exe.path", ExecutablePath);
-        c.SetBool("debugmode", DebugMode);
-        c.SetBool("ai.trainman", VirtualShunting);
-        c.SetBool("starter.logmissingvehicles", LogMissingVehicleFiles);
-
-        c.Set("gfxrenderer", RenderEngines[Clamp(RenderEngine, 0, RenderEngines.Length - 1)]);
-        c.SetInt("width", Width);
-        c.SetInt("height", Height);
-        c.SetInt("starter.bufferscale", BufferScalePercent);
-        int fbw = (int)Math.Round(Width * BufferScalePercent / 100.0);
-        int fbh = (int)Math.Round(Height * BufferScalePercent / 100.0);
-        c.SetInt("gfx.framebuffer.width", fbw);
-        c.SetInt("gfx.framebuffer.height", fbh);
-        c.SetInt("maxtexturesize", MaxTextureSize);
-        c.SetInt("maxcabtexturesize", MaxCabTextureSize);
-        c.SetInt("anisotropicfiltering", TextureFiltering);
-        c.SetInt("multisampling", Multisampling);
-        c.SetInt("dynamiclights", DynamicLights);
-        c.SetDouble("gfx.drawrange.factor.max", DrawRangeFactor);
-        c.SetBool("vsync", VSync);
-        c.SetBool("gfx.smoke", Smoke);
-        c.SetInt("gfx.smoke.fidelity", SmokeFidelity);
-        c.SetBool("gfx.postfx.chromaticaberration.enabled", ChromaticAberration);
-        c.SetBool("gfx.postfx.motionblur.enabled", MotionBlur);
-        c.SetBool("gfx.extraeffects", ExtraEffects);
-        c.SetBool("gfx.envmap.enabled", EnvMap);
-        c.SetBool("usevbo", UseVbo);
-        c.SetBool("shadows", RenderShadows);
-        c.SetBool("gfx.shadowmap.enabled", RenderShadows);
-        c.SetInt("gfx.reflections.framerate", ReflectionsFramerate);
-        c.Set("shadowtune",
-            $"{ShadowMapResolution} {ShadowProjectionRange} " +
-            $"{_shadowTuneExtra[0]} {_shadowTuneExtra[1]}");
-        c.SetInt("gfx.shadows.cab.range", CabShadowsRange);
-        c.SetInt("gfx.shadow.rank.cutoff", ShadowRankCutoff);
-        c.SetInt("gfx.reflections.fidelity", ReflectionsFidelity);
-        c.SetInt("fieldofview", FieldOfView);
-        c.SetBool("python.enabled", PythonScreens);
-        c.SetBool("python.threadedupload", PythonThreadedUpload);
-        if (FpsLimitEnabled) c.SetInt("fpslimit", FpsLimit); else c.Remove("fpslimit");
-        c.SetDouble("gfx.shadow.angle.min", ShadowAngleLimit);
-        c.SetBool("fullscreenwindowed", FullscreenWindowed);
-        if (RenderAngleVulkan) c.Set("gfx.angleplatform", "vulkan"); else c.Remove("gfx.angleplatform");
-
-        c.SetInt("splinefidelity", SplineFidelity);
-        c.SetBool("fullphysics", FullPhysics);
-        c.SetBool("enabletraction", EnableTraction);
-        c.SetBool("livetraction", LiveTraction);
-        c.SetBool("physicslog", PhysicsLog);
-        c.SetInt("debuglog",
-            (DebugLog ? 1 : 0) | (DebugLogVisible ? 2 : 0) | _debugLogExtraBits);
-        c.SetBool("multiplelogs", MultipleLogs);
-        c.SetBool("gfx.skiprendering", !DisplaySimulation);
-        c.SetBool("crashdamage", CrashDamage);
-        c.SetDouble("friction", Friction);
-        c.SetDouble("brakestep", BrakeStep);
-        c.SetDouble("brakespeed", BrakeSpeed);
-
-        c.SetBool("soundenabled", SoundEnabled);
-        c.SetDouble("sound.volume", Volume / 50.0);
-        c.SetDouble("sound.volume.radio", RadioVolume / 100.0);
-        c.SetDouble("sound.volume.vehicle", VehiclesVolume / 100.0);
-        c.SetDouble("sound.volume.positional", PositionalVolume / 100.0);
-        c.SetDouble("sound.volume.ambient", AmbientVolume / 100.0);
-        c.SetBool("gfx.skippipeline", SkipPipeline);
-        c.SetInt("python.updatetime", PythonScreenUpdateRate);
-
-        c.SetBool("compresstex", CompressTextures);
-        c.SetBool("scalespeculars", ScaleSpeculars);
-        c.SetBool("gfx.usegles", UseGLES);
-        c.SetBool("gfx.shadergamma", ShaderGamma);
-        c.SetBool("python.mipmaps", ScreenMipmaps);
-        c.Set("convertmodels", ExtendedModelConversion ? "143" : "0");
-        c.SetBool("gfx.resource.move", GfxResourceMove);
-        c.SetBool("gfx.resource.sweep", GfxResourceSweep);
-        c.SetInt("async.trainThreads", TrainPhysicsThreads);
-        c.SetBool("starter.ignoreirrelevant", IgnoreIrrelevantTrains);
-
-        c.SetBool("starter.autoclose", AutoCloseStarter);
-        c.SetBool("starter.largethumbnails", LargeThumbnails);
-        c.SetBool("starter.expandtree", AutoExpandSceneryTree);
-        c.SetInt("starter.batterydefault", (int)BatteryDefault);
-        c.SetBool("starter.show.ai", ShowAiVehicles);
-        c.SetBool("starter.drivableonly", DrivableOnly);
-        c.SetBool("starter.show.archival", ShowArchivalSceneries);
-        c.SetBool("starter.hide.archivalvehicles", HideArchivalVehicles);
-        if (!string.IsNullOrWhiteSpace(LastScenery))
-            c.Set("starter.last.scenery", LastScenery);
-        else
-            c.Remove("starter.last.scenery");
-        c.SetBool("starter.window.maximized", WindowMaximized);
-    }
-
-    private static int Clamp(int v, int lo, int hi) => v < lo ? lo : (v > hi ? hi : v);
-
-    private static int ParseInt(string s, int fallback) =>
-        int.TryParse(s, NumberStyles.Integer, CultureInfo.InvariantCulture, out int n) ? n : fallback;
-
-    private static int IndexOf(string[] values, string token, int fallback)
-    {
-        for (int i = 0; i < values.Length; i++)
-            if (string.Equals(values[i], token, StringComparison.OrdinalIgnoreCase))
-                return i;
-        return fallback;
-    }
-
-    private static int MapOldPyScreenPriority(string priority) =>
-        priority.ToLowerInvariant() switch
-        {
-            "lower" => 400,
-            "lowest" => 800,
-            "idle" => 1600,
-            "off" => 0,
-            _ => 200
-        };
-}
--- a/StarterNG/Classes/SettingsProfileStore.cs
+++ b/StarterNG/Classes/SettingsProfileStore.cs
@@ -2,13 +2,14 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using StarterNG.Application;

 namespace StarterNG.Classes;

 public static class SettingsProfileStore
 {
    public static string DirectoryPath { get; } =
-        Path.Combine(Settings.UserConfigDirectory(), "starter", "profiles");
+        Path.Combine(AppServices.Current.SettingsPaths.UserConfigDirectory(), "starter", "profiles");

