// Copyright (c) 2026 AlphaSierraPapa for the SharpDevelop Team
//
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using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

using Avalonia.Controls;
using Avalonia.Headless.NUnit;
using Avalonia.Input;
using Avalonia.Interactivity;
using Avalonia.Layout;
using Avalonia.VisualTree;

using AwesomeAssertions;

using ICSharpCode.ILSpy.AppEnv;
using ICSharpCode.ILSpy.Metadata;
using ICSharpCode.ILSpy.TextView;
using ICSharpCode.ILSpy.ViewModels;
using ICSharpCode.ILSpy.Views;

using NUnit.Framework;

namespace ICSharpCode.ILSpy.Tests.Metadata;

[TestFixture]
public class MetadataRowDetailsTests
{
	[AvaloniaTest]
	public void Shell_Rebuilds_Its_Content_Whenever_The_DataContext_Changes()
	{
		// The DataGrid builds a row-details template once per details element and then reuses
		// the built control across row recycling, swapping only the DataContext. Per-item
		// content (text blob vs. sub-grid) therefore has to be produced by a control that
		// re-runs its factory on every DataContext change — that is the shell's contract.
		var factoryInputs = new List<object?>();
		var shell = new MetadataRowDetailsControl(item => {
			factoryInputs.Add(item);
			return item switch {
				string s => new TextBox { Text = s },
				IList<BitEntry> bits => new DataGrid { ItemsSource = bits },
				_ => null,
			};
		});

		shell.DataContext = "blob text";
		shell.Content.Should().BeOfType<TextBox>()
			.Which.Text.Should().Be("blob text");

		var bits = new List<BitEntry> { new(true, "<0001> bit") };
		shell.DataContext = bits;
		shell.Content.Should().BeOfType<DataGrid>()
			.Which.ItemsSource.Should().BeSameAs(bits);

		shell.DataContext = null;
		shell.Content.Should().BeNull("a recycled details element gets its DataContext nulled and must drop stale content");

		factoryInputs.Should().Equal("blob text", bits, null);
	}

	[AvaloniaTest]
	public void CreateTemplate_Builds_A_DataContext_Tracking_Shell()
	{
		var template = MetadataRowDetails.CreateTemplate(
			item => item is string s ? new TextBox { Text = s } : null);

		var control = template.Build("ignored-build-parameter");

		var shell = control.Should().BeOfType<MetadataRowDetailsControl>().Subject;
		shell.DataContext = "hello";
		shell.Content.Should().BeOfType<TextBox>().Which.Text.Should().Be("hello");
	}

	[AvaloniaTest]
	public async Task Coff_Characteristics_Row_Renders_Its_Flag_Bits_In_Expanded_Row_Details()
	{
		// The COFF header view keeps the Characteristics flags word permanently expanded:
		// the row's details area lists all 16 bits with their meanings, while every other
		// row of the header stays detail-less.
		var (window, vm) = await TestHarness.BootAsync();

		var coffNode = vm.AssemblyTreeModel.FindCoreLib()
			.GetChild<MetadataTreeNode>()
			.GetChild<CoffHeaderTreeNode>();

		vm.AssemblyTreeModel.SelectNode(coffNode);
		var tab = await vm.DockWorkspace.WaitForMetadataTabAsync();
		TestCapture.Step("coff-header-grid");

		tab.RowDetailsTemplate.Should().NotBeNull("the COFF header page carries a flags details template");
		tab.IsRowDetailsVisible.Should().NotBeNull();

		var metadataPage = await window.WaitForComponent<MetadataTablePage>();
		var grid = metadataPage.FindControl<DataGrid>("Grid")!;
		await grid.WaitForComponent<DataGridRow>();

		await Waiters.WaitForAsync(() => grid.GetVisualDescendants().OfType<DataGridRow>()
			.Any(r => r.DataContext is Entry { Member: "Characteristics" } && r.AreDetailsVisible));
		TestCapture.Step("characteristics-row-expanded");

		var rows = grid.GetVisualDescendants().OfType<DataGridRow>().ToList();
		var characteristicsRow = rows.Single(r => r.DataContext is Entry { Member: "Characteristics" });
		characteristicsRow.AreDetailsVisible.Should().BeTrue();
		rows.Where(r => r != characteristicsRow).Should()
			.OnlyContain(r => !r.AreDetailsVisible, "only the flags row carries details");

		var shell = await characteristicsRow.WaitForComponent<MetadataRowDetailsControl>();
		var flagsGrid = shell.Content.Should().BeOfType<DataGrid>().Subject;
		((IEnumerable)flagsGrid.ItemsSource!).Cast<BitEntry>().Should().HaveCount(16);
		flagsGrid.HeadersVisibility.Should().Be(DataGridHeadersVisibility.None);
	}

