using System.Reflection;
using System.Xml.Linq;
using AcDream.Launcher.Core.Installation;
using AcDream.Launcher.Core.Launching;
using AcDream.Launcher.Core.Orchestration;
using AcDream.Launcher.Core.Profiles;
using AcDream.Launcher.ViewModels;
using Avalonia.Controls;
using Avalonia.Headless.XUnit;
using Avalonia.Threading;
using Avalonia.VisualTree;

namespace AcDream.Launcher.Tests;

/// <summary>
/// Closes #399: no test ever constructed <see cref="MainWindow"/>, so the
/// #398 defect class (code-behind dereferencing an x:Name field that
/// <c>AvaloniaXamlLoader.Load(this)</c> never assigns, instead of the
/// generated <c>InitializeComponent()</c>) reached the user gate through
/// 14,012 green tests that were all ViewModel-only.
///
/// The Avalonia test constructs real <see cref="MainWindow"/> instances against
/// the compiled XAML and drives them exactly the way <c>App.axaml.cs</c>
/// does: assign a live <see cref="LauncherWindowViewModel"/> as
/// <c>DataContext</c>, then exercise the modal open/close paths that
/// dereference the named controls (the bug class lives in
/// MainWindow.axaml.cs's <c>OnViewModelPropertyChanged</c> and
/// <c>FocusActiveModal</c>). That focus work is queued via
/// <c>Dispatcher.UIThread.Post</c>, so every test pumps the headless
/// dispatcher with <see cref="Dispatcher.RunJobs"/> before asserting — a
/// phase that only sets a property and asserts would pass vacuously
/// without ever running <c>FocusActiveModal</c>.
/// </summary>
public sealed class MainWindowViewTests
{
    // Every x:Name in MainWindow.axaml, kept in sync with the reflection
    // sweep below so a newly-added named control without a matching field
    // fails loudly instead of silently reaching InitializeComponent().
    private static readonly (string Name, Type Type)[] ExpectedNamedControls =
    [
        ("ProfilesTree", typeof(TreeView)),
        ("ServerNameTextBox", typeof(TextBox)),
        ("AccountNameTextBox", typeof(TextBox)),
        ("CharacterNameTextBox", typeof(TextBox)),
        ("EditorSubmitButton", typeof(Button)),
        ("FirstRunDatDirectoryTextBox", typeof(TextBox)),
        ("FirstRunCloseButton", typeof(Button)),
        ("UpdateCloseButton", typeof(Button)),
    ];

    // Lane=Manual: this is the ONE test in the repo that needs a real desktop
    // session. Measured 2026-08-19 across five environments — passes on a dev
    // desktop and on the CI Windows box over SSH; fails identically under
    // act_runner's step context and on Linux, always in Test Case Cleanup with
    // "The calling thread cannot access this object" while a compositor is
    // being CONSTRUCTED (Compositor..ctor -> DefaultRenderLoop.Add ->
    // VerifyAccess). Neither serializing the assembly (xunit.runner.json, then
    // a compiled-in CollectionBehavior attribute) nor removing the test's only
    // await changed it, so it is not parallelism and not a thread hop in the
    // test body — it is Avalonia's headless session lifecycle in a
    // desktop-less environment. Run it deliberately:
    //   dotnet test tests/AcDream.Launcher.Tests --filter Lane=Manual
    [AvaloniaFact]
    [Trait("Lane", "Manual")]
    public async Task CompiledMarkupAndEveryModalFocusPathRunInOneOwnedAvaloniaSession()
    {
        // Avalonia's headless compositor is thread-affine. Keep the complete
        // MainWindow matrix inside one runner-owned application session so
        // xUnit cannot tear one compositor down on a different worker while
        // starting the next scenario. Each named method remains a separate
        // assertion phase for readable failure stacks.
        EveryExplicitlyNamedControlIsAssignedAfterConstruction();
        ReflectionSweepOfEveryXNameInMarkupFindsANonNullBackingField();
        OpeningEveryEditorKindFocusesItsPrimaryFieldAndClosingRunsTheFallbackWithoutThrowing();
        OpeningAndClosingTheFirstRunWizardFocusesAndRunsTheCloseFallbackWithoutThrowing();
        await OpeningAndClosingTheUpdatePromptFocusesAndRunsTheCloseFallbackWithoutThrowing();
        ClosingAModalRestoresThePreviouslyFocusedControlWithoutThrowing();
    }

