Move rolling stock and physics into the domain

VehicleDatabase becomes VehicleCatalog, Physics becomes VehiclePhysics, and the
textures.txt and .fiz parsers move to Infrastructure. GameLibrary replaces the
GameData singleton.

StarterNG.Tests/Fakes/InMemoryFileSystem.cs

@@ -92,6 +92,17 @@ public sealed class InMemoryFileSystem : IFileSystem
             .ToList();
     }
 
+    public IReadOnlyList<string> GetFilesRecursive(string path, string searchPattern)
+    {
+        string prefix = Normalize(path) + "/";
+        var pattern = ToRegex(searchPattern);
+        return _files.Keys
+            .Where(key => key.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
+            .Where(key => pattern.IsMatch(key[(key.LastIndexOf('/') + 1)..]))
+            .OrderBy(key => key, StringComparer.OrdinalIgnoreCase)
+            .ToList();
+    }
+
     public IReadOnlyList<string> GetDirectories(string path)
     {
         string prefix = Normalize(path) + "/";

StarterNG.Tests/Fakes/TestInstallation.cs

@@ -0,0 +1,48 @@
+using StarterNG.Application;
+using StarterNG.Infrastructure.Adapters;
+using StarterNG.Infrastructure.Sceneries;
+using StarterNG.Infrastructure.Vehicles;
+
+namespace StarterNG.Tests.Fakes;
+
+/// <summary>
+/// The production object graph wired over an in-memory installation: the same
+/// composition as <c>AppServices</c>, with disk, clock and randomness replaced.
+/// </summary>
+public sealed class TestInstallation
+{
+    public const string Root = "game";
+
+    public TestInstallation(InMemoryFileSystem? files = null, DateTime? now = null)
+    {
+        Files = files ?? new InMemoryFileSystem();
+        Paths = new GamePaths(Root);
+        Clock = new FixedClock(now ?? new DateTime(2026, 1, 1, 12, 0, 0));
+        Random = new StubRandom();
+        Log = new FileDiagnosticsLog(Files, Clock, Paths);
+        Strings = new FakeStrings();
+
+        MiniTextures = new MiniTextureIndex(Files, Paths);
+        Physics = new FizPhysicsRepository(Files, Paths, Log);
+        Vehicles = new TexturesTxtVehicleRepository(Files, Paths, Log, new TexturesTxtParser());
+        Sceneries = new SceneryRepository(Files, Paths, Log, new SceneryParser(Clock, Random));
+        MissingAssets = new MissingAssetScanner(Files, Paths);
+        Library = new GameLibrary(Vehicles, Sceneries, MiniTextures, Physics, Log);
+    }
+
+    public InMemoryFileSystem Files { get; }
+    public GamePaths Paths { get; }
+    public FixedClock Clock { get; }
+    public StubRandom Random { get; }
+    public FileDiagnosticsLog Log { get; }
+    public FakeStrings Strings { get; }
+    public MiniTextureIndex MiniTextures { get; }
+    public FizPhysicsRepository Physics { get; }
+    public TexturesTxtVehicleRepository Vehicles { get; }
+    public SceneryRepository Sceneries { get; }
+    public MissingAssetScanner MissingAssets { get; }
+    public GameLibrary Library { 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/GameLibraryTests.cs

@@ -0,0 +1,75 @@
+using StarterNG.Application;
+using StarterNG.Tests.Fakes;
+
+namespace StarterNG.Tests;
+
+public class GameLibraryTests
+{
+    private static TestInstallation Complete() =>
+        new(new InMemoryFileSystem()
+            .WithFile(TestInstallation.At("dynamic", "pkp", "ep07", "textures.txt"), "ep07-135.mat=ep07.e3d,ep07")
+            .WithFile(TestInstallation.At("scenery", "kato.scn"), "//$n Katowice")
+            .WithFile(TestInstallation.At("textures", "mini", "ep07.bmp"), "bitmap"));
+
+    [Fact]
+    public void Loading_reads_both_the_rolling_stock_and_the_scenarios()
+    {
+        var library = Complete().Library;
+
+        library.Load();
+
+        Assert.True(library.Loaded);
+        Assert.Single(library.Vehicles.Textures);
+        Assert.Equal("Katowice", Assert.Single(library.Sceneries).Name);
+    }
+
+    [Fact]
+    public void Loading_reports_progress_through_to_done()
+    {
+        var phases = new List<LoadPhase>();
+        var progress = new Progress<LoadStatus>(status => { lock (phases) phases.Add(status.Phase); });
+
+        Complete().Library.Load(progress);
+
+        SpinWait.SpinUntil(() => { lock (phases) return phases.Contains(LoadPhase.Done); }, TimeSpan.FromSeconds(2));
+        lock (phases)
+        {
+            Assert.Contains(LoadPhase.Vehicles, phases);
+            Assert.Contains(LoadPhase.Done, phases);
+        }
+    }
+
+    [Fact]
+    public void Loading_twice_does_not_duplicate_the_scenarios()
+    {
+        var library = Complete().Library;
+
+        library.Load();
+        library.Load();
+
+        Assert.Single(library.Sceneries);
+    }
+
+    [Fact]
+    public void Reloading_picks_up_a_scenery_added_after_startup()
+    {
+        var installation = Complete();
+        var library = installation.Library;
+        library.Load();
+
+        installation.Files.WithFile(TestInstallation.At("scenery", "gdansk.scn"), "//$n Gdańsk");
+        library.ReloadSceneries();
+
+        Assert.Equal(2, library.Sceneries.Count);
+    }
+
+    [Fact]
+    public void An_installation_with_no_rolling_stock_is_logged()
+    {
+        var installation = new TestInstallation();
+
+        installation.Library.Load();
+
+        Assert.Contains("textures.txt", installation.Log.Text);
+    }
+}

StarterNG.Tests/InstallationCheckTests.cs

@@ -9,8 +9,10 @@ public class InstallationCheckTests
     [Fact]
     public void An_empty_folder_reports_every_missing_game_directory()
     {
-        var strings = new FakeStrings().With("FaultNoDir", "missing {0}");
-        var check = new InstallationCheck(new GamePaths("game"), new InMemoryFileSystem(), strings);
+        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);
 
         var faults = check.Run();
 
@@ -29,9 +31,11 @@ public class InstallationCheckTests
             .WithDirectory(Path.Combine("game", "scenery"))
             .WithDirectory(Path.Combine("game", "textures"))
             .WithFile(Path.Combine("game", "data", "load_weights.txt"), "");
-        var strings = new FakeStrings().With("FaultNoDir", "missing {0}");
+        var installation = new TestInstallation(files);
+        var strings = installation.Strings.With("FaultNoDir", "missing {0}");
 
-        var faults = new InstallationCheck(new GamePaths("game"), files, strings).Run();
+        var faults = new InstallationCheck(installation.Paths, files, strings,
+                                           installation.Physics, installation.Library).Run();
 
         Assert.DoesNotContain(faults, fault => fault.StartsWith("missing "));
         Assert.DoesNotContain("FaultNoWeights", faults);

StarterNG.Tests/PhysicsAndAssetsTests.cs

@@ -0,0 +1,128 @@
+using StarterNG.Tests.Fakes;
+
+namespace StarterNG.Tests;
+
+public class PhysicsAndAssetsTests
+{
+    private static string Fiz(string maker, string vehicle, string name) =>
+        TestInstallation.At("dynamic", maker, vehicle, name + ".fiz");
+
+    [Fact]
+    public void A_fiz_yields_the_properties_the_starter_shows()
+    {
+        const string fiz = """
+            Param: M=80000 Vmax=125
+            Dimensions: L=15.9
+            Load: LoadAccepted=Coal MaxLoad=40
+            Engine: EngineType=DieselElectric
+            """;
+        var installation = new TestInstallation(new InMemoryFileSystem()
+            .WithFile(Fiz("pkp", "sm42", "sm42"), fiz));
+
+        var physics = installation.Physics.For("pkp/sm42/", "sm42.e3d");
+
+        Assert.NotNull(physics);
+        Assert.Equal(80000, physics!.Mass);
+        Assert.Equal(125, physics.VMax);
+        Assert.Equal(15.9, physics.Length);
+        Assert.Equal("Coal", physics.LoadAccepted);
+        Assert.Equal(40, physics.MaxLoad);
+        Assert.True(physics.IsDieselEngine);
+    }
+
+    [Fact]
+    public void A_vehicle_declaring_one_coupler_gets_the_same_at_both_ends()
+    {
+        var installation = new TestInstallation(new InMemoryFileSystem()
+            .WithFile(Fiz("pkp", "111a", "111a"), "BuffCoupl1: AllowedFlag=3 ControlType=screw"));
+
+        var physics = installation.Physics.For("pkp/111a/", "111a")!;
+
+        Assert.Equal(3, physics.AllowedFlagA);
+        Assert.Equal(3, physics.AllowedFlagB);
+        Assert.Equal("screw", physics.ControlTypeB);
+    }
+
+    [Fact]
+    public void A_negative_coupler_flag_is_encoded_as_disabled()
+    {
+        var installation = new TestInstallation(new InMemoryFileSystem()
+            .WithFile(Fiz("pkp", "111a", "111a"), "BuffCoupl1: AllowedFlag=-3"));
+
+        Assert.Equal(131, installation.Physics.For("pkp/111a/", "111a")!.AllowedFlagA);
+    }
+
+    [Fact]
+    public void An_include_is_followed_and_its_parameters_substituted()
+    {
+        var installation = new TestInstallation(new InMemoryFileSystem()
+            .WithFile(Fiz("pkp", "ep07", "ep07"), "include common.fiz 84000 end")
+            .WithFile(TestInstallation.At("dynamic", "pkp", "ep07", "common.fiz"), "Param: M=(1) Vmax=125"));
+
+        var physics = installation.Physics.For("pkp/ep07/", "ep07")!;
+
+        Assert.Equal(84000, physics.Mass);
+        Assert.Equal(125, physics.VMax);
+    }
+
+    [Fact]
+    public void A_dumb_variant_stands_in_when_the_model_has_no_fiz_of_its_own()
+    {
+        var installation = new TestInstallation(new InMemoryFileSystem()
+            .WithFile(Fiz("pkp", "ep07", "ep07dumb"), "Param: M=1000"));
+
+        Assert.NotNull(installation.Physics.For("pkp/ep07/", "ep07"));
+    }
+
+    [Fact]
+    public void An_unknown_model_has_no_physics_and_an_empty_installation_indexes_nothing()
+    {
+        var installation = new TestInstallation();
+
+        Assert.Null(installation.Physics.For("pkp/x/", "nieznany"));
+        installation.Physics.Preload();
+        Assert.Equal(0, installation.Physics.IndexedCount);
+    }
+
+    [Fact]
+    public void Thumbnails_are_looked_up_by_name_with_a_fallback_to_other()
+    {
+        var installation = new TestInstallation(new InMemoryFileSystem()
+            .WithFile(TestInstallation.At("textures", "mini", "ep07.bmp"), "bitmap")
+            .WithFile(TestInstallation.At("textures", "mini", "other.bmp"), "bitmap"));
+
+        Assert.True(installation.MiniTextures.Has("EP07"));
+        Assert.False(installation.MiniTextures.Has("nieznany"));
+        Assert.EndsWith("ep07.bmp", installation.MiniTextures.PathFor("ep07"));
+        Assert.EndsWith("other.bmp", installation.MiniTextures.PathFor("nieznany"));
+    }
+
+    [Fact]
+    public void A_livery_whose_skin_and_model_are_absent_is_reported()
+    {
+        var files = new InMemoryFileSystem()
+            .WithFile(TestInstallation.At("dynamic", "pkp", "ep07", "textures.txt"),
+                      "ep07-135.mat=ep07.e3d,ep07");
+        var installation = new TestInstallation(files);
+        installation.Vehicles.Load(installation.Library.Vehicles);
+
+        var missing = installation.MissingAssets.Scan(installation.Library.Vehicles);
+
+        Assert.Contains(missing, line => line.Contains("no file:") && line.Contains("ep07-135"));
+        Assert.Contains(missing, line => line.Contains("no model:") && line.Contains("ep07.e3d"));
+    }
+
+    [Fact]
+    public void A_skin_present_under_an_accepted_extension_is_not_reported()
+    {
+        var files = new InMemoryFileSystem()
+            .WithFile(TestInstallation.At("dynamic", "pkp", "ep07", "textures.txt"),
+                      "ep07-135.mat=ep07.e3d,ep07")
+            .WithFile(TestInstallation.At("dynamic", "pkp", "ep07", "ep07-135.bmp"), "bitmap")
+            .WithFile(TestInstallation.At("dynamic", "pkp", "ep07", "ep07.t3d"), "model");
+        var installation = new TestInstallation(files);
+        installation.Vehicles.Load(installation.Library.Vehicles);
+
+        Assert.Empty(installation.MissingAssets.Scan(installation.Library.Vehicles));
+    }
+}

StarterNG.Tests/TexturesTxtParserTests.cs

@@ -0,0 +1,103 @@
+using StarterNG.Infrastructure.Vehicles;
+
+namespace StarterNG.Tests;
+
+public class TexturesTxtParserTests
+{
+    private static readonly TexturesTxtParser Parser = new();
+
+    [Fact]
+    public void A_livery_line_yields_a_texture_with_its_model_and_thumbnail()
+    {
+        var entry = Parser.Parse("pkp/ep07/", new[] { "ep07-135.mat=ep07.e3d,ep07" });
+
+        var texture = Assert.Single(entry!.Textures);
+        Assert.Equal("ep07-135", texture.Skinfile);
+        Assert.Equal("pkp/ep07/", texture.Directory);
+        Assert.Equal("ep07.e3d", texture.Model);
+        Assert.Equal("ep07", texture.MiniRef);
+        Assert.False(texture.Wreck);
+    }
+
+    [Fact]
+    public void The_trailing_comment_is_read_as_the_credit_line()
+    {
+        var entry = Parser.Parse("pkp/ep07/", new[]
+        {
+            "ep07-135.mat=ep07.e3d,ep07 // 1.0,EP07-135,PKP Intercity,Warszawa,2019-04-01,Wrocław,Autor,Fotograf"
+        });
+
+        var meta = Assert.Single(entry!.Textures).Meta;
+        Assert.NotNull(meta);
+        Assert.Equal("EP07-135", meta!.Vehicle);
+        Assert.Equal("PKP Intercity", meta.Operator);
+        Assert.Equal("Warszawa", meta.Depot);
+        Assert.Equal("Autor", meta.TextureAuthor);
+        Assert.Equal("Fotograf", meta.PhotoAuthor);
+    }
+
+    [Fact]
+    public void Wreck_liveries_are_marked_so_the_depot_can_hide_them()
+    {
+        var entry = Parser.Parse("pkp/ep07/", new[] { "ep07wreck.mat=ep07.e3d,ep07" });
+
+        Assert.True(Assert.Single(entry!.Textures).Wreck);
+    }
+
+    [Fact]
+    public void The_dollar_a_marker_archives_everything_after_it()
+    {
+        var entry = Parser.Parse("pkp/ep07/", new[]
+        {
+            "ep07-135.mat=ep07.e3d,ep07",
+            "$a",
+            "ep07-old.mat=ep07.e3d,ep07old"
+        });
+
+        var groups = entry!.Groups;
+        Assert.Contains(groups, group => group is { Mini: "ep07", Archived: false });
+        Assert.Contains(groups, group => group is { Mini: "ep07old", Archived: true });
+    }
+
+    [Fact]
+    public void A_caret_opens_a_fixed_set_of_the_following_vehicles()
+    {
+        var entry = Parser.Parse("pkp/en57/", new[]
+        {
+            "^3",
+            "en57-a.mat=en57.e3d,en57",
+            "en57-b.mat=en57.e3d,en57",
+            "en57-c.mat=en57.e3d,en57"
+        });
+
+        var set = Assert.Single(entry!.Sets);
+        Assert.Equal(3, set.Count);
+        Assert.Equal(3, set.TextureRefs.Count);
+    }
+
+    [Fact]
+    public void Extra_equals_segments_become_alternative_models()
+    {
+        var entry = Parser.Parse("pkp/111a/", new[] { "111a.mat=111a.e3d,111a=111ab.e3d,111ab" });
+
+        var texture = Assert.Single(entry!.Textures);
+        Assert.Equal("111a.e3d", texture.Model);
+        Assert.Equal("111ab.e3d", Assert.Single(texture.Aliases).Model);
+    }
+
+    [Fact]
+    public void Comments_headers_and_blank_lines_are_ignored()
+    {
+        var entry = Parser.Parse("pkp/ep07/", new[] { "", "# nagłówek", "@ coś", "// komentarz", "bez znaku równości" });
+
+        Assert.Null(entry);
+    }
+
+    [Fact]
+    public void The_category_marker_applies_to_the_liveries_after_it()
+    {
+        var entry = Parser.Parse("pkp/ep07/", new[] { "!=e", "ep07-135.mat=ep07.e3d,ep07" });
+
+        Assert.Equal("e", Assert.Single(entry!.Groups).Category);
+    }
+}

