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.

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());
+    }
+}

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);
+    }
+}

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

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());

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);

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;
+    }
+}