// Copyright (c) 2026 AlphaSierraPapa for the SharpDevelop Team
//
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// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
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// DEALINGS IN THE SOFTWARE.

#if DEBUG

using System.Linq;
using System.Threading.Tasks;

using Avalonia.Controls;
using Avalonia.Headless.NUnit;
using Avalonia.VisualTree;

using AwesomeAssertions;

using ICSharpCode.ILSpy;
using ICSharpCode.ILSpy.AppEnv;
using ICSharpCode.ILSpy.Docking;
using ICSharpCode.ILSpy.Languages;
using ICSharpCode.ILSpy.TreeNodes;
using ICSharpCode.ILSpy.ViewModels;
using ICSharpCode.ILSpy.Views;

using NUnit.Framework;

namespace ICSharpCode.ILSpy.Tests.Views;

/// <summary>
/// Pins the Debug Steps wiring at the composition layer. Tests are gated by DEBUG since
/// the feature is itself DEBUG-only — Release builds wouldn't have the types these
/// assertions reference.
/// </summary>
[TestFixture]
public class DebugStepsTests
{
	[AvaloniaTest]
	public Task DebugStepsPaneModel_Is_Exported_As_A_ToolPane()
	{
		// MEF tool-pane registry contract: DebugStepsPaneModel registers under its
		// PaneContentId so DockWorkspace.ShowToolPane(...) can surface it.
		var pane = AppComposition.Current.GetExport<DebugStepsPaneModel>();
		((object?)pane).Should().NotBeNull("DebugStepsPaneModel must resolve as a [Shared] export");
		pane.Id.Should().Be(DebugStepsPaneModel.PaneContentId);
		pane.Title.Should().Be("Debug Steps");
		return Task.CompletedTask;
	}

	[AvaloniaTest]
	public Task DebugStepsPaneModel_WritingOptions_Default_Enables_Field_And_LogicOperation_Sugar()
	{
		// The default writing options match the WPF baseline: field sugar and
		// logic-operation sugar on; IL ranges and child-index-in-block off. The four
		// CheckBoxes in DebugSteps.axaml bind two-way against these defaults.
		var options = DebugStepsPaneModel.WritingOptions;
		options.UseFieldSugar.Should().BeTrue();
		options.UseLogicOperationSugar.Should().BeTrue();
		options.ShowILRanges.Should().BeFalse();
		options.ShowChildIndexInBlock.Should().BeFalse();
		return Task.CompletedTask;
	}

	[AvaloniaTest]
	public async Task Debug_Steps_VM_Populates_After_ILAst_Decompile_Regardless_Of_View_Lifecycle()
	{
		// End-to-end repro of the user-reported "Debug Steps pane is empty" bug:
		// 1. Boot the window, load assemblies.
		// 2. Select a method.
		// 3. Switch the active language to BlockIL (ILAst).
		// 4. Wait for the BlockIL decompile to finish — its OnStepperUpdated event fires.
		// 5. Assert the DebugStepsPaneModel's Steps property is populated.
		//
		// Asserting against the VM (not the View) decouples this test from the dock layout's
		// view-realisation timing — which is the whole point of the fix that moved state
		// from the View into the VM. If `Steps` is populated, any view that binds to it (now
		// or later) will render the correct content.

		var window = AppComposition.Current.GetExport<MainWindow>();
		window.Show();
		var vm = (MainWindowViewModel)window.DataContext!;
		await vm.AssemblyTreeModel.WaitForAssembliesAsync(minimumCount: 3);

		var typeNode = vm.AssemblyTreeModel.FindNode<TypeTreeNode>(
			"System.Linq", "System.Linq", "System.Linq.Enumerable");
		typeNode.IsExpanded = true;
		var method = typeNode.Children.OfType<MethodTreeNode>()
			.First(m => m.MethodDefinition.Name == "AsEnumerable");
		vm.AssemblyTreeModel.SelectNode(method);
		await vm.DockWorkspace.WaitForDecompiledTextAsync();

		var languageService = AppComposition.Current.GetExport<LanguageService>();
		var blockIL = languageService.Languages.OfType<ILAstLanguage>()
			.Single(l => l.Name == "ILAst");
		languageService.CurrentLanguage = blockIL;
		await vm.DockWorkspace.WaitForDecompiledTextAsync();