StarterNG.Tests/VehicleCatalogTests.cs

@@ -0,0 +1,120 @@
+using StarterNG.Domain.Vehicles;
+using StarterNG.Tests.Fakes;
+
+namespace StarterNG.Tests;
+
+public class VehicleCatalogTests
+{
+    private static string TexturesFile(string maker, string vehicle) =>
+        TestInstallation.At("dynamic", maker, vehicle, "textures.txt");
+
+    [Fact]
+    public void The_catalogue_is_filled_from_every_vehicle_folder()
+    {
+        var files = new InMemoryFileSystem()
+            .WithFile(TexturesFile("pkp", "ep07"), "ep07-135.mat=ep07.e3d,ep07")
+            .WithFile(TexturesFile("pkp", "111a"), "111a-1.mat=111a.e3d,111a");
+        var installation = new TestInstallation(files);
+
+        int liveries = installation.Vehicles.Load(installation.Library.Vehicles);
+
+        Assert.Equal(2, liveries);
+        Assert.Equal(2, installation.Library.Vehicles.Textures.Count);
+    }
+
+    [Fact]
+    public void The_data_folder_is_recorded_the_way_the_scenery_format_spells_it()
+    {
+        var files = new InMemoryFileSystem()
+            .WithFile(TexturesFile("pkp", "ep07"), "ep07-135.mat=ep07.e3d,ep07");
+        var installation = new TestInstallation(files);
+        installation.Vehicles.Load(installation.Library.Vehicles);
+
+        Assert.Equal("pkp/ep07/", Assert.Single(installation.Library.Vehicles.Textures).Directory);
+    }
+
+    [Fact]
+    public void Wrecks_are_indexed_but_kept_out_of_the_offered_liveries()
+    {
+        var files = new InMemoryFileSystem()
+            .WithFile(TexturesFile("pkp", "ep07"), "ep07wrak.mat=ep07.e3d,ep07\nep07-135.mat=ep07.e3d,ep07");
+        var installation = new TestInstallation(files);
+        installation.Vehicles.Load(installation.Library.Vehicles);
+
+        var catalog = installation.Library.Vehicles;
+        Assert.Equal("ep07-135", Assert.Single(catalog.Textures).Skinfile);
+        Assert.NotNull(catalog.TextureForSkin("ep07wrak"));
+    }
+
+    [Fact]
+    public void A_livery_is_found_by_its_skin_file_whatever_the_extension()
+    {
+        var files = new InMemoryFileSystem()
+            .WithFile(TexturesFile("pkp", "ep07"), "ep07-135.mat=ep07.e3d,ep07");
+        var installation = new TestInstallation(files);
+        installation.Vehicles.Load(installation.Library.Vehicles);
+
+        Assert.NotNull(installation.Library.Vehicles.TextureForSkin("EP07-135.bmp"));
+        Assert.Null(installation.Library.Vehicles.TextureForSkin("nieznany"));
+    }
+
+    [Fact]
+    public void A_star_category_is_derived_from_the_first_letter_of_the_thumbnail()
+    {
+        var catalog = new VehicleCatalog(new MiniStub());
+        catalog.BeginLoad();
+        catalog.Ingest(ParsedEntry("pkp/ep07/", "ep07-135.mat=ep07.e3d,ep07"));
+        catalog.EndLoad();
+
+        Assert.Equal("E", Assert.Single(catalog.Textures).ResolvedCategory);
+    }
+
+    [Fact]
+    public void Members_of_a_set_after_the_first_are_followers()
+    {
+        var files = new InMemoryFileSystem()
+            .WithFile(TexturesFile("pkp", "en57"),
+                      "^2\nen57-a.mat=en57.e3d,en57\nen57-b.mat=en57.e3d,en57");
+        var installation = new TestInstallation(files);
+        installation.Vehicles.Load(installation.Library.Vehicles);
+        var catalog = installation.Library.Vehicles;
+
+        var lead = catalog.TextureForSkin("en57-a")!;
+        var follower = catalog.TextureForSkin("en57-b")!;
+
+        Assert.False(catalog.IsSetFollower(lead));
+        Assert.True(catalog.IsSetFollower(follower));
+        Assert.Equal(2, catalog.ResolveSet(lead)!.Count);
+    }
+
+    [Fact]
+    public void A_livery_falls_back_to_its_groups_thumbnail_when_its_own_is_missing()
+    {
+        var catalog = new VehicleCatalog(new MiniStub(known: "ep07"));
+        catalog.BeginLoad();
+        catalog.Ingest(ParsedEntry("pkp/ep07/", "ep07-135.mat=ep07.e3d,ep07,brakujacy"));
+        catalog.EndLoad();
+
+        Assert.Equal("ep07", catalog.ResolveMiniName(Assert.Single(catalog.Textures)));
+    }
+
+    /// <summary>Thumbnail index that knows about exactly one name.</summary>
+    private sealed class MiniStub : StarterNG.Application.Abstractions.IMiniTextureIndex
+    {
+        private readonly string? _known;
+
+        public MiniStub(string? known = null) => _known = known;
+
+        public void Preload() { }
+
+        public bool Has(string? miniName) => miniName is not null && miniName == _known;
+
+        public string? PathFor(string? miniName) => Has(miniName) ? miniName : FallbackPath;
+
+        public string? FallbackPath => null;
+    }
+
+    /// <summary>Builds an entry through the real parser, for catalogue-level tests.</summary>
+    private static VehicleEntry ParsedEntry(string directory, params string[] lines) =>
+        new StarterNG.Infrastructure.Vehicles.TexturesTxtParser().Parse(directory, lines)!;
+}

StarterNG/App.axaml.cs

@@ -125,7 +125,7 @@ public partial class App : Avalonia.Application
                     });
                 });
 
-                GameData.Instance.Load(progress);
+                AppServices.Current.Library.Load(progress);
             }).ContinueWith(load =>
             {
                 Dispatcher.UIThread.Post(async () =>

StarterNG/Application/Abstractions/IFileSystem.cs

@@ -51,5 +51,11 @@ public interface IFileSystem
     /// <summary>Top-level directories, empty when the directory does not exist.</summary>
     IReadOnlyList<string> GetDirectories(string path);
 
+    /// <summary>
+    /// Files matching the pattern anywhere below the path. Empty when the
+    /// directory does not exist.
+    /// </summary>
+    IReadOnlyList<string> GetFilesRecursive(string path, string searchPattern);
+
     DateTime GetLastWriteTimeUtc(string path);
 }

StarterNG/Application/Abstractions/IMiniTextureIndex.cs

@@ -0,0 +1,19 @@
+namespace StarterNG.Application.Abstractions;
+
+/// <summary>
+/// The thumbnails in textures/mini, looked up by name. Backed by one directory
+/// scan; a name with no bitmap falls back to the generic "other" thumbnail.
+/// </summary>
+public interface IMiniTextureIndex
+{
+    /// <summary>Builds the index up front, off the UI thread.</summary>
+    void Preload();
+
+    bool Has(string? miniName);
+
+    /// <summary>Bitmap for the name, the fallback thumbnail, or null when neither exists.</summary>
+    string? PathFor(string? miniName);
+
+    /// <summary>The generic thumbnail shown for unknown stock.</summary>
+    string? FallbackPath { get; }
+}

StarterNG/Application/Abstractions/IPhysicsRepository.cs

@@ -0,0 +1,21 @@
+using StarterNG.Domain.Vehicles;
+
+namespace StarterNG.Application.Abstractions;
+
+/// <summary>
+/// Looks up the .fiz physics of a vehicle type by model name.
+/// </summary>
+public interface IPhysicsRepository
+{
+    /// <summary>Indexes the installation's .fiz files up front, off the UI thread.</summary>
+    void Preload();
+
+    /// <summary>How many vehicle types were indexed; zero means a broken installation.</summary>
+    int IndexedCount { get; }
+
+    /// <summary>
+    /// Physics for a model name (with or without extension), or null when the
+    /// installation has no .fiz for it.
+    /// </summary>
+    VehiclePhysics? For(string? dataFolder, string? model);
+}

StarterNG/Application/Abstractions/IVehicleRepository.cs

@@ -0,0 +1,17 @@
+using StarterNG.Domain.Vehicles;
+
+namespace StarterNG.Application.Abstractions;
+
+/// <summary>
+/// Reads the installation's rolling stock. The only route from the dynamic/
+/// folder to a <see cref="VehicleCatalog"/>.
+/// </summary>
+public interface IVehicleRepository
+{
+    /// <summary>
+    /// Fills the catalogue from every textures.txt under dynamic/. Returns the
+    /// number of liveries read, which the caller uses to spot an installation
+    /// with no rolling stock at all.
+    /// </summary>
+    int Load(VehicleCatalog catalog);
+}

StarterNG/Application/AppServices.cs

@@ -2,6 +2,7 @@ using System;
 using StarterNG.Application.Abstractions;
 using StarterNG.Infrastructure.Adapters;
 using StarterNG.Infrastructure.Sceneries;
+using StarterNG.Infrastructure.Vehicles;
 using StarterNG.Services;
 
 namespace StarterNG.Application;
@@ -39,6 +40,11 @@ public sealed class AppServices
         Localization = new LocalizationService(log);
         Sceneries = new SceneryRepository(files, paths, log, new SceneryParser(clock, Random));
         SceneryImages = new SceneryImageLocator(files);
+        MiniTextures = new MiniTextureIndex(files, paths);
+        Vehicles = new TexturesTxtVehicleRepository(files, paths, log, new TexturesTxtParser());
+        Physics = new FizPhysicsRepository(files, paths, log);
+        MissingAssets = new MissingAssetScanner(files, paths);
+        Library = new GameLibrary(Vehicles, Sceneries, MiniTextures, Physics, log);
     }
 
     /// <summary>
@@ -76,6 +82,17 @@ public sealed class AppServices
 
     public SceneryImageLocator SceneryImages { get; }
 
+    public IMiniTextureIndex MiniTextures { get; }
+
+    public IVehicleRepository Vehicles { get; }
+
+    public IPhysicsRepository Physics { get; }
+
+    public MissingAssetScanner MissingAssets { get; }
+
+    /// <summary>Everything read out of the installation: rolling stock and scenarios.</summary>
+    public GameLibrary Library { 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

StarterNG/Application/GameLibrary.cs

@@ -0,0 +1,88 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using StarterNG.Application.Abstractions;
+using StarterNG.Domain.Sceneries;
+using StarterNG.Domain.Vehicles;
+
+namespace StarterNG.Application;
+
+/// <summary>Which part of the installation the loader is working through.</summary>
+public enum LoadPhase
+{
+    Vehicles,
+    Sceneries,
+    Done
+}
+
+/// <summary>How far the load has got, for the splash screen.</summary>
+public readonly record struct LoadStatus(double Fraction, LoadPhase Phase, string? Detail);
+
+/// <summary>
+/// Everything the starter reads out of the installation once: the rolling stock
+/// catalogue and the list of scenarios.
+/// </summary>
+/// <remarks>
+/// Was the <c>GameData</c> singleton, which also owned directory enumeration and
+/// parallel parsing. It is now an ordinary object built by the composition root,
+/// delegating to the repositories; the loading policy (what is read, in what
+/// order, what counts as progress) is all that is left here.
+/// </remarks>
+public sealed class GameLibrary
+{
+    private readonly IVehicleRepository _vehicles;
+    private readonly ISceneryRepository _sceneries;
+    private readonly IMiniTextureIndex _minis;
+    private readonly IPhysicsRepository _physics;
+    private readonly IDiagnosticsLog _log;
+
+    public GameLibrary(IVehicleRepository vehicles, ISceneryRepository sceneries, IMiniTextureIndex minis,
+                       IPhysicsRepository physics, IDiagnosticsLog log)
+    {
+        _vehicles = vehicles;
+        _sceneries = sceneries;
+        _minis = minis;
+        _physics = physics;
+        _log = log;
+        Vehicles = new VehicleCatalog(minis);
+    }
+
+    public VehicleCatalog Vehicles { get; }
+
+    public List<Scenery> Sceneries { get; } = new();
+
+    public bool Loaded { get; private set; }
+
+    /// <summary>
+    /// Reads the whole installation. Vehicles first, because the scenery list
+    /// resolves consists against them; the thumbnail and physics indexes are
+    /// built alongside since they are independent directory scans.
+    /// </summary>
+    public void Load(IProgress<LoadStatus>? progress = null)
+    {
+        if (Loaded)
+            return;
+
+        progress?.Report(new LoadStatus(0, LoadPhase.Vehicles, "textures.txt"));
+        if (_vehicles.Load(Vehicles) == 0)
+            _log.Log("dynamic: brak plikow textures.txt");
+
+        Parallel.Invoke(_minis.Preload, _physics.Preload);
+
+        ReloadSceneries(progress is null
+            ? null
+            : new Progress<SceneryLoadProgress>(step => progress.Report(
+                new LoadStatus((double)step.Loaded / step.Total, LoadPhase.Sceneries, step.FileName))));
+
+        progress?.Report(new LoadStatus(1.0, LoadPhase.Done, null));
+        Loaded = true;
+    }
+
+    /// <summary>Re-reads the scenery folder, picking up files added since startup.</summary>
+    public void ReloadSceneries(IProgress<SceneryLoadProgress>? progress = null)
+    {
+        var reloaded = _sceneries.LoadAll(progress);
+        Sceneries.Clear();
+        Sceneries.AddRange(reloaded);
+    }
+}