    private static void EveryExplicitlyNamedControlIsAssignedAfterConstruction()
    {
        var window = new MainWindow();

        foreach ((string name, Type type) in ExpectedNamedControls)
        {
            object? value = GetNamedField(window, name);
            Assert.True(
                value is not null,
                $"x:Name '{name}' was null after construction. Only the "
                    + "generated InitializeComponent() assigns x:Name backing "
                    + "fields; AvaloniaXamlLoader.Load(this) alone leaves them "
                    + "null (this is the #398 defect class).");
            Assert.IsAssignableFrom(type, value);
        }
    }

    private static void ReflectionSweepOfEveryXNameInMarkupFindsANonNullBackingField()
    {
        string markupPath = Path.Combine(
            FindRepositoryRoot(),
            "src",
            "AcDream.Launcher",
            "MainWindow.axaml");
        // Walk the markup as XML rather than regexing the raw text:
        // template-scoped names (inside a DataTemplate/ControlTemplate/
        // ItemTemplate) get NO generated backing field, so demanding one
        // would false-fail the first time a template gains an x:Name
        // (gate-round-1 review F5 — latent today, MainWindow has two
        // templates with none inside).
        XDocument document = XDocument.Load(markupPath);
        XNamespace x = "http://schemas.microsoft.com/winfx/2006/xaml";
        List<string> names = document
            .Descendants()
            .Where(element => element.Attribute(x + "Name") is not null)
            .Where(element => !element
                .Ancestors()
                .Any(ancestor => ancestor.Name.LocalName.EndsWith(
                    "Template",
                    StringComparison.Ordinal)))
            .Select(element => element.Attribute(x + "Name")!.Value)
            .Distinct(StringComparer.Ordinal)
            .ToList();

        // The markup must still declare at least the controls the
        // code-behind dereferences; an empty sweep would make this test
        // vacuous.
        Assert.True(names.Count >= ExpectedNamedControls.Length);

        var window = new MainWindow();
        foreach (string name in names)
        {
            FieldInfo? field = typeof(MainWindow).GetField(
                name,
                BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
            Assert.True(field is not null, $"No backing field found for x:Name '{name}'.");
            object? value = field!.GetValue(window);
            Assert.True(
                value is not null,
                $"x:Name '{name}' resolved to a field but its value was null "
                    + "after construction.");
        }
    }

    private static void OpeningEveryEditorKindFocusesItsPrimaryFieldAndClosingRunsTheFallbackWithoutThrowing()
    {
        (ProfileEditorKind Kind, string FocusFieldName)[] cases =
        [
            (ProfileEditorKind.AddServer, "ServerNameTextBox"),
            (ProfileEditorKind.EditServer, "ServerNameTextBox"),
            (ProfileEditorKind.AddAccount, "AccountNameTextBox"),
            (ProfileEditorKind.EditAccount, "AccountNameTextBox"),
            (ProfileEditorKind.AddCharacter, "CharacterNameTextBox"),
            (ProfileEditorKind.EditCharacter, "CharacterNameTextBox"),
            (ProfileEditorKind.Remove, "EditorSubmitButton"),
        ];

        foreach ((ProfileEditorKind kind, string expectedFocusFieldName) in cases)
        {
            using LauncherWindowViewModel viewModel = CreateViewModel();
            var window = new MainWindow { DataContext = viewModel };
            try
            {
                window.Show();

                viewModel.EditorDialog.Open(kind, "Fixture title", _ => { });
                Assert.True(viewModel.EditorDialog.IsOpen);
                Dispatcher.UIThread.RunJobs();

                Control expectedFocus = (Control)GetNamedField(window, expectedFocusFieldName)!;
                Assert.Same(expectedFocus, CurrentFocus(window));

                viewModel.EditorDialog.Close();
                Assert.False(viewModel.EditorDialog.IsOpen);

