using System;
using System.Drawing;
using System.Runtime.InteropServices;

namespace GeekDesk.Util
{
    class SystemIcon
    {
        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        public struct SHFILEINFO
        {
            public IntPtr hIcon;
            public int iIcon;
            public uint dwAttributes;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
            public string szDisplayName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 80)]
            public string szTypeName;
        }
        [DllImport("Shell32.dll", EntryPoint = "SHGetFileInfo", SetLastError = true, CharSet = CharSet.Auto)]
        public static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref SHFILEINFO psfi, uint cbFileInfo, uint uFlags);
        [DllImport("User32.dll", EntryPoint = "DestroyIcon")]
        public static extern int DestroyIcon(IntPtr hIcon);
        #region API 参数的常量定义
        public enum FileInfoFlags : uint
        {
            SHGFI_ICON = 0x000000100, // get icon
            SHGFI_DISPLAYNAME = 0x000000200, // get display name
            SHGFI_TYPENAME = 0x000000400, // get type name
            SHGFI_ATTRIBUTES = 0x000000800, // get attributes
            SHGFI_ICONLOCATION = 0x000001000, // get icon location
            SHGFI_EXETYPE = 0x000002000, // return exe type
            SHGFI_SYSICONINDEX = 0x000004000, // get system icon index
            SHGFI_LINKOVERLAY = 0x000008000, // put a link overlay on icon
            SHGFI_SELECTED = 0x000010000, // show icon in selected state
            SHGFI_ATTR_SPECIFIED = 0x000020000, // get only specified attributes
            SHGFI_LARGEICON = 0x000000000, // get large icon
            SHGFI_SMALLICON = 0x000000001, // get small icon
            SHGFI_OPENICON = 0x000000002, // get open icon
            SHGFI_SHELLICONSIZE = 0x000000004, // get shell size icon
            SHGFI_PIDL = 0x000000008, // pszPath is a pidl
            SHGFI_USEFILEATTRIBUTES = 0x000000010, // use passed dwFileAttribute
            SHGFI_ADDOVERLAYS = 0x000000020, // apply the appropriate overlays
            SHGFI_OVERLAYINDEX = 0x000000040 // Get the index of the overlay
        }
        public enum FileAttributeFlags : uint
        {
            FILE_ATTRIBUTE_READONLY = 0x00000001,
            FILE_ATTRIBUTE_HIDDEN = 0x00000002,
            FILE_ATTRIBUTE_SYSTEM = 0x00000004,
            FILE_ATTRIBUTE_DIRECTORY = 0x00000010,
            FILE_ATTRIBUTE_ARCHIVE = 0x00000020,
            FILE_ATTRIBUTE_DEVICE = 0x00000040,
            FILE_ATTRIBUTE_NORMAL = 0x00000080,
            FILE_ATTRIBUTE_TEMPORARY = 0x00000100,
            FILE_ATTRIBUTE_SPARSE_FILE = 0x00000200,
            FILE_ATTRIBUTE_REPARSE_POINT = 0x00000400,
            FILE_ATTRIBUTE_COMPRESSED = 0x00000800,
            FILE_ATTRIBUTE_OFFLINE = 0x00001000,
            FILE_ATTRIBUTE_NOT_CONTENT_INDEXED = 0x00002000,
            FILE_ATTRIBUTE_ENCRYPTED = 0x00004000
        }
        #endregion
        /// <summary>
        /// 获取文件类型的关联图标
        /// </summary>
        /// <param name="fileName">文件类型的扩展名或文件的绝对路径</param>
        /// <param name="isLargeIcon">是否返回大图标</param>
        /// <returns>获取到的图标</returns>
        public static Icon GetIcon(string fileName, bool isLargeIcon)
        {
            //SHFILEINFO shfi = new SHFILEINFO();
            //IntPtr hI;
            //if (isLargeIcon)
            //    hI = SHGetFileInfo(fileName, 0, ref shfi, (uint)Marshal.SizeOf(shfi), (uint)FileInfoFlags.SHGFI_ICON | (uint)FileInfoFlags.SHGFI_USEFILEATTRIBUTES | (uint)FileInfoFlags.SHGFI_LARGEICON);
            //else
            //    hI = SHGetFileInfo(fileName, 0, ref shfi, (uint)Marshal.SizeOf(shfi), (uint)FileInfoFlags.SHGFI_ICON | (uint)FileInfoFlags.SHGFI_USEFILEATTRIBUTES | (uint)FileInfoFlags.SHGFI_SMALLICON);
            //Icon icon = Icon.FromHandle(shfi.hIcon).Clone() as Icon;
            //DestroyIcon(shfi.hIcon); //释放资源