StarterNG/Classes/GameData.cs

@@ -1,62 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.IO;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
-using StarterNG.Application;
-using StarterNG.Application.Abstractions;
-using StarterNG.Domain.Sceneries;
-
-namespace StarterNG.Classes;
-
-public enum LoadPhase
-{
-    Vehicles,
-    Sceneries,
-    Done
-}
-
-public readonly record struct LoadStatus(double Fraction, LoadPhase Phase, string? Detail);
-
-public sealed class GameData
-{
-    public static GameData Instance { get; } = new();
-
-    public VehicleDatabase Vehicles { get; } = new();
-    public List<Scenery> Sceneries { get; } = new();
-
-    public bool Loaded { get; private set; }
-
-    public void Load(IProgress<LoadStatus>? progress = null,
-                     string miniDir = "textures/mini/",
-                     string dynamicRoot = "dynamic")
-    {
-        if (Loaded)
-            return;
-
-        progress?.Report(new LoadStatus(0, LoadPhase.Vehicles, "textures.txt"));
-        int vehicles = Vehicles.LoadFromTexturesTxt(dynamicRoot);
-        if (vehicles == 0)
-            Infrastructure.Diagnostics.Log($"{dynamicRoot}: brak plikow textures.txt");
-
-        Parallel.Invoke(
-            () => VehicleDatabase.PreloadMiniIndex(miniDir),
-            () => Physics.PreloadIndex());
-
-        var sceneryProgress = progress is null
-            ? null
-            : new Progress<SceneryLoadProgress>(step => progress.Report(
-                new LoadStatus((double)step.Loaded / step.Total, LoadPhase.Sceneries, step.FileName)));
-        ReloadSceneries(sceneryProgress);
-
-        progress?.Report(new LoadStatus(1.0, LoadPhase.Done, null));
-        Loaded = true;
-    }
-
-    public void ReloadSceneries(IProgress<SceneryLoadProgress>? progress = null)
-    {
-        Sceneries.Clear();
-        Sceneries.AddRange(AppServices.Current.Sceneries.LoadAll(progress));
-    }
-}

StarterNG/Classes/Physics.cs

@@ -1,232 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.IO;
-using System.Linq;
-using System.Text;
-
-namespace StarterNG.Classes;
-
-public sealed class Physics
-{
-    public double Mass;
-    public double VMax;
-    public double Length;
-    public string LoadAccepted = "";
-    public string LoadQ = "";
-    public int MaxLoad;
-    public int AllowedFlagA = 3;
-    public int AllowedFlagB = 3;
-    public string ControlTypeA = "";
-    public string ControlTypeB = "";
-
-    public string EngineType = "";
-
-    /// <summary>
-    /// True for the engine types the simulator actually runs its diesel heat model for.
-    /// Mover.cpp calls dizel_Update - and through it dizel_Heat - only for DieselEngine
-    /// and DieselElectric; LoadFIZ_EngineDecode maps the legacy "DumbDE" onto
-    /// DieselElectric. On anything else the coolant temperature struct is written and
-    /// never read.
-    /// </summary>
-    public bool IsDieselEngine =>
-        EngineType.Equals("DieselEngine", StringComparison.OrdinalIgnoreCase)
-        || EngineType.Equals("DieselElectric", StringComparison.OrdinalIgnoreCase)
-        || EngineType.Equals("DumbDE", StringComparison.OrdinalIgnoreCase);
-
-    private static readonly Dictionary<string, Physics?> Cache = new(StringComparer.OrdinalIgnoreCase);
-
-    private static Dictionary<string, string>? _fizIndex;
-
-    public static void PreloadIndex(string dynamicRoot = "dynamic") => FizIndex(dynamicRoot);
-
-    public static int IndexedCount => _fizIndex?.Count ?? 0;
-
-    private static Dictionary<string, string> FizIndex(string dynamicRoot)
-    {
-        if (_fizIndex != null)
-            return _fizIndex;
-
-        var index = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
-        try
-        {
-            if (Directory.Exists(dynamicRoot))
-                foreach (string f in Directory.EnumerateFiles(dynamicRoot, "*.fiz", SearchOption.AllDirectories))
-                    index[Path.GetFileNameWithoutExtension(f)] = f;
-        }
-        catch (Exception ex)
-        {
-            StarterNG.Infrastructure.Diagnostics.Log($"indexing {dynamicRoot}", ex);
-        }
-
-        _fizIndex = index;
-        return index;
-    }
-
-    public static Physics? For(string? dataFolder, string? model, string dynamicRoot = "dynamic")
-    {
-        if (string.IsNullOrEmpty(model))
-            return null;
-
-        string m = Path.GetFileNameWithoutExtension(model!);
-        if (m.Length == 0)
-            return null;
-
-        if (Cache.TryGetValue(m, out var cached))
-            return cached;
-
-        var index = FizIndex(dynamicRoot);
-        string? path = null;
-        if (index.TryGetValue(m, out var p1)) path = p1;
-        else if (index.TryGetValue(m + "dumb", out var p2)) path = p2;
-
-        Physics? phys = null;
-        if (path != null)
-        {
-            phys = new Physics { AllowedFlagB = -1 };
-            try { Parse(phys, path, Path.GetDirectoryName(path) ?? "", null, 0); }
-            catch (Exception ex) { StarterNG.Infrastructure.Diagnostics.Log($"physics/{Path.GetFileName(path)}", ex); }
-
-            if (phys.AllowedFlagB == -1)
-            {
-                phys.AllowedFlagB = phys.AllowedFlagA;
-                if (string.IsNullOrEmpty(phys.ControlTypeB))
-                    phys.ControlTypeB = phys.ControlTypeA;
-            }
-        }
-
-        Cache[m] = phys;
-        return phys;
-    }
-
-    private static readonly HashSet<string> KnownKeys = new(StringComparer.OrdinalIgnoreCase)
-    {
-        "M", "Vmax", "L", "LoadAccepted", "LoadQ", "MaxLoad", "AllowedFlag", "ControlType",
-        "EngineType"
-    };
-
-    private static void Parse(Physics p, string path, string dir, string[]? prms, int depth)
-    {
-        if (depth > 6 || !File.Exists(path))
-            return;
-
-        var tokens = Tokenize(File.ReadAllText(path, Encoding.GetEncoding(1250)));
-
-        string section = "";
-        string? pendingKey = null;
-
-        for (int i = 0; i < tokens.Count; i++)
-        {
-            string tok = tokens[i];
-            if (tok == "=")
-                continue;
-
-            if (tok.Equals("include", StringComparison.OrdinalIgnoreCase))
-            {
-                if (++i >= tokens.Count) break;
-                string incFile = Resolve(tokens[i], prms);
-                var incParams = new List<string>();
-                i++;
-                while (i < tokens.Count && !tokens[i].Equals("end", StringComparison.OrdinalIgnoreCase))
-                    incParams.Add(Resolve(tokens[i++], prms));
-                Parse(p, Path.Combine(dir, incFile), dir, incParams.ToArray(), depth + 1);
-                pendingKey = null;
-                continue;
-            }
-
-            int eq = tok.IndexOf('=');
-            if (eq >= 0)
-            {
-                string k = tok[..eq].TrimStart('.').Trim();
-                string v = tok[(eq + 1)..].Trim();
-                if (v.Length == 0) { pendingKey = k; continue; }
-                Apply(p, section, k, Resolve(v, prms));
-                pendingKey = null;
-                continue;
-            }
-
-            string t = tok.TrimStart('.').Trim();
-            if (pendingKey != null)
-            {
-                Apply(p, section, pendingKey, Resolve(t, prms));
-                pendingKey = null;
-            }
-            else if (KnownKeys.Contains(t))
-            {
-                pendingKey = t;
-            }
-            else
-            {
-
-                section = new string(t.Where(char.IsLetterOrDigit).ToArray()).ToLowerInvariant();
-            }
-        }
-    }
-
-    private static void Apply(Physics p, string section, string key, string value)
-    {
-        switch (section)
-        {
-            case "param":
-                if (key.Equals("M", StringComparison.OrdinalIgnoreCase)) p.Mass = ParseD(value, p.Mass);
-                else if (key.Equals("Vmax", StringComparison.OrdinalIgnoreCase)) p.VMax = ParseD(value, p.VMax);
-                break;
-            case "load":
-                if (key.Equals("LoadAccepted", StringComparison.OrdinalIgnoreCase)) p.LoadAccepted = value;
-                else if (key.Equals("LoadQ", StringComparison.OrdinalIgnoreCase)) p.LoadQ = value;
-                else if (key.Equals("MaxLoad", StringComparison.OrdinalIgnoreCase)) p.MaxLoad = (int)ParseD(value, p.MaxLoad);
-                break;
-            case "engine":
-                if (key.Equals("EngineType", StringComparison.OrdinalIgnoreCase)) p.EngineType = value;
-                break;
-            case "dimensions":
-                if (key.Equals("L", StringComparison.OrdinalIgnoreCase)) p.Length = ParseD(value, p.Length);
-                break;
-            case "buffcoupl":
-            case "buffcoupl1":
-                if (key.Equals("AllowedFlag", StringComparison.OrdinalIgnoreCase)) p.AllowedFlagA = Flag(value, p.AllowedFlagA);
-                else if (key.Equals("ControlType", StringComparison.OrdinalIgnoreCase)) p.ControlTypeA = value;
-                break;
-            case "buffcoupl2":
-                if (key.Equals("AllowedFlag", StringComparison.OrdinalIgnoreCase)) p.AllowedFlagB = Flag(value, p.AllowedFlagB);
-                else if (key.Equals("ControlType", StringComparison.OrdinalIgnoreCase)) p.ControlTypeB = value;
-                break;
-        }
-    }
-
-    private static int Flag(string v, int fallback)
-        => int.TryParse(v, System.Globalization.NumberStyles.Integer,
-               System.Globalization.CultureInfo.InvariantCulture, out int f)
-            ? (f < 0 ? -f + 128 : f)
-            : fallback;
-
-    private static double ParseD(string v, double fallback)
-        => double.TryParse(v, System.Globalization.NumberStyles.Float,
-               System.Globalization.CultureInfo.InvariantCulture, out double d)
-            ? d
-            : fallback;
-
-    private static string Resolve(string token, string[]? prms)
-    {
-        if (prms == null || token.Length < 3 || token[0] != '(' || token[^1] != ')')
-            return token;
-        string digits = new string(token.Where(char.IsDigit).ToArray());
-        return int.TryParse(digits, out int idx) && idx >= 1 && idx <= prms.Length
-            ? prms[idx - 1]
-            : token;
-    }
-
-    private static List<string> Tokenize(string text)
-    {
-        var sb = new StringBuilder();
-        foreach (var line in text.Split('\n'))
-        {
-            string l = line;
-            int hash = l.IndexOf('#');
-            if (hash >= 0) l = l[..hash];
-            sb.Append(l).Append(' ');
-        }
-        return sb.ToString()
-            .Split(new[] { ' ', '\t', '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries)
-            .ToList();
-    }
-}

StarterNG/Classes/Settings.cs

@@ -4,6 +4,7 @@ using System.Globalization;
 using System.IO;
 using System.Linq;
 using System.Text;
+using StarterNG.Application;
 
 namespace StarterNG.Classes;
 
@@ -395,7 +396,7 @@ public sealed class Settings
         if (!LogMissingVehicleFiles) return;
         try
         {
-            var lines = GameData.Instance.Vehicles.CollectMissingAssetLines();
+            var lines = AppServices.Current.MissingAssets.Scan(AppServices.Current.Library.Vehicles);
             if (lines.Count == 0) return;
             Infrastructure.Diagnostics.Log(lines);
         }

StarterNG/Classes/TexturesTxt.cs

@@ -1,209 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.IO;
-using System.Text;
-
-namespace StarterNG.Classes;
-
-public static class TexturesTxt
-{
-    public static List<string> EnumerateFiles(string dynamicRoot = "dynamic")
-    {
-        var files = new List<string>();
-        if (!Directory.Exists(dynamicRoot))
-            return files;
-
-        foreach (string group in Directory.EnumerateDirectories(dynamicRoot))
-        foreach (string sub in Directory.EnumerateDirectories(group))
-        {
-            string path = Path.Combine(sub, "textures.txt");
-            if (File.Exists(path))
-                files.Add(path);
-        }
-        return files;
-    }
-
-    public static VehicleEntry? Parse(string path, string dynamicRoot = "dynamic")
-    {
-        string[] lines;
-        try
-        {
-            lines = File.ReadAllLines(path, Encoding.GetEncoding(1250));
-        }
-        catch (Exception ex)
-        {
-            Infrastructure.Diagnostics.Log($"textures.txt {path}", ex);
-            return null;
-        }
-
-        string dir = RelativeDirectory(path, dynamicRoot);
-        var entry = new VehicleEntry { Uuid = "legacy:" + dir };
-
-        bool archived = false;
-        string categorySign = "*";
-        int setSize = 0;
-        var pending = new List<string>();
-
-        foreach (string raw in lines)
-        {
-            string line = raw.Trim();
-            if (line.Length == 0) continue;
-
-            char c = line[0];
-            if (c is '#' or '@' or '*') continue;
-
-            if (line.StartsWith("$a", StringComparison.OrdinalIgnoreCase))
-            {
-                archived = true;
-                continue;
-            }
-
-            if (c == '^')
-            {
-                FlushSet(entry, pending, setSize);
-                setSize = line.Length > 1 && char.IsDigit(line[1]) ? line[1] - '0' : 0;
-                continue;
-            }
-
-            if (line.StartsWith("!=", StringComparison.Ordinal))
-            {
-                categorySign = line.Length > 2 ? line[2].ToString() : "*";
-                continue;
-            }
-
-            if (line.IndexOf('=') < 0) continue;
-            if (line.StartsWith("//", StringComparison.Ordinal)) continue;
-
-            var texture = ParseEntryLine(line, dir, categorySign, archived, entry);
-            if (texture is null) continue;
-
-            entry.Textures.Add(texture);
-
-            if (setSize > 1)
-            {
-                pending.Add(texture.Uuid!);
-                if (pending.Count == setSize)
-                    FlushSet(entry, pending, setSize);
-            }
-        }
-
-        FlushSet(entry, pending, setSize);
-        return entry.Textures.Count > 0 ? entry : null;
-    }
-
-    private static void FlushSet(VehicleEntry entry, List<string> pending, int size)
-    {
-        if (pending.Count > 1)
-            entry.Sets.Add(new VehicleSet
-            {
-                Uuid = "legacy-set:" + pending[0],
-                Mode = "sequence",
-                Count = size > 0 ? size : pending.Count,
-                TextureRefs = new List<string>(pending)
-            });
-        pending.Clear();
-    }
-
-    private static VehicleTexture? ParseEntryLine(string line, string dir,
-        string categorySign, bool archived, VehicleEntry entry)
-    {
-        string desc = "";
-        int comment = line.IndexOf("//", StringComparison.Ordinal);
-        if (comment >= 0)
-        {
-            desc = line[(comment + 2)..].Trim();
-            line = line[..comment].Trim();
-        }
-
-        var parts = line.Split('=');
-        if (parts.Length < 2) return null;
-
-        string skin = StripExtension(parts[0].Trim());
-        if (skin.Length == 0) return null;
-
-        var specs = new List<(string Model, string Mini, string MiniD)>();
-        for (int i = 1; i < parts.Length; i++)
-        {
-            var f = parts[i].Split(',');
-            if (f.Length < 2) continue;
-            specs.Add((f[0].Trim(), f[1].Trim(), f.Length > 2 ? f[2].Trim() : ""));
-        }
-        if (specs.Count == 0) return null;
-
-        var first = specs[0];
-        string groupId = $"legacy:{dir}:{first.Mini}:{categorySign}:{(archived ? 1 : 0)}";
-
-        if (!entry.Groups.Exists(g => g.Id == groupId))
-            entry.Groups.Add(new VehicleGroup
-            {
-                Id = groupId,
-                Category = categorySign,
-                Mini = first.Mini,
-                Archived = archived
-            });
-
-        var texture = new VehicleTexture
-        {
-            Uuid = $"legacy:{dir}{skin}",
-            Directory = dir,
-            Skinfile = skin,
-            Wreck = skin.Contains("wreck", StringComparison.OrdinalIgnoreCase) ||
-                    skin.Contains("wrak", StringComparison.OrdinalIgnoreCase),
-            Model = first.Model,
-            Group = groupId,
-            MiniRef = first.Mini,
-            TextureMini = string.IsNullOrEmpty(first.MiniD) ? null : first.MiniD,
-            Meta = ParseDescription(desc)
-        };
-
-        for (int i = 1; i < specs.Count; i++)
-            texture.Aliases.Add(new VehicleAlias
-            {
-                Model = specs[i].Model,
-                MiniRef = specs[i].Mini,
-                TextureMini = string.IsNullOrEmpty(specs[i].MiniD) ? null : specs[i].MiniD
-            });
-
-        return texture;
-    }
-
-    private static VehicleMeta? ParseDescription(string desc)
-    {
-        if (string.IsNullOrWhiteSpace(desc)) return null;
-
-        var f = desc.Replace('_', ' ').Split(',');
-        string At(int i) => i < f.Length ? f[i].Trim() : "";
-
-        return new VehicleMeta
-        {
-            Raw = desc,
-            Version = At(0),
-            Vehicle = At(1),
-            Operator = At(2),
-            Depot = At(3),
-            RevisionDate = At(4),
-            RevisionPlace = At(5),
-            TextureAuthor = At(6),
-            PhotoAuthor = At(7)
-        };
-    }
-
-    private static string StripExtension(string name)
-    {
-        int dot = name.LastIndexOf('.');
-        return dot > 0 ? name[..dot] : name;
-    }
-
-    private static string RelativeDirectory(string texturesPath, string dynamicRoot)
-    {
-        string dir = Path.GetDirectoryName(texturesPath) ?? "";
-        string full = Path.GetFullPath(dir);
-        string root = Path.GetFullPath(dynamicRoot);
-
-        string rel = full.StartsWith(root, StringComparison.OrdinalIgnoreCase)
-            ? full[root.Length..].TrimStart(Path.DirectorySeparatorChar, '/')
-            : dir;
-
-        return rel.Replace('\\', '/').TrimEnd('/') + "/";
-    }
-}