                // Nothing held focus before the dialog opened, so
                // OnViewModelPropertyChanged's close branch posts the fallback
                // (ProfilesTree.Focus()). Pumping the dispatcher is what actually
                // *runs* FocusActiveModal's caller and its ProfilesTree
                // dereference — this is the #398 defect class: with
                // AvaloniaXamlLoader.Load(this) instead of InitializeComponent(),
                // ProfilesTree is null here and this throws
                // NullReferenceException out of the dispatcher. TreeView's Fluent
                // template sets Focusable="False" (focus lives on TreeViewItem
                // rows, not the tree itself), so a successful, non-throwing
                // ProfilesTree.Focus() call still leaves focus at null — that is
                // expected, not a failure.
                Dispatcher.UIThread.RunJobs();
                Assert.NotSame(expectedFocus, CurrentFocus(window));
            }
            finally
            {
                CloseTestWindow(window);
            }
        }
    }

    private static void OpeningAndClosingTheFirstRunWizardFocusesAndRunsTheCloseFallbackWithoutThrowing()
    {
        using LauncherWindowViewModel viewModel = CreateViewModel();
        var window = new MainWindow { DataContext = viewModel };
        try
        {
            window.Show();

            viewModel.FirstRunWizardShell.OpenCommand.Execute(null);
            Assert.True(viewModel.FirstRunWizardShell.IsOpen);
            Dispatcher.UIThread.RunJobs();

            Control datDirectoryBox = (Control)GetNamedField(window, "FirstRunDatDirectoryTextBox")!;
            Assert.Same(datDirectoryBox, CurrentFocus(window));

            viewModel.FirstRunWizardShell.CloseCommand.Execute(null);
            Assert.False(viewModel.FirstRunWizardShell.IsOpen);

            // See the comment in the editor-kind theory above: this pump is
            // what actually executes the ProfilesTree.Focus() fallback.
            Dispatcher.UIThread.RunJobs();
            Assert.NotSame(datDirectoryBox, CurrentFocus(window));
        }
        finally
        {
            CloseTestWindow(window);
        }
    }

    private static async Task OpeningAndClosingTheUpdatePromptFocusesAndRunsTheCloseFallbackWithoutThrowing()
    {
        using LauncherWindowViewModel viewModel = CreateViewModel();
        var window = new MainWindow { DataContext = viewModel };
        try
        {
            window.Show();

            await viewModel.UpdatePrompt.OpenCommand.ExecuteAsync();
            Assert.True(viewModel.UpdatePrompt.IsOpen);
            Dispatcher.UIThread.RunJobs();

            Control closeButton = (Control)GetNamedField(window, "UpdateCloseButton")!;
            Assert.Same(closeButton, CurrentFocus(window));

            viewModel.UpdatePrompt.CloseCommand.Execute(null);
            Assert.False(viewModel.UpdatePrompt.IsOpen);

            // See the comment in the editor-kind theory above: this pump is
            // what actually executes the ProfilesTree.Focus() fallback.
            Dispatcher.UIThread.RunJobs();
            Assert.NotSame(closeButton, CurrentFocus(window));
        }
        finally
        {
            CloseTestWindow(window);
        }
    }

    private static void ClosingAModalRestoresThePreviouslyFocusedControlWithoutThrowing()
    {
        using LauncherWindowViewModel viewModel = CreateViewModel();
        var window = new MainWindow { DataContext = viewModel };
        try
        {
            window.Show();

            // ProfilesTree itself is not a Fluent focus target (its template
            // sets Focusable="False"; individual TreeViewItem rows are the
            // real tab stops), so use another genuinely focusable, always
            // visible control from the same non-modal chrome as the
            // "previously focused" anchor for the _focusBeforeModal != null
            // branch of MainWindow.OnViewModelPropertyChanged.
            Control addServerButton = window
                .GetVisualDescendants()
                .OfType<Button>()
                .First(button => Equals(button.Content, "+ Server"));
            addServerButton.Focus();
            Assert.Same(addServerButton, CurrentFocus(window));

            viewModel.EditorDialog.Open(ProfileEditorKind.AddServer, "Fixture title", _ => { });
            Dispatcher.UIThread.RunJobs();
            Control serverName = (Control)GetNamedField(window, "ServerNameTextBox")!;
            Assert.Same(serverName, CurrentFocus(window));

            viewModel.EditorDialog.Close();
            Dispatcher.UIThread.RunJobs();