		blockIL.Stepper.Steps.Should().NotBeEmpty(
			"BlockILLanguage.DecompileMethod must populate context.Stepper.Steps when STEP is defined");

		var debugStepsVm = AppComposition.Current.GetExport<DebugStepsPaneModel>();
		await Waiters.WaitForAsync(
			() => debugStepsVm.Steps?.Count > 0,
			description: "DebugStepsPaneModel.Steps to be populated after the ILAst decompile");

		debugStepsVm.Steps.Should().NotBeNullOrEmpty(
			"after switching to ILAst and decompiling, the VM's Steps must list the stepper's recorded transforms");
	}

	[AvaloniaTest]
	public Task ILAst_And_TypedIL_Languages_Are_Registered_In_Debug_Builds()
	{
		// Two ILAstLanguage subclasses: BlockILLanguage ("ILAst") drives the stepper,
		// TypedILLanguage ("Typed IL") writes type-annotated raw IL without transforms.
		// Both register via [Export(typeof(Language))]; the language picker uses them
		// in addition to C# and the disassembler-IL language.
		var languageService = AppComposition.Current.GetExport<LanguageService>();
		languageService.Languages.OfType<ILAstLanguage>().Should().HaveCount(2,
			"both BlockIL and TypedIL must be registered when DEBUG is defined");
		languageService.Languages.Should().Contain(l => l.Name == "ILAst");
		languageService.Languages.Should().Contain(l => l.Name == "Typed IL");
		return Task.CompletedTask;
	}
	[AvaloniaTest]
	public Task Pane_Reports_Not_Available_For_Languages_Without_Debug_Steps()
	{
		// The step tree only makes sense for IDebugStepProvider languages (C#, ILAst, Typed IL).
		// For the plain IL disassembler the pane must not keep showing the previous language's
		// stale step tree (whose commands would trigger pointless re-decompiles); it reports
		// unavailability so the view swaps in a "not available" message instead.
		var languageService = AppComposition.Current.GetExport<LanguageService>();
		var debugStepsVm = AppComposition.Current.GetExport<DebugStepsPaneModel>();

		languageService.CurrentLanguage = languageService.Languages.OfType<CSharpLanguage>().First();
		global::Avalonia.Threading.Dispatcher.UIThread.RunJobs();
		debugStepsVm.IsAvailable.Should().BeTrue("C# provides debug steps");

		// Simulate a populated tree from the C# run, then flip to the disassembler language.
		debugStepsVm.Steps = new[] { new ICSharpCode.Decompiler.IL.Transforms.Stepper.Node("stale") };
		languageService.CurrentLanguage = languageService.Languages.OfType<ILLanguage>().First(l => l.Name == "IL");
		global::Avalonia.Threading.Dispatcher.UIThread.RunJobs();

		debugStepsVm.IsAvailable.Should().BeFalse("the IL disassembler provides no debug steps");
		debugStepsVm.Steps.Should().BeNull("the previous language's step tree must not linger");
		return Task.CompletedTask;
	}

	[AvaloniaTest]
	public async Task Window_Menu_Toggle_Surfaces_The_Default_Hidden_Debug_Steps_Pane()
	{
		// Repro of "Window > Debug Steps does nothing": the menu toggles ToolPaneMenuItem.IsPaneVisible,
		// which used factory.RestoreDockable — a no-op for a pane that is hidden by default (never
		// placed in the layout, so there's nothing to restore). Toggling it on must actually surface
		// the pane (ShowToolPane materialises it and creates its home dock).
		var window = AppComposition.Current.GetExport<MainWindow>();
		window.Show();
		var vm = (MainWindowViewModel)window.DataContext!;
		await vm.AssemblyTreeModel.WaitForAssembliesAsync(minimumCount: 1);

		var menuItem = vm.DockWorkspace.ToolPaneMenuItems
			.Single(p => p.Title == "Debug Steps");
		menuItem.IsPaneVisible.Should().BeFalse("Debug Steps is hidden by default");

		menuItem.IsPaneVisible = true;

		menuItem.IsPaneVisible.Should().BeTrue(
			"toggling Window > Debug Steps on must make the pane visible in the layout");
	}

}

#endif