StarterNG/Classes/VehicleDatabase.cs

@@ -1,312 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.IO;
-using System.Linq;
-using System.Threading.Tasks;
-
-namespace StarterNG.Classes;
-
-public class VehicleEntry
-{
-    public string? Uuid { get; set; }
-    public List<VehicleGroup> Groups { get; set; } = new();
-    public List<VehicleTexture> Textures { get; set; } = new();
-    public List<VehicleSet> Sets { get; set; } = new();
-}
-
-public class VehicleGroup
-{
-    public string Id { get; set; } = "";
-    public string? Category { get; set; }
-    public string? Mini { get; set; }
-    public bool Archived { get; set; }
-}
-
-public class VehicleTexture
-{
-    public string? Uuid { get; set; }
-    public string Directory { get; set; } = "";
-    public string Skinfile { get; set; } = "";
-    public string? Model { get; set; }
-    public string? Group { get; set; }
-    public string? MiniRef { get; set; }
-    public string? TextureMini { get; set; }
-    public bool Wreck { get; set; }
-    public List<VehicleAlias> Aliases { get; set; } = new();
-    public VehicleMeta? Meta { get; set; }
-
-    public string FullPath => Directory + Skinfile;
-
-    public string ResolvedClass { get; internal set; } = "";
-
-    public string? ResolvedCategory { get; internal set; }
-
-    public bool ResolvedArchived { get; internal set; }
-}
-
-public class VehicleAlias
-{
-    public string? Model { get; set; }
-    public string? Group { get; set; }
-    public string? MiniRef { get; set; }
-    public string? TextureMini { get; set; }
-}
-
-public class VehicleMeta
-{
-    public string? Raw { get; set; }
-    public string? Version { get; set; }
-    public string? Vehicle { get; set; }
-    public string? Operator { get; set; }
-    public string? Depot { get; set; }
-    public string? RevisionDate { get; set; }
-    public string? RevisionPlace { get; set; }
-    public string? TextureAuthor { get; set; }
-    public string? PhotoAuthor { get; set; }
-    public List<string> Extra { get; set; } = new();
-}
-
-public class VehicleDatabase
-{
-    public List<VehicleTexture> Textures { get; } = new();
-    public Dictionary<string, VehicleGroup> GroupsById { get; } = new();
-    public List<VehicleSet> Sets { get; } = new();
-
-    public Dictionary<string, VehicleSet> SetByTextureUuid { get; } = new();
-
-    public Dictionary<string, VehicleTexture> TextureByUuid { get; } = new();
-
-    public Dictionary<string, VehicleTexture> TextureBySkin { get; } = new();
-
-    public int LoadFromTexturesTxt(string dynamicRoot = "dynamic")
-    {
-        BeginLoad();
-
-        int count = 0;
-        foreach (string file in TexturesTxt.EnumerateFiles(dynamicRoot))
-        {
-            var entry = TexturesTxt.Parse(file, dynamicRoot);
-            if (entry is null) continue;
-
-            count += entry.Textures.Count;
-            Ingest(entry);
-        }
-
-        EndLoad();
-        return count;
-    }
-
-    public void BeginLoad()
-    {
-        Textures.Clear();
-        GroupsById.Clear();
-        Sets.Clear();
-        SetByTextureUuid.Clear();
-        TextureByUuid.Clear();
-        TextureBySkin.Clear();
-    }
-
-    public void EndLoad()
-    {
-        BuildSetIndex();
-        BuildTextureIndex();
-    }
-
-    private void Ingest(VehicleEntry entry)
-    {
-        foreach (var group in entry.Groups)
-        {
-            if (!string.IsNullOrEmpty(group.Id))
-                GroupsById.TryAdd(group.Id, group);
-        }
-
-        foreach (var texture in entry.Textures)
-        {
-
-            if (!string.IsNullOrEmpty(texture.Uuid))
-                TextureByUuid[texture.Uuid!] = texture;
-            if (!string.IsNullOrEmpty(texture.Skinfile))
-                TextureBySkin.TryAdd(Path.GetFileNameWithoutExtension(texture.Skinfile).ToLowerInvariant(), texture);
-
-            if (texture.Wreck) continue;
-            Textures.Add(texture);
-        }
-
-        Sets.AddRange(entry.Sets);
-    }
-
-    public List<VehicleTexture>? ResolveSet(VehicleTexture texture)
-    {
-        if (string.IsNullOrEmpty(texture.Uuid)) return null;
-        if (!SetByTextureUuid.TryGetValue(texture.Uuid!, out var set) || set.TextureRefs is null)
-            return null;
-
-        var cars = new List<VehicleTexture>();
-        foreach (string uuid in set.TextureRefs)
-        {
-            if (!string.IsNullOrEmpty(uuid) && TextureByUuid.TryGetValue(uuid, out var tex))
-                cars.Add(tex);
-        }
-        return cars.Count > 0 ? cars : null;
-    }
-
-    private void BuildSetIndex()
-    {
-        foreach (var set in Sets)
-        {
-            if (set.TextureRefs is null) continue;
-            foreach (string uuid in set.TextureRefs)
-            {
-                if (!string.IsNullOrEmpty(uuid))
-                    SetByTextureUuid[uuid] = set;
-            }
-        }
-    }
-
-    private void BuildTextureIndex()
-    {
-        foreach (var t in Textures)
-        {
-            VehicleGroup? g = null;
-            if (t.Group != null)
-                GroupsById.TryGetValue(t.Group, out g);
-
-            string mini = g != null && !string.IsNullOrEmpty(g.Mini)
-                ? g.Mini!
-                : t.MiniRef ?? "";
-
-            string? category = g?.Category;
-
-            if (category == "*")
-            {
-                string source = !string.IsNullOrEmpty(mini) ? mini : (t.TextureMini ?? "");
-                if (source.Length > 0)
-                    category = char.ToUpperInvariant(source[0]).ToString();
-            }
-
-            t.ResolvedCategory = category;
-            t.ResolvedClass = mini;
-            t.ResolvedArchived = g?.Archived ?? false;
-        }
-    }
-
-    public bool IsSetFollower(VehicleTexture texture)
-    {
-        if (string.IsNullOrEmpty(texture.Uuid)) return false;
-        if (!SetByTextureUuid.TryGetValue(texture.Uuid!, out var set) ||
-            set.TextureRefs is null || set.TextureRefs.Count < 2)
-            return false;
-
-        string? lead = set.TextureRefs.FirstOrDefault(r => !string.IsNullOrEmpty(r));
-        return lead != null &&
-               !string.Equals(lead, texture.Uuid, StringComparison.OrdinalIgnoreCase);
-    }
-
-    public string? ResolveMiniName(VehicleTexture texture)
-    {
-        if (HasMini(texture.TextureMini))
-            return texture.TextureMini;
-
-        if (texture.Group != null && GroupsById.TryGetValue(texture.Group, out var grp)
-            && !string.IsNullOrEmpty(grp.Mini))
-            return grp.Mini;
-
-        return texture.TextureMini;
-    }
-
-    public string? MiniForSkin(string? skinFile)
-    {
-        if (string.IsNullOrEmpty(skinFile)) return null;
-        string key = Path.GetFileNameWithoutExtension(skinFile).ToLowerInvariant();
-        return TextureBySkin.TryGetValue(key, out var tex) ? ResolveMiniName(tex) : null;
-    }
-
-    public VehicleTexture? TextureForSkin(string? skinFile)
-    {
-        if (string.IsNullOrEmpty(skinFile)) return null;
-        string key = Path.GetFileNameWithoutExtension(skinFile).ToLowerInvariant();
-        return TextureBySkin.TryGetValue(key, out var tex) ? tex : null;
-    }
-
-    public List<string> CollectMissingAssetLines()
-    {
-        var lines = new List<string>();
-        foreach (var t in Textures)
-        {
-            string dir = Path.Combine(Directory.GetCurrentDirectory(), "dynamic",
-                t.Directory.Replace('/', Path.DirectorySeparatorChar).TrimEnd('\\', '/'));
-            string skin = Path.Combine(dir, t.Skinfile);
-            if (!string.IsNullOrEmpty(t.Skinfile) && !File.Exists(skin) &&
-                !File.Exists(Path.ChangeExtension(skin, ".mat")) &&
-                !File.Exists(Path.ChangeExtension(skin, ".bmp")))
-                lines.Add($"# no file: {t.Directory}{t.Skinfile}");
-
-            if (!string.IsNullOrEmpty(t.Model))
-            {
-                string model = Path.Combine(dir, t.Model!);
-                if (!File.Exists(model) && !File.Exists(Path.ChangeExtension(model, ".t3d")) &&
-                    !File.Exists(Path.ChangeExtension(model, ".e3d")))
-                    lines.Add($"# no model: {t.Directory}{t.Model}");
-            }
-        }
-        return lines;
-    }
-
-    public string GroupHeader(string? groupId)
-    {
-        if (!string.IsNullOrEmpty(groupId) && GroupsById.TryGetValue(groupId, out var grp))
-        {
-            string mini = string.IsNullOrEmpty(grp.Mini) ? grp.Id : grp.Mini!;
-            return string.IsNullOrEmpty(grp.Category) ? mini : $"{mini}  ({grp.Category})";
-        }
-        return groupId ?? "";
-    }
-
-    private static Dictionary<string, string>? _miniIndex;
-
-    public static void PreloadMiniIndex(string miniDir = "textures/mini/") =>
-        _miniIndex ??= BuildMiniIndex(miniDir);
-
-    public static string? MiniPath(string? miniName, string miniDir = "textures/mini/")
-    {
-        var index = _miniIndex ??= BuildMiniIndex(miniDir);
-
-        if (!string.IsNullOrEmpty(miniName) &&
-            index.TryGetValue(miniName!.ToLowerInvariant(), out var path))
-            return path;
-
-        return FallbackMiniPath(miniDir);
-    }
-
-    public static bool HasMini(string? miniName, string miniDir = "textures/mini/")
-    {
-        if (string.IsNullOrEmpty(miniName)) return false;
-        var index = _miniIndex ??= BuildMiniIndex(miniDir);
-        return index.ContainsKey(miniName!.ToLowerInvariant());
-    }
-
-    public static string? FallbackMiniPath(string miniDir = "textures/mini/")
-    {
-        var index = _miniIndex ??= BuildMiniIndex(miniDir);
-        return index.TryGetValue("other", out var other) ? other : null;
-    }
-
-    private static Dictionary<string, string> BuildMiniIndex(string miniDir)
-    {
-        var index = new Dictionary<string, string>();
-        if (!Directory.Exists(miniDir))
-            return index;
-
-        foreach (string file in Directory.GetFiles(miniDir, "*.bmp"))
-            index[Path.GetFileNameWithoutExtension(file).ToLowerInvariant()] = file;
-        return index;
-    }
-}
-
-public class VehicleSet
-{
-    public string? Uuid { get; set; }
-    public string? Mode { get; set; }
-    public int Count { get; set; }
-    public List<string> TextureRefs { get; set; } = new();
-}

StarterNG/Domain/Consist.cs

@@ -5,6 +5,7 @@ using System.Linq;
 
 using StarterNG.Classes;
 using StarterNG.Domain.Sceneries;
+using StarterNG.Domain.Vehicles;
 
 namespace StarterNG.Domain;
 
@@ -12,12 +13,12 @@ public sealed class Consist : IReadOnlyList<ConsistItem>
 {
     private static readonly string[] CarSuffixes = { "sa", "sb", "ra", "rb", "s" };
 
-    private readonly VehicleDatabase _db;
+    private readonly VehicleCatalog _db;
     private readonly VehicleInfo _info;
     private readonly List<ConsistItem> _items = new();
     private int _nameCounter;
 
-    public Consist(VehicleDatabase db, VehicleInfo info)
+    public Consist(VehicleCatalog db, VehicleInfo info)
     {
         _db = db;
         _info = info;