	[AvaloniaTest]
	public async Task Optional_Header_Expands_Details_For_The_Dll_Characteristics_Row_Only()
	{
		var (_, vm) = await TestHarness.BootAsync();

		var optionalNode = vm.AssemblyTreeModel.FindCoreLib()
			.GetChild<MetadataTreeNode>()
			.GetChild<OptionalHeaderTreeNode>();

		vm.AssemblyTreeModel.SelectNode(optionalNode);
		var tab = await vm.DockWorkspace.WaitForMetadataTabAsync();
		TestCapture.Step("optional-header-grid");

		tab.RowDetailsTemplate.Should().NotBeNull();
		tab.RowDetailsVisibilityMode.Should().Be(DataGridRowDetailsVisibilityMode.Collapsed,
			"non-flag rows must never grow a details area, not even on selection");
		tab.IsRowDetailsVisible.Should().NotBeNull();

		var entries = tab.Items.Cast<Entry>().ToList();
		var dllCharacteristics = entries.Single(e => e.Member == "DLL Characteristics");
		tab.IsRowDetailsVisible!(dllCharacteristics).Should().BeTrue();
		entries.Where(e => e != dllCharacteristics).Should()
			.OnlyContain(e => !tab.IsRowDetailsVisible!(e));
	}

	[AvaloniaTest]
	public void Details_Content_Stretches_Across_The_Full_Row_Width()
	{
		// The details area spans the host row, and its content fills it: a capped or
		// left-pinned control would leave dead space to the right of the blob text or
		// sub-grid columns.
		var text = MetadataRowDetails.BuildTextBlob("blob text");
		text.HorizontalAlignment.Should().Be(HorizontalAlignment.Stretch);
		text.MaxWidth.Should().Be(double.PositiveInfinity, "the text blob must not cap its width");

		var flagsGrid = (DataGrid)MetadataRowDetails.BuildFlagsGrid(new List<BitEntry> { new(true, "<0001> bit") });
		flagsGrid.HorizontalAlignment.Should().Be(HorizontalAlignment.Stretch);
		flagsGrid.Columns[^1].Width.UnitType.Should().Be(DataGridLengthUnitType.Star,
			"the meaning column takes the leftover width");

		var detailsGrid = (DataGrid)MetadataRowDetails.BuildDetailsGrid(
			new List<BitEntry> { new(true, "<0001> bit") },
			("Value", nameof(BitEntry.Value)), ("Meaning", nameof(BitEntry.Meaning)));
		detailsGrid.HorizontalAlignment.Should().Be(HorizontalAlignment.Stretch);
		detailsGrid.Columns[^1].Width.UnitType.Should().Be(DataGridLengthUnitType.Star,
			"the last column takes the leftover width");
	}

	[AvaloniaTest]
	public void Text_Blob_Is_A_Read_Only_Editor_With_Extension_Driven_Highlighting()
	{
		// Text payloads are code (embedded source, source-link JSON): they render in the
		// theme-aware AvaloniaEdit editor, which adds syntax colours and virtualizes long
		// documents, while staying read-only but selectable. The optional extension picks
		// the highlighting; without one (hex dumps) the text stays plain.
		var editor = MetadataRowDetails.BuildTextBlob("class C { }", ".cs")
			.Should().BeOfType<DecompilerTextEditor>().Subject;
		editor.Text.Should().Be("class C { }");
		editor.IsReadOnly.Should().BeTrue();
		editor.WordWrap.Should().BeTrue();
		editor.MaxHeight.Should().Be(400, "the host row must stay bounded; the editor scrolls internally");
		editor.MinHeight.Should().Be(100, "a short payload must still get a recognisable details area, not a squeezed strip");
		editor.SyntaxHighlighting.Should().NotBeNull();
		editor.SyntaxHighlighting!.Name.Should().Be("C#");

		var json = (DecompilerTextEditor)MetadataRowDetails.BuildTextBlob("{ }", ".json");
		json.SyntaxHighlighting.Should().NotBeNull("AvaloniaEdit ships a built-in JSON definition");

		var plain = (DecompilerTextEditor)MetadataRowDetails.BuildTextBlob("01-02-03");
		plain.SyntaxHighlighting.Should().BeNull();

		var unknown = (DecompilerTextEditor)MetadataRowDetails.BuildTextBlob("text", ".xyz");
		unknown.SyntaxHighlighting.Should().BeNull("an unrecognized extension degrades to plain text");
	}

