/*
    Tesses.VirtualFilesystem a library for virtual filesystems in .NET
    Copyright (C) 2023  Mike Nolan

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/
using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.CompilerServices;
using System.Threading;
using System.Threading.Tasks;
using Tesses.VirtualFilesystem;
using Tesses.VirtualFilesystem.Extensions;
using System.Linq;
namespace Tesses.VirtualFilesystem
{
    public class SubdirFilesystem : IVirtualFilesystem
    {
        IVirtualFilesystem _fs;
        UnixPath _path;
        public SubdirFilesystem(IVirtualFilesystem fs,UnixPath path)
        {
            this._fs=fs;
            this._path=path;
        }

        public bool CanHandleSymlinks(UnixPath path)
        {
            return _fs.CanHandleSymlinks(_path / path);
        }

        public bool CanWatch(UnixPath path)
        {
            return _fs.CanWatch(_path / path);
        }

        private UnixPath ChopOff(UnixPath path)
        {
            if(path.Parts.Length > _path.Parts.Length)
            {
                return new UnixPath(path.Parts.Skip(_path.Parts.Length));
            }
            return new UnixPath();
        }

        public string ConvertPathFromUnixPath(UnixPath path)
        {
           return _fs.ConvertPathFromUnixPath(path);
        }

        public UnixPath ConvertPathToUnixPath(string path)
        {
            return _fs.ConvertPathToUnixPath(path);
        }

        public void CreateDirectory(UnixPath directory)
        {
            _fs.CreateDirectory(_path / directory);
        }

        public async Task CreateDirectoryAsync(UnixPath directory, CancellationToken token = default)
        {
           await _fs.CreateDirectoryAsync(_path / directory,token);
        }

        public void CreateHardlink(UnixPath src, UnixPath dest)
        {
            _fs.CreateHardlink(_path / src,_path / dest);
        }

        public async Task CreateHardlinkAsync(UnixPath src, UnixPath dest, CancellationToken token = default)
        {
            await _fs.CreateHardlinkAsync(_path / src,_path /dest,token);
        }

        public void CreateSymlink(UnixPath src, UnixPath dest)
        {
            _fs.CreateSymlink(_path / src,_path / dest);
        }

        public async Task CreateSymlinkAsync(UnixPath src, UnixPath dest, CancellationToken token = default)
        {
            await _fs.CreateSymlinkAsync(_path / src,_path / dest,token);
        }

        public void DeleteDirectory(UnixPath path)
        {
            _fs.DeleteDirectory(_path / path);
        }

        public async Task DeleteDirectoryAsync(UnixPath path, CancellationToken token = default)
        {
            await _fs.DeleteDirectoryAsync(_path / path,token);
        }

        public void DeleteFile(UnixPath path)
        {
            _fs.DeleteFile(_path / path);
        }

        public async Task DeleteFileAsync(UnixPath path, CancellationToken token = default)
        {
           await _fs.DeleteFileAsync(_path / path,token);
        }

        public bool DirectoryExists(UnixPath path)
        {
            return _fs.DirectoryExists(_path / path);
        }

        public async Task<bool> DirectoryExistsAsync(UnixPath path, CancellationToken token = default)
        {
           return await _fs.DirectoryExistsAsync(_path / path,token);
        }

        public void Dispose()
        {
            
        }

        public IEnumerable<UnixPath> EnumerateDirectories(UnixPath path)
        {
            foreach(var dir in _fs.EnumerateDirectories(_path / path))
            {
                yield return ChopOff(dir);
            }
        }

        public async IAsyncEnumerable<UnixPath> EnumerateDirectoriesAsync(UnixPath path, [EnumeratorCancellation]CancellationToken token = default)
        {
            await foreach(var dir in _fs.EnumerateDirectoriesAsync(_path / path,token))
            {
                if(token.IsCancellationRequested) yield break;
                yield return ChopOff(dir);
            }
        }

        public IEnumerable<UnixPath> EnumerateFiles(UnixPath path)
        {
            foreach(var file in _fs.EnumerateFiles(_path / path))
            {
               
