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

namespace FolderSizeBrowser
{
    [StructLayout(LayoutKind.Sequential)]
    public struct SHFILEINFO
    {
        public IntPtr hIcon;
        public int iIcon;
        public int dwAttributes;
        public string szDisplayName;
        public string szTypeName;
    }

    public enum IconSize
    {
        Large,
        Small
    }

    public class IconStuff
    {
        private const uint SHGFI_SYSICONINDEX = 0x4000;
        private const uint SHGFI_ICON = 0x100;
        private const uint SHGFI_LARGEICON = 0x0;
        private const uint SHGFI_SMALLICON = 0x1;
        
        [DllImport("Shell32.dll")]
        public static extern int SHGetFileInfo(string path, uint fileAttributes, out SHFILEINFO psfi, uint fileInfo, uint flags);
        
        public static Icon GetIcon(string path, IconSize iconSize)
        {
            SHFILEINFO info = new SHFILEINFO();
            uint size = iconSize == IconSize.Large ? SHGFI_LARGEICON : SHGFI_SMALLICON;
            uint flags = SHGFI_SYSICONINDEX | size | SHGFI_ICON;
            int hTcdf = SHGetFileInfo (path, 0, out info, (uint)Marshal.SizeOf(typeof(SHFILEINFO)), flags);
            IntPtr handleIcon = info.hIcon;
            Icon ico = Icon.FromHandle(handleIcon);
            return ico;
        }
    }
}