    public static IReadOnlyList<string> ListProfiles()
    {
--- a/StarterNG/Domain/Settings/SimulatorSettings.cs
+++ b/StarterNG/Domain/Settings/SimulatorSettings.cs
@@ -0,0 +1,161 @@
+using System;
+
+namespace StarterNG.Domain.Settings;
+
+/// <summary>How the simulator should treat the battery switch when a run starts.</summary>
+public enum BatteryDefault { Default = 0, AlwaysOff = 1, AlwaysOn = 2 }
+
+/// <summary>What is wrong with the executable the starter would launch.</summary>
+public enum ExeProblem { None, NotFound, NotExecutable, WrongPlatform }
+
+/// <summary>
+/// Everything the starter writes into eu07.ini, plus the handful of preferences
+/// it keeps for itself.
+/// </summary>
+/// <remarks>
+/// Plain state with sensible defaults, and nothing else: reading and writing the
+/// ini is <c>Infrastructure.Settings.SettingsSerializer</c>, locating the file
+/// and the executable is the rest of that folder, and the load/save lifecycle is
+/// <c>Application.SettingsStore</c>. Splitting those out is what makes it
+/// possible to test the ini mapping without a disk.
+/// </remarks>
+public sealed class SimulatorSettings
+{
+    /// <summary>
+    /// False until the ini names a language, which is how the first run knows to
+    /// follow the operating system instead.
+    /// </summary>
+    public bool LanguageWasSet { get; internal set; }
+
+    public string Language = "English";
+    public bool Fullscreen;
+    public bool PauseWhenInactive = true;
+    public bool PauseOnStart;
+    public int CursorSensitivity = 2;
+    public bool InvertMouseHorizontal;
+    public bool InvertMouseVertical;
+
+    public bool IgnoreGamepad;
+    public int FeedbackMode = 1;
+    public int FeedbackPort = 888;
+    public bool UartEnabled;
+    public string UartPort = "";
+    public string UartTune = "";
+    public bool UartDebug;
+    public bool UartMain, UartScnd, UartTrain, UartLocal, UartRadioVolume, UartRadioChannel;
+
+    public bool SelectExeAutomatically = true;
+    public string ExecutablePath = "eu07.exe";
+    public bool DebugMode;
+    public bool VirtualShunting = true;
+    public bool LogMissingVehicleFiles;
+
+    public int RenderEngine;
+    public int Width = 1280;
+    public int Height = 720;
+    public int BufferScalePercent = 100;
+    public int MaxTextureSize = 4096;
+    public int MaxCabTextureSize = 4096;
+    public int TextureFiltering = 8;
+    public int Multisampling = 2;
+    public int DynamicLights = 7;
+    public double DrawRangeFactor = 3.0;
+    public bool VSync;
+    public bool Smoke = true;
+    public int SmokeFidelity = 1;
+    public bool ChromaticAberration = true;
+    public bool MotionBlur = true;
+    public bool ExtraEffects = true;
+    public bool EnvMap = true;
+    public bool UseVbo = true;
+    public bool RenderShadows = true;
+    public int ReflectionsFramerate = 60;
+    public int ShadowMapResolution = 2048;
+    public int ShadowProjectionRange = 250;
+    public int CabShadowsRange;
+    public int ShadowRankCutoff = 3;
+    public int ReflectionsFidelity;
+    public int FieldOfView = 45;
+    public bool PythonScreens = true;
+    public bool PythonThreadedUpload = true;
+    public bool FpsLimitEnabled;
+    public int FpsLimit = 30;
+    public double ShadowAngleLimit = 0.2;
+    public bool FullscreenWindowed;
+    public bool RenderAngleVulkan;
+
+    public int SplineFidelity = 1;
+    public bool FullPhysics = true;
+    public bool EnableTraction = true;
+    public bool LiveTraction = true;
+    public bool PhysicsLog;
+    public bool DebugLog = true;
+    public bool MultipleLogs;
+    public bool DisplaySimulation = true;
+    public bool CrashDamage = true;
+    public double Friction = 1.0;
+    public double BrakeStep = 1.0;
+    public double BrakeSpeed = 3.0;
+
+    public bool SoundEnabled = true;
+    public int Volume = 50;
+    public int RadioVolume = 75;
+    public int VehiclesVolume = 100;
+    public int PositionalVolume = 100;
+    public int AmbientVolume = 100;
+    public bool SkipPipeline;
+    public int PythonScreenUpdateRate = 200;
+    public bool DebugLogVisible;
+    /// <summary>
+    /// Debug log bits beyond the two the UI exposes, carried through a round trip
+    /// so a hand-configured log level is not silently narrowed.
+    /// </summary>
+    internal int DebugLogExtraBits { get; set; }
+
+    public bool CompressTextures = true;
+    public bool ScaleSpeculars = true;
+    public bool UseGLES;
+    public bool ShaderGamma;
+    public bool ScreenMipmaps = true;
+    public bool ExtendedModelConversion;
+    public bool GfxResourceMove;
+    public bool GfxResourceSweep = true;
+    public int TrainPhysicsThreads;
+    public bool IgnoreIrrelevantTrains;
+
+    public bool AutoCloseStarter;
+    public bool LargeThumbnails;
+    public bool AutoExpandSceneryTree;
+    public BatteryDefault BatteryDefault = BatteryDefault.Default;
+
+    public bool ShowAiVehicles = true;
+    public bool DrivableOnly = true;
+    public bool ShowArchivalSceneries = true;
+    public bool HideArchivalVehicles = true;
+    public string LastScenery = "";
+
+    /// <summary>
+    /// Starter's own window state, the way the old one kept WindowMaximized in
+    /// starter.ini. Only the maximised flag is remembered - a normal window
+    /// always opens at its design size, centred on the screen.
+    /// </summary>
+    public bool WindowMaximized;
+
+    public static readonly string[] RenderEngines =
+        { "full", "legacy", "simpleshader", "simple", "off", "experimental" };
+
+    public static readonly int[] AnisotropySteps = { 1, 2, 4, 8, 16 };
+
+    /// <summary>
+    /// Vertical mouse scale as the ini stored it. The UI only exposes one
+    /// sensitivity, so the authored vertical magnitude is carried through a
+    /// round trip rather than being overwritten.
+    /// </summary>
+    internal double MouseScaleYMagnitude { get; set; } = 0.2;
+
+    /// <summary>
+    /// Shadow tuning values beyond the two the UI edits, carried through a round
+    /// trip unchanged.
+    /// </summary>
+    internal string[] ShadowTuneExtra { get; set; } = { "400", "300" };
+}
--- a/StarterNG/Infrastructure/Adapters/PhysicalFileSystem.cs
+++ b/StarterNG/Infrastructure/Adapters/PhysicalFileSystem.cs
@@ -52,4 +52,14 @@ public sealed class PhysicalFileSystem : IFileSystem
        Directory.Exists(path) ? Directory.GetDirectories(path) : Array.Empty<string>();

    public DateTime GetLastWriteTimeUtc(string path) => File.GetLastWriteTimeUtc(path);
+
+    public bool IsExecutable(string path)
+    {
+        if (OperatingSystem.IsWindows())
+            return true;
+
+        const UnixFileMode anyExecute =
+            UnixFileMode.UserExecute | UnixFileMode.GroupExecute | UnixFileMode.OtherExecute;
+        return (File.GetUnixFileMode(path) & anyExecute) != 0;
+    }
 }
--- a/StarterNG/Infrastructure/Adapters/SystemEnvironment.cs
+++ b/StarterNG/Infrastructure/Adapters/SystemEnvironment.cs
@@ -0,0 +1,18 @@
+using System;
+using StarterNG.Application.Abstractions;
+
+namespace StarterNG.Infrastructure.Adapters;
+
+/// <summary><see cref="IEnvironment"/> backed by the running process.</summary>
+public sealed class SystemEnvironment : IEnvironment
+{
+    public bool IsWindows => OperatingSystem.IsWindows();
+
+    public bool IsLinux => OperatingSystem.IsLinux();
+
+    public bool IsMacOS => OperatingSystem.IsMacOS();
+
+    public string? GetVariable(string name) => Environment.GetEnvironmentVariable(name);
+
+    public string BaseDirectory => AppContext.BaseDirectory;
+}
--- a/StarterNG/Infrastructure/Diagnostics.cs
+++ b/StarterNG/Infrastructure/Diagnostics.cs
@@ -72,6 +72,7 @@ public static class Diagnostics
                AppServices.Current.Files,
                AppServices.Current.Localization,
                AppServices.Current.Physics,
-                AppServices.Current.Library)
+                AppServices.Current.Library,
+                AppServices.Current.SettingsStore)
            .Run();
 }
--- a/StarterNG/Infrastructure/InstallationCheck.cs
+++ b/StarterNG/Infrastructure/InstallationCheck.cs
@@ -3,6 +3,7 @@ using System.IO;
 using StarterNG.Application.Abstractions;
 using StarterNG.Classes;
 using StarterNG.Application;
+using StarterNG.Domain.Settings;

 namespace StarterNG.Infrastructure;

@@ -23,15 +24,17 @@ public sealed class InstallationCheck
    private readonly ILocalizedStrings _strings;
    private readonly IPhysicsRepository _physics;
    private readonly GameLibrary _library;
+    private readonly SettingsStore _settings;

    public InstallationCheck(IGamePaths paths, IFileSystem files, ILocalizedStrings strings,
-                             IPhysicsRepository physics, GameLibrary library)
+                             IPhysicsRepository physics, GameLibrary library, SettingsStore settings)
    {
        _paths = paths;
        _files = files;
        _strings = strings;
        _physics = physics;
        _library = library;
+        _settings = settings;
    }

    public List<string> Run()
@@ -54,7 +57,8 @@ public sealed class InstallationCheck
        if (_physics.IndexedCount == 0)
            faults.Add(_strings["FaultNoPhysics"]);