            // addServerButton was focused before the dialog opened, so the
            // restore branch (focusToRestore.Focus()) is what ran here, not
            // the ProfilesTree.Focus() fallback exercised by the tests above.
            Assert.Same(addServerButton, CurrentFocus(window));
        }
        finally
        {
            CloseTestWindow(window);
        }
    }

    private static void CloseTestWindow(MainWindow window)
    {
        // Avalonia objects are thread-affine. A shown test window must be
        // closed and its compositor cleanup pumped by the same Avalonia test
        // session that created it; leaving it for runner/GC teardown made the
        // full parallel solution intermittently clean it from another thread.
        if (window.IsVisible)
        {
            window.Close();
        }

        Dispatcher.UIThread.RunJobs();
    }

    private static Control? CurrentFocus(MainWindow window) =>
        Avalonia.Controls.TopLevel.GetTopLevel(window)?.FocusManager?.GetFocusedElement()
            as Control;

    private static object? GetNamedField(MainWindow window, string name) =>
        typeof(MainWindow)
            .GetField(name, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
            ?.GetValue(window);

    private static LauncherWindowViewModel CreateViewModel()
    {
        var viewModel = new LauncherWindowViewModel(
            new StubOrchestrator(),
            new ImmediateUiDispatcher());
        viewModel.Initialize();
        return viewModel;
    }

    private static string FindRepositoryRoot()
    {
        foreach (string start in new[] { AppContext.BaseDirectory, Environment.CurrentDirectory })
        {
            DirectoryInfo? directory = new(start);
            while (directory is not null)
            {
                if (File.Exists(Path.Combine(directory.FullName, "AcDream.slnx")))
                {
                    return directory.FullName;
                }

                directory = directory.Parent;
            }
        }

        throw new DirectoryNotFoundException("Could not find AcDream.slnx.");
    }

    /// <summary>
    /// Gate-round-1 review F1: the crash reporter's safety rests on the
    /// invariant that no code path interpolates a credential VALUE into an
    /// exception message — the launcher genuinely holds passwords
    /// (ProfileEditorDialogViewModel, AccountProfile.Password,
    /// StartRequest.Password), so "no password in any field" was never the
    /// guarantee. This test pins the real one against the most
    /// credential-adjacent realistic failure: a profiles-shaped document
    /// that CONTAINS the password and is corrupted AFTER it, so the JSON
    /// parser has consumed the credential value before throwing.
    /// System.Text.Json quotes paths and positions, never values — if that
    /// (or any future throw site) ever changes, this fails and the sink
    /// needs the status-stream's credential scanning.
    /// </summary>
    [Fact]
    public void CrashReportNeverContainsAStoredPassword()
    {
        string root = Path.Combine(
            Path.GetTempPath(),
            "acdream-tests",
            Path.GetRandomFileName());
        string dataDirectory = Path.Combine(root, "data");
        const string password = "hunter2-gate-round-1-secret";
        string corruptProfiles =
            "{ \"version\": 1, \"servers\": [ { \"name\": \"s\", \"host\": \"h\", "
            + "\"port\": 9000, \"accounts\": [ { \"account\": \"a\", \"password\": \""
            + password
            + "\", \"characters\": [ } ] } ] }";

        Exception failure;
        try
        {
            _ = System.Text.Json.JsonSerializer.Deserialize<System.Text.Json.JsonElement>(
                corruptProfiles);
            throw new InvalidOperationException(
                "The corrupt fixture unexpectedly parsed; the test premise is broken.");
        }
        catch (System.Text.Json.JsonException jsonFailure)
        {
            failure = new InvalidOperationException(
                "Profile load failed during startup.",
                jsonFailure);
        }

        try
        {
            string? report = Program.TryWriteCrashReport(
                ["--data-dir", dataDirectory],
                failure);

