using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Drawing;
using System.IO;

namespace VSoft.Prams
{
    public static class ShellIcon
    {
        [StructLayout(LayoutKind.Sequential)]
        public struct SHFILEINFO
        {
            public IntPtr hIcon;
            public IntPtr iIcon;
            public uint dwAttributes;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
            public string szDisplayName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 80)]
            public string szTypeName;
        };


       public static class Win32
        {
            public const uint SHGFI_ICON = 0x000000100;// get icon
            public const uint SHGFI_DISPLAYNAME = 0x000000200;// get display name
            public const uint SHGFI_TYPENAME = 0x000000400;// get type name
            public const uint SHGFI_ATTRIBUTES = 0x000000800;// get attributes
            public const uint SHGFI_ICONLOCATION = 0x000001000;// get icon location
            public const uint SHGFI_EXETYPE = 0x000002000;// return exe type
            public const uint SHGFI_SYSICONINDEX = 0x000004000;// get system icon index
            public const uint SHGFI_LINKOVERLAY = 0x000008000;// put a link overlay on icon
            public const uint SHGFI_SELECTED = 0x000010000;// show icon in selected state
            public const uint SHGFI_ATTR_SPECIFIED = 0x000020000;// get only specified attributes
            public const uint SHGFI_JUMBO = 0x000000004;// get large icon
            public const uint SHGFI_LARGEICON = 0x000000000;// get large icon
            public const uint SHGFI_SMALLICON = 0x000000001;// get small icon
            public const uint SHGFI_OPENICON = 0x000000002;// get open icon
            public const uint SHGFI_SHELLICONSIZE = 0x000000004;// get shell size icon
            public const uint SHGFI_PIDL = 0x000000008;// pszPath is a pidl
            public const uint SHGFI_USEFILEATTRIBUTES = 0x000000010;// use passed dwFileAttribute

            public const uint FILE_ATTRIBUTE_READONLY = 0x00000001;
            public const uint FILE_ATTRIBUTE_HIDDEN = 0x00000002;
            public const uint FILE_ATTRIBUTE_SYSTEM = 0x00000004;
            public const uint FILE_ATTRIBUTE_DIRECTORY = 0x00000010;
            public const uint FILE_ATTRIBUTE_ARCHIVE = 0x00000020;
            public const uint FILE_ATTRIBUTE_DEVICE = 0x00000040;
            public const uint FILE_ATTRIBUTE_NORMAL = 0x00000080;
            public const uint FILE_ATTRIBUTE_TEMPORARY = 0x00000100;
            public const uint FILE_ATTRIBUTE_SPARSE_FILE = 0x00000200;
            public const uint FILE_ATTRIBUTE_REPARSE_POINT = 0x00000400;
            public const uint FILE_ATTRIBUTE_COMPRESSED = 0x00000800;
            public const uint FILE_ATTRIBUTE_OFFLINE = 0x00001000;
            public const uint FILE_ATTRIBUTE_NOT_CONTENT_INDEXED = 0x00002000;
            public const uint FILE_ATTRIBUTE_ENCRYPTED = 0x00004000;

            [DllImport("shell32.dll", CharSet = CharSet.Unicode)]
            public static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref SHFILEINFO psfi, uint cbSizeFileInfo, uint uFlags);

            [DllImport("User32.dll")]
            public static extern int DestroyIcon(System.IntPtr hIcon);
        }

        /// <summary>
        /// 获取扩展名信息
        /// </summary>
        /// <param name="ext"></param>
        /// <returns></returns>
        public static string GetTypeInfo(string ext)
        {
            SHFILEINFO shinfo = new SHFILEINFO();
            Win32.SHGetFileInfo(ext, Win32.FILE_ATTRIBUTE_NORMAL, ref shinfo, (uint)Marshal.SizeOf(shinfo), Win32.SHGFI_TYPENAME | Win32.SHGFI_USEFILEATTRIBUTES);
            return shinfo.szTypeName;
        }

        /// <summary>
        /// 获取扩展名的图标
        /// </summary>
        /// <param name="ext"></param>
        /// <returns></returns>
        public static Icon GetSmallTypeIcon(string ext)
        {
            SHFILEINFO shinfo = new SHFILEINFO();
            Win32.SHGetFileInfo(ext, Win32.FILE_ATTRIBUTE_NORMAL, ref shinfo, (uint)Marshal.SizeOf(shinfo), Win32.SHGFI_ICON | Win32.SHGFI_SMALLICON | Win32.SHGFI_USEFILEATTRIBUTES);
            if (shinfo.hIcon.ToInt32() == 0) return null;
            Icon shellIcon = (Icon)System.Drawing.Icon.FromHandle(shinfo.hIcon).Clone();
            Win32.DestroyIcon(shinfo.hIcon);
            return shellIcon;
        }

        /// <summary>
        /// 获取文件的小图标
        /// </summary>
        /// <param name="fileName"></param>
        /// <returns></returns>
        public static Icon GetSmallIcon(string fileName)
        {
            SHFILEINFO shinfo = new SHFILEINFO();
            Win32.SHGetFileInfo(fileName, 0, ref shinfo, (uint)Marshal.SizeOf(shinfo), Win32.SHGFI_ICON | Win32.SHGFI_SMALLICON);
            if (shinfo.hIcon.ToInt32() == 0) return null;
            Icon shellIcon = (Icon)System.Drawing.Icon.FromHandle(shinfo.hIcon).Clone();
            Win32.DestroyIcon(shinfo.hIcon);
            return shellIcon;
        }

        /// <summary>
        /// 获取文件的大图标
        /// </summary>
        /// <param name="fileName"></param>
        /// <returns></returns>
        public static Bitmap GetLargeIcon(string fileName)
        {
            var icon = c_icon_of_path.icon_of_path_large(fileName, true, true);
            if (icon == null) { return null; }
            return icon.ToBitmap();
            //SHFILEINFO shinfo = new SHFILEINFO();
            //Win32.SHGetFileInfo(fileName, Win32.FILE_ATTRIBUTE_NORMAL, ref shinfo, (uint)Marshal.SizeOf(shinfo),Win32.SHGFI_ICON  | Win32.SHGFI_SHELLICONSIZE);
            //if (shinfo.hIcon.ToInt32() == 0) return null;
            //Icon shellIcon = (Icon)System.Drawing.Icon.FromHandle(shinfo.hIcon).Clone();
            //Win32.DestroyIcon(shinfo.hIcon);
            //return shellIcon;
        }
    }
}
