using System;
using System.IO;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace SystemTrayMenu.UserInterface.FolderDialog
{
    public class FolderDialog : IFolderDialog, IDisposable
    {
        private bool isDisposed;

        /// <summary>
        /// Gets/sets folder in which dialog will be open.
        /// </summary>
        public string InitialFolder { get; set; }

        /// <summary>
        /// Gets/sets directory in which dialog will be open 
        /// if there is no recent directory available.
        /// </summary>
        public string DefaultFolder { get; set; }

        /// <summary>
        /// Gets selected folder.
        /// </summary>
        public string Folder { get; set; }
        public DialogResult ShowDialog()
        {
            return ShowDialog(owner: new WindowWrapper(IntPtr.Zero));
        }
        public DialogResult ShowDialog(IWin32Window owner)
        {
            if (Environment.OSVersion.Version.Major >= 6)
            {
                return ShowVistaDialog(owner);
            }
            else
            {
                return ShowLegacyDialog(owner);
            }
        }
        public DialogResult ShowVistaDialog(IWin32Window owner)
        {
            NativeMethods.IFileDialog frm = (NativeMethods.IFileDialog)(new NativeMethods.FileOpenDialogRCW());
            frm.GetOptions(out uint options);
            options |= NativeMethods.FOS_PICKFOLDERS |
                       NativeMethods.FOS_FORCEFILESYSTEM |
                       NativeMethods.FOS_NOVALIDATE |
                       NativeMethods.FOS_NOTESTFILECREATE |
                       NativeMethods.FOS_DONTADDTORECENT;
            frm.SetOptions(options);
            if (InitialFolder != null)
            {
                Guid riid = new Guid("43826D1E-E718-42EE-BC55-A1E261C37BFE"); //IShellItem
                if (NativeMethods.SHCreateItemFromParsingName
                   (InitialFolder, IntPtr.Zero, ref riid,
                    out NativeMethods.IShellItem directoryShellItem) == NativeMethods.S_OK)
                {
                    frm.SetFolder(directoryShellItem);
                }
            }
            if (DefaultFolder != null)
            {
                Guid riid = new Guid("43826D1E-E718-42EE-BC55-A1E261C37BFE"); //IShellItem
                if (NativeMethods.SHCreateItemFromParsingName
                   (DefaultFolder, IntPtr.Zero, ref riid,
                    out NativeMethods.IShellItem directoryShellItem) == NativeMethods.S_OK)
                {
                    frm.SetDefaultFolder(directoryShellItem);
                }
            }

            if (frm.Show(owner.Handle) == NativeMethods.S_OK)
            {
                if (frm.GetResult(out NativeMethods.IShellItem shellItem) == NativeMethods.S_OK)
                {
                    if (shellItem.GetDisplayName(NativeMethods.SIGDN_FILESYSPATH,
                        out IntPtr pszString) == NativeMethods.S_OK)
                    {
                        if (pszString != IntPtr.Zero)
                        {
                            try
                            {
                                Folder = Marshal.PtrToStringAuto(pszString);
                                return DialogResult.OK;
                            }
                            finally
                            {
                                Marshal.FreeCoTaskMem(pszString);
                            }
                        }
                    }
                }
            }
            return DialogResult.Cancel;
        }
        public DialogResult ShowLegacyDialog(IWin32Window owner)
        {
            using (SaveFileDialog frm = new SaveFileDialog())
            {
                frm.CheckFileExists = false;
                frm.CheckPathExists = true;
                frm.CreatePrompt = false;
                frm.Filter = "|" + Guid.Empty.ToString();
                frm.FileName = "any";
                if (InitialFolder != null) { frm.InitialDirectory = InitialFolder; }
                frm.OverwritePrompt = false;
                frm.Title = "Select Folder";
                frm.ValidateNames = false;
                if (frm.ShowDialog(owner) == DialogResult.OK)
                {
                    Folder = Path.GetDirectoryName(frm.FileName);
                    return DialogResult.OK;
                }
                else
                {
                    return DialogResult.Cancel;
                }
            }
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (!isDisposed)
            {
                //just to have possibility of Using statement.
            }
            isDisposed = true;
        }
    }
    public class WindowWrapper : System.Windows.Forms.IWin32Window
    {
        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="handle">Handle to wrap</param>
        public WindowWrapper(IntPtr handle)
        {
            _hwnd = handle;
        }

        /// <summary>
        /// Original ptr
        /// </summary>
        public IntPtr Handle => _hwnd;

        private readonly IntPtr _hwnd;
    }
    internal static class NativeMethods
    {
        #region Constants

        public const uint FOS_PICKFOLDERS = 0x00000020;
        public const uint FOS_FORCEFILESYSTEM = 0x00000040;
        public const uint FOS_NOVALIDATE = 0x00000100;
        public const uint FOS_NOTESTFILECREATE = 0x00010000;
        public const uint FOS_DONTADDTORECENT = 0x02000000;

        public const uint S_OK = 0x0000;

        public const uint SIGDN_FILESYSPATH = 0x80058000;