                yield return ChopOff(file);
            }
        }

        public async IAsyncEnumerable<UnixPath> EnumerateFilesAsync(UnixPath path, [EnumeratorCancellation] CancellationToken token = default)
        {
            await foreach(var file in _fs.EnumerateFilesAsync(_path / path,token))
            {
                if(token.IsCancellationRequested) yield break;
                yield return ChopOff(file);
            }
        }

        public bool FileExists(UnixPath path)
        {
           return _fs.FileExists(_path / path);
        }

        public async Task<bool> FileExistsAsync(UnixPath path, CancellationToken token = default)
        {
            return await _fs.FileExistsAsync(_path / path,token);
        }

        public FileAttributes GetAttributes(UnixPath path)
        {
            return _fs.GetAttributes(_path / path);
        }

        public async Task<FileAttributes> GetAttributesAsync(UnixPath path, CancellationToken token = default)
        {
             return await _fs.GetAttributesAsync(_path / path,token);
        }

        public DateTime GetCreationTime(UnixPath path)
        {
            return _fs.GetCreationTime(_path / path);
        }

        public async Task<DateTime> GetCreationTimeAsync(UnixPath path, CancellationToken token = default)
        {
            return await _fs.GetCreationTimeAsync(_path / path,token);
        }

        public DateTime GetLastAccessTime(UnixPath path)
        {
            return _fs.GetLastAccessTime(_path / path);
        }

        public async Task<DateTime> GetLastAccessTimeAsync(UnixPath path, CancellationToken token = default)
        {
            return await _fs.GetLastAccessTimeAsync(_path / path,token);
        }

        public DateTime GetLastWriteTime(UnixPath path)
        {
            return _fs.GetLastWriteTime(_path / path);
        }

        public async Task<DateTime> GetLastWriteTimeAsync(UnixPath path, CancellationToken token = default)
        {
            return await _fs.GetLastWriteTimeAsync(_path / path,token);
        }

        public IVirtualFilesystem GetSubdirFilesystem(UnixPath path)
        {
            return new SubdirFilesystem(this,path);
        }

        public void MoveDirectory(UnixPath src, UnixPath dest)
        {
            _fs.MoveDirectory(_path / src,_path / dest);
        }

        public async Task MoveDirectoryAsync(UnixPath src, UnixPath dest)
        {
            await _fs.MoveDirectoryAsync(_path / src, _path / dest);
        }

        public void MoveFile(UnixPath src, UnixPath dest)
        {
            _fs.MoveFile(_path / src,_path / dest);
        }

        public async Task MoveFileAsync(UnixPath src, UnixPath dest)
        {
            await _fs.MoveFileAsync(_path / src, _path / dest);
        }

        public Stream Open(UnixPath path, FileMode mode, FileAccess access, FileShare share)
        {
            return _fs.Open(_path / path,mode,access,share);
        }

        public async Task<Stream> OpenAsync(UnixPath path, FileMode mode, FileAccess access, FileShare share, CancellationToken token = default)
        {
            return await _fs.OpenAsync(_path / path,mode,access,share,token);
        }

        public DirectoryPointer OpenDirectory()
        {
            return new DirectoryPointer(this);
        }

        public DirectoryPointer OpenDirectory(UnixPath path)
        {
            return new DirectoryPointer(this,path);
        }

        public UnixPath ReadLink(UnixPath file)
        {
            return _fs.ReadLink(_path / file);
        }

        public async Task<UnixPath> ReadLinkAsync(UnixPath file, CancellationToken token = default)
        {
            return await _fs.ReadLinkAsync(_path / file,token);
        }

        public bool SameFileSystem(UnixPath src, UnixPath dest)
        {
            return _fs.SameFileSystem(_path / src,_path / dest);
        }

        public async Task<bool> SameFileSystemAsync(UnixPath src, UnixPath dest, CancellationToken token = default)
        {
            return await _fs.SameFileSystemAsync(_path / src, _path / dest,token);
        }

        public void SetAttributes(UnixPath path, FileAttributes attributes)
        {
            _fs.SetAttributes(_path / path,attributes);
        }