-        if (Settings.Instance.ResolveExecutable(out var problem) is var _ && problem == ExeProblem.NotFound)
+        _settings.ResolveExecutable(out var problem);
+        if (problem == ExeProblem.NotFound)
            faults.Add(_strings["FaultNoExe"]);

        return faults;
--- a/StarterNG/Infrastructure/Settings/ExecutableLocator.cs
+++ b/StarterNG/Infrastructure/Settings/ExecutableLocator.cs
@@ -0,0 +1,166 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using StarterNG.Application.Abstractions;
+using StarterNG.Domain.Settings;
+
+namespace StarterNG.Infrastructure.Settings;
+
+/// <summary>
+/// Finds and vets the simulator executable the starter will launch.
+/// </summary>
+/// <remarks>
+/// Installations ship the binary under several names (eu07.exe, eu07,
+/// eu07-vulkan, ...), and a folder shared between platforms may hold both a PE
+/// and an ELF build. So a candidate is not just found by name: it is checked for
+/// the execute bit and for a magic number matching the platform we are on.
+/// </remarks>
+public sealed class ExecutableLocator
+{
+    /// <summary>Extensions that are never the simulator, whatever they are named.</summary>
+    private static readonly string[] NeverExecutable =
+    {
+        ".ini", ".log", ".txt", ".cfg", ".config", ".json", ".dll", ".so", ".dat", ".bak", ".csv", ".xml"
+    };
+
+    private readonly IFileSystem _files;
+    private readonly IGamePaths _paths;
+    private readonly IEnvironment _environment;
+    private readonly IDiagnosticsLog _log;
+
+    public ExecutableLocator(IFileSystem files, IGamePaths paths, IEnvironment environment, IDiagnosticsLog log)
+    {
+        _files = files;
+        _paths = paths;
+        _environment = environment;
+        _log = log;
+    }
+
+    /// <summary>The canonical name for the platform, used when nothing is found.</summary>
+    public string CanonicalName => _environment.IsWindows ? "eu07.exe" : "eu07";
+
+    /// <summary>
+    /// The executable to launch for these settings, along with what is wrong with
+    /// it. A path is always returned so the UI can show what it was looking for.
+    /// </summary>
+    public string Resolve(SimulatorSettings settings, out ExeProblem problem)
+    {
+        if (!settings.SelectExeAutomatically && !string.IsNullOrWhiteSpace(settings.ExecutablePath))
+        {
+            problem = Validate(FullPath(settings.ExecutablePath));
+            return settings.ExecutablePath;
+        }
+
+        string? fallback = null;
+        try
+        {
+            // Prefer the canonical name, then the shortest: "eu07" over "eu07-dev".
+            var candidates = _files.GetFiles(_paths.Root, "eu07*")
+                .Where(IsCandidate)
+                .OrderBy(path => string.Equals(Path.GetFileName(path), CanonicalName,
+                                               StringComparison.OrdinalIgnoreCase) ? 0 : 1)
+                .ThenBy(path => Path.GetFileName(path).Length);
+
+            foreach (string path in candidates)
+            {
+                if (Validate(path) == ExeProblem.None)
+                {
+                    problem = ExeProblem.None;
+                    return path;
+                }
+                fallback ??= path;
+            }
+        }
+        catch (Exception ex)
+        {
+            _log.Log("looking for the simulator executable", ex);
+        }
+
+        if (fallback is not null)
+        {
+            problem = Validate(fallback);
+            return fallback;
+        }
+
+        problem = ExeProblem.NotFound;
+        return CanonicalName;
+    }
+
+    /// <summary>Executables the user can pick from, most recently built first.</summary>
+    public List<string> ListCandidates(string? directory = null)
+    {
+        try
+        {
+            return _files.GetFiles(directory ?? _paths.Root, "eu07*")
+                .Where(IsCandidate)
+                .OrderByDescending(_files.GetLastWriteTimeUtc)
+                .Select(Path.GetFileName)
+                .ToList()!;
+        }
+        catch (Exception)
+        {
+            return new List<string>();
+        }
+    }
+
+    public ExeProblem Validate(string path)
+    {
+        try
+        {
+            if (!_files.FileExists(path))
+                return ExeProblem.NotFound;
+
+            if (!_environment.IsWindows && !_files.IsExecutable(path))
+                return ExeProblem.NotExecutable;
+
+            return MatchesPlatform(path) ? ExeProblem.None : ExeProblem.WrongPlatform;
+        }
+        catch (Exception)
+        {
+            return ExeProblem.NotFound;
+        }
+    }
+
+    /// <summary>
+    /// Reads the file's magic number: "MZ" for a Windows binary, 0x7F "ELF" for a
+    /// Linux one. A file we cannot read four bytes from is given the benefit of
+    /// the doubt.
+    /// </summary>
+    private bool MatchesPlatform(string path)
+    {
+        byte[] head = new byte[4];
+        using var stream = _files.OpenRead(path);
+        if (stream.Read(head, 0, 4) != 4)
+            return true;
+
+        bool portableExecutable = head[0] == 0x4D && head[1] == 0x5A;
+        bool elf = head[0] == 0x7F && head[1] == 0x45 && head[2] == 0x4C && head[3] == 0x46;
+
+        if (_environment.IsWindows && elf)
+            return false;
+        if (_environment.IsLinux && portableExecutable)
+            return false;
+
+        return true;
+    }
+
+    private bool IsCandidate(string path)
+    {
+        string extension = Path.GetExtension(path).ToLowerInvariant();
+
+        if (NeverExecutable.Contains(extension))
+            return false;
+
+        if (_environment.IsWindows)
+            return extension == ".exe";
+
+        if (_environment.IsLinux)
+            return extension.Length == 0 || extension is ".x86_64" or ".run" or ".appimage";
+
+        return extension.Length == 0 || extension is ".exe" or ".x86_64" or ".run" or ".appimage";
+    }
+
+    private string FullPath(string path) =>
+        Path.IsPathRooted(path) ? path : Path.Combine(_paths.Root, path);
+}
--- a/StarterNG/Infrastructure/Settings/SettingsPaths.cs
+++ b/StarterNG/Infrastructure/Settings/SettingsPaths.cs
@@ -0,0 +1,54 @@
+using System.IO;
+using StarterNG.Application.Abstractions;
+
+namespace StarterNG.Infrastructure.Settings;
+
+/// <summary>
+/// Where the simulator's eu07.ini lives: per user on each platform, with the
+/// installation's own copy as the template for a first run.
+/// </summary>
+public sealed class SettingsPaths
+{
+    private const string ConfigFileName = "eu07.ini";
+    private const string VendorFolder = "MaSzyna";
+
+    private readonly IEnvironment _environment;
+    private readonly IGamePaths _paths;
+
+    public SettingsPaths(IEnvironment environment, IGamePaths paths)
+    {
+        _environment = environment;
+        _paths = paths;
+    }
+
+    /// <summary>The user's own settings file, which is what the starter writes.</summary>
+    public string UserConfigPath()
+    {
+        if (_environment.IsWindows)
+        {
+            string? appData = _environment.GetVariable("APPDATA");
+            if (!string.IsNullOrEmpty(appData))
+                return Path.Combine(appData, VendorFolder, ConfigFileName);
+        }
+        else if (_environment.IsMacOS)
+        {
+            string? home = _environment.GetVariable("HOME");
+            if (!string.IsNullOrEmpty(home))
+                return Path.Combine(home, "Library", "Application Support", VendorFolder, ConfigFileName);
+        }
+        else
+        {
+            string? home = _environment.GetVariable("HOME");
+            if (!string.IsNullOrEmpty(home))
+                return Path.Combine(home, ".config", VendorFolder, ConfigFileName);
+        }
+
+        return Path.Combine(_environment.BaseDirectory, ConfigFileName);
+    }
+
+    /// <summary>The ini shipped with the installation, read when the user has none.</summary>
+    public string InstallationConfigPath() => _paths.FromRoot(ConfigFileName);
+
+    public string UserConfigDirectory() =>
+        Path.GetDirectoryName(UserConfigPath()) ?? _environment.BaseDirectory;
+}
--- a/StarterNG/Infrastructure/Settings/SettingsSerializer.cs
+++ b/StarterNG/Infrastructure/Settings/SettingsSerializer.cs
@@ -0,0 +1,310 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Text;