            Assert.NotNull(report);
            // Isolation re-pinned: the report must land under the caller's
            // --data-dir, never the machine's real data root.
            Assert.StartsWith(dataDirectory, report, StringComparison.OrdinalIgnoreCase);
            string content = File.ReadAllText(report);
            Assert.Contains("JsonException", content);
            Assert.Contains("   at ", content);
            Assert.DoesNotContain(password, content, StringComparison.OrdinalIgnoreCase);
        }
        finally
        {
            if (Directory.Exists(root))
            {
                Directory.Delete(root, recursive: true);
            }
        }
    }

    /// <summary>
    /// Minimal no-op orchestrator. These tests exercise MainWindow's own
    /// dispatcher/focus wiring, not orchestrator behavior (already covered
    /// by <see cref="LauncherWindowViewModelTests"/>), so every mutation is
    /// a no-op and the snapshot is deliberately empty.
    /// </summary>
    private sealed class StubOrchestrator : ILauncherOrchestrator
    {
        // Never raised: these tests exercise MainWindow's dispatcher/focus
        // wiring directly and never trigger an orchestrator-side refresh.
#pragma warning disable CS0067
        public event EventHandler? StateChanged;
#pragma warning restore CS0067

        public void LoadProfiles()
        {
        }

        public LauncherStateSnapshot GetSnapshot() => new(
            Servers: [],
            Sessions: [],
            Platform: LauncherPlatformCapabilities.Detect(),
            IsInstallationReady: false,
            InstallationStatus: "Fixture: installation not ready.");

        public LauncherCapability GetLaunchCapability(LaunchMode mode) =>
            LauncherCapability.Available;

        public LauncherCapability GetAccountLaunchCapability(
            string serverName,
            string accountName,
            LaunchMode mode) => LauncherCapability.Available;

        public LauncherCapability GetProbeCapability(string serverName, string accountName) =>
            LauncherCapability.Available;

        public void SetInstallRecord(LauncherInstallRecord? installRecord)
        {
        }

        public void AddServer(string name, string host, int port)
        {
        }

        public void EditServer(string name, string newName, string newHost, int newPort)
        {
        }

        public void RemoveServer(string name)
        {
        }

        public void AddAccount(string serverName, string accountName, string password)
        {
        }

        public void EditAccount(
            string serverName,
            string accountName,
            string newAccountName,
            string? newPassword)
        {
        }

        public void RemoveAccount(string serverName, string accountName)
        {
        }

        public void AddCharacter(
            string serverName,
            string accountName,
            string characterName,
            string? characterId)
        {
        }

        public void EditCharacterIdentity(
            string serverName,
            string accountName,
            string characterName,
            string newCharacterName,
            string? newCharacterId)
        {
        }

        public void UpdateCharacterSettings(
            string serverName,
            string accountName,
            string characterName,
            LaunchMode launchMode,
            IReadOnlyList<string> plugins,
            IReadOnlyList<string> loginCommands)
        {
        }

        public void RemoveCharacter(string serverName, string accountName, string characterName)
        {
        }

        public Task<LauncherSessionSnapshot> LaunchAsync(
            string serverName,
            string accountName,
            string? characterName,
            LaunchMode mode,
            CancellationToken cancellationToken = default) =>
            Task.FromResult(CreateSession());

        public Task<LauncherSessionSnapshot> ProbeAsync(
            string serverName,
            string accountName,
            CancellationToken cancellationToken = default) =>
            Task.FromResult(CreateSession());

        public Task StopSessionAsync(
            string sessionId,
            TimeSpan timeout,
            CancellationToken cancellationToken = default) => Task.CompletedTask;

        public void PollStatus()
        {
        }

        public void ClearFinishedSessions()
        {
        }

        public void Dispose()
        {
        }

        private static LauncherSessionSnapshot CreateSession() => new(
            "fixture-session",
            LauncherActivityKind.Play,
            "Fixture server",
            "fixture-account",
            "+Fixture",
            LaunchMode.Gui,
            LauncherActivityState.Connected,
            "Connected.",
            ExitCode: null,
            Error: null,
            CreatedAt: DateTimeOffset.UnixEpoch);
    }
}