        public async Task SetAttributesAsync(UnixPath path, FileAttributes attributes, CancellationToken token = default)
        {
            await _fs.SetAttributesAsync(_path / path,attributes,token);
        }

        public void SetCreationTime(UnixPath path, DateTime time)
        {
            _fs.SetCreationTime(_path / path,time);
        }

        public async Task SetCreationTimeAsync(UnixPath path, DateTime time, CancellationToken token = default)
        {
            await _fs.SetCreationTimeAsync(_path / path,time,token);
        }

        public void SetLastAccessTime(UnixPath path, DateTime time)
        {
            _fs.SetLastAccessTime(_path / path,time);
        }

        public async Task SetLastAccessTimeAsync(UnixPath path, DateTime time, CancellationToken token = default)
        {
            await _fs.SetLastAccessTimeAsync(_path / path,time,token);
        }

        public void SetLastWriteTime(UnixPath path, DateTime time)
        {
            _fs.SetLastWriteTime(_path / path,time);
        }

        public async Task SetLastWriteTimeAsync(UnixPath path, DateTime time, CancellationToken token = default)
        {
            await _fs.SetLastWriteTimeAsync(_path / path,time,token);
        }

        public bool SymlinkExists(UnixPath file)
        {
            return _fs.SymlinkExists(_path / file);
        }

        public async Task<bool> SymlinkExistsAsync(UnixPath file, CancellationToken token = default)
        {
            return await _fs.SymlinkExistsAsync(_path / file,token);
        }

        public UnixPath UpPath(UnixPath path)
        {
            return path.Parent;
        }

        public IVirtualWatcher WatchDirectory(UnixPath dir)
        {
            return _fs.WatchDirectory(_path / dir);
        }

        public EntryPointer OpenEntry(UnixPath path)
        {
            return _fs.OpenEntry(_path / path);
        }

        public FilePointer OpenFile(UnixPath path)
        {
            return _fs.OpenFile(path);
        }

        public SymlinkPointer OpenSymlink(UnixPath path)
        {
            return _fs.OpenSymlink(path);
        }

        public IEnumerable<UnixPath> EnumerateFileSystemEntries(UnixPath path)
        {
            foreach(var item in _fs.EnumerateFileSystemEntries(_path/path))
            {
                yield return ChopOff(item);
            }
        }

        public IEnumerable<UnixPath> EnumerateSymlinks(UnixPath path)
        {
            foreach(var item in _fs.EnumerateSymlinks(_path/path))
            {
                yield return ChopOff(item);
            }
        }

        public async IAsyncEnumerable<UnixPath> EnumerateSymlinksAsync(UnixPath path, [EnumeratorCancellation]CancellationToken token = default)
        {
            await foreach(var item in _fs.EnumerateSymlinksAsync(_path/path))
            {
                if(token.IsCancellationRequested) yield break;
                yield return await Task.FromResult(ChopOff(item));
            }
        }

        public async IAsyncEnumerable<UnixPath> EnumerateFileSystemEntriesAsync(UnixPath path, [EnumeratorCancellation]CancellationToken token = default)
        {
          await foreach(var item in _fs.EnumerateFileSystemEntriesAsync(_path/path))
            {
                if(token.IsCancellationRequested) yield break;
                yield return await Task.FromResult(ChopOff(item));
            }
        }

        public void DeleteDirectory(UnixPath path, bool recursive)
        {
            _fs.DeleteDirectory(_path/path,recursive);
        }

        public async Task DeleteDirectoryAsync(UnixPath path, bool recursive, CancellationToken token = default)
        {
            await _fs.DeleteDirectoryAsync(_path/path,token);
        }
    }
    public abstract class SyncFileSystem : IVirtualFilesystem
    {
         public virtual void Dispose()
        {
            
