using System.Globalization;
using System.Windows.Data;

namespace Melskin.Converters.Internal;

/// <summary>
/// 将浮点数类型的强度值转换为左上边距的 Thickness 对象。该转换器适用于需要根据浮点数值动态调整 UI 元素边距的场景。
/// 当输入的强度值为 1 时，生成的边距最小，随着强度值减小，边距逐渐增大，从而影响 UI 元素显示效果，如阴影或光照效果的范围。
/// </summary>
[ValueConversion(typeof(double), typeof(Thickness))]
internal class IntensityToEmbossMarginLeftTopConverter : IValueConverter
{
    public static readonly IntensityToEmbossMarginLeftTopConverter Instance = new();
        
    public object Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
    {
        var intensity = (double)(value ?? 0.5);
        //数值为1的时候边距最小，露出的着色边框越大
        var marginValue = 2 * intensity;
        return new Thickness(-marginValue, -marginValue, marginValue, marginValue);
    }

    public object ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
    {
        return Binding.DoNothing;
    }
}