        #endregion

        #region COM

        [ComImport, ClassInterface(ClassInterfaceType.None),
        TypeLibType(TypeLibTypeFlags.FCanCreate),
                    Guid("DC1C5A9C-E88A-4DDE-A5A1-60F82A20AEF7")]
        internal class FileOpenDialogRCW { }

        [ComImport(), Guid("42F85136-DB7E-439C-85F1-E4075D135FC8"),
                      InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        internal interface IFileDialog
        {
            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            [PreserveSig()]
            uint Show([In, Optional] IntPtr hwndOwner); //IModalWindow 

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint SetFileTypes([In] uint cFileTypes,
            [In, MarshalAs(UnmanagedType.LPArray)] IntPtr rgFilterSpec);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint SetFileTypeIndex([In] uint iFileType);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint GetFileTypeIndex(out uint piFileType);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint Advise([In, MarshalAs(UnmanagedType.Interface)] IntPtr pfde,
            out uint pdwCookie);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint Unadvise([In] uint dwCookie);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint SetOptions([In] uint fos);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint GetOptions(out uint fos);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            void SetDefaultFolder([In, MarshalAs(UnmanagedType.Interface)] IShellItem psi);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint SetFolder([In, MarshalAs(UnmanagedType.Interface)] IShellItem psi);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint GetFolder([MarshalAs(UnmanagedType.Interface)] out IShellItem ppsi);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint GetCurrentSelection
                 ([MarshalAs(UnmanagedType.Interface)] out IShellItem ppsi);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint SetFileName([In, MarshalAs(UnmanagedType.LPWStr)] string pszName);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint GetFileName([MarshalAs(UnmanagedType.LPWStr)] out string pszName);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint SetTitle([In, MarshalAs(UnmanagedType.LPWStr)] string pszTitle);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint SetOkButtonLabel([In, MarshalAs(UnmanagedType.LPWStr)] string pszText);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint SetFileNameLabel([In, MarshalAs(UnmanagedType.LPWStr)] string pszLabel);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint GetResult([MarshalAs(UnmanagedType.Interface)] out IShellItem ppsi);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint AddPlace
              ([In, MarshalAs(UnmanagedType.Interface)] IShellItem psi, uint fdap);

            [MethodImpl(MethodImplOptions.InternalCall,
             MethodCodeType = MethodCodeType.Runtime)]
            uint SetDefaultExtension([In, MarshalAs(UnmanagedType.LPWStr)]
                                     string pszDefaultExtension);

            [MethodImpl(MethodImplOptions.InternalCall,
                        MethodCodeType = MethodCodeType.Runtime)]
            uint Close([MarshalAs(UnmanagedType.Error)] uint hr);

            [MethodImpl(MethodImplOptions.InternalCall,
                        MethodCodeType = MethodCodeType.Runtime)]
            uint SetClientGuid([In] ref Guid guid);

            [MethodImpl(MethodImplOptions.InternalCall,
                        MethodCodeType = MethodCodeType.Runtime)]
            uint ClearClientData();

            [MethodImpl(MethodImplOptions.InternalCall,
                        MethodCodeType = MethodCodeType.Runtime)]
            uint SetFilter([MarshalAs(UnmanagedType.Interface)] IntPtr pFilter);
        }

        [ComImport, Guid("43826D1E-E718-42EE-BC55-A1E261C37BFE"),
                    InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        internal interface IShellItem
        {
            [MethodImpl(MethodImplOptions.InternalCall,
                        MethodCodeType = MethodCodeType.Runtime)]
            uint BindToHandler([In] IntPtr pbc, [In] ref Guid rbhid,
            [In] ref Guid riid, [Out, MarshalAs(UnmanagedType.Interface)] out IntPtr ppvOut);

            [MethodImpl(MethodImplOptions.InternalCall,
                        MethodCodeType = MethodCodeType.Runtime)]
            uint GetParent([MarshalAs(UnmanagedType.Interface)] out IShellItem ppsi);

            [MethodImpl(MethodImplOptions.InternalCall,
                        MethodCodeType = MethodCodeType.Runtime)]
            uint GetDisplayName([In] uint sigdnName, out IntPtr ppszName);

            [MethodImpl(MethodImplOptions.InternalCall,
                        MethodCodeType = MethodCodeType.Runtime)]
            uint GetAttributes([In] uint sfgaoMask, out uint psfgaoAttribs);

            [MethodImpl(MethodImplOptions.InternalCall,
                        MethodCodeType = MethodCodeType.Runtime)]
            uint Compare([In, MarshalAs(UnmanagedType.Interface)] IShellItem psi,
                         [In] uint hint, out int piOrder);
        }

        #endregion

        [DllImport("shell32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
        internal static extern int SHCreateItemFromParsingName
         ([MarshalAs(UnmanagedType.LPWStr)] string pszPath, IntPtr pbc,
         ref Guid riid, [MarshalAs(UnmanagedType.Interface)] out IShellItem ppv);
    }
}