        }
        public virtual UnixPath UpPath(UnixPath path)
        {
            return path.Parent;
        }
        public virtual UnixPath ConvertPathToUnixPath(string path)
        {
            return path;
        }
        public virtual string ConvertPathFromUnixPath(UnixPath path)
        {
            return path.ToString();
        }
        public virtual bool CanWatch(UnixPath path)
        {
            return false;
        }

        public virtual bool CanHandleSymlinks(UnixPath path)
        {
            return false;
        }

        public abstract void CreateDirectory(UnixPath directory);

        public virtual async Task CreateDirectoryAsync(UnixPath directory,CancellationToken token=default)
        {
            if(token.IsCancellationRequested) return;
            await Task.Run(()=>CreateDirectory(directory));
        }

        public virtual void CreateHardlink(UnixPath src, UnixPath dest)
        {
            this.CopyFile(src,dest);
        }

        public virtual async Task CreateHardlinkAsync(UnixPath src, UnixPath dest, CancellationToken token = default)
        {
            if(token.IsCancellationRequested) return;
            await Task.Run(()=>CreateHardlink(src,dest));
        }

        public virtual void CreateSymlink(UnixPath src, UnixPath dest)
        {
           
        }

        public virtual async Task CreateSymlinkAsync(UnixPath src, UnixPath dest, CancellationToken token = default)
        {
            if(token.IsCancellationRequested) return;
            await Task.Run(()=>CreateHardlink(src,dest));
        }

        public abstract void DeleteDirectory(UnixPath path);

        public virtual async Task DeleteDirectoryAsync(UnixPath path, CancellationToken token = default)
        {
           if(token.IsCancellationRequested) return;
            await Task.Run(()=>DeleteDirectory(path));
        }

        public abstract void DeleteFile(UnixPath path);
        public virtual async Task DeleteFileAsync(UnixPath path, CancellationToken token = default)
        {
           if(token.IsCancellationRequested) return;
            await Task.Run(()=>DeleteFile(path));
        }

        public abstract bool DirectoryExists(UnixPath path);

        public async Task<bool> DirectoryExistsAsync(UnixPath path, CancellationToken token = default)
        {
            if(token.IsCancellationRequested) return false;
            return await Task.Run<bool>(()=>DirectoryExistsAsync(path));
        }

        public IEnumerable<UnixPath> EnumerateDirectories(UnixPath path)
        {
            foreach(var item in EnumerateFileSystemEntries(path))
            {
                if(DirectoryExists(item) && !SymlinkExists(item))
                {
                    yield return item;
                }
            }
        }

        public async IAsyncEnumerable<UnixPath> EnumerateDirectoriesAsync(UnixPath path, [EnumeratorCancellation]CancellationToken token = default)
        {
            await foreach(var item in EnumerateFileSystemEntriesAsync(path))
            {
                if(token.IsCancellationRequested) yield break;
                if(await DirectoryExistsAsync(item) && !await SymlinkExistsAsync(item))
                yield return await Task.FromResult(item);
            }
        }

        public  IEnumerable<UnixPath> EnumerateFiles(UnixPath path)
        {
             foreach(var item in EnumerateFileSystemEntries(path))
            {
                if(FileExists(item) && !SymlinkExists(item))
                {
                    yield return item;
                }
            }
        }

        public async IAsyncEnumerable<UnixPath> EnumerateFilesAsync(UnixPath path, [EnumeratorCancellation] CancellationToken token = default)
        {
            await foreach(var item in EnumerateFileSystemEntriesAsync(path))
            {
                if(token.IsCancellationRequested) yield break;
                if(await FileExistsAsync(item) && !await SymlinkExistsAsync(item))
                yield return await Task.FromResult(item);
            }
        }

        public abstract bool FileExists(UnixPath path);

        public virtual async Task<bool> FileExistsAsync(UnixPath path, CancellationToken token = default)
        {
            if(token.IsCancellationRequested) return false;
            return await Task.Run<bool>(()=>FileExists(path));
        }

        public virtual FileAttributes GetAttributes(UnixPath path)
        {
            return FileAttributes.Normal;
        }

        public virtual async Task<FileAttributes> GetAttributesAsync(UnixPath path, CancellationToken token = default)
        {
            if(token.IsCancellationRequested) return FileAttributes.Normal;
            return await Task.Run<FileAttributes>(()=>GetAttributes(path));
        }

        public abstract DateTime GetCreationTime(UnixPath path);

        public virtual async Task<DateTime> GetCreationTimeAsync(UnixPath path, CancellationToken token = default)
        {
           if(token.IsCancellationRequested) return DateTime.Now;
            return await Task.Run<DateTime>(()=>GetCreationTime(path));
        }

