namespace NeoUI.Controls.Decorations;

/// <summary>
/// 可裁剪 Boder
/// </summary>
public class ClippingBorder : System.Windows.Controls.Border
{
    /// <inheritdoc/>
    protected override void OnRender(DrawingContext dc)
    {
        if(Child is { })
        {
            var topLeft = CornerRadius.TopLeft - Math.Max(BorderThickness.Top, BorderThickness.Left) / 2;
            var bottomLeft = CornerRadius.BottomLeft - Math.Max(BorderThickness.Bottom, BorderThickness.Left) / 2;
            var topRight = CornerRadius.TopRight - Math.Max(BorderThickness.Top, BorderThickness.Right) / 2;
            var bottomRight = CornerRadius.BottomRight - Math.Max(BorderThickness.Bottom, BorderThickness.Right) / 2;
            if(topLeft < 0)
                topLeft = 0;
            if(bottomLeft < 0)
                bottomLeft = 0;
            if(topRight < 0)
                topRight = 0;
            if(bottomRight < 0)
                bottomRight = 0;
            var mask = new System.Windows.Controls.Border()
            {
                CornerRadius = new CornerRadius(topLeft, topRight, bottomRight, bottomLeft),
                Height = ActualHeight - BorderThickness.Top - BorderThickness.Bottom,
                Width = ActualWidth - BorderThickness.Left - BorderThickness.Right,
                Background = Brushes.Black,
                SnapsToDevicePixels = true,
            };

            Child.OpacityMask = new VisualBrush(mask);
        }

        base.OnRender(dc);
    }
}