+using StarterNG.Classes;
+using StarterNG.Domain.Settings;
+
+namespace StarterNG.Infrastructure.Settings;
+
+/// <summary>
+/// Maps <see cref="SimulatorSettings"/> onto the simulator's eu07.ini and back.
+/// </summary>
+/// <remarks>
+/// Every key the starter understands is named exactly once, here. Reads clamp
+/// and default so a hand-edited ini cannot put the UI into an impossible state,
+/// and writes preserve the keys the starter does not manage - which is why a
+/// round trip through this class is worth testing on its own.
+/// </remarks>
+public sealed class SettingsSerializer
+{
+    public void Read(SimulatorSettings s, ConfigFile c)
+    {
+
+        s.LanguageWasSet = c.Has("lang");
+        s.Language = c.GetString("lang", "en").ToLowerInvariant() == "pl" ? "Polski" : "English";
+        s.Fullscreen = c.GetBool("fullscreen", false);
+        s.PauseWhenInactive = c.GetBool("inactivepause", true);
+        s.PauseOnStart = c.GetBool("pause", false);
+
+        var mouse = c.GetTokens("mousescale");
+        if (mouse.Length >= 1 && double.TryParse(mouse[0], NumberStyles.Float, CultureInfo.InvariantCulture, out double mx))
+        {
+            s.InvertMouseHorizontal = mx < 0;
+            s.CursorSensitivity = Clamp((int)Math.Round(Math.Abs(mx)), 1, 5);
+        }
+        if (mouse.Length >= 2 && double.TryParse(mouse[1], NumberStyles.Float, CultureInfo.InvariantCulture, out double my))
+        {
+            s.InvertMouseVertical = my < 0;
+            s.MouseScaleYMagnitude = Math.Abs(my);
+        }
+
+        s.IgnoreGamepad = !c.GetBool("input.gamepad", true);
+        s.FeedbackMode = Clamp(c.GetInt("feedbackmode", 1), 0, 5);
+        s.FeedbackPort = c.GetInt("feedbackport", 888);
+        s.UartEnabled = c.Has("uart");
+        s.UartPort = c.GetString("uart", "");
+        s.UartTune = c.GetString("uarttune", "");
+        s.UartDebug = c.GetBool("uartdebug", false);
+        if (c.Has("uartfeature"))
+        {
+            var uartTokens = (c.GetRaw("uartfeature") ?? "").Split('|', StringSplitOptions.RemoveEmptyEntries);
+            var uf = new HashSet<string>(uartTokens, StringComparer.OrdinalIgnoreCase);
+            s.UartMain = uf.Contains("main"); s.UartScnd = uf.Contains("scnd"); s.UartTrain = uf.Contains("train");
+            s.UartLocal = uf.Contains("local"); s.UartRadioVolume = uf.Contains("radiovolume"); s.UartRadioChannel = uf.Contains("radiochannel");
+        }
+        else
+        {
+            s.UartMain = s.UartScnd = s.UartTrain = s.UartLocal = true;
+            s.UartRadioVolume = s.UartRadioChannel = false;
+        }
+
+        s.SelectExeAutomatically = c.GetBool("starter.exe.auto", true);
+        s.ExecutablePath = c.GetString("starter.exe.path", "eu07.exe");
+        s.DebugMode = c.GetBool("debugmode", false);
+        s.VirtualShunting = c.GetBool("ai.trainman", true);
+        s.LogMissingVehicleFiles = c.GetBool("starter.logmissingvehicles", false);
+
+        s.RenderEngine = IndexOf(SimulatorSettings.RenderEngines, c.GetString("gfxrenderer", "full"), 0);
+        s.Width = c.GetInt("width", 1280);
+        s.Height = c.GetInt("height", 720);
+        s.BufferScalePercent = Clamp(c.GetInt("starter.bufferscale", 100), 50, 200);
+        s.MaxTextureSize = c.GetInt("maxtexturesize", 4096);
+        s.MaxCabTextureSize = c.GetInt("maxcabtexturesize", 4096);
+        s.TextureFiltering = c.GetInt("anisotropicfiltering", 8);
+        s.Multisampling = Clamp(c.GetInt("multisampling", 2), 0, 3);
+        s.DynamicLights = Clamp(c.GetInt("dynamiclights", 7), 0, 7);
+        s.DrawRangeFactor = c.GetDouble("gfx.drawrange.factor.max", 3.0);
+        s.VSync = c.GetBool("vsync", false);
+        s.Smoke = c.GetBool("gfx.smoke", true);
+        s.SmokeFidelity = Clamp(c.GetInt("gfx.smoke.fidelity", 1), 1, 4);
+        s.ChromaticAberration = c.GetBool("gfx.postfx.chromaticaberration.enabled", true);
+        s.MotionBlur = c.GetBool("gfx.postfx.motionblur.enabled", true);
+        s.ExtraEffects = c.GetBool("gfx.extraeffects", true);
+        s.EnvMap = c.GetBool("gfx.envmap.enabled", true);
+        s.UseVbo = c.GetBool("usevbo", true);
+        s.RenderShadows = c.GetBool("shadows", true);
+        s.ReflectionsFramerate = c.GetInt("gfx.reflections.framerate", 60);
+
+        var shadowTune = c.GetTokens("shadowtune");
+        if (shadowTune.Length >= 1) s.ShadowMapResolution = ParseInt(shadowTune[0], 2048);
+        if (shadowTune.Length >= 2) s.ShadowProjectionRange = ParseInt(shadowTune[1], 250);
+        if (shadowTune.Length >= 4) s.ShadowTuneExtra = new[] { shadowTune[2], shadowTune[3] };
+
+        s.CabShadowsRange = (int)Math.Round(c.GetDouble("gfx.shadows.cab.range", 0));
+        s.ShadowRankCutoff = c.GetInt("gfx.shadow.rank.cutoff", 3);
+        s.ReflectionsFidelity = Clamp(c.GetInt("gfx.reflections.fidelity", 0), 0, 2);
+        s.FieldOfView = Clamp((int)Math.Round(c.GetDouble("fieldofview", 45)), 15, 75);
+        s.PythonScreens = c.GetBool("python.enabled", true);
+        s.PythonThreadedUpload = c.GetBool("python.threadedupload", true);
+        s.FpsLimitEnabled = c.Has("fpslimit");
+        s.FpsLimit = Clamp(c.GetInt("fpslimit", 30), 1, 100);
+        s.ShadowAngleLimit = c.GetDouble("gfx.shadow.angle.min", 0.2);
+        s.FullscreenWindowed = c.GetBool("fullscreenwindowed", false);
+        s.RenderAngleVulkan = string.Equals(c.GetString("gfx.angleplatform", ""), "vulkan", StringComparison.OrdinalIgnoreCase);
+
+        s.SplineFidelity = Clamp(c.GetInt("splinefidelity", 1), 1, 4);
+        s.FullPhysics = c.GetBool("fullphysics", true);
+        s.EnableTraction = c.GetBool("enabletraction", true);
+        s.LiveTraction = c.GetBool("livetraction", true);
+        s.PhysicsLog = c.GetBool("physicslog", false);
+        int debugLog = c.GetInt("debuglog", 3);
+        s.DebugLog = (debugLog & 1) != 0;
+        s.DebugLogVisible = (debugLog & 2) != 0;
+        s.DebugLogExtraBits = debugLog & ~3;
+        s.MultipleLogs = c.GetBool("multiplelogs", false);
+        s.DisplaySimulation = !c.GetBool("gfx.skiprendering", false);
+        s.CrashDamage = c.GetBool("crashdamage", true);
+        s.Friction = c.GetDouble("friction", 1.0);
+        s.BrakeStep = c.GetDouble("brakestep", 1.0);
+        s.BrakeSpeed = c.GetDouble("brakespeed", 3.0);
+
+        s.SoundEnabled = c.GetBool("soundenabled", true);
+        s.Volume = Clamp((int)Math.Round(c.GetDouble("sound.volume", 1.0) * 50), 1, 100);
+        s.RadioVolume = Clamp((int)Math.Round(c.GetDouble("sound.volume.radio", 0.75) * 100), 1, 100);
+        s.VehiclesVolume = Clamp((int)Math.Round(c.GetDouble("sound.volume.vehicle", 1.0) * 100), 1, 100);
+        s.PositionalVolume = Clamp((int)Math.Round(c.GetDouble("sound.volume.positional", 1.0) * 100), 1, 100);
+        s.AmbientVolume = Clamp((int)Math.Round(c.GetDouble("sound.volume.ambient", 1.0) * 100), 1, 100);
+        s.SkipPipeline = c.GetBool("gfx.skippipeline", false);
+        s.PythonScreenUpdateRate = c.Has("python.updatetime")
+            ? Clamp(c.GetInt("python.updatetime", 200), 0, 10000)
+            : MapOldPyScreenPriority(c.GetString("pyscreenrendererpriority", "normal"));
+
+        s.CompressTextures = c.GetBool("compresstex", true);
+        s.ScaleSpeculars = c.GetBool("scalespeculars", true);
+        s.UseGLES = c.GetBool("gfx.usegles", false);
+        s.ShaderGamma = c.GetBool("gfx.shadergamma", false);
+        s.ScreenMipmaps = c.GetBool("python.mipmaps", true);
+        s.ExtendedModelConversion = c.GetInt("convertmodels", 0) != 0;
+        s.GfxResourceMove = c.GetBool("gfx.resource.move", false);
+        s.GfxResourceSweep = c.GetBool("gfx.resource.sweep", true);
+        s.TrainPhysicsThreads = Clamp(c.GetInt("async.trainThreads", 0), 0, Environment.ProcessorCount);
+        s.IgnoreIrrelevantTrains = c.GetBool("starter.ignoreirrelevant", false);
+
+        s.AutoCloseStarter = c.GetBool("starter.autoclose", false);
+        s.LargeThumbnails = c.GetBool("starter.largethumbnails", false);
+        s.AutoExpandSceneryTree = c.GetBool("starter.expandtree", false);
+        s.BatteryDefault = (BatteryDefault)Clamp(c.GetInt("starter.batterydefault", 0), 0, 2);
+        s.ShowAiVehicles = c.GetBool("starter.show.ai", true);
