using Avalonia;
using Avalonia.Automation;
using Avalonia.Controls;
using Avalonia.Controls.Documents;
using Avalonia.Headless.XUnit;
using Avalonia.Styling;
using Avalonia.Threading;
using Avalonia.VisualTree;
using CSharpMath.Avalonia;
using AgentWikiUi.Gui;

namespace AgentWikiUi.Tests;

/// <summary>Formule LaTeX nel markdown (ADR-0008): matrice MD-31…MD-38 in docs/TESTING.md.</summary>
[Trait("Category", "Gui")]
public sealed class MarkdownMathTests
{
    static (Window Window, MarkdownView View) Show(string markdown, double width = 600)
    {
        var view = new MarkdownView();
        var window = new Window { Width = width, Height = 800, Content = view };
        window.Show();
        view.Source = markdown;
        Dispatcher.UIThread.RunJobs();
        window.UpdateLayout();
        return (window, view);
    }

    static List<MathView> Formulas(Visual v) => v.GetVisualDescendants().OfType<MathView>().ToList();

    static string Text(Visual v) => string.Concat(v.GetVisualDescendants().OfType<TextBlock>()
        .Select(t => t.Inlines is { Count: > 0 } ? string.Concat(t.Inlines.OfType<Run>().Select(r => r.Text)) : t.Text));

    [AvaloniaFact]
    public void Formula_inline()
    {
        var (_, view) = Show("Il gap è $E_g = E_{LUMO} - E_{HOMO}$ in eV.");
        var f = Assert.Single(Formulas(view));
        Assert.Equal("E_g = E_{LUMO} - E_{HOMO}", AutomationProperties.GetName(f));
        Assert.True(string.IsNullOrEmpty(f.ErrorMessage));
        Assert.True(f.Bounds.Width > 0 && f.Bounds.Height > 0);
        var text = Text(view);
        Assert.Contains("Il gap è", text);
        Assert.Contains("in eV.", text);
        Assert.DoesNotContain("$", text);
    }

    [AvaloniaFact]
    public void Formula_a_blocco()
    {
        var (_, view) = Show("Prima.\n\n$$\n\\frac{a}{b} = c\n$$\n\nDopo.");
        var f = Assert.Single(Formulas(view));
        Assert.Equal("\\frac{a}{b} = c", AutomationProperties.GetName(f));
        Assert.True(string.IsNullOrEmpty(f.ErrorMessage));
        Assert.True(f.Bounds.Height > 0);
        Assert.DoesNotContain("\\frac", Text(view)); // non è un blocco di codice col sorgente
        Assert.Contains("Prima.", Text(view));
        Assert.Contains("Dopo.", Text(view));
    }

    [AvaloniaTheory]
    [InlineData("Testo $\\frac{a$ fine")]
    [InlineData("$$\n\\unknowncommand{x}\n$$")]
    [InlineData("Testo $\\begin{matrix$ fine")]
    public void Formula_non_valida_ripiego(string markdown)
    {
        var (_, view) = Show(markdown);
        Assert.Empty(Formulas(view));
        Assert.Contains("$", Text(view)); // il sorgente resta visibile come testo
    }

    [AvaloniaTheory]
    [InlineData("\\frac{a}{b}")]
    [InlineData("x^2 + y_i")]
    [InlineData("\\mathbf{A} \\times \\mathbf{B}")]
    [InlineData("\\overline{x}")]
    [InlineData("\\left( \\frac{1}{2} \\right)")]
    [InlineData("\\lambda_{max} \\approx \\pi \\cdot \\tau")]
    [InlineData("\\sum_{i=1}^{n} x_i")]
    [InlineData("\\text{Mn} = \\chi \\varepsilon")]
    public void Costrutti_latex_comuni(string latex)
    {
        var (_, view) = Show($"Prima $${latex}$$ dopo".Replace("$$", "$"));
        var f = Assert.Single(Formulas(view));
        Assert.Equal(latex, AutomationProperties.GetName(f));
        Assert.True(string.IsNullOrEmpty(f.ErrorMessage), f.ErrorMessage);
        Assert.True(f.Bounds.Width > 0);
    }

    [AvaloniaFact]
    public void Formula_cambio_tema()
    {
        var (window, view) = Show("Gap $E_g$ e\n\n$$\\frac{a}{b}$$");
        Assert.Equal(2, Formulas(view).Count);
        window.RequestedThemeVariant = ThemeVariant.Dark;
        Dispatcher.UIThread.RunJobs();
        Assert.Equal(2, Formulas(view).Count);
        window.RequestedThemeVariant = ThemeVariant.Light;
        Dispatcher.UIThread.RunJobs();
        Assert.Equal(2, Formulas(view).Count);
    }

    [AvaloniaFact]
    public void Formula_in_contesti_annidati()
    {
        var markdown = """
            Testo $a_1$ e un [link](https://example.com).

            [vai a $b^2$](https://example.com)

            - voce $c_3$

            | x | y |
            |---|---|
            | $d_4$ | z |
            """;
        var (_, view) = Show(markdown);
        Assert.Equal(4, Formulas(view).Count);
        Assert.Contains("link", Text(view));
        Assert.Contains("vai a", Text(view));
    }

    [AvaloniaFact]
    public void Formula_nome_accessibile()
    {
        var (_, view) = Show("Gap $E_g$.");
        var f = Assert.Single(Formulas(view));
        Assert.Equal("E_g", AutomationProperties.GetName(f));
    }

    [AvaloniaFact]
    public void Dollari_isolati_restano_testo()
    {
        var (_, view) = Show("Costa 10 $ e poi 20 $ in totale.");
        Assert.Empty(Formulas(view));
        Assert.Contains("10 $ e poi 20 $", Text(view));
    }
}