StarterNG/Domain/TexRandomizer.cs

@@ -3,12 +3,13 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using StarterNG.Classes;
+using StarterNG.Domain.Vehicles;
 
 namespace StarterNG.Domain;
 
 public sealed class TexRandomizer
 {
-    private readonly VehicleDatabase _db;
+    private readonly VehicleCatalog _db;
     private readonly Random _rng;
     private readonly List<string[]> _stock = new();
 
@@ -29,7 +30,7 @@ public sealed class TexRandomizer
         }
     }
 
-    public TexRandomizer(VehicleDatabase db, Random? rng = null)
+    public TexRandomizer(VehicleCatalog db, Random? rng = null)
     {
         _db = db;
         _rng = rng ?? Random.Shared;

StarterNG/Domain/TrainsetDisplay.cs

@@ -6,6 +6,8 @@ using System.Linq;
 using System.Text;
 using StarterNG.Classes;
 using StarterNG.Domain.Sceneries;
+using StarterNG.Domain.Vehicles;
+using StarterNG.Application;
 
 namespace StarterNG.Domain;
 
@@ -65,14 +67,14 @@ public static class TrainsetDisplay
 
     public static string VehicleLabel(Dynamic v, bool head = false)
     {
-        var tex = GameData.Instance.Vehicles.TextureForSkin(v.SkinFile);
+        var tex = AppServices.Current.Library.Vehicles.TextureForSkin(v.SkinFile);
         string? cls = string.IsNullOrEmpty(tex?.ResolvedClass) ? null : tex!.ResolvedClass;
         string? name = string.IsNullOrWhiteSpace(v.Name) ? null : v.Name;
         return (head ? name ?? cls : cls ?? name) ?? BaseSkin(v);
     }
 
     public static bool IsPowered(Dynamic v) =>
-        GameData.Instance.Vehicles.TextureForSkin(v.SkinFile)?.ResolvedCategory
+        AppServices.Current.Library.Vehicles.TextureForSkin(v.SkinFile)?.ResolvedCategory
             is "e" or "s" or "p" or "z" or "a";
 
     private static string BaseSkin(Dynamic v) =>
@@ -94,7 +96,7 @@ public static class TrainsetDisplay
     }
 
     public static List<(string Label, string Value)> StatsFields(
-        Trainset? trainset, Func<Dynamic, Physics?> physicsFor,
+        Trainset? trainset, Func<Dynamic, VehiclePhysics?> physicsFor,
         Func<Dynamic, string?>? categoryOf = null,
         Func<string?, int>? loadWeightKg = null)
     {
@@ -120,7 +122,7 @@ public static class TrainsetDisplay
         return fields;
     }
 
-    public static string FormatStats(Trainset? trainset, Func<Dynamic, Physics?> physicsFor,
+    public static string FormatStats(Trainset? trainset, Func<Dynamic, VehiclePhysics?> physicsFor,
         string lengthLabel, string massLabel, string vehiclesLabel, string trackLabel,
         Func<Dynamic, string?>? categoryOf = null,
         Func<string?, int>? loadWeightKg = null)
@@ -149,7 +151,7 @@ public static class TrainsetDisplay
 
     private static (double lengthM, double massKg, double loadKg) RecalcParams(
         Trainset trainset,
-        Func<Dynamic, Physics?> physicsFor,
+        Func<Dynamic, VehiclePhysics?> physicsFor,
         Func<Dynamic, string?>? categoryOf,
         Func<string?, int>? loadWeightKg,
         bool allVehicles)
@@ -176,7 +178,7 @@ public static class TrainsetDisplay
         return (lengthM, massKg, loadKg);
     }
 
-    private static bool IncludeVehicleToMass(Dynamic car, Physics? p, string? category, bool allVehicles)
+    private static bool IncludeVehicleToMass(Dynamic car, VehiclePhysics? p, string? category, bool allVehicles)
     {
         if (p == null) return false;
         if (allVehicles) return true;
@@ -184,7 +186,7 @@ public static class TrainsetDisplay
         return car.DriverType is eDriverType.Passenger or eDriverType.Nobody;
     }
 
-    private static bool LoadAccepted(Physics? p, string loadType)
+    private static bool LoadAccepted(VehiclePhysics? p, string loadType)
     {
         if (p == null || string.IsNullOrWhiteSpace(p.LoadAccepted))
             return false;
@@ -194,7 +196,7 @@ public static class TrainsetDisplay
     public static string? UniquifyForLaunch(Trainset trainset, Scenery scenery, string? startName)
     {
         var used = CollectNames(scenery);
-        var db = GameData.Instance.Vehicles;
+        var db = AppServices.Current.Library.Vehicles;
 
         bool mu = trainset.Vehicles.Any(v =>
         {
@@ -224,7 +226,7 @@ public static class TrainsetDisplay
 
     public static string PreferredBaseName(Dynamic v)
     {
-        var tex = GameData.Instance.Vehicles.TextureForSkin(v.SkinFile);
+        var tex = AppServices.Current.Library.Vehicles.TextureForSkin(v.SkinFile);
         if (tex != null)
         {
 

StarterNG/Domain/UData.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using StarterNG.Classes;
+using StarterNG.Domain.Vehicles;
 
 namespace StarterNG.Domain;
 
@@ -9,7 +10,7 @@ public static class UData
 {
     public readonly record struct TrainParams(double Length, double Mass, double LoadMass, int CountVehicles);
 
-    public static int GetMaxCoupler(Dynamic v, Func<Dynamic, Physics?> physicsFor, bool leftCoupler = true)
+    public static int GetMaxCoupler(Dynamic v, Func<Dynamic, VehiclePhysics?> physicsFor, bool leftCoupler = true)
     {
         var fiz = physicsFor(v);
         if (fiz == null) return 3;
@@ -18,7 +19,7 @@ public static class UData
             : (v.Offset >= 0 ? fiz.AllowedFlagB : fiz.AllowedFlagA);
     }
 
-    public static string GetControlType(Dynamic v, Func<Dynamic, Physics?> physicsFor, bool leftCoupler = true)
+    public static string GetControlType(Dynamic v, Func<Dynamic, VehiclePhysics?> physicsFor, bool leftCoupler = true)
     {
         var fiz = physicsFor(v);
         if (fiz == null) return "";
@@ -43,7 +44,7 @@ public static class UData
     }
 
     public static void AutoConnect(IList<Dynamic> vehicles, int leftVehicle,
-        Func<Dynamic, Physics?> physicsFor)
+        Func<Dynamic, VehiclePhysics?> physicsFor)
     {
         if (leftVehicle < 0 || vehicles.Count - 1 <= leftVehicle) return;
 
@@ -98,7 +99,7 @@ public static class UData
         d is eDriverType.Headdriver or eDriverType.Reardriver;
 
     public static bool IncludeVehicleToMass(Dynamic v, bool allVehicles,
-        Func<Dynamic, Physics?> physicsFor, Func<Dynamic, string?> categoryOf)
+        Func<Dynamic, VehiclePhysics?> physicsFor, Func<Dynamic, string?> categoryOf)
     {
         if (physicsFor(v) == null) return false;
         if (allVehicles) return true;
@@ -109,7 +110,7 @@ public static class UData
     }
 
     public static TrainParams RecalcTrainParams(Trainset? train, bool allVehicles,
-        Func<Dynamic, Physics?> physicsFor, Func<Dynamic, string?> categoryOf,
+        Func<Dynamic, VehiclePhysics?> physicsFor, Func<Dynamic, string?> categoryOf,
         Func<string?, int> loadWeight)
     {
         double length = 0, mass = 0, loadMass = 0;
@@ -138,7 +139,7 @@ public static class UData
     }
 
     public static void RandomLoad(IEnumerable<Dynamic> vehicles,
-        Func<Dynamic, Physics?> physicsFor, Random rng)
+        Func<Dynamic, VehiclePhysics?> physicsFor, Random rng)
     {
         foreach (var v in vehicles)
         {
@@ -157,7 +158,7 @@ public static class UData
     }
 
     public static void ReverseMultiple(IList<Dynamic> vehicles, int position,
-        Func<Dynamic, string?> setIdOf, Func<Dynamic, Physics?> physicsFor)
+        Func<Dynamic, string?> setIdOf, Func<Dynamic, VehiclePhysics?> physicsFor)
     {
         var indexes = GetMultiple(vehicles, position, setIdOf);
 

StarterNG/Domain/VehicleInfo.cs

@@ -1,12 +1,14 @@
 using StarterNG.Classes;
+using StarterNG.Domain.Vehicles;
+using StarterNG.Application;
 
 namespace StarterNG.Domain;
 
 public sealed class VehicleInfo
 {
-    private readonly VehicleDatabase _db;
+    private readonly VehicleCatalog _db;
 
-    public VehicleInfo(VehicleDatabase db) => _db = db;
+    public VehicleInfo(VehicleCatalog db) => _db = db;
 
     public static string ClassOf(VehicleTexture t) => t.ResolvedClass;
 
@@ -20,11 +22,11 @@ public sealed class VehicleInfo
     public string? CategoryOf(Dynamic car) =>
         TextureFor(car) is { } t ? CategoryOf(t) : null;
 
-    public Physics? PhysicsFor(Dynamic car)
+    public VehiclePhysics? PhysicsFor(Dynamic car)
     {
         string? dbModel = TextureFor(car)?.Model;
-        return Physics.For(car.DataFolder, dbModel)
-            ?? Physics.For(car.DataFolder, car.MmdFile)
-            ?? Physics.For(car.DataFolder, car.SkinFile);
+        return AppServices.Current.Physics.For(car.DataFolder, dbModel)
+            ?? AppServices.Current.Physics.For(car.DataFolder, car.MmdFile)
+            ?? AppServices.Current.Physics.For(car.DataFolder, car.SkinFile);
     }
 }

StarterNG/Domain/Vehicles/VehicleCatalog.cs

@@ -0,0 +1,198 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using StarterNG.Application.Abstractions;
+
+namespace StarterNG.Domain.Vehicles;
+
+/// <summary>
+/// Every livery the installation offers, indexed for the lookups the depot and
+/// the consist editor make: by uuid, by skin file, and by the set a vehicle
+/// belongs to.
+/// </summary>
+/// <remarks>
+/// Was <c>VehicleCatalog</c>, which also owned file enumeration, textures.txt
+/// parsing, a static thumbnail dictionary and a missing-asset scan. Those moved
+/// to Infrastructure; what is left is the model and its resolution rules, filled
+/// by a repository through <see cref="Ingest"/>.
+/// </remarks>
+public sealed class VehicleCatalog
+{
+    private readonly IMiniTextureIndex _minis;
+
+    public VehicleCatalog(IMiniTextureIndex minis)
+    {
+        _minis = minis;
+    }
+
+    /// <summary>Every livery worth offering (wrecks excluded).</summary>
+    public List<VehicleTexture> Textures { get; } = new();
+
+    public Dictionary<string, VehicleGroup> GroupsById { get; } = new();
+
+    public List<VehicleSet> Sets { get; } = new();
+
+    public Dictionary<string, VehicleSet> SetByTextureUuid { get; } = new();
+
+    public Dictionary<string, VehicleTexture> TextureByUuid { get; } = new();
+
+    /// <summary>Liveries by skin file name without extension, lower cased.</summary>
+    public Dictionary<string, VehicleTexture> TextureBySkin { get; } = new();
+
+    public void BeginLoad()
+    {
+        Textures.Clear();
+        GroupsById.Clear();
+        Sets.Clear();
+        SetByTextureUuid.Clear();
+        TextureByUuid.Clear();
+        TextureBySkin.Clear();
+    }
+
+    /// <summary>Adds one vehicle folder's liveries to the catalogue.</summary>
+    public void Ingest(VehicleEntry entry)
+    {
+        foreach (var group in entry.Groups)
+            if (!string.IsNullOrEmpty(group.Id))
+                GroupsById.TryAdd(group.Id, group);
+
+        foreach (var texture in entry.Textures)
+        {
+            if (!string.IsNullOrEmpty(texture.Uuid))
+                TextureByUuid[texture.Uuid] = texture;
+
+            if (!string.IsNullOrEmpty(texture.Skinfile))
+                TextureBySkin.TryAdd(Path.GetFileNameWithoutExtension(texture.Skinfile).ToLowerInvariant(), texture);
+
+            if (texture.Wreck)
+                continue;
+
+            Textures.Add(texture);
+        }
+
+        Sets.AddRange(entry.Sets);
+    }
+
+    /// <summary>Builds the indexes that depend on the catalogue being complete.</summary>
+    public void EndLoad()
+    {
+        BuildSetIndex();
+        ResolveGroupInheritance();
+    }
+
+    /// <summary>The vehicles of the fixed set this livery leads or belongs to.</summary>
+    public List<VehicleTexture>? ResolveSet(VehicleTexture texture)
+    {
+        if (string.IsNullOrEmpty(texture.Uuid))
+            return null;
+        if (!SetByTextureUuid.TryGetValue(texture.Uuid, out var set) || set.TextureRefs is null)
+            return null;
+
+        var cars = new List<VehicleTexture>();
+        foreach (string uuid in set.TextureRefs)
+            if (!string.IsNullOrEmpty(uuid) && TextureByUuid.TryGetValue(uuid, out var car))
+                cars.Add(car);
+
+        return cars.Count > 0 ? cars : null;
+    }
+
+    /// <summary>
+    /// True when the livery is a non-leading member of a set, and so is added
+    /// along with its leader rather than on its own.
+    /// </summary>
+    public bool IsSetFollower(VehicleTexture texture)
+    {
+        if (string.IsNullOrEmpty(texture.Uuid))
+            return false;
+        if (!SetByTextureUuid.TryGetValue(texture.Uuid, out var set) ||
+            set.TextureRefs is null || set.TextureRefs.Count < 2)
+            return false;
+
+        string? lead = set.TextureRefs.FirstOrDefault(reference => !string.IsNullOrEmpty(reference));
+        return lead is not null && !string.Equals(lead, texture.Uuid, StringComparison.OrdinalIgnoreCase);
+    }
+
+    /// <summary>
+    /// The thumbnail to draw for a livery: its own if we have that bitmap,
+    /// otherwise the one its group declares.
+    /// </summary>
+    public string? ResolveMiniName(VehicleTexture texture)
+    {
+        if (_minis.Has(texture.TextureMini))
+            return texture.TextureMini;
+
+        if (texture.Group is not null && GroupsById.TryGetValue(texture.Group, out var group) &&
+            !string.IsNullOrEmpty(group.Mini))
+            return group.Mini;
+
+        return texture.TextureMini;
+    }
+
+    public string? MiniForSkin(string? skinFile) =>
+        TextureForSkin(skinFile) is { } texture ? ResolveMiniName(texture) : null;
+
+    public VehicleTexture? TextureForSkin(string? skinFile)
+    {
+        if (string.IsNullOrEmpty(skinFile))
+            return null;
+
+        string key = Path.GetFileNameWithoutExtension(skinFile).ToLowerInvariant();
+        return TextureBySkin.TryGetValue(key, out var texture) ? texture : null;
+    }
+
+    /// <summary>Heading shown above a group in the depot browser.</summary>
+    public string GroupHeader(string? groupId)
+    {
+        if (string.IsNullOrEmpty(groupId) || !GroupsById.TryGetValue(groupId, out var group))
+            return groupId ?? "";
+
+        string mini = string.IsNullOrEmpty(group.Mini) ? group.Id : group.Mini;
+        return string.IsNullOrEmpty(group.Category) ? mini : $"{mini}  ({group.Category})";
+    }
+
+    private void BuildSetIndex()
+    {
+        foreach (var set in Sets)
+        {
+            if (set.TextureRefs is null)
+                continue;
+
+            foreach (string uuid in set.TextureRefs)
+                if (!string.IsNullOrEmpty(uuid))
+                    SetByTextureUuid[uuid] = set;
+        }
+    }
+
+    /// <summary>
+    /// Copies thumbnail, category and archived status down from each group onto
+    /// its liveries, so the browser can sort and filter without walking back up.
+    /// </summary>
+    private void ResolveGroupInheritance()
+    {
+        foreach (var texture in Textures)
+        {
+            VehicleGroup? group = null;
+            if (texture.Group is not null)
+                GroupsById.TryGetValue(texture.Group, out group);
+
+            string mini = group is not null && !string.IsNullOrEmpty(group.Mini)
+                ? group.Mini
+                : texture.MiniRef ?? "";
+
+            string? category = group?.Category;
+
+            // "*" means "categorise by the first letter of the thumbnail name".
+            if (category == "*")
+            {
+                string source = !string.IsNullOrEmpty(mini) ? mini : texture.TextureMini ?? "";
+                if (source.Length > 0)
+                    category = char.ToUpperInvariant(source[0]).ToString();
+            }
+
+            texture.ResolvedCategory = category;
+            texture.ResolvedClass = mini;
+            texture.ResolvedArchived = group?.Archived ?? false;
+        }
+    }
+}