+        s.DrivableOnly = c.GetBool("starter.drivableonly", true);
+        s.ShowArchivalSceneries = c.GetBool("starter.show.archival", true);
+        s.HideArchivalVehicles = c.GetBool("starter.hide.archivalvehicles", true);
+        s.LastScenery = c.GetString("starter.last.scenery", "");
+        s.WindowMaximized = c.GetBool("starter.window.maximized", false);
+    }
+
+    private static readonly string[] ObsoleteKeys =
+    {
+        "gfx.postfx.tonemapping",
+    };
+
+    public void Write(SimulatorSettings s, ConfigFile c)
+    {
+
+        foreach (string key in ObsoleteKeys)
+            c.Remove(key);
+
+        c.Set("lang", s.Language == "Polski" ? "pl" : "en");
+        c.SetBool("fullscreen", s.Fullscreen);
+        c.SetBool("inactivepause", s.PauseWhenInactive);
+        c.SetBool("pause", s.PauseOnStart);
+
+        double mx = s.CursorSensitivity * (s.InvertMouseHorizontal ? -1 : 1);
+        double my = s.MouseScaleYMagnitude * (s.InvertMouseVertical ? -1 : 1);
+        c.Set("mousescale",
+            $"{mx.ToString("0.###", CultureInfo.InvariantCulture)} " +
+            $"{my.ToString("0.###", CultureInfo.InvariantCulture)}");
+
+        c.SetBool("input.gamepad", !s.IgnoreGamepad);
+        c.SetInt("feedbackmode", s.FeedbackMode);
+        c.SetInt("feedbackport", s.FeedbackPort);
+        if (s.UartEnabled && !string.IsNullOrWhiteSpace(s.UartPort)) c.Set("uart", s.UartPort); else c.Remove("uart");
+        c.Set("uarttune", s.UartTune);
+        c.SetBool("uartdebug", s.UartDebug);
+        var sb = new StringBuilder();
+        if (s.UartMain) sb.Append("main|");
+        if (s.UartScnd) sb.Append("scnd|");
+        if (s.UartTrain) sb.Append("train|");
+        if (s.UartLocal) sb.Append("local|");
+        if (s.UartRadioVolume) sb.Append("radiovolume|");
+        if (s.UartRadioChannel) sb.Append("radiochannel|");
+        c.Set("uartfeature", sb.ToString());
+
+        c.SetBool("starter.exe.auto", s.SelectExeAutomatically);
+        c.Set("starter.exe.path", s.ExecutablePath);
+        c.SetBool("debugmode", s.DebugMode);
+        c.SetBool("ai.trainman", s.VirtualShunting);
+        c.SetBool("starter.logmissingvehicles", s.LogMissingVehicleFiles);
+
+        c.Set("gfxrenderer", SimulatorSettings.RenderEngines[Clamp(s.RenderEngine, 0, SimulatorSettings.RenderEngines.Length - 1)]);
+        c.SetInt("width", s.Width);
+        c.SetInt("height", s.Height);
+        c.SetInt("starter.bufferscale", s.BufferScalePercent);
+        int fbw = (int)Math.Round(s.Width * s.BufferScalePercent / 100.0);
+        int fbh = (int)Math.Round(s.Height * s.BufferScalePercent / 100.0);
+        c.SetInt("gfx.framebuffer.width", fbw);
+        c.SetInt("gfx.framebuffer.height", fbh);
+        c.SetInt("maxtexturesize", s.MaxTextureSize);
+        c.SetInt("maxcabtexturesize", s.MaxCabTextureSize);
+        c.SetInt("anisotropicfiltering", s.TextureFiltering);
+        c.SetInt("multisampling", s.Multisampling);
+        c.SetInt("dynamiclights", s.DynamicLights);
+        c.SetDouble("gfx.drawrange.factor.max", s.DrawRangeFactor);
+        c.SetBool("vsync", s.VSync);
+        c.SetBool("gfx.smoke", s.Smoke);
+        c.SetInt("gfx.smoke.fidelity", s.SmokeFidelity);
+        c.SetBool("gfx.postfx.chromaticaberration.enabled", s.ChromaticAberration);
+        c.SetBool("gfx.postfx.motionblur.enabled", s.MotionBlur);
+        c.SetBool("gfx.extraeffects", s.ExtraEffects);
+        c.SetBool("gfx.envmap.enabled", s.EnvMap);
+        c.SetBool("usevbo", s.UseVbo);
+        c.SetBool("shadows", s.RenderShadows);
+        c.SetBool("gfx.shadowmap.enabled", s.RenderShadows);
+        c.SetInt("gfx.reflections.framerate", s.ReflectionsFramerate);
+        c.Set("shadowtune",
+            $"{s.ShadowMapResolution} {s.ShadowProjectionRange} " +
+            $"{s.ShadowTuneExtra[0]} {s.ShadowTuneExtra[1]}");
+        c.SetInt("gfx.shadows.cab.range", s.CabShadowsRange);
+        c.SetInt("gfx.shadow.rank.cutoff", s.ShadowRankCutoff);
+        c.SetInt("gfx.reflections.fidelity", s.ReflectionsFidelity);
+        c.SetInt("fieldofview", s.FieldOfView);
+        c.SetBool("python.enabled", s.PythonScreens);
+        c.SetBool("python.threadedupload", s.PythonThreadedUpload);
+        if (s.FpsLimitEnabled) c.SetInt("fpslimit", s.FpsLimit); else c.Remove("fpslimit");
+        c.SetDouble("gfx.shadow.angle.min", s.ShadowAngleLimit);
+        c.SetBool("fullscreenwindowed", s.FullscreenWindowed);
+        if (s.RenderAngleVulkan) c.Set("gfx.angleplatform", "vulkan"); else c.Remove("gfx.angleplatform");
+
+        c.SetInt("splinefidelity", s.SplineFidelity);
+        c.SetBool("fullphysics", s.FullPhysics);
+        c.SetBool("enabletraction", s.EnableTraction);
+        c.SetBool("livetraction", s.LiveTraction);
+        c.SetBool("physicslog", s.PhysicsLog);
+        c.SetInt("debuglog",
+            (s.DebugLog ? 1 : 0) | (s.DebugLogVisible ? 2 : 0) | s.DebugLogExtraBits);
+        c.SetBool("multiplelogs", s.MultipleLogs);
+        c.SetBool("gfx.skiprendering", !s.DisplaySimulation);
+        c.SetBool("crashdamage", s.CrashDamage);
+        c.SetDouble("friction", s.Friction);
+        c.SetDouble("brakestep", s.BrakeStep);
+        c.SetDouble("brakespeed", s.BrakeSpeed);
+
+        c.SetBool("soundenabled", s.SoundEnabled);
+        c.SetDouble("sound.volume", s.Volume / 50.0);
+        c.SetDouble("sound.volume.radio", s.RadioVolume / 100.0);
+        c.SetDouble("sound.volume.vehicle", s.VehiclesVolume / 100.0);
+        c.SetDouble("sound.volume.positional", s.PositionalVolume / 100.0);
+        c.SetDouble("sound.volume.ambient", s.AmbientVolume / 100.0);
+        c.SetBool("gfx.skippipeline", s.SkipPipeline);
+        c.SetInt("python.updatetime", s.PythonScreenUpdateRate);
+
+        c.SetBool("compresstex", s.CompressTextures);
+        c.SetBool("scalespeculars", s.ScaleSpeculars);
+        c.SetBool("gfx.usegles", s.UseGLES);
+        c.SetBool("gfx.shadergamma", s.ShaderGamma);
+        c.SetBool("python.mipmaps", s.ScreenMipmaps);
+        c.Set("convertmodels", s.ExtendedModelConversion ? "143" : "0");
+        c.SetBool("gfx.resource.move", s.GfxResourceMove);
+        c.SetBool("gfx.resource.sweep", s.GfxResourceSweep);
+        c.SetInt("async.trainThreads", s.TrainPhysicsThreads);
+        c.SetBool("starter.ignoreirrelevant", s.IgnoreIrrelevantTrains);
+
+        c.SetBool("starter.autoclose", s.AutoCloseStarter);
+        c.SetBool("starter.largethumbnails", s.LargeThumbnails);
+        c.SetBool("starter.expandtree", s.AutoExpandSceneryTree);
+        c.SetInt("starter.batterydefault", (int)s.BatteryDefault);
+        c.SetBool("starter.show.ai", s.ShowAiVehicles);
+        c.SetBool("starter.drivableonly", s.DrivableOnly);
+        c.SetBool("starter.show.archival", s.ShowArchivalSceneries);
+        c.SetBool("starter.hide.archivalvehicles", s.HideArchivalVehicles);
+        if (!string.IsNullOrWhiteSpace(s.LastScenery))
+            c.Set("starter.last.scenery", s.LastScenery);
+        else
+            c.Remove("starter.last.scenery");
+        c.SetBool("starter.window.maximized", s.WindowMaximized);
+    }
+
+    private static int Clamp(int v, int lo, int hi) => v < lo ? lo : (v > hi ? hi : v);
+
+    private static int ParseInt(string s, int fallback) =>
+        int.TryParse(s, NumberStyles.Integer, CultureInfo.InvariantCulture, out int n) ? n : fallback;
+
+    private static int IndexOf(string[] values, string token, int fallback)
+    {
+        for (int i = 0; i < values.Length; i++)
+            if (string.Equals(values[i], token, StringComparison.OrdinalIgnoreCase))
+                return i;
+        return fallback;
+    }
+
+    private static int MapOldPyScreenPriority(string priority) =>
+        priority.ToLowerInvariant() switch
+        {
+            "lower" => 400,
+            "lowest" => 800,
+            "idle" => 1600,
+            "off" => 0,
+            _ => 200
+        };
+}
--- a/StarterNG/MainWindow.axaml.cs
+++ b/StarterNG/MainWindow.axaml.cs
@@ -16,9 +16,9 @@ using StarterNG.Domain;
 using StarterNG.Infrastructure;
 using StarterNG.Services;
 using StarterNG.Views;
-using SettingsModel = StarterNG.Classes.Settings;
 using StarterNG.Application;
 using StarterNG.Domain.Sceneries;
+using StarterNG.Domain.Settings;

