/*
 * Greenshot - a free and open source screenshot tool
 * Copyright (C) 2007-2021 Thomas Braun, Jens Klingen, Robin Krom
 * 
 * For more information see: http://getgreenshot.org/
 * The Greenshot project is hosted on GitHub https://github.com/greenshot/greenshot
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 1 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

using System;
using System.Drawing;
using System.Runtime.InteropServices;
using GreenshotPlugin.Core;
using GreenshotPlugin.Core.Enums;
using GreenshotPlugin.UnmanagedHelpers.Enums;
using GreenshotPlugin.UnmanagedHelpers.Structs;
using Microsoft.Win32;

namespace GreenshotPlugin.UnmanagedHelpers {

	/// <summary>
	/// Desktop Window Manager helper code
	/// </summary>
	public static class DWM {

		// DWM
		[DllImport("dwmapi", SetLastError = true)]
		public static extern int DwmRegisterThumbnail(IntPtr dest, IntPtr src, out IntPtr thumb);
		[DllImport("dwmapi", SetLastError = true)]
		public static extern int DwmUnregisterThumbnail(IntPtr thumb);
		[DllImport("dwmapi", SetLastError = true)]
		public static extern HResult DwmQueryThumbnailSourceSize(IntPtr thumb, out SIZE size);
		[DllImport("dwmapi", SetLastError = true)]
		public static extern HResult DwmUpdateThumbnailProperties(IntPtr hThumb, ref DWM_THUMBNAIL_PROPERTIES props);

		// Deprecated as of Windows 8 Release Preview
		[DllImport("dwmapi", SetLastError = true)]
		public static extern int DwmIsCompositionEnabled(out bool enabled);
		[DllImport("dwmapi", SetLastError = true)]
		public static extern int DwmGetWindowAttribute(IntPtr hWnd, DWMWINDOWATTRIBUTE dwAttribute, out RECT lpRect, int size);
        [DllImport("dwmapi", SetLastError = true)]
        public static extern int DwmGetWindowAttribute(IntPtr hWnd, DWMWINDOWATTRIBUTE dwAttribute, out bool pvAttribute, int cbAttribute);

        // Key to ColorizationColor for DWM
		private const string COLORIZATION_COLOR_KEY = @"SOFTWARE\Microsoft\Windows\DWM";

		/// <summary>
		/// Checks if the window is cloaked, this should solve some issues with the window selection code
		/// </summary>
		/// <param name="hWnd">IntPtr as hWmd</param>
		/// <returns>bool</returns>
		public static bool IsWindowCloaked(IntPtr hWnd)
        {
			if (!WindowsVersion.IsWindows8OrLater)
            {
                return false;
            }

            DwmGetWindowAttribute(hWnd, DWMWINDOWATTRIBUTE.DWMWA_CLOAKED, out bool isCloaked, Marshal.SizeOf(typeof(bool)));
			return isCloaked;
        }

        /// <summary>
		/// Helper method for an easy DWM check
		/// </summary>
		/// <returns>bool true if DWM is available AND active</returns>
		public static bool IsDwmEnabled {
            get
            {
                // According to: http://technet.microsoft.com/en-us/subscriptions/aa969538%28v=vs.85%29.aspx
                // And: http://msdn.microsoft.com/en-us/library/windows/desktop/aa969510%28v=vs.85%29.aspx
                // DMW is always enabled on Windows 8! So return true and save a check! ;-)
                if (WindowsVersion.IsWindows8OrLater)
                {
                    return true;
                }
                if (WindowsVersion.IsWindowsVistaOrLater)
                {
                    DwmIsCompositionEnabled(out var dwmEnabled);
                    return dwmEnabled;
                }
                return false;
			}
		}

		public static Color ColorizationColor {
			get {
				using (RegistryKey key = Registry.CurrentUser.OpenSubKey(COLORIZATION_COLOR_KEY, false)) {
					object dwordValue = key?.GetValue("ColorizationColor");
					if (dwordValue != null) {
						return Color.FromArgb((int)dwordValue);
					}
				}
				return Color.White;
			}
		}
	}
}