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

namespace AgentWikiUi.Tests;

/// <summary>Immagini nel markdown (ADR-0006): matrice MD-14 e MD-19…MD-26 in docs/TESTING.md.</summary>
[Trait("Category", "Gui")]
public sealed class MarkdownImageTests : IDisposable
{
    readonly string dir = Directory.CreateTempSubdirectory("awui-img-").FullName;
    readonly List<string> inBase = [];

    public void Dispose()
    {
        Directory.Delete(dir, true);
        foreach (var f in inBase) File.Delete(f);
    }

    string Png(string name, int w, int h)
    {
        var path = Path.Combine(dir, name);
        File.WriteAllBytes(path, PngFactory.Create(w, h));
        return path;
    }

    static (Window Window, MarkdownView View) Show(string markdown, double width = 500)
    {
        var view = new MarkdownView();
        var window = new Window { Width = width, Height = 800, Content = view };
        window.Show();
        view.Source = markdown;
        WaitForImages(view);
        return (window, view);
    }

    // il caricamento è in background (ADR-0006): si fa girare la coda della GUI finché tutte le immagini sono decodificate
    static void WaitForImages(MarkdownView view)
    {
        var deadline = DateTime.UtcNow.AddSeconds(10);
        while (view.PendingImages > 0 && DateTime.UtcNow < deadline) { Dispatcher.UIThread.RunJobs(); Thread.Sleep(5); }
        Dispatcher.UIThread.RunJobs();
        (TopLevel.GetTopLevel(view) as Window)?.UpdateLayout();
        Assert.Equal(0, view.PendingImages);
    }

    static List<Image> Images(Visual v) => v.GetVisualDescendants().OfType<Image>().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));

    [AvaloniaTheory]
    [InlineData("https://example.com/a.png")]
    [InlineData("http://example.com/a.png")]
    [InlineData("ftp://example.com/a.png")]
    [InlineData("data:image/png;base64,AAAA")]
    public void Immagini_remote_come_testo(string url)
    {
        var (_, view) = Show($"Vedi ![logo]({url}) qui");
        Assert.Empty(Images(view));
        Assert.Contains("[logo]", Text(view));
    }

    [AvaloniaFact]
    public void Immagine_percorso_assoluto()
    {
        var path = Png("a.png", 40, 20);
        var (_, view) = Show($"![griglia]({path})");
        var img = Assert.Single(Images(view));
        var bmp = Assert.IsAssignableFrom<Bitmap>(img.Source);
        Assert.Equal(new PixelSize(40, 20), bmp.PixelSize);
        Assert.Equal(40, img.Bounds.Width, 0.5);
        Assert.DoesNotContain("[griglia]", Text(view));
    }

    [AvaloniaFact]
    public void Immagine_percorso_relativo_e_file_uri()
    {
        var name = $"awui-{Guid.NewGuid():N}.png";
        var inBasePath = Path.Combine(AppContext.BaseDirectory, name);
        File.WriteAllBytes(inBasePath, PngFactory.Create(10, 10));
        inBase.Add(inBasePath);
        var (_, relative) = Show($"![r]({name})");
        Assert.Single(Images(relative));

        var uri = new Uri(Png("b.png", 12, 12)).AbsoluteUri;
        var (_, fileUri) = Show($"![u]({uri})");
        Assert.Single(Images(fileUri));
    }

    [AvaloniaTheory]
    [InlineData("manca")]
    [InlineData("corrotto")]
    [InlineData("estensione")]
    public void Immagine_non_valida_ripiego(string caso)
    {
        var path = caso switch
        {
            "manca" => Path.Combine(dir, "non-esiste.png"),
            "corrotto" => Write("rotto.png", "questo non è un png"u8.ToArray()),
            _ => Write("dati.txt", PngFactory.Create(8, 8)),
        };
        var (_, view) = Show($"![alt]({path})");
        Assert.Empty(Images(view));
        Assert.Contains("[alt]", Text(view));
    }

    string Write(string name, byte[] bytes)
    {
        var path = Path.Combine(dir, name);
        File.WriteAllBytes(path, bytes);
        return path;
    }

    [AvaloniaFact]
    public void Immagine_oltre_limite()
    {
        var path = Path.Combine(dir, "grande.png");
        using (var fs = File.Create(path)) { fs.Write(PngFactory.Create(8, 8)); fs.SetLength(20L * 1024 * 1024 + 1); }
        var (_, view) = Show($"![enorme]({path})");
        Assert.Empty(Images(view));
        Assert.Contains("[enorme]", Text(view));
    }

    [AvaloniaFact]
    public void Immagine_larghezza_massima()
    {
        var (_, wide) = Show($"![larga]({Png("larga.png", 2000, 100)})", width: 500);
        var img = Assert.Single(Images(wide));
        Assert.True(img.Bounds.Width <= 500, $"larghezza {img.Bounds.Width}");
        Assert.Equal(img.Bounds.Width / 20, img.Bounds.Height, 1); // proporzioni 20:1

        var (_, small) = Show($"![piccola]({Png("piccola.png", 50, 50)})", width: 500);
        Assert.Equal(50, Assert.Single(Images(small)).Bounds.Width, 0.5); // mai ingrandita
    }

    [AvaloniaFact]
    public void Immagine_testo_alternativo_accessibile()
    {
        var (_, view) = Show($"![un grafico]({Png("g.png", 10, 10)})");
        var img = Assert.Single(Images(view));
        Assert.Equal("un grafico", AutomationProperties.GetName(img));
        Assert.Equal("un grafico", ToolTip.GetTip(img));
    }

    [AvaloniaFact]
    public void Immagine_in_contesti_annidati()
    {
        var p = Png("n.png", 10, 10);
        var markdown = $"""
            Testo ![in riga]({p}) e ancora testo con [un link](https://example.com).

            [![dentro link]({p})](https://example.com)

            - voce ![in lista]({p})

            | a | b |
            |---|---|
            | ![in tabella]({p}) | x |
            """;
        var (_, view) = Show(markdown);
        Assert.Equal(4, Images(view).Count);
        Assert.Contains("un link", Text(view));
    }

    [AvaloniaFact]
    public void Immagine_cambio_tema()
    {
        var (window, view) = Show($"![t]({Png("t.png", 10, 10)})");
        window.RequestedThemeVariant = ThemeVariant.Dark;
        WaitForImages(view);
        Assert.Single(Images(view));
        window.RequestedThemeVariant = ThemeVariant.Light;
        WaitForImages(view);
        Assert.Single(Images(view));
    }

    [AvaloniaFact]
    public void Immagine_caricamento_in_background()
    {
        var path = Png("bg.png", 30, 30);
        var view = new MarkdownView();
        var window = new Window { Width = 500, Height = 800, Content = view };
        window.Show();
        view.Source = $"![segnaposto]({path})";
        // subito dopo il rendering: immagine in attesa e solo il segnaposto (il completamento passa dalla coda della GUI)
        Assert.Equal(1, view.PendingImages);
        Assert.Empty(Images(view));
        Assert.Contains("[segnaposto]", Text(view));
        WaitForImages(view);
        Assert.Single(Images(view));
        Assert.DoesNotContain("[segnaposto]", Text(view));

        // file corrotto: la decodifica fallisce e il segnaposto resta
        var rotto = Write("rotto2.png", "no"u8.ToArray());
        view.Source = $"![guasta]({rotto})";
        WaitForImages(view);
        Assert.Empty(Images(view));
        Assert.Contains("[guasta]", Text(view));
    }
}