using Avalonia;
using Avalonia.Headless;
using DodoSSH.Client.App.Layout.Tests;

[assembly: AvaloniaTestApplication(typeof(HeadlessApp))]

namespace DodoSSH.Client.App.Layout.Tests;

/// <summary>
/// Builds the real application for a headless renderer.
/// </summary>
/// <remarks>
/// <para>
/// <see cref="DodoSshApp"/> itself, not a stand-in, because the thing being measured is how the shipped
/// styles lay out — a harness with its own theme would measure a window nobody sees. Its
/// <c>OnFrameworkInitializationCompleted</c> only composes the object graph when the lifetime is a classic
/// desktop one, and a headless session's is not, so loading it here brings the Fluent theme and the dark
/// variant and starts no vault, no listener and no browser.
/// </para>
/// <para>
/// Skia rather than the headless drawing stub, which is the one deliberate cost in this file. The stub's
/// font manager returns invented glyph metrics, and text height is an input to every stacked panel in this
/// window — measuring against it would produce numbers that are self-consistent and unrelated to the
/// application. With Skia and the same Inter font the application registers, a measured height is the
/// height a user gets.
/// </para>
/// </remarks>
internal static class HeadlessApp
{
    /// <summary>Found by name; <see cref="AvaloniaTestApplicationAttribute"/> is the contract.</summary>
    public static AppBuilder BuildAvaloniaApp() =>
        AppBuilder.Configure<DodoSshApp>()
            .UseSkia()
            .UseHeadless(new AvaloniaHeadlessPlatformOptions { UseHeadlessDrawing = false })
            .WithInterFont();
}