        public abstract DateTime GetLastAccessTime(UnixPath path);

        public virtual async Task<DateTime> GetLastAccessTimeAsync(UnixPath path, CancellationToken token = default)
        {
            if(token.IsCancellationRequested) return DateTime.Now;
            return await Task.Run<DateTime>(()=>GetLastAccessTime(path));
        }

        public abstract DateTime GetLastWriteTime(UnixPath path);

        public virtual async Task<DateTime> GetLastWriteTimeAsync(UnixPath path, CancellationToken token = default)
        {
           if(token.IsCancellationRequested) return DateTime.Now;
            return await Task.Run<DateTime>(()=>GetLastWriteTime(path));
        }

       
       

        public abstract void MoveDirectory(UnixPath src, UnixPath dest);

        public virtual async Task MoveDirectoryAsync(UnixPath src, UnixPath dest)
        {
            await Task.Run(()=>MoveDirectory(src,dest));
        }

        public abstract void MoveFile(UnixPath src, UnixPath dest);

        public virtual async Task MoveFileAsync(UnixPath src, UnixPath dest)
        {
            await Task.Run(()=>MoveFile(src,dest));
        }

        public abstract Stream Open(UnixPath path, FileMode mode, FileAccess access, FileShare share);

        public virtual async Task<Stream> OpenAsync(UnixPath path, FileMode mode, FileAccess access, FileShare share, CancellationToken token = default)
        {
            if(token.IsCancellationRequested) return Stream.Null;
            return await Task.Run<Stream>(()=>Open(path,mode,access,share));
        }

        public virtual UnixPath ReadLink(UnixPath file)
        {
            return file;
        }

        public virtual async Task<UnixPath> ReadLinkAsync(UnixPath file, CancellationToken token = default)
        {
            if(token.IsCancellationRequested) return file;
            return await Task.Run<UnixPath>(()=>ReadLink(file));
        }

        public virtual async Task<bool> SameFileSystemAsync(UnixPath src, UnixPath dest, CancellationToken token = default)
        {
            if(token.IsCancellationRequested) return false;
            return await Task.Run<bool>(()=>SameFileSystem(src,dest));
        }

        public virtual bool SameFileSystem(UnixPath src, UnixPath dest)
        {
            return false;
        }

        public virtual void SetAttributes(UnixPath path, FileAttributes attributes)
        {
            
        }

        public virtual async Task SetAttributesAsync(UnixPath path, FileAttributes attributes, CancellationToken token = default)
        {
            if(token.IsCancellationRequested) return;
            await Task.Run(()=>SetAttributes(path,attributes));
        }

        public abstract void SetCreationTime(UnixPath path, DateTime time);

        public virtual async Task SetCreationTimeAsync(UnixPath path, DateTime time, CancellationToken token = default)
        {
            if(token.IsCancellationRequested) return;
            await Task.Run(()=>SetCreationTime(path,time));
        }

        public abstract void SetLastAccessTime(UnixPath path, DateTime time);

        public virtual async Task SetLastAccessTimeAsync(UnixPath path, DateTime time, CancellationToken token = default)
        {
           if(token.IsCancellationRequested) return;
            await Task.Run(()=>SetLastAccessTime(path,time));
        }

        public abstract void SetLastWriteTime(UnixPath path, DateTime time);

        public virtual async Task SetLastWriteTimeAsync(UnixPath path, DateTime time, CancellationToken token = default)
        {
            if(token.IsCancellationRequested) return;
            await Task.Run(()=>SetLastWriteTimeAsync(path,time));
        }

        public virtual async Task<bool> SymlinkExistsAsync(UnixPath file, CancellationToken token = default)
        {
           if(token.IsCancellationRequested) return false;
            return await Task.Run<bool>(()=>SymlinkExists(file));
        }

        public virtual bool SymlinkExists(UnixPath file)
        {
            return false;
        }

        public virtual IVirtualWatcher WatchDirectory(UnixPath dir)
        {
            return null;
        }

