using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Interop;
using System.Windows.Media;

namespace FeenPhone.WPFApp
{
    public class GlassHelper
    {
        struct MARGINS
        {
            public MARGINS(Thickness t)
            {
                Left = (int)t.Left;
                Right = (int)t.Right;
                Top = (int)t.Top;
                Bottom = (int)t.Bottom;
            }
            public int Left;
            public int Right;
            public int Top;
            public int Bottom;
        }

        [DllImport("dwmapi.dll", PreserveSig = false)]
        static extern void DwmExtendFrameIntoClientArea(IntPtr hwnd, ref MARGINS margins);

        [DllImport("dwmapi.dll", PreserveSig = false)]
        static extern bool DwmIsCompositionEnabled();

        public static bool ExtendGlassFrame(Window window, Thickness margin)
        {
            if (!DwmIsCompositionEnabled())
                return false;

            IntPtr hwnd = new WindowInteropHelper(window).Handle;
            if (hwnd == IntPtr.Zero)
                throw new InvalidOperationException("The Window must be shown before extending glass.");

            // Set the background to transparent from both the WPF and Win32 perspectives
            window.Background = Brushes.Transparent;
            HwndSource.FromHwnd(hwnd).CompositionTarget.BackgroundColor = Colors.Transparent;

            MARGINS margins = new MARGINS(margin);
            DwmExtendFrameIntoClientArea(hwnd, ref margins);
            return true;
        }
    }

}