StarterNG/Domain/Vehicles/VehiclePhysics.cs

@@ -0,0 +1,54 @@
+using System;
+
+namespace StarterNG.Domain.Vehicles;
+
+/// <summary>
+/// The physical properties of a vehicle type, as declared by its .fiz file:
+/// what it weighs, how fast it goes, what it can carry and what it couples to.
+/// </summary>
+/// <remarks>
+/// Was <c>Classes.Physics</c>, which also owned the .fiz index, the parser and a
+/// static cache. Those are now <c>Infrastructure.Vehicles.FizPhysicsRepository</c>;
+/// this is the value the rest of the application reasons about.
+/// </remarks>
+public sealed class VehiclePhysics
+{
+    /// <summary>Tare mass in kilograms.</summary>
+    public double Mass { get; set; }
+
+    /// <summary>Design speed in km/h.</summary>
+    public double VMax { get; set; }
+
+    /// <summary>Length over buffers in metres.</summary>
+    public double Length { get; set; }
+
+    public string LoadAccepted { get; set; } = "";
+
+    public string LoadQ { get; set; } = "";
+
+    public int MaxLoad { get; set; }
+
+    /// <summary>Coupling capabilities of the front end.</summary>
+    public int AllowedFlagA { get; set; } = 3;
+
+    /// <summary>Coupling capabilities of the rear end.</summary>
+    public int AllowedFlagB { get; set; } = 3;
+
+    public string ControlTypeA { get; set; } = "";
+
+    public string ControlTypeB { get; set; } = "";
+
+    public string EngineType { get; set; } = "";
+
+    /// <summary>
+    /// True for the engine types the simulator actually runs its diesel heat model for.
+    /// Mover.cpp calls dizel_Update - and through it dizel_Heat - only for DieselEngine
+    /// and DieselElectric; LoadFIZ_EngineDecode maps the legacy "DumbDE" onto
+    /// DieselElectric. On anything else the coolant temperature struct is written and
+    /// never read.
+    /// </summary>
+    public bool IsDieselEngine =>
+        EngineType.Equals("DieselEngine", StringComparison.OrdinalIgnoreCase)
+        || EngineType.Equals("DieselElectric", StringComparison.OrdinalIgnoreCase)
+        || EngineType.Equals("DumbDE", StringComparison.OrdinalIgnoreCase);
+}

StarterNG/Domain/Vehicles/VehicleTexture.cs

@@ -0,0 +1,97 @@
+using System.Collections.Generic;
+
+namespace StarterNG.Domain.Vehicles;
+
+/// <summary>
+/// One vehicle folder's contribution to the catalogue: the liveries it defines,
+/// the groups they belong to and any fixed sets they form.
+/// </summary>
+public sealed class VehicleEntry
+{
+    public string? Uuid { get; set; }
+    public List<VehicleGroup> Groups { get; } = new();
+    public List<VehicleTexture> Textures { get; } = new();
+    public List<VehicleSet> Sets { get; } = new();
+}
+
+/// <summary>
+/// A family of liveries sharing a thumbnail and a category letter, as declared
+/// by one textures.txt block.
+/// </summary>
+public sealed class VehicleGroup
+{
+    public string Id { get; set; } = "";
+    public string? Category { get; set; }
+    public string? Mini { get; set; }
+
+    /// <summary>Withdrawn stock, hidden from the depot unless asked for.</summary>
+    public bool Archived { get; set; }
+}
+
+/// <summary>A single livery: one skin file on one model.</summary>
+public sealed class VehicleTexture
+{
+    public string? Uuid { get; set; }
+    public string Directory { get; set; } = "";
+    public string Skinfile { get; set; } = "";
+    public string? Model { get; set; }
+    public string? Group { get; set; }
+    public string? MiniRef { get; set; }
+    public string? TextureMini { get; set; }
+
+    /// <summary>Wreck liveries exist in the files but are not offered in the depot.</summary>
+    public bool Wreck { get; set; }
+
+    public List<VehicleAlias> Aliases { get; } = new();
+    public VehicleMeta? Meta { get; set; }
+
+    public string FullPath => Directory + Skinfile;
+
+    /// <summary>Thumbnail name after group inheritance; filled by the catalogue.</summary>
+    public string ResolvedClass { get; internal set; } = "";
+
+    /// <summary>Category letter after group inheritance; filled by the catalogue.</summary>
+    public string? ResolvedCategory { get; internal set; }
+
+    /// <summary>Whether the owning group is archived; filled by the catalogue.</summary>
+    public bool ResolvedArchived { get; internal set; }
+}
+
+/// <summary>An alternative model this same skin can be worn by.</summary>
+public sealed class VehicleAlias
+{
+    public string? Model { get; set; }
+    public string? Group { get; set; }
+    public string? MiniRef { get; set; }
+    public string? TextureMini { get; set; }
+}
+
+/// <summary>
+/// The comma separated description a livery carries after "//": who made it, for
+/// which operator and depot, and when it was last revised.
+/// </summary>
+public sealed class VehicleMeta
+{
+    public string? Raw { get; set; }
+    public string? Version { get; set; }
+    public string? Vehicle { get; set; }
+    public string? Operator { get; set; }
+    public string? Depot { get; set; }
+    public string? RevisionDate { get; set; }
+    public string? RevisionPlace { get; set; }
+    public string? TextureAuthor { get; set; }
+    public string? PhotoAuthor { get; set; }
+    public List<string> Extra { get; } = new();
+}
+
+/// <summary>
+/// Vehicles that belong together and are added to a consist as a unit, such as a
+/// multiple unit or a fixed rake.
+/// </summary>
+public sealed class VehicleSet
+{
+    public string? Uuid { get; set; }
+    public string? Mode { get; set; }
+    public int Count { get; set; }
+    public List<string> TextureRefs { get; set; } = new();
+}

StarterNG/Infrastructure/Adapters/PhysicalFileSystem.cs

@@ -43,6 +43,11 @@ public sealed class PhysicalFileSystem : IFileSystem
     public IReadOnlyList<string> GetFiles(string path, string searchPattern = "*") =>
         Directory.Exists(path) ? Directory.GetFiles(path, searchPattern) : Array.Empty<string>();
 
+    public IReadOnlyList<string> GetFilesRecursive(string path, string searchPattern) =>
+        Directory.Exists(path)
+            ? Directory.GetFiles(path, searchPattern, SearchOption.AllDirectories)
+            : Array.Empty<string>();
+
     public IReadOnlyList<string> GetDirectories(string path) =>
         Directory.Exists(path) ? Directory.GetDirectories(path) : Array.Empty<string>();
 

StarterNG/Infrastructure/Diagnostics.cs

@@ -70,6 +70,8 @@ public static class Diagnostics
         new InstallationCheck(
                 AppServices.Current.Paths,
                 AppServices.Current.Files,
-                AppServices.Current.Localization)
+                AppServices.Current.Localization,
+                AppServices.Current.Physics,
+                AppServices.Current.Library)
             .Run();
 }

StarterNG/Infrastructure/InstallationCheck.cs

@@ -2,6 +2,7 @@ using System.Collections.Generic;
 using System.IO;
 using StarterNG.Application.Abstractions;
 using StarterNG.Classes;
+using StarterNG.Application;
 
 namespace StarterNG.Infrastructure;
 
@@ -20,12 +21,17 @@ public sealed class InstallationCheck
     private readonly IGamePaths _paths;
     private readonly IFileSystem _files;
     private readonly ILocalizedStrings _strings;
+    private readonly IPhysicsRepository _physics;
+    private readonly GameLibrary _library;
 
-    public InstallationCheck(IGamePaths paths, IFileSystem files, ILocalizedStrings strings)
+    public InstallationCheck(IGamePaths paths, IFileSystem files, ILocalizedStrings strings,
+                             IPhysicsRepository physics, GameLibrary library)
     {
         _paths = paths;
         _files = files;
         _strings = strings;
+        _physics = physics;
+        _library = library;
     }
 
     public List<string> Run()
@@ -39,13 +45,13 @@ public sealed class InstallationCheck
         if (!_files.FileExists(Path.Combine(_paths.Data, "load_weights.txt")))
             faults.Add(_strings["FaultNoWeights"]);
 
-        if (GameData.Instance.Sceneries.Count == 0)
+        if (_library.Sceneries.Count == 0)
             faults.Add(_strings["FaultNoScenery"]);
 
-        if (GameData.Instance.Vehicles.Textures.Count == 0)
+        if (_library.Vehicles.Textures.Count == 0)
             faults.Add(_strings["FaultNoVehicles"]);
 
-        if (Physics.IndexedCount == 0)
+        if (_physics.IndexedCount == 0)
             faults.Add(_strings["FaultNoPhysics"]);
 
         if (Settings.Instance.ResolveExecutable(out var problem) is var _ && problem == ExeProblem.NotFound)