        public IVirtualFilesystem GetSubdirFilesystem(UnixPath path)
        {
            return new SubdirFilesystem(this,path);
        }
        public SymlinkPointer OpenSymlink(UnixPath path)
        {
            return new SymlinkPointer(this,path);
        }
        public FilePointer OpenFile(UnixPath path)
        {
            return new FilePointer(this,path);
        }
        public DirectoryPointer OpenDirectory(UnixPath path)
        {
            return new DirectoryPointer(this,path);
        }
        public DirectoryPointer OpenDirectory()
        {
            return new DirectoryPointer(this);
        }

        public EntryPointer OpenEntry(UnixPath path)
        {
            if(FileExists(path))
            {
                return new FilePointer(this,path);
            }else if(SymlinkExists(path))
            {
                return new SymlinkPointer(this,path);
            }
            else if(DirectoryExists(path)){
                return new DirectoryPointer(this,path);
            }
            return new NonExistantPointer(this,path);
        }


      

        public abstract IEnumerable<UnixPath> EnumerateFileSystemEntries(UnixPath path);

        public IEnumerable<UnixPath> EnumerateSymlinks(UnixPath path)
        {
            foreach(var item in EnumerateFileSystemEntries(path))
            {
                if(SymlinkExists(item))
                {
                    yield return item;
                }
            }
        }

        public async IAsyncEnumerable<UnixPath> EnumerateSymlinksAsync(UnixPath path, [EnumeratorCancellation]CancellationToken token = default)
        {
             await foreach(var item in EnumerateFileSystemEntriesAsync(path))
            {
                if(token.IsCancellationRequested) yield break;
                if(await SymlinkExistsAsync(item))
                yield return await Task.FromResult(item);
            }
        }

        public virtual async IAsyncEnumerable<UnixPath> EnumerateFileSystemEntriesAsync(UnixPath path, [EnumeratorCancellation]CancellationToken token = default)
        {
            foreach(var item in EnumerateFileSystemEntries(path))
            {
                if(token.IsCancellationRequested) yield break;
                yield return await Task.FromResult(item);
            }
        }

        public virtual void DeleteDirectory(UnixPath path, bool recursive)
        {
            if(recursive)
            {
                foreach(var item in EnumerateFileSystemEntries(path))
                {
                    if(DirectoryExists(item))
                    {
                        DeleteDirectory(item,true);
                    }else{
                        DeleteFile(item);
                    }
                }
            }
            DeleteDirectory(path);
        }

        public virtual async Task DeleteDirectoryAsync(UnixPath path, bool recursive, CancellationToken token = default)
        {
            if(recursive){
            await foreach(var item in EnumerateFileSystemEntriesAsync(path))
            {
                if(token.IsCancellationRequested) return;
                if(await DirectoryExistsAsync(item))
                {
                    await DeleteDirectoryAsync(item,true,token);
                }else{
                    await DeleteFileAsync(item,token);
                }
            }
            }
            await DeleteDirectoryAsync(path,token);
        }
    }
    public abstract class AsyncFileSystem : IVirtualFilesystem
    {
            public SymlinkPointer OpenSymlink(UnixPath path)
        {
            return new SymlinkPointer(this,path);
        }
        public FilePointer OpenFile(UnixPath path)
        {
            return new FilePointer(this,path);
        }
          public EntryPointer OpenEntry(UnixPath path)
        {
            if(FileExists(path))
            {
                return new FilePointer(this,path);
            }else if(SymlinkExists(path))
            {
                return new SymlinkPointer(this,path);
            }
            else if(DirectoryExists(path)){
                return new DirectoryPointer(this,path);
            }
            return new NonExistantPointer(this,path);
        }
         public virtual void DeleteDirectory(UnixPath path, bool recursive)
        {
            if(recursive)
            {
                foreach(var item in EnumerateFileSystemEntries(path))
                {
                    if(DirectoryExists(item))
                    {
                        DeleteDirectory(item,true);
                    }else{
                        DeleteFile(item);
                    }
                }
            }
            DeleteDirectory(path);
        }

