using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Runtime.InteropServices.ComTypes;

namespace PdbFind.Gui;

static class ShowSelectedInExplorer
{
    [Flags]
    enum SHCONT : ushort
    {
        SHCONTF_CHECKING_FOR_CHILDREN = 0x0010,
        SHCONTF_FOLDERS = 0x0020,
        SHCONTF_NONFOLDERS = 0x0040,
        SHCONTF_INCLUDEHIDDEN = 0x0080,
        SHCONTF_INIT_ON_FIRST_NEXT = 0x0100,
        SHCONTF_NETPRINTERSRCH = 0x0200,
        SHCONTF_SHAREABLE = 0x0400,
        SHCONTF_STORAGE = 0x0800,
        SHCONTF_NAVIGATION_ENUM = 0x1000,
        SHCONTF_FASTITEMS = 0x2000,
        SHCONTF_FLATLIST = 0x4000,
        SHCONTF_ENABLE_ASYNC = 0x8000
    }

    [ComImport,
     Guid("000214E6-0000-0000-C000-000000000046"),
     InterfaceType(ComInterfaceType.InterfaceIsIUnknown),
     ComConversionLoss]
    interface IShellFolder
    {
        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
        void ParseDisplayName(IntPtr hwnd, [In, MarshalAs(UnmanagedType.Interface)] IBindCtx pbc,
            [In, MarshalAs(UnmanagedType.LPWStr)] string pszDisplayName, [Out] out uint pchEaten,
            [Out] out IntPtr ppidl, [In, Out] ref uint pdwAttributes);

        [PreserveSig]
        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
        int EnumObjects([In] IntPtr hwnd, [In] SHCONT grfFlags,
            [MarshalAs(UnmanagedType.Interface)] out IEnumIDList ppenumIDList);

        [PreserveSig]
        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
        int BindToObject([In] IntPtr pidl, [In, MarshalAs(UnmanagedType.Interface)] IBindCtx pbc, [In] ref Guid riid,
            [Out, MarshalAs(UnmanagedType.Interface)] out IShellFolder ppv);

        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
        void BindToStorage([In] ref IntPtr pidl, [In, MarshalAs(UnmanagedType.Interface)] IBindCtx pbc,
            [In] ref Guid riid, out IntPtr ppv);

        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
        void CompareIDs([In] IntPtr lParam, [In] ref IntPtr pidl1, [In] ref IntPtr pidl2);

        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
        void CreateViewObject([In] IntPtr hwndOwner, [In] ref Guid riid, out IntPtr ppv);

        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
        void GetAttributesOf([In] uint cidl, [In] IntPtr apidl, [In, Out] ref uint rgfInOut);


        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
        void GetUIObjectOf([In] IntPtr hwndOwner, [In] uint cidl, [In] IntPtr apidl, [In] ref Guid riid,
            [In, Out] ref uint rgfReserved, out IntPtr ppv);

        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
        void GetDisplayNameOf([In] ref IntPtr pidl, [In] uint uFlags, out IntPtr pName);

        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
        void SetNameOf([In] IntPtr hwnd, [In] ref IntPtr pidl, [In, MarshalAs(UnmanagedType.LPWStr)] string pszName,
            [In] uint uFlags, [Out] IntPtr ppidlOut);
    }

    [ComImport,
     Guid("000214F2-0000-0000-C000-000000000046"),
     InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    interface IEnumIDList
    {
        [PreserveSig]
        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
        int Next(uint celt, IntPtr rgelt, out uint pceltFetched);

        [PreserveSig]
        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
        int Skip([In] uint celt);

        [PreserveSig]
        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
        int Reset();

        [PreserveSig]
        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
        int Clone([MarshalAs(UnmanagedType.Interface)] out IEnumIDList ppenum);
    }

    static class NativeMethods
    {
        [DllImport("shell32.dll", EntryPoint = "SHGetDesktopFolder", CharSet = CharSet.Unicode,
            SetLastError = true)]
        static extern int SHGetDesktopFolder_([MarshalAs(UnmanagedType.Interface)] out IShellFolder ppshf);

        public static IShellFolder SHGetDesktopFolder()
        {
            IShellFolder result;
            Marshal.ThrowExceptionForHR(SHGetDesktopFolder_(out result));
            return result;
        }

        [DllImport("shell32.dll", EntryPoint = "SHOpenFolderAndSelectItems")]
        static extern int SHOpenFolderAndSelectItems_(
            [In] IntPtr pidlFolder, uint cidl, [In, Optional, MarshalAs(UnmanagedType.LPArray)] IntPtr[] apidl,
            int dwFlags);

        public static void SHOpenFolderAndSelectItems(IntPtr pidlFolder, IntPtr[] apidl, int dwFlags)
        {
            var cidl = (apidl != null) ? (uint)apidl.Length : 0U;
            var result = SHOpenFolderAndSelectItems_(pidlFolder, cidl, apidl, dwFlags);
            Marshal.ThrowExceptionForHR(result);
        }