StarterNG/Infrastructure/Vehicles/FizPhysicsRepository.cs

@@ -0,0 +1,284 @@
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Globalization;
+using System.IO;
+using System.Linq;
+using System.Text;
+using StarterNG.Application.Abstractions;
+using StarterNG.Domain.Vehicles;
+
+namespace StarterNG.Infrastructure.Vehicles;
+
+/// <summary>
+/// Reads vehicle physics from the .fiz files under dynamic/.
+/// </summary>
+/// <remarks>
+/// The format is a flat token stream of "section" headings and "key value"
+/// pairs, with an <c>include file p1 p2 end</c> directive whose parameters are
+/// substituted for <c>(1)</c>-style placeholders in the included file. Only the
+/// handful of keys the starter shows are decoded; everything else is skipped.
+///
+/// Both the name index and the parsed results are cached, because the depot asks
+/// for the same model repeatedly while the user scrolls.
+/// </remarks>
+public sealed class FizPhysicsRepository : IPhysicsRepository
+{
+    /// <summary>Guard against an include cycle in hand written files.</summary>
+    private const int MaxIncludeDepth = 6;
+
+    /// <summary>Sentinel meaning "the rear coupler was never declared".</summary>
+    private const int UndeclaredCoupler = -1;
+
+    private static readonly HashSet<string> KnownKeys = new(StringComparer.OrdinalIgnoreCase)
+    {
+        "M", "Vmax", "L", "LoadAccepted", "LoadQ", "MaxLoad", "AllowedFlag", "ControlType", "EngineType"
+    };
+
+    private readonly IFileSystem _files;
+    private readonly IGamePaths _paths;
+    private readonly IDiagnosticsLog _log;
+    private readonly Encoding _encoding;
+
+    private readonly ConcurrentDictionary<string, VehiclePhysics?> _cache =
+        new(StringComparer.OrdinalIgnoreCase);
+
+    private readonly object _indexGate = new();
+    private Dictionary<string, string>? _index;
+
+    public FizPhysicsRepository(IFileSystem files, IGamePaths paths, IDiagnosticsLog log)
+    {
+        _files = files;
+        _paths = paths;
+        _log = log;
+        _encoding = LegacyEncoding();
+    }
+
+    public void Preload() => Index();
+
+    public int IndexedCount => _index?.Count ?? 0;
+
+    public VehiclePhysics? For(string? dataFolder, string? model)
+    {
+        if (string.IsNullOrEmpty(model))
+            return null;
+
+        string name = Path.GetFileNameWithoutExtension(model);
+        if (name.Length == 0)
+            return null;
+
+        if (_cache.TryGetValue(name, out var cached))
+            return cached;
+
+        var physics = Read(name);
+        _cache[name] = physics;
+        return physics;
+    }
+
+    private VehiclePhysics? Read(string name)
+    {
+        var index = Index();
+
+        // Unpowered variants are shipped as "<model>dumb.fiz".
+        if (!index.TryGetValue(name, out string? path) &&
+            !index.TryGetValue(name + "dumb", out path))
+            return null;
+
+        var physics = new VehiclePhysics { AllowedFlagB = UndeclaredCoupler };
+        try
+        {
+            Parse(physics, path, Path.GetDirectoryName(path) ?? "", parameters: null, depth: 0);
+        }
+        catch (Exception ex)
+        {
+            _log.Log($"physics/{Path.GetFileName(path)}", ex);
+        }
+
+        // A vehicle that only declares one coupler has the same at both ends.
+        if (physics.AllowedFlagB == UndeclaredCoupler)
+        {
+            physics.AllowedFlagB = physics.AllowedFlagA;
+            if (string.IsNullOrEmpty(physics.ControlTypeB))
+                physics.ControlTypeB = physics.ControlTypeA;
+        }
+
+        return physics;
+    }
+
+    private Dictionary<string, string> Index()
+    {
+        lock (_indexGate)
+        {
+            if (_index is not null)
+                return _index;
+
+            var index = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+            try
+            {
+                foreach (string file in _files.GetFilesRecursive(_paths.Dynamic, "*.fiz"))
+                    index[Path.GetFileNameWithoutExtension(file)] = file;
+            }
+            catch (Exception ex)
+            {
+                _log.Log($"indexing {_paths.Dynamic}", ex);
+            }
+
+            _index = index;
+            return index;
+        }
+    }
+
+    private void Parse(VehiclePhysics physics, string path, string directory, string[]? parameters, int depth)
+    {
+        if (depth > MaxIncludeDepth || !_files.FileExists(path))
+            return;
+
+        var tokens = Tokenize(_files.ReadAllText(path, _encoding));
+
+        string section = "";
+        string? pendingKey = null;
+
+        for (int i = 0; i < tokens.Count; i++)
+        {
+            string token = tokens[i];
+            if (token == "=")
+                continue;
+
+            if (token.Equals("include", StringComparison.OrdinalIgnoreCase))
+            {
+                if (++i >= tokens.Count)
+                    break;
+
+                string includeFile = Resolve(tokens[i], parameters);
+                var includeParameters = new List<string>();
+                i++;
+                while (i < tokens.Count && !tokens[i].Equals("end", StringComparison.OrdinalIgnoreCase))
+                    includeParameters.Add(Resolve(tokens[i++], parameters));
+
+                Parse(physics, Path.Combine(directory, includeFile), directory, includeParameters.ToArray(),
+                      depth + 1);
+                pendingKey = null;
+                continue;
+            }
+
+            int equals = token.IndexOf('=');
+            if (equals >= 0)
+            {
+                string key = token[..equals].TrimStart('.').Trim();
+                string value = token[(equals + 1)..].Trim();
+                if (value.Length == 0)
+                {
+                    pendingKey = key;
+                    continue;
+                }
+                Apply(physics, section, key, Resolve(value, parameters));
+                pendingKey = null;
+                continue;
+            }
+
+            string bare = token.TrimStart('.').Trim();
+            if (pendingKey is not null)
+            {
+                Apply(physics, section, pendingKey, Resolve(bare, parameters));
+                pendingKey = null;
+            }
+            else if (KnownKeys.Contains(bare))
+            {
+                pendingKey = bare;
+            }
+            else
+            {
+                // Anything else at this level opens a section, e.g. "Param:" or "BuffCoupl1:".
+                section = new string(bare.Where(char.IsLetterOrDigit).ToArray()).ToLowerInvariant();
+            }
+        }
+    }
+
+    private static void Apply(VehiclePhysics physics, string section, string key, string value)
+    {
+        switch (section)
+        {
+            case "param":
+                if (Is(key, "M")) physics.Mass = ParseDouble(value, physics.Mass);
+                else if (Is(key, "Vmax")) physics.VMax = ParseDouble(value, physics.VMax);
+                break;
+            case "load":
+                if (Is(key, "LoadAccepted")) physics.LoadAccepted = value;
+                else if (Is(key, "LoadQ")) physics.LoadQ = value;
+                else if (Is(key, "MaxLoad")) physics.MaxLoad = (int)ParseDouble(value, physics.MaxLoad);
+                break;
+            case "engine":
+                if (Is(key, "EngineType")) physics.EngineType = value;
+                break;
+            case "dimensions":
+                if (Is(key, "L")) physics.Length = ParseDouble(value, physics.Length);
+                break;
+            case "buffcoupl":
+            case "buffcoupl1":
+                if (Is(key, "AllowedFlag")) physics.AllowedFlagA = ParseFlag(value, physics.AllowedFlagA);
+                else if (Is(key, "ControlType")) physics.ControlTypeA = value;
+                break;
+            case "buffcoupl2":
+                if (Is(key, "AllowedFlag")) physics.AllowedFlagB = ParseFlag(value, physics.AllowedFlagB);
+                else if (Is(key, "ControlType")) physics.ControlTypeB = value;
+                break;
+        }
+    }
+
+    private static bool Is(string key, string name) => key.Equals(name, StringComparison.OrdinalIgnoreCase);
+
+    /// <summary>
+    /// A negative flag means the coupling is present but disabled; the simulator
+    /// encodes that as its absolute value plus 128.
+    /// </summary>
+    private static int ParseFlag(string value, int fallback) =>
+        int.TryParse(value, NumberStyles.Integer, CultureInfo.InvariantCulture, out int flag)
+            ? flag < 0 ? -flag + 128 : flag
+            : fallback;
+
+    private static double ParseDouble(string value, double fallback) =>
+        double.TryParse(value, NumberStyles.Float, CultureInfo.InvariantCulture, out double parsed)
+            ? parsed
+            : fallback;
+
+    /// <summary>Substitutes an include's "(n)" placeholder with its n-th parameter.</summary>
+    private static string Resolve(string token, string[]? parameters)
+    {
+        if (parameters is null || token.Length < 3 || token[0] != '(' || token[^1] != ')')
+            return token;
+
+        string digits = new(token.Where(char.IsDigit).ToArray());
+        return int.TryParse(digits, out int index) && index >= 1 && index <= parameters.Length
+            ? parameters[index - 1]
+            : token;
+    }
+
+    private static List<string> Tokenize(string text)
+    {
+        var sb = new StringBuilder();
+        foreach (string line in text.Split('\n'))
+        {
+            string stripped = line;
+            int comment = stripped.IndexOf('#');
+            if (comment >= 0)
+                stripped = stripped[..comment];
+            sb.Append(stripped).Append(' ');
+        }
+
+        return sb.ToString()
+                 .Split(new[] { ' ', '\t', '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries)
+                 .ToList();
+    }
+
+    private static Encoding LegacyEncoding()
+    {
+        try
+        {
+            return Encoding.GetEncoding(1250);
+        }
+        catch (Exception)
+        {
+            return Encoding.Latin1;
+        }
+    }
+}

StarterNG/Infrastructure/Vehicles/MiniTextureIndex.cs

@@ -0,0 +1,65 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using StarterNG.Application.Abstractions;
+
+namespace StarterNG.Infrastructure.Vehicles;
+
+/// <summary>
+/// <see cref="IMiniTextureIndex"/> over the installation's textures/mini folder.
+/// </summary>
+/// <remarks>
+/// Replaces the static thumbnail dictionary that used to live on the vehicle
+/// database: an installation-scoped lookup with its own lifetime, which is what
+/// lets a test point the depot at thumbnails that only exist in memory.
+/// </remarks>
+public sealed class MiniTextureIndex : IMiniTextureIndex
+{
+    /// <summary>Thumbnail shown when a vehicle names one we do not have.</summary>
+    private const string FallbackName = "other";
+
+    private readonly IFileSystem _files;
+    private readonly IGamePaths _paths;
+    private readonly object _gate = new();
+
+    private Dictionary<string, string>? _index;
+
+    public MiniTextureIndex(IFileSystem files, IGamePaths paths)
+    {
+        _files = files;
+        _paths = paths;
+    }
+
+    public void Preload() => Index();
+
+    public bool Has(string? miniName) =>
+        !string.IsNullOrEmpty(miniName) && Index().ContainsKey(miniName.ToLowerInvariant());
+
+    public string? PathFor(string? miniName)
+    {
+        if (!string.IsNullOrEmpty(miniName) &&
+            Index().TryGetValue(miniName.ToLowerInvariant(), out string? path))
+            return path;
+
+        return FallbackPath;
+    }
+
+    public string? FallbackPath =>
+        Index().TryGetValue(FallbackName, out string? path) ? path : null;
+
+    private Dictionary<string, string> Index()
+    {
+        lock (_gate)
+        {
+            if (_index is not null)
+                return _index;
+
+            var index = new Dictionary<string, string>(StringComparer.Ordinal);
+            foreach (string file in _files.GetFiles(_paths.MiniTextures, "*.bmp"))
+                index[Path.GetFileNameWithoutExtension(file).ToLowerInvariant()] = file;
+
+            _index = index;
+            return index;
+        }
+    }
+}

StarterNG/Infrastructure/Vehicles/MissingAssetScanner.cs

@@ -0,0 +1,63 @@
+using System.Collections.Generic;
+using System.IO;
+using StarterNG.Application.Abstractions;
+using StarterNG.Domain.Vehicles;
+
+namespace StarterNG.Infrastructure.Vehicles;
+
+/// <summary>
+/// Reports liveries whose skin or model file is not actually present, for the
+/// optional "log missing vehicle files" diagnostic.
+/// </summary>
+/// <remarks>
+/// Both assets are looked up under several extensions because the simulator
+/// accepts a texture as .mat or .bmp and a model as .t3d or .e3d.
+/// </remarks>
+public sealed class MissingAssetScanner
+{
+    private static readonly string[] TextureExtensions = { ".mat", ".bmp" };
+    private static readonly string[] ModelExtensions = { ".t3d", ".e3d" };
+
+    private readonly IFileSystem _files;
+    private readonly IGamePaths _paths;
+
+    public MissingAssetScanner(IFileSystem files, IGamePaths paths)
+    {
+        _files = files;
+        _paths = paths;
+    }
+
+    public List<string> Scan(VehicleCatalog catalog)
+    {
+        var lines = new List<string>();
+
+        foreach (var texture in catalog.Textures)
+        {
+            string directory = Path.Combine(
+                _paths.Dynamic,
+                texture.Directory.Replace('/', Path.DirectorySeparatorChar).TrimEnd('\\', '/'));
+
+            if (!string.IsNullOrEmpty(texture.Skinfile) &&
+                !ExistsWithAnyExtension(Path.Combine(directory, texture.Skinfile), TextureExtensions))
+                lines.Add($"# no file: {texture.Directory}{texture.Skinfile}");
+
+            if (!string.IsNullOrEmpty(texture.Model) &&
+                !ExistsWithAnyExtension(Path.Combine(directory, texture.Model), ModelExtensions))
+                lines.Add($"# no model: {texture.Directory}{texture.Model}");
+        }
+
+        return lines;
+    }
+
+    private bool ExistsWithAnyExtension(string path, string[] extensions)
+    {
+        if (_files.FileExists(path))
+            return true;
+
+        foreach (string extension in extensions)
+            if (_files.FileExists(Path.ChangeExtension(path, extension)))
+                return true;
+
+        return false;
+    }
+}

StarterNG/Infrastructure/Vehicles/TexturesTxtParser.cs

@@ -0,0 +1,204 @@
+using System;
+using System.Collections.Generic;
+using StarterNG.Domain.Vehicles;
+
+namespace StarterNG.Infrastructure.Vehicles;
+
+/// <summary>
+/// Reads one vehicle folder's textures.txt into a <see cref="VehicleEntry"/>.
+/// </summary>
+/// <remarks>
+/// The format is line oriented and stateful: '$a' marks the rest of the file as
+/// archived, '!=' sets the category letter, and '^n' opens a fixed set of n
+/// vehicles. Everything else with an '=' is a livery. Unknown lines are skipped
+/// rather than rejected, because the files are hand written.
+///
+/// Pure text in, model out: the repository does the reading, so the format can
+/// be tested from a string array.
+/// </remarks>
+public sealed class TexturesTxtParser
+{
+    /// <summary>Category letter meaning "derive it from the thumbnail name".</summary>
+    private const string DeriveCategory = "*";
+
+    /// <summary>
+    /// Parses the file's lines. Returns null when the folder declares no liveries.
+    /// </summary>
+    /// <param name="directory">
+    /// The folder path relative to dynamic/, with a trailing slash; it forms the
+    /// livery ids and is what the scenery format writes as the data folder.
+    /// </param>
+    public VehicleEntry? Parse(string directory, IReadOnlyList<string> lines)
+    {
+        var entry = new VehicleEntry { Uuid = "legacy:" + directory };
+
+        bool archived = false;
+        string categorySign = DeriveCategory;
+        int setSize = 0;
+        var pendingSet = new List<string>();
+
+        foreach (string raw in lines)
+        {
+            string line = raw.Trim();
+            if (line.Length == 0)
+                continue;
+
+            char first = line[0];
+            if (first is '#' or '@' or '*')
+                continue;
+
+            if (line.StartsWith("$a", StringComparison.OrdinalIgnoreCase))
+            {
+                archived = true;
+                continue;
+            }
+
+            if (first == '^')
+            {
+                FlushSet(entry, pendingSet, setSize);
+                setSize = line.Length > 1 && char.IsDigit(line[1]) ? line[1] - '0' : 0;
+                continue;
+            }
+
+            if (line.StartsWith("!=", StringComparison.Ordinal))
+            {
+                categorySign = line.Length > 2 ? line[2].ToString() : DeriveCategory;
+                continue;
+            }
+
+            if (line.IndexOf('=') < 0 || line.StartsWith("//", StringComparison.Ordinal))
+                continue;
+
+            var texture = ParseLivery(line, directory, categorySign, archived, entry);
+            if (texture is null)
+                continue;
+
+            entry.Textures.Add(texture);
+
+            if (setSize > 1)
+            {
+                pendingSet.Add(texture.Uuid!);
+                if (pendingSet.Count == setSize)
+                    FlushSet(entry, pendingSet, setSize);
+            }
+        }
+
+        FlushSet(entry, pendingSet, setSize);
+        return entry.Textures.Count > 0 ? entry : null;
+    }
+
+    private static void FlushSet(VehicleEntry entry, List<string> pending, int size)
+    {
+        if (pending.Count > 1)
+            entry.Sets.Add(new VehicleSet
+            {
+                Uuid = "legacy-set:" + pending[0],
+                Mode = "sequence",
+                Count = size > 0 ? size : pending.Count,
+                TextureRefs = new List<string>(pending)
+            });
+
+        pending.Clear();
+    }
+
+    private static VehicleTexture? ParseLivery(string line, string directory, string categorySign, bool archived,
+                                               VehicleEntry entry)
+    {
+        string description = "";
+        int comment = line.IndexOf("//", StringComparison.Ordinal);
+        if (comment >= 0)
+        {
+            description = line[(comment + 2)..].Trim();
+            line = line[..comment].Trim();
+        }
+
+        string[] parts = line.Split('=');
+        if (parts.Length < 2)
+            return null;
+
+        string skin = StripExtension(parts[0].Trim());
+        if (skin.Length == 0)
+            return null;
+
+        // Every "=" segment is "model, thumbnail[, per-texture thumbnail]"; the
+        // first is the livery proper and the rest are alternative models.
+        var specs = new List<(string Model, string Mini, string TextureMini)>();
+        for (int i = 1; i < parts.Length; i++)
+        {
+            string[] fields = parts[i].Split(',');
+            if (fields.Length < 2)
+                continue;
+            specs.Add((fields[0].Trim(), fields[1].Trim(), fields.Length > 2 ? fields[2].Trim() : ""));
+        }
+        if (specs.Count == 0)
+            return null;
+
+        var lead = specs[0];
+        string groupId = $"legacy:{directory}:{lead.Mini}:{categorySign}:{(archived ? 1 : 0)}";
+
+        if (!entry.Groups.Exists(group => group.Id == groupId))
+            entry.Groups.Add(new VehicleGroup
+            {
+                Id = groupId,
+                Category = categorySign,
+                Mini = lead.Mini,
+                Archived = archived
+            });
+
+        var texture = new VehicleTexture
+        {
+            Uuid = $"legacy:{directory}{skin}",
+            Directory = directory,
+            Skinfile = skin,
+            Wreck = skin.Contains("wreck", StringComparison.OrdinalIgnoreCase) ||
+                    skin.Contains("wrak", StringComparison.OrdinalIgnoreCase),
+            Model = lead.Model,
+            Group = groupId,
+            MiniRef = lead.Mini,
+            TextureMini = string.IsNullOrEmpty(lead.TextureMini) ? null : lead.TextureMini,
+            Meta = ParseDescription(description)
+        };
+
+        for (int i = 1; i < specs.Count; i++)
+            texture.Aliases.Add(new VehicleAlias
+            {
+                Model = specs[i].Model,
+                MiniRef = specs[i].Mini,
+                TextureMini = string.IsNullOrEmpty(specs[i].TextureMini) ? null : specs[i].TextureMini
+            });
+
+        return texture;
+    }
+
+    /// <summary>
+    /// The trailing comment is a fixed, comma separated credit line. Underscores
+    /// stand in for spaces, a convention from the era the format comes from.
+    /// </summary>
+    private static VehicleMeta? ParseDescription(string description)
+    {
+        if (string.IsNullOrWhiteSpace(description))
+            return null;
+
+        string[] fields = description.Replace('_', ' ').Split(',');
+        string At(int index) => index < fields.Length ? fields[index].Trim() : "";
+
+        return new VehicleMeta
+        {
+            Raw = description,
+            Version = At(0),
+            Vehicle = At(1),
+            Operator = At(2),
+            Depot = At(3),
+            RevisionDate = At(4),
+            RevisionPlace = At(5),
+            TextureAuthor = At(6),
+            PhotoAuthor = At(7)
+        };
+    }
+
+    private static string StripExtension(string name)
+    {
+        int dot = name.LastIndexOf('.');
+        return dot > 0 ? name[..dot] : name;
+    }
+}