 namespace StarterNG;

@@ -37,13 +37,13 @@ public partial class MainWindow : Window
        ExtendClientAreaToDecorationsHint = true;
        ExtendClientAreaTitleBarHeightHint = TitleBarHeight;

-        if (SettingsModel.Instance.WindowMaximized)
+        if (AppServices.Current.Settings.WindowMaximized)
            WindowState = WindowState.Maximized;

        PropertyChanged += (_, e) =>
        {
            if (e.Property == WindowStateProperty && WindowState != WindowState.Minimized)
-                SettingsModel.Instance.WindowMaximized = WindowState == WindowState.Maximized;
+                AppServices.Current.Settings.WindowMaximized = WindowState == WindowState.Maximized;
        };

        if (OperatingSystem.IsWindows())
@@ -429,7 +429,7 @@ public partial class MainWindow : Window

        if (trainset.Vehicles.Count > 0)
        {
-            trainset.Velocity = SettingsModel.Instance.BatteryDefault switch
+            trainset.Velocity = AppServices.Current.Settings.BatteryDefault switch
            {
                BatteryDefault.AlwaysOff => 0f,
                BatteryDefault.AlwaysOn  => MathF.Abs(trainset.OriginalVelocity) < 0.01f ? 0.1f : trainset.OriginalVelocity,
@@ -452,7 +452,7 @@ public partial class MainWindow : Window
        string exportPath = Path.Combine(dir, exportName);
        try
        {
-            File.WriteAllText(exportPath, scenery.BuildExportContent(SettingsModel.Instance.IgnoreIrrelevantTrains, AppServices.Current.Random), Encoding.GetEncoding(1250));
+            File.WriteAllText(exportPath, scenery.BuildExportContent(AppServices.Current.Settings.IgnoreIrrelevantTrains, AppServices.Current.Random), Encoding.GetEncoding(1250));
        }
        catch (Exception ex)
        {
@@ -461,9 +461,9 @@ public partial class MainWindow : Window
        }

        if (saveSettings)
-            SettingsModel.Instance.CaptureAndSave();
+            AppServices.Current.SettingsStore.CaptureAndSave();

-        string exe = Path.GetFullPath(SettingsModel.Instance.ResolveExecutable(out var exeProblem));
+        string exe = Path.GetFullPath(AppServices.Current.SettingsStore.ResolveExecutable(out var exeProblem));
        if (exeProblem != ExeProblem.None)
        {
            await ShowExeProblem(exeProblem, exe);
@@ -488,7 +488,7 @@ public partial class MainWindow : Window
            return;
        }

-        if (SettingsModel.Instance.AutoCloseStarter)
+        if (AppServices.Current.Settings.AutoCloseStarter)
        {
            Close();
            return;
@@ -525,7 +525,7 @@ public partial class MainWindow : Window
    {
        if (sim is null)
        {
-            string name = Path.GetFileNameWithoutExtension(SettingsModel.Instance.ResolveExecutable());
+            string name = Path.GetFileNameWithoutExtension(AppServices.Current.SettingsStore.ResolveExecutable());
            sim = Process.GetProcessesByName(name).FirstOrDefault();
        }

@@ -555,7 +555,7 @@ public partial class MainWindow : Window
    {
        if ((DateTime.UtcNow - _openedUtc).TotalSeconds < 3)
            return;
-        if (!SettingsModel.Instance.IsConfigNewerOnDisk())
+        if (!AppServices.Current.SettingsStore.IsConfigNewerOnDisk())
            return;

        var result = await MessageBox.Show(
@@ -565,11 +565,11 @@ public partial class MainWindow : Window
            MessageBoxButtons.YesNo);
        if (result)
        {
-            SettingsModel.Instance.Load();
+            AppServices.Current.SettingsStore.Load();
            SettingsView?.ReloadFromSettings();
        }
        else
-            SettingsModel.Instance.TouchConfigAge();
+            AppServices.Current.SettingsStore.TouchConfigAge();
    }

    private void RestoreFromSimulator()
--- a/StarterNG/Views/AdvancedSettingsWindow.cs
+++ b/StarterNG/Views/AdvancedSettingsWindow.cs
@@ -4,7 +4,7 @@ using Avalonia.Controls.Primitives;
 using Avalonia.Layout;
 using Avalonia.Media;
 using StarterNG.Infrastructure;
-using SettingsModel = StarterNG.Classes.Settings;
+using StarterNG.Application;

 namespace StarterNG.Views;

@@ -156,7 +156,7 @@ public sealed class AdvancedSettingsWindow : Window

    private void Load()
    {
-        var s = SettingsModel.Instance;
+        var s = AppServices.Current.Settings;
        _compressTex.IsChecked = s.CompressTextures;
        _mipmaps.IsChecked = s.ScreenMipmaps;
        _scaleSpeculars.IsChecked = s.ScaleSpeculars;
@@ -172,7 +172,7 @@ public sealed class AdvancedSettingsWindow : Window

    private void Store()
    {
-        var s = SettingsModel.Instance;
+        var s = AppServices.Current.Settings;
        s.CompressTextures = _compressTex.IsChecked == true;
        s.ScreenMipmaps = _mipmaps.IsChecked == true;
        s.ScaleSpeculars = _scaleSpeculars.IsChecked == true;
--- a/StarterNG/Views/Depot.axaml.cs
+++ b/StarterNG/Views/Depot.axaml.cs
@@ -91,7 +91,7 @@ public partial class Depot : UserControl

        Dispatcher.UIThread.Post(() =>
        {
-            hideArchivalCheck.IsChecked = StarterNG.Classes.Settings.Instance.HideArchivalVehicles;
+            hideArchivalCheck.IsChecked = AppServices.Current.Settings.HideArchivalVehicles;
            _browser.InitClassComboTemplates();
            _browser.PopulateCategoryCombo();
            PopulateSceneryConsists();
@@ -232,8 +232,8 @@ public partial class Depot : UserControl
    private void ConsistFilter_OnChanged(object? sender, Avalonia.Interactivity.RoutedEventArgs e)
    {
        if (_suppress) return;
-        StarterNG.Classes.Settings.Instance.ShowAiVehicles = depotShowAiCheck.IsChecked == true;
-        StarterNG.Classes.Settings.Instance.DrivableOnly = depotDrivableOnlyCheck.IsChecked == true;
+        AppServices.Current.Settings.ShowAiVehicles = depotShowAiCheck.IsChecked == true;
+        AppServices.Current.Settings.DrivableOnly = depotDrivableOnlyCheck.IsChecked == true;
        PopulateSceneryConsists();
    }

