using System.Globalization;
using Avalonia;
using Avalonia.Controls;
using Avalonia.Data.Converters;
using Avalonia.Media;

namespace AvParser.UI.Converters;

/// <summary>Small one-way converters used by the views.</summary>
public static class AppConverters
{
    /// <summary>Collection counts to a boolean, for showing a panel only when it has content.</summary>
    public static readonly FuncValueConverter<int, bool> IsPositive = new(static count => count > 0);

    /// <summary>Inverts a boolean, for enabling a control while a command is idle.</summary>
    public static readonly FuncValueConverter<bool, bool> Not = new(static value => !value);

    /// <summary>Formats a 0..1 fraction as a whole-number percentage.</summary>
    public static readonly FuncValueConverter<double, string> Percent = new(static value =>
        value.ToString("P0", CultureInfo.CurrentCulture)
    );

    /// <summary>
    /// Resolves an icon key from <c>Styles/Icons.axaml</c> to the geometry it names.
    /// </summary>
    /// <remarks>
    /// Lets view models refer to icons by a plain string instead of holding
    /// <see cref="Geometry"/> instances, which keeps them trivially constructible in tests.
    /// </remarks>
    public static readonly FuncValueConverter<string?, Geometry?> IconKeyToGeometry = new(static key =>
        key is not null && Application.Current is { } app && app.TryFindResource(key, out var resource)
            ? resource as Geometry
            : null
    );
}