            //选中文件中的图标总数
            //var iconTotalCount = PrivateExtractIcons(fileName, 0, 0, 0, null, null, 1, 0);
            //用于接收获取到的图标指针
            //IntPtr[] hIcons = new IntPtr[1];
            ////对应的图标id
            //int[] ids = new int[1];
            ////成功获取到的图标个数
            //int successCount = PrivateExtractIcons(fileName, 0, 0, 0, hIcons, ids, 1, 0);
            //Icon ico = Icon.FromHandle(hIcons[0]);
            //var myIcon = ico.ToBitmap();
            //myIcon.Save("D:\\" + ids[0].ToString("000") + ".png", ImageFormat.Png);
            IntPtr hIcon = FileIcon.GetJumboIcon(FileIcon.GetIconIndex(fileName));
            //IntPtr hIcon = GetJumboIcon(GetIconIndex("*." + ext));

            // from native to managed
            Icon ico = Icon.FromHandle(hIcon);
            string path = "D:\\test\\" + System.Guid.NewGuid().ToString() + ".png";
            //using ( ico = (Icon)Icon.FromHandle(hIcon).Clone())
            //{
            //    // save to file (or show in a picture box)
            //    ico.ToBitmap().Save(path, ImageFormat.Png);
            //}
            //FileIcon.Shell32.DestroyIcon(hIcon); // don't forget to cleanup

            return ico;
        }
        /// <summary> 
        /// 获取文件夹图标
        /// </summary> 
        /// <returns>图标</returns> 
        public static Icon GetDirectoryIcon(bool isLargeIcon)
        {
            SHFILEINFO _SHFILEINFO = new SHFILEINFO();
            IntPtr _IconIntPtr;
            if (isLargeIcon)
            {
                _IconIntPtr = SHGetFileInfo(@"", 0, ref _SHFILEINFO, (uint)Marshal.SizeOf(_SHFILEINFO), ((uint)FileInfoFlags.SHGFI_ICON | (uint)FileInfoFlags.SHGFI_LARGEICON));
            }
            else
            {
                _IconIntPtr = SHGetFileInfo(@"", 0, ref _SHFILEINFO, (uint)Marshal.SizeOf(_SHFILEINFO), ((uint)FileInfoFlags.SHGFI_ICON | (uint)FileInfoFlags.SHGFI_SMALLICON));
            }
            if (_IconIntPtr.Equals(IntPtr.Zero)) return null;
            Icon _Icon = System.Drawing.Icon.FromHandle(_SHFILEINFO.hIcon);
            return _Icon;
        }

        [DllImport("User32.dll")]
        public static extern int PrivateExtractIcons(
             string lpszFile, //file name
             int nIconIndex,  //The zero-based index of the first icon to extract.
             int cxIcon,      //The horizontal icon size wanted.
             int cyIcon,      //The vertical icon size wanted.
             IntPtr[] phicon, //(out) A pointer to the returned array of icon handles.
             int[] piconid,   //(out) A pointer to a returned resource identifier.
             int nIcons,      //The number of icons to extract from the file. Only valid when *.exe and *.dll
             int flags        //Specifies flags that control this function.
         );

        //[DllImport("User32.dll")]
        //public static extern bool DestroyIcon(
        //     IntPtr hIcon //A handle to the icon to be destroyed. The icon must not be in use.
        // );
    }
}