@@ -242,8 +242,8 @@ public partial class Depot : UserControl
        _suppress = true;
        sceneryConsistList.Items.Clear();

-        depotShowAiCheck.IsChecked = StarterNG.Classes.Settings.Instance.ShowAiVehicles;
-        depotDrivableOnlyCheck.IsChecked = StarterNG.Classes.Settings.Instance.DrivableOnly;
+        depotShowAiCheck.IsChecked = AppServices.Current.Settings.ShowAiVehicles;
+        depotDrivableOnlyCheck.IsChecked = AppServices.Current.Settings.DrivableOnly;

        _listScenery = AppServices.Current.State.CurrentScenery ?? _sceneries.FirstOrDefault();
        sceneryConsistsTab.Header = App.Loc["SceneryConsists"];
@@ -252,8 +252,8 @@ public partial class Depot : UserControl

        if (_listScenery != null)
        {
-            bool showAi = StarterNG.Classes.Settings.Instance.ShowAiVehicles;
-            bool drivableOnly = StarterNG.Classes.Settings.Instance.DrivableOnly;
+            bool showAi = AppServices.Current.Settings.ShowAiVehicles;
+            bool drivableOnly = AppServices.Current.Settings.DrivableOnly;

            foreach (var trainset in _listScenery.Trainsets)
            {
--- a/StarterNG/Views/Depot/VehicleBrowser.cs
+++ b/StarterNG/Views/Depot/VehicleBrowser.cs
@@ -16,6 +16,7 @@ using StarterNG.Classes;
 using StarterNG.Domain;
 using StarterNG.Domain.Sceneries;
 using StarterNG.Domain.Vehicles;
+using StarterNG.Application;

 namespace StarterNG.Views;

@@ -35,7 +36,7 @@ public sealed class VehicleBrowser

    public void SyncHideArchival()
    {
-        bool hideArchival = Classes.Settings.Instance.HideArchivalVehicles;
+        bool hideArchival = AppServices.Current.Settings.HideArchivalVehicles;
        if (hideArchivalCheck.IsChecked == hideArchival)
            return;

@@ -246,7 +247,7 @@ public sealed class VehicleBrowser
        _db.Textures
            .Where(t => category == null || category(VehicleInfo.CategoryOf(t)))
            .Where(t => !_db.IsSetFollower(t))
-            .Where(t => !StarterNG.Classes.Settings.Instance.HideArchivalVehicles || !t.ResolvedArchived)
+            .Where(t => !AppServices.Current.Settings.HideArchivalVehicles || !t.ResolvedArchived)
            .Select(VehicleInfo.ClassOf)
            .Where(s => !string.IsNullOrEmpty(s))
            .Distinct(StringComparer.OrdinalIgnoreCase)
@@ -469,7 +470,7 @@ public sealed class VehicleBrowser
        if (_db.IsSetFollower(t))
            return false;

-        if (StarterNG.Classes.Settings.Instance.HideArchivalVehicles && t.ResolvedArchived)
+        if (AppServices.Current.Settings.HideArchivalVehicles && t.ResolvedArchived)
            return false;

        if (hasSearch && !Matches(t, search))
@@ -515,8 +516,8 @@ public sealed class VehicleBrowser
    public void HideArchivalCheck_OnChanged(object? sender, Avalonia.Interactivity.RoutedEventArgs e)
    {
        if (_suppress) return;
-        StarterNG.Classes.Settings.Instance.HideArchivalVehicles = hideArchivalCheck.IsChecked ?? true;
-        StarterNG.Classes.Settings.Instance.Save();
+        AppServices.Current.Settings.HideArchivalVehicles = hideArchivalCheck.IsChecked ?? true;
+        AppServices.Current.SettingsStore.Save();
        Rebuild();
    }

--- a/StarterNG/Views/Depot/VehicleCardStyle.cs
+++ b/StarterNG/Views/Depot/VehicleCardStyle.cs
@@ -1,4 +1,5 @@
 using Avalonia.Media;
+using StarterNG.Application;

 namespace StarterNG.Views;

@@ -14,5 +15,5 @@ public static class VehicleCardStyle
    public static readonly IBrush Placeholder = new SolidColorBrush(Color.Parse("#22808080"));

    public static int ThumbHeight =>
-        Classes.Settings.Instance.LargeThumbnails ? 68 : 34;
+        AppServices.Current.Settings.LargeThumbnails ? 68 : 34;
 }
--- a/StarterNG/Views/Scenarios.axaml.cs
+++ b/StarterNG/Views/Scenarios.axaml.cs
@@ -41,7 +41,7 @@ public partial class Scenarios : UserControl
        Sceneries = AppServices.Current.Library.Sceneries;

        _loadingFilters = true;
-        archivalSwitch.IsChecked = !StarterNG.Classes.Settings.Instance.ShowArchivalSceneries;
+        archivalSwitch.IsChecked = !AppServices.Current.Settings.ShowArchivalSceneries;
        _loadingFilters = false;

        BuildSceneryTree();
@@ -75,7 +75,7 @@ public partial class Scenarios : UserControl
            if (scenery.Archival && !showArchival)
                continue;

-            bool expand = StarterNG.Classes.Settings.Instance.AutoExpandSceneryTree;
+            bool expand = AppServices.Current.Settings.AutoExpandSceneryTree;
            AppServices.Current.SceneryTexts.LoadFor(scenery, App.Loc.CurrentLangCode);
            string label = scenery.DisplayName;

@@ -123,7 +123,7 @@ public partial class Scenarios : UserControl

    private void RestoreLastScenery()
    {
-        string last = StarterNG.Classes.Settings.Instance.LastScenery;
+        string last = AppServices.Current.Settings.LastScenery;
        string want = Path.GetFileNameWithoutExtension(last);

        TreeViewItem? MatchLeaf(TreeViewItem node)
@@ -193,10 +193,10 @@ public partial class Scenarios : UserControl
    {

        string name = scenery.DisplayName;
-        if (string.Equals(StarterNG.Classes.Settings.Instance.LastScenery, name, StringComparison.OrdinalIgnoreCase))
+        if (string.Equals(AppServices.Current.Settings.LastScenery, name, StringComparison.OrdinalIgnoreCase))
            return;
-        StarterNG.Classes.Settings.Instance.LastScenery = name;
-        StarterNG.Classes.Settings.Instance.Save();
+        AppServices.Current.Settings.LastScenery = name;
+        AppServices.Current.SettingsStore.Save();
    }

    private static string TrainsetListLabel(Trainset trainset) =>
@@ -215,8 +215,8 @@ public partial class Scenarios : UserControl
    {
        vehicleList.Items.Clear();

-        bool showAi = StarterNG.Classes.Settings.Instance.ShowAiVehicles;
-        bool drivableOnly = StarterNG.Classes.Settings.Instance.DrivableOnly;
+        bool showAi = AppServices.Current.Settings.ShowAiVehicles;
+        bool drivableOnly = AppServices.Current.Settings.DrivableOnly;

        for (int i = 0; i < scn.Trainsets.Count; i++)
        {
@@ -250,8 +250,8 @@ public partial class Scenarios : UserControl
    {
        if (_loadingFilters) return;

-        StarterNG.Classes.Settings.Instance.ShowArchivalSceneries = archivalSwitch.IsChecked != true;
-        StarterNG.Classes.Settings.Instance.Save();
+        AppServices.Current.Settings.ShowArchivalSceneries = archivalSwitch.IsChecked != true;
+        AppServices.Current.SettingsStore.Save();

        BuildSceneryTree();
        RestoreLastScenery();
@@ -405,7 +405,7 @@ public partial class Scenarios : UserControl
        BuildSceneryTree();
        if (!string.IsNullOrEmpty(selected))
        {
-            StarterNG.Classes.Settings.Instance.LastScenery =
+            AppServices.Current.Settings.LastScenery =
                Path.GetFileNameWithoutExtension(selected);
            RestoreLastScenery();
        }
@@ -428,7 +428,7 @@ public partial class Scenarios : UserControl
            BuildSceneryTree();
            if (!string.IsNullOrEmpty(selected))
            {
-                StarterNG.Classes.Settings.Instance.LastScenery =
+                AppServices.Current.Settings.LastScenery =
                    Path.GetFileNameWithoutExtension(selected);
            }
            RestoreLastScenery();
@@ -895,7 +895,7 @@ public partial class Scenarios : UserControl
            string miniName = db.MiniForSkin(train.SkinFile) ?? train.SkinFile;
            if (!AppServices.Current.MiniTextures.Has(miniName) && AppServices.Current.MiniTextures.Has(train.SkinFile))
                miniName = train.SkinFile;
-            int thumbH = StarterNG.Classes.Settings.Instance.LargeThumbnails ? 64 : 32;
+            int thumbH = AppServices.Current.Settings.LargeThumbnails ? 64 : 32;

            var bmp = LoadMini(miniName, thumbH);
            Control visual = bmp is not null
--- a/StarterNG/Views/Settings.axaml.cs
+++ b/StarterNG/Views/Settings.axaml.cs
@@ -19,10 +19,12 @@ using StarterNG.Infrastructure;
 using StarterNG.Services;

 using KeyBinding = StarterNG.Classes.KeyBinding;
+using StarterNG.Domain.Settings;
+using StarterNG.Application;

 namespace StarterNG.Views;

