using System.Windows;

namespace AntDesignWPF.Extensions;

internal static class UiElementExtensions
{
    private static int Get_X_LParam(IntPtr lParam) { return (short)(lParam.ToInt32() & 0xFFFF); }

    private static int Get_Y_LParam(IntPtr lParam) { return (short)(lParam.ToInt32() >> 16); }

    /// <summary>
    /// 不要在 NCHITTEST、NCLBUTTONUP、NCLBUTTONDOWN 消息之外调用它！
    /// </summary>
    /// <returns>如果鼠标位于元素上<see langword="true"/>。 否则，<see langword="false"/> </returns>
    public static bool IsMouseOverElement(this UIElement element, IntPtr lParam)
    {
        // 此方法将非常频繁地调用，并且必须尽可能简单。
        if (lParam == IntPtr.Zero)
        {
            return false;
        }

        try
        {
            var mousePosScreen = new Point(Get_X_LParam(lParam), Get_Y_LParam(lParam));
            var bounds = new Rect(default, element.RenderSize);

            Point mousePosRelative = element.PointFromScreen(mousePosScreen);

            return bounds.Contains(mousePosRelative);
        } catch
        {
            return false;
        }
    }
}