        [DllImport("shell32.dll")]
        public static extern void ILFree([In] IntPtr pidl);
    }

    static IntPtr GetShellFolderChildrenRelativePIDL(IShellFolder parentFolder, string displayName)
    {
        uint pchEaten;
        uint pdwAttributes = 0;
        IntPtr ppidl;
        parentFolder.ParseDisplayName(IntPtr.Zero, null, displayName, out pchEaten, out ppidl, ref pdwAttributes);

        return ppidl;
    }

    static IntPtr PathToAbsolutePIDL(string path)
    {
        var desktopFolder = NativeMethods.SHGetDesktopFolder();
        return GetShellFolderChildrenRelativePIDL(desktopFolder, path);
    }

    static Guid IID_IShellFolder = typeof(IShellFolder).GUID;

    static IShellFolder PIDLToShellFolder(IShellFolder parent, IntPtr pidl)
    {
        IShellFolder folder;
        var result = parent.BindToObject(pidl, null, ref IID_IShellFolder, out folder);
        Marshal.ThrowExceptionForHR((int)result);
        return folder;
    }

    static IShellFolder PIDLToShellFolder(IntPtr pidl)
    {
        return PIDLToShellFolder(NativeMethods.SHGetDesktopFolder(), pidl);
    }

    static void SHOpenFolderAndSelectItems(IntPtr pidlFolder, IntPtr[] apidl, bool edit)
    {
        NativeMethods.SHOpenFolderAndSelectItems(pidlFolder, apidl, edit ? 1 : 0);
    }

    public static void FileOrFolder(string path, bool edit = false)
    {
        if (path == null) throw new ArgumentNullException("path");

        var pidl = PathToAbsolutePIDL(path);
        try
        {
            SHOpenFolderAndSelectItems(pidl, null, edit);
        }
        finally
        {
            NativeMethods.ILFree(pidl);
        }
    }

    static IEnumerable<FileSystemInfo> PathToFileSystemInfo(IEnumerable<string> paths)
    {
        foreach (var path in paths)
        {
            var fixedPath = path;
            if (fixedPath.EndsWith(Path.DirectorySeparatorChar.ToString())
                || fixedPath.EndsWith(Path.AltDirectorySeparatorChar.ToString()))
            {
                fixedPath = fixedPath.Remove(fixedPath.Length - 1);
            }

            if (Directory.Exists(fixedPath))
            {
                yield return new DirectoryInfo(fixedPath);
            }
            else if (File.Exists(fixedPath))
            {
                yield return new FileInfo(fixedPath);
            }
            else
            {
                throw new FileNotFoundException
                (string.Format("The specified file or folder doesn't exists : {0}", fixedPath),
                    fixedPath);
            }
        }
    }

    public static void FilesOrFolders(string parentDirectory, ICollection<string> filenames)
    {
        if (filenames == null) throw new ArgumentNullException("filenames");
        if (filenames.Count == 0) return;

        var parentPidl = PathToAbsolutePIDL(parentDirectory);
        try
        {
            var parent = PIDLToShellFolder(parentPidl);
            var filesPidl = filenames
                .Select(filename => GetShellFolderChildrenRelativePIDL(parent, filename))
                .ToArray();

            try
            {
                SHOpenFolderAndSelectItems(parentPidl, filesPidl, false);
            }
            finally
            {
                foreach (var pidl in filesPidl)
                {
                    NativeMethods.ILFree(pidl);
                }
            }
        }
        finally
        {
            NativeMethods.ILFree(parentPidl);
        }
    }

    public static void FilesOrFolders(params string[] paths)
    {
        FilesOrFolders((IEnumerable<string>)paths);
    }

    public static void FilesOrFolders(IEnumerable<string> paths)
    {
        if (paths == null) throw new ArgumentNullException("paths");

        FilesOrFolders(PathToFileSystemInfo(paths));
    }

    public static void FilesOrFolders(IEnumerable<FileSystemInfo> paths)
    {
        if (paths == null) throw new ArgumentNullException("paths");
        var pathsArray = paths.ToArray();
        if (pathsArray.Length == 0) return;

        var explorerWindows = pathsArray.GroupBy(p => Path.GetDirectoryName(p.FullName));

        foreach (var explorerWindowPaths in explorerWindows)
        {
            var parentDirectory = Path.GetDirectoryName(explorerWindowPaths.First().FullName);
            FilesOrFolders(parentDirectory, explorerWindowPaths.Select(fsi => fsi.Name).ToList());
        }
    }
}