-public partial class Settings : UserControl
+public partial class Settings : UserControl, ISettingsCapture
 {
    private bool _loading;

@@ -33,14 +35,14 @@ public partial class Settings : UserControl
    public event Action? ThumbnailSizeChanged;

    /// <summary>Thumbnail size the other tabs were last drawn at.</summary>
-    private bool _drawnThumbs = StarterNG.Classes.Settings.Instance.LargeThumbnails;
+    private bool _drawnThumbs = AppServices.Current.Settings.LargeThumbnails;

    public Settings()
    {
        InitializeComponent();

-        SettingsPathText.Text = StarterNG.Classes.Settings.Instance.LoadedFrom;
-        ToolTip.SetTip(SettingsPathText, StarterNG.Classes.Settings.Instance.LoadedFrom);
+        SettingsPathText.Text = AppServices.Current.SettingsStore.LoadedFrom;
+        ToolTip.SetTip(SettingsPathText, AppServices.Current.SettingsStore.LoadedFrom);

        this.AttachedToVisualTree += (_, _) =>
        {
@@ -60,7 +62,7 @@ public partial class Settings : UserControl
        FeedbackCb.SelectionChanged += FeedbackCb_OnSelectionChanged;
        FpsLimitEnableCb.IsCheckedChanged += (_, _) => FpsLimitSlider.IsEnabled = IsChecked(FpsLimitEnableCb);

-        StarterNG.Classes.Settings.Instance.CaptureFromUi = ReadFromUi;
+        AppServices.Current.SettingsStore.RegisterCapture(this);

        PopulateProfileCombo();
        ApplyToUi();
@@ -111,7 +113,7 @@ public partial class Settings : UserControl
            return;
        string path = SettingsProfileStore.PathFor(name);
        if (!File.Exists(path)) return;
-        StarterNG.Classes.Settings.Instance.LoadFrom(path);
+        AppServices.Current.SettingsStore.LoadFrom(path);
        ApplyToUi();
        RedrawThumbnailsIfNeeded();
    }
@@ -129,8 +131,8 @@ public partial class Settings : UserControl
        void Commit()
        {
            if (string.IsNullOrWhiteSpace(nameBox.Text)) return;
-            ReadFromUi();
-            StarterNG.Classes.Settings.Instance.SaveTo(SettingsProfileStore.PathFor(nameBox.Text));
+            CaptureInto(AppServices.Current.Settings);
+            AppServices.Current.SettingsStore.SaveTo(SettingsProfileStore.PathFor(nameBox.Text));
            PopulateProfileCombo();
            int idx = FindComboIndexByContent(ProfileCb, nameBox.Text.Trim());
            if (idx >= 0) ProfileCb.SelectedIndex = idx;
@@ -147,7 +149,7 @@ public partial class Settings : UserControl
        string? current = (SelectExeCb.SelectedItem as ComboBoxItem)?.Content?.ToString();
        SelectExeCb.Items.Clear();
        SelectExeCb.Items.Add(new ComboBoxItem { Content = App.Loc["SelectEXEAuto"] });
-        foreach (string exe in StarterNG.Classes.Settings.ListCandidateExecutables())
+        foreach (string exe in AppServices.Current.Executables.ListCandidates())
            SelectExeCb.Items.Add(new ComboBoxItem { Content = exe });
        if (current is not null)
        {
@@ -160,7 +162,7 @@ public partial class Settings : UserControl

    private void ApplyToUi()
    {
-        var s = StarterNG.Classes.Settings.Instance;
+        var s = AppServices.Current.Settings;
        _loading = true;
        try
        {
@@ -268,9 +270,12 @@ public partial class Settings : UserControl
        UpdateQualityCaptions();
    }

-    private void ReadFromUi()
+    /// <summary>
+    /// Writes the pending edits on this screen into the settings, so a save from
+    /// anywhere in the application picks them up.
+    /// </summary>
+    public void CaptureInto(SimulatorSettings s)
    {
-        var s = StarterNG.Classes.Settings.Instance;

        s.Language = (ChangeLanguageCb.SelectedItem as ComboBoxItem)?.Content?.ToString()
                     ?? App.Loc.CurrentLanguage;
@@ -297,8 +302,8 @@ public partial class Settings : UserControl
        s.BufferScalePercent = (int)bufferScale.Value;
        s.MaxTextureSize = 1 << (int)textureResolutionSlider.Value;
        s.MaxCabTextureSize = 1 << (int)cabTextureResolutionSlider.Value;
-        s.TextureFiltering = StarterNG.Classes.Settings.AnisotropySteps[
-            Clamp((int)TexFilteringSlider.Value - 1, 0, StarterNG.Classes.Settings.AnisotropySteps.Length - 1)];
+        s.TextureFiltering = SimulatorSettings.AnisotropySteps[
+            Clamp((int)TexFilteringSlider.Value - 1, 0, SimulatorSettings.AnisotropySteps.Length - 1)];
        s.Multisampling = Clamp((int)MultisamplingSlider.Value - 1, 0, 3);
        s.DynamicLights = (int)DynamicLightsSlider.Value;
        s.DrawRangeFactor = RenderRangeSlider.Value;
@@ -363,8 +368,8 @@ public partial class Settings : UserControl

    private void SaveButton_OnClick(object? sender, RoutedEventArgs e)
    {
-        ReadFromUi();
-        StarterNG.Classes.Settings.Instance.Save();
+        CaptureInto(AppServices.Current.Settings);
+        AppServices.Current.SettingsStore.Save();
        KeyboardConfig.Instance.Save();
        RedrawThumbnailsIfNeeded();
        _dirty = false;
@@ -375,7 +380,7 @@ public partial class Settings : UserControl

    private void RedrawThumbnailsIfNeeded()
    {
-        bool large = StarterNG.Classes.Settings.Instance.LargeThumbnails;
+        bool large = AppServices.Current.Settings.LargeThumbnails;
        if (large == _drawnThumbs)
            return;

@@ -385,7 +390,7 @@ public partial class Settings : UserControl

    private void ResetButton_OnClick(object? sender, RoutedEventArgs e)
    {
-        StarterNG.Classes.Settings.Instance.Load();
+        AppServices.Current.SettingsStore.Load();
        ApplyToUi();
        RedrawThumbnailsIfNeeded();
        CancelCapture();
@@ -413,7 +418,7 @@ public partial class Settings : UserControl
        ResolutionCb.SelectedItem = added;
    }

-    private void ReadResolution(Classes.Settings s)
+    private void ReadResolution(SimulatorSettings s)
    {
        var text = (ResolutionCb.SelectedItem as ComboBoxItem)?.Content?.ToString();
        if (string.IsNullOrEmpty(text))
@@ -688,7 +693,7 @@ public partial class Settings : UserControl

    private static int AnisotropyToSlider(int anisotropy)
    {
-        var steps = StarterNG.Classes.Settings.AnisotropySteps;
+        var steps = SimulatorSettings.AnisotropySteps;
        for (int i = 0; i < steps.Length; i++)
            if (steps[i] == anisotropy)
                return i + 1;
--- a/StarterNG/Views/UartWindow.cs
+++ b/StarterNG/Views/UartWindow.cs
@@ -2,7 +2,7 @@ using Avalonia.Controls;
 using Avalonia.Controls.Primitives;
 using Avalonia.Layout;
 using Avalonia.Media;
-using SettingsModel = StarterNG.Classes.Settings;
+using StarterNG.Application;

 namespace StarterNG.Views;

@@ -99,7 +99,7 @@ public sealed class UartWindow : Window

    private void Load()
    {
-        var s = SettingsModel.Instance;
+        var s = AppServices.Current.Settings;
        _enabled.IsChecked = s.UartEnabled;
        _port.Text = s.UartPort;
        _tune.Text = s.UartTune;
@@ -114,7 +114,7 @@ public sealed class UartWindow : Window

    private void Store()
    {
-        var s = SettingsModel.Instance;
+        var s = AppServices.Current.Settings;
        s.UartEnabled = _enabled.IsChecked == true;
        s.UartPort = _port.Text ?? "";
        s.UartTune = _tune.Text ?? "";