	[AvaloniaTest]
	public void Text_Blob_Editor_Uses_The_Decompiler_View_Styling()
	{
		// The details editor is a second surface showing code, so it must look like the main
		// decompiler view: the user-selected editor font (applied live, the same way the text
		// view reacts to the Options page), the flat square-cornered selection highlight, and
		// the themed editor background.
		var settings = AppComposition.Current.GetExport<SettingsService>().DisplaySettings;
		var originalFont = settings.SelectedFont;
		var originalSize = settings.SelectedFontSize;
		var editor = (DecompilerTextEditor)MetadataRowDetails.BuildTextBlob("class C { }", ".cs");
		var window = new Window { Content = editor };
		try
		{
			settings.SelectedFont = "Liberation Mono";
			settings.SelectedFontSize = 17;
			window.Show();

			editor.FontFamily.Name.Should().Be("Liberation Mono",
				"the details editor renders in the user-selected editor font");
			editor.FontSize.Should().Be(17);

			settings.SelectedFontSize = 21;
			editor.FontSize.Should().Be(21, "font settings apply live while the details row is open");

			editor.TextArea.SelectionCornerRadius.Should().Be(0,
				"selection styling matches the decompiler view (flat, square corners)");
			window.TryFindResource("ILSpy.EditorSelectionBrush", window.ActualThemeVariant, out var selectionBrush)
				.Should().BeTrue();
			editor.TextArea.SelectionBrush.Should().Be(selectionBrush);
			window.TryFindResource("ILSpy.EditorBackground", window.ActualThemeVariant, out var background)
				.Should().BeTrue();
			editor.Background.Should().Be(background);

			window.Close();
			settings.SelectedFontSize = 13;
			editor.FontSize.Should().Be(21,
				"an editor detached by row recycling must stop tracking the settings instance");
		}
		finally
		{
			window.Close();
			settings.SelectedFont = originalFont;
			settings.SelectedFontSize = originalSize;
		}
	}

	[AvaloniaTest]
	public void Text_Blob_Editor_Carries_Its_Own_Copy_And_Select_All_Context_Menu()
	{
		// Without a menu of its own, a right-click inside the details editor inherits the
		// metadata grid's cell-oriented context menu, whose Copy entries are bound to the
		// hovered DataGridCell and therefore permanently disabled inside the details area.
		// The editor must instead offer the decompiler-view editor menu shape: Copy
		// following the selection, plus Select All.
		var editor = (DecompilerTextEditor)MetadataRowDetails.BuildTextBlob("class C { }", ".cs");
		var window = new Window { Content = editor };
		window.Show();
		try
		{
			var menu = editor.ContextMenu;
			menu.Should().NotBeNull("the editor must not inherit the metadata grid's cell menu");

			// Raise the context-request gesture (what a right-click produces) rather than
			// calling menu.Open(): only the gesture path raises ContextMenu.Opening, where
			// the enablement of Copy is decided.
			editor.RaiseEvent(new ContextRequestedEventArgs());
			menu!.IsOpen.Should().BeTrue();
			var items = menu.Items.OfType<MenuItem>().ToList();
			items.Should().HaveCount(2);
			var copy = items[0];
			var selectAll = items[1];
			copy.Header.Should().Be("Copy");
			selectAll.Header.Should().Be("Select All");
			copy.IsEnabled.Should().BeFalse("nothing is selected yet");
			menu.Close();

			editor.Select(0, 5);
			editor.RaiseEvent(new ContextRequestedEventArgs());
			copy.IsEnabled.Should().BeTrue("a non-empty selection makes Copy actionable");
			menu.Close();

			selectAll.RaiseEvent(new RoutedEventArgs(MenuItem.ClickEvent));
			editor.SelectionLength.Should().Be(editor.Text.Length);
		}
		finally
		{
			window.Close();
		}
	}

	[AvaloniaTest]
	public async Task Double_Tap_Inside_The_Details_Area_Does_Not_Resolve_To_An_Activatable_Row()
	{
		// Row activation navigates away from the metadata view. A double-click inside the
		// details area (e.g. word-selection in an embedded-source editor, or a click in the
		// flags sub-grid) is interacting with the details content, not requesting navigation,
		// so the row-resolution walk must reject sources under the details presenter.
		var (window, vm) = await TestHarness.BootAsync();

		var coffNode = vm.AssemblyTreeModel.FindCoreLib()
			.GetChild<MetadataTreeNode>()
			.GetChild<CoffHeaderTreeNode>();

		vm.AssemblyTreeModel.SelectNode(coffNode);
		await vm.DockWorkspace.WaitForMetadataTabAsync();

		var metadataPage = await window.WaitForComponent<MetadataTablePage>();
		var grid = metadataPage.FindControl<DataGrid>("Grid")!;
		await grid.WaitForComponent<DataGridRow>();
		await Waiters.WaitForAsync(() => grid.GetVisualDescendants().OfType<DataGridRow>()
			.Any(r => r.DataContext is Entry { Member: "Characteristics" } && r.AreDetailsVisible));

		var characteristicsRow = grid.GetVisualDescendants().OfType<DataGridRow>()
			.Single(r => r.DataContext is Entry { Member: "Characteristics" });
		var shell = await characteristicsRow.WaitForComponent<MetadataRowDetailsControl>();

		MetadataTablePage.FindActivatableRow(shell).Should().BeNull(
			"visuals under the details presenter must not trigger row activation");

		var cell = characteristicsRow.GetVisualDescendants().OfType<DataGridCell>().First();
		MetadataTablePage.FindActivatableRow(cell).Should().BeSameAs(characteristicsRow,
			"regular cells keep resolving to their owning row");
	}
}