StarterNG/Infrastructure/Vehicles/TexturesTxtVehicleRepository.cs

@@ -0,0 +1,112 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Text;
+using StarterNG.Application.Abstractions;
+using StarterNG.Domain.Vehicles;
+
+namespace StarterNG.Infrastructure.Vehicles;
+
+/// <summary>
+/// Loads the catalogue from the dynamic/&lt;maker&gt;/&lt;vehicle&gt;/textures.txt
+/// files an installation ships.
+/// </summary>
+public sealed class TexturesTxtVehicleRepository : IVehicleRepository
+{
+    private const string TexturesFileName = "textures.txt";
+
+    private readonly IFileSystem _files;
+    private readonly IGamePaths _paths;
+    private readonly IDiagnosticsLog _log;
+    private readonly TexturesTxtParser _parser;
+    private readonly Encoding _encoding;
+
+    public TexturesTxtVehicleRepository(IFileSystem files, IGamePaths paths, IDiagnosticsLog log,
+                                        TexturesTxtParser parser)
+    {
+        _files = files;
+        _paths = paths;
+        _log = log;
+        _parser = parser;
+        _encoding = LegacyEncoding();
+    }
+
+    public int Load(VehicleCatalog catalog)
+    {
+        catalog.BeginLoad();
+
+        int liveries = 0;
+        foreach (string file in TexturesFiles())
+        {
+            var entry = ReadEntry(file);
+            if (entry is null)
+                continue;
+
+            liveries += entry.Textures.Count;
+            catalog.Ingest(entry);
+        }
+
+        catalog.EndLoad();
+        return liveries;
+    }
+
+    private VehicleEntry? ReadEntry(string path)
+    {
+        try
+        {
+            // Read as text so the code page survives: the credit lines carry
+            // Polish characters that ReadAllLines' default encoding would mangle.
+            string[] lines = _files.ReadAllText(path, _encoding).Split('\n');
+            return _parser.Parse(RelativeDirectory(path), lines);
+        }
+        catch (Exception ex)
+        {
+            _log.Log($"textures.txt {path}", ex);
+            return null;
+        }
+    }
+
+    /// <summary>
+    /// Rolling stock sits exactly two levels below dynamic/: a maker folder and a
+    /// vehicle folder.
+    /// </summary>
+    private IEnumerable<string> TexturesFiles()
+    {
+        foreach (string maker in _files.GetDirectories(_paths.Dynamic))
+        foreach (string vehicle in _files.GetDirectories(maker))
+        {
+            string path = Path.Combine(vehicle, TexturesFileName);
+            if (_files.FileExists(path))
+                yield return path;
+        }
+    }
+
+    /// <summary>
+    /// The folder as the scenery format spells it: relative to dynamic/, forward
+    /// slashes, trailing slash.
+    /// </summary>
+    private string RelativeDirectory(string texturesPath)
+    {
+        string directory = Path.GetDirectoryName(texturesPath) ?? "";
+        string full = Path.GetFullPath(directory);
+        string root = Path.GetFullPath(_paths.Dynamic);
+
+        string relative = full.StartsWith(root, StringComparison.OrdinalIgnoreCase)
+            ? full[root.Length..].TrimStart(Path.DirectorySeparatorChar, '/')
+            : directory;
+
+        return relative.Replace('\\', '/').TrimEnd('/') + "/";
+    }
+
+    private static Encoding LegacyEncoding()
+    {
+        try
+        {
+            return Encoding.GetEncoding(1250);
+        }
+        catch (Exception)
+        {
+            return Encoding.Latin1;
+        }
+    }
+}

StarterNG/SplashWindow.axaml.cs

@@ -1,5 +1,6 @@
-using Avalonia.Controls;
+using Avalonia.Controls;
 using StarterNG.Classes;
+using StarterNG.Application;
 
 namespace StarterNG;
 

StarterNG/Views/Depot.axaml.cs

@@ -19,14 +19,16 @@ using Avalonia.VisualTree;
 using StarterNG.Classes;
 using StarterNG.Domain;
 using StarterNG.Domain.Sceneries;
+using StarterNG.Domain.Vehicles;
+using StarterNG.Application;
 
 namespace StarterNG.Views;
 
 public partial class Depot : UserControl
 {
 
-    private readonly VehicleDatabase _db = GameData.Instance.Vehicles;
-    private readonly List<Scenery> _sceneries = GameData.Instance.Sceneries;
+    private readonly VehicleCatalog _db = AppServices.Current.Library.Vehicles;
+    private readonly List<Scenery> _sceneries = AppServices.Current.Library.Sceneries;
 
     private readonly VehicleInfo _info;
 

StarterNG/Views/Depot/ConsistDragging.cs

@@ -9,6 +9,7 @@ using Avalonia.Media.Imaging;
 using StarterNG.Classes;
 using StarterNG.Domain;
 using StarterNG.Infrastructure;
+using StarterNG.Domain.Vehicles;
 
 namespace StarterNG.Views;
 

StarterNG/Views/Depot/MiniTextures.cs

@@ -5,6 +5,7 @@ using Avalonia.Media;
 using Avalonia.Media.Imaging;
 
 using StarterNG.Classes;
+using StarterNG.Application;
 
 namespace StarterNG.Views;
 
@@ -28,7 +29,7 @@ public sealed class MiniTextures
     {
         if (string.IsNullOrEmpty(name))
             return null;
-        if (strict && !VehicleDatabase.HasMini(name))
+        if (strict && !AppServices.Current.MiniTextures.Has(name))
             return null;
 
         string key = $"{(strict ? "!" : "")}{name}@{height}";
@@ -36,7 +37,7 @@ public sealed class MiniTextures
             return cached;
 
         Bitmap? bmp = null;
-        string? path = VehicleDatabase.MiniPath(name);
+        string? path = AppServices.Current.MiniTextures.PathFor(name);
         if (path != null)
         {
             try

StarterNG/Views/Depot/VehicleBrowser.cs

@@ -15,6 +15,7 @@ using Avalonia.Threading;
 using StarterNG.Classes;
 using StarterNG.Domain;
 using StarterNG.Domain.Sceneries;
+using StarterNG.Domain.Vehicles;
 
 namespace StarterNG.Views;
 
@@ -28,7 +29,7 @@ public sealed class VehicleBrowser
     private readonly Image miniPreview;
     private readonly Button addVehicleButton;
 
-    private readonly VehicleDatabase _db;
+    private readonly VehicleCatalog _db;
     private readonly MiniTextures _minis;
     private readonly Action _openTextureBase;
 
@@ -57,7 +58,7 @@ public sealed class VehicleBrowser
     public VehicleBrowser(
         ComboBox categoryCombo, ComboBox classCombo, ListBox vehicleListBox, TextBox searchBox,
         CheckBox hideArchivalCheck, Image miniPreview, Button addVehicleButton,
-        VehicleDatabase db, MiniTextures minis, Action openTextureBase)
+        VehicleCatalog db, MiniTextures minis, Action openTextureBase)
     {
         this.categoryCombo = categoryCombo;
         this.classCombo = classCombo;

StarterNG/Views/Depot/VehicleCards.cs

@@ -12,6 +12,7 @@ using Material.Icons.Avalonia;
 
 using StarterNG.Classes;
 using StarterNG.Domain;
+using StarterNG.Domain.Vehicles;
 
 namespace StarterNG.Views;
 
@@ -19,7 +20,7 @@ public sealed class VehicleCards
 {
     private readonly Panel consistStack;
 
-    private readonly VehicleDatabase _db;
+    private readonly VehicleCatalog _db;
     private readonly Consist _consist;
     private readonly Cargo _cargo;
     private readonly MiniTextures _minis;
@@ -36,7 +37,7 @@ public sealed class VehicleCards
 
     public Dynamic? PressedCar { get; set; }
 
-    public VehicleCards(Panel consistStack, VehicleDatabase db, Consist consist,
+    public VehicleCards(Panel consistStack, VehicleCatalog db, Consist consist,
                               Cargo cargo, MiniTextures minis, Cursor hand,
                               Action redraw, Action refreshDetails, Action<Dynamic> selectInBrowser,
                               Action<int, PointerPressedEventArgs> armDrag)

StarterNG/Views/Depot/VehicleDetails.cs

@@ -12,6 +12,7 @@ using Avalonia.Media;
 using StarterNG.Classes;
 using StarterNG.Controls;
 using StarterNG.Domain;
+using StarterNG.Domain.Vehicles;
 
 namespace StarterNG.Views;
 
@@ -26,7 +27,7 @@ public sealed class VehicleDetails
     private readonly StackPanel damagePanel;
     private readonly Button removeVehicleButton;
 
-    private readonly VehicleDatabase _db;
+    private readonly VehicleCatalog _db;
     private readonly VehicleInfo _info;
     private readonly Consist _consist;
     private readonly Cargo _cargo;
@@ -41,7 +42,7 @@ public sealed class VehicleDetails
         Panel couplerActions,
         StackPanel brakesPanel, StackPanel loadsPanel, StackPanel damagePanel,
         Button removeVehicleButton,
-        VehicleDatabase db, VehicleInfo info, Consist consist, Cargo cargo, Cursor hand,
+        VehicleCatalog db, VehicleInfo info, Consist consist, Cargo cargo, Cursor hand,
         Action redraw, Action refreshChrome, Action<VehicleTexture, StackPanel> showTextureInfo)
     {
         this.generalPanel = generalPanel;

StarterNG/Views/RulesWindow.cs

@@ -9,6 +9,8 @@ using Avalonia.Media;
 using StarterNG.Classes;
 using StarterNG.Domain;
 using StarterNG.Infrastructure;
+using StarterNG.Domain.Vehicles;
+using StarterNG.Application;
 
 namespace StarterNG.Views;
 
@@ -19,7 +21,7 @@ public sealed class RulesWindow : Window
     private readonly WrapPanel _members = new() { Orientation = Orientation.Horizontal };
     private readonly ComboBox _category = new();
     private readonly ComboBox _model = new();
-    private readonly VehicleDatabase _db = GameData.Instance.Vehicles;
+    private readonly VehicleCatalog _db = AppServices.Current.Library.Vehicles;
 
     public RulesWindow()
     {

StarterNG/Views/Scenarios.axaml.cs

@@ -38,7 +38,7 @@ public partial class Scenarios : UserControl
     {
         InitializeComponent();
 
-        Sceneries = GameData.Instance.Sceneries;
+        Sceneries = AppServices.Current.Library.Sceneries;
 
         _loadingFilters = true;
         archivalSwitch.IsChecked = !StarterNG.Classes.Settings.Instance.ShowArchivalSceneries;
@@ -339,7 +339,7 @@ public partial class Scenarios : UserControl
         var lines = new List<string>();
         lines.AddRange(scenery.Faults);
 
-        var db = GameData.Instance.Vehicles;
+        var db = AppServices.Current.Library.Vehicles;
         foreach (var ts in scenery.Trainsets)
         {
             if (!ts.Parsed)
@@ -423,8 +423,8 @@ public partial class Scenarios : UserControl
         try
         {
             string? selected = AppState.Instance.CurrentScenery?.Path;
-            await Task.Run(() => GameData.Instance.ReloadSceneries());
-            Sceneries = GameData.Instance.Sceneries;
+            await Task.Run(() => AppServices.Current.Library.ReloadSceneries());
+            Sceneries = AppServices.Current.Library.Sceneries;
             BuildSceneryTree();
             if (!string.IsNullOrEmpty(selected))
             {
@@ -486,7 +486,7 @@ public partial class Scenarios : UserControl
             return cached;
 
         Bitmap? bmp = null;
-        string? path = VehicleDatabase.MiniPath(name);
+        string? path = AppServices.Current.MiniTextures.PathFor(name);
         if (path != null)
         {
             try
@@ -888,12 +888,12 @@ public partial class Scenarios : UserControl
                 UpdateTrainStats(trainset);
             });
 
-        var db = GameData.Instance.Vehicles;
+        var db = AppServices.Current.Library.Vehicles;
         foreach (var train in trainset.Vehicles)
         {
 
             string miniName = db.MiniForSkin(train.SkinFile) ?? train.SkinFile;
-            if (!VehicleDatabase.HasMini(miniName) && VehicleDatabase.HasMini(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;
 
@@ -1193,12 +1193,12 @@ public partial class Scenarios : UserControl
             return;
         }
 
-        var db = GameData.Instance.Vehicles;
+        var db = AppServices.Current.Library.Vehicles;
         StarterNG.Infrastructure.StatsBar.Fill(trainStats, TrainsetDisplay.StatsFields(
             trainset,
-            car => Physics.For(car.DataFolder, db.TextureForSkin(car.SkinFile)?.Model)
-                   ?? Physics.For(car.DataFolder, car.MmdFile)
-                   ?? Physics.For(car.DataFolder, car.SkinFile),
+            car => AppServices.Current.Physics.For(car.DataFolder, db.TextureForSkin(car.SkinFile)?.Model)
+                   ?? AppServices.Current.Physics.For(car.DataFolder, car.MmdFile)
+                   ?? AppServices.Current.Physics.For(car.DataFolder, car.SkinFile),
             car => db.TextureForSkin(car.SkinFile)?.ResolvedCategory));
     }
 

StarterNG/Views/TextureBaseWindow.axaml.cs

@@ -8,12 +8,14 @@ using Avalonia.Input;
 using Avalonia.Input.Platform;
 using Avalonia.Interactivity;
 using StarterNG.Classes;
+using StarterNG.Domain.Vehicles;
+using StarterNG.Application;
 
 namespace StarterNG.Views;
 
 public partial class TextureBaseWindow : Window
 {
-    private readonly VehicleDatabase _db = GameData.Instance.Vehicles;
+    private readonly VehicleCatalog _db = AppServices.Current.Library.Vehicles;
     private readonly List<TextureRow> _all = new();
 
     public VehicleTexture? Picked { get; private set; }
@@ -193,7 +195,7 @@ internal sealed class TextureRow
     public string Directory { get; }
     public DateTime? RevisionDate { get; }
 
-    public TextureRow(VehicleTexture t, VehicleDatabase db)
+    public TextureRow(VehicleTexture t, VehicleCatalog db)
     {
         Texture = t;
         Skin = Path.GetFileNameWithoutExtension(t.Skinfile);