        public virtual async Task DeleteDirectoryAsync(UnixPath path, bool recursive, CancellationToken token = default)
        {
            if(recursive){
            await foreach(var item in EnumerateFileSystemEntriesAsync(path))
            {
                if(token.IsCancellationRequested) return;
                if(await DirectoryExistsAsync(item))
                {
                    await DeleteDirectoryAsync(item,true,token);
                }else{
                    await DeleteFileAsync(item,token);
                }
            }
            }
            await DeleteDirectoryAsync(path,token);
        }
   
        public IVirtualFilesystem GetSubdirFilesystem(UnixPath path)
        {
            return new SubdirFilesystem(this,path);
        }

        public DirectoryPointer OpenDirectory()
        {
            return new DirectoryPointer(this);
        }

        public DirectoryPointer OpenDirectory(UnixPath path)
        {
            return new DirectoryPointer(this,path);
        }
        public virtual void Dispose()
        {

        }
         public virtual UnixPath UpPath(UnixPath path)
        {
            return path.Parent;
        }
         public virtual UnixPath ConvertPathToUnixPath(string path)
        {
            return path;
        }
        public virtual string ConvertPathFromUnixPath(UnixPath path)
        {
            return path.ToString();
        }
        public virtual bool CanWatch(UnixPath path)
        {
            return false;
        }
        public virtual void CreateDirectory(UnixPath directory)
        {
            Task.Run(async()=>await CreateDirectoryAsync(directory)).Wait();
        }

        public abstract Task CreateDirectoryAsync(UnixPath directory, CancellationToken token = default);

        public virtual void CreateHardlink(UnixPath src, UnixPath dest)
        {
            Task.Run(async()=>await CreateHardlinkAsync(src,dest)).Wait();
        }

        public virtual async Task CreateHardlinkAsync(UnixPath src, UnixPath dest, CancellationToken token = default)
        {
            //await this.CopyFile()
            await this.CopyFileAsync(src,dest,token);
        }
        

        public virtual void CreateSymlink(UnixPath src, UnixPath dest)
        {
            Task.Run(async()=>await CreateSymlinkAsync(src,dest)).Wait();
        }

        public virtual async Task CreateSymlinkAsync(UnixPath src, UnixPath dest, CancellationToken token = default)
        {
            await Task.FromResult(0);
        }


        public virtual bool CanHandleSymlinks(UnixPath path)
        {
            return false;
        }


        public virtual void DeleteDirectory(UnixPath path)
        {
            Task.Run(async()=>await DeleteDirectoryAsync(path)).Wait();
        }

        public abstract Task DeleteDirectoryAsync(UnixPath path, CancellationToken token = default);

        public virtual void DeleteFile(UnixPath path)
        {
            Task.Run(async()=>await DeleteFileAsync(path)).Wait();
        }

        public abstract Task DeleteFileAsync(UnixPath path, CancellationToken token = default);

        public virtual bool DirectoryExists(UnixPath path)
        {
            bool res=false;
            Task.Run(async()=>res=await DirectoryExistsAsync(path)).Wait();
            return res;
        }

        public abstract Task<bool> DirectoryExistsAsync(UnixPath path, CancellationToken token = default);

        public virtual IEnumerable<UnixPath> EnumerateDirectories(UnixPath path)
        {
            var enumerator = EnumerateDirectoriesAsync(path).GetAsyncEnumerator();
            while(Task.Run<bool>(async()=>await enumerator.MoveNextAsync()).GetAwaiter().GetResult())
            {
                yield return enumerator.Current;
            }
            Task.Run(enumerator.DisposeAsync).Wait();
        }

       
        public virtual IEnumerable<UnixPath> EnumerateFiles(UnixPath path)
        {
            var enumerator = EnumerateFilesAsync(path).GetAsyncEnumerator();
            while(Task.Run<bool>(async()=>await enumerator.MoveNextAsync()).GetAwaiter().GetResult())
            {
                yield return enumerator.Current;
            }
            Task.Run(enumerator.DisposeAsync).Wait();
        }

        public virtual async IAsyncEnumerable<UnixPath> EnumerateFilesAsync(UnixPath path, [EnumeratorCancellation] CancellationToken token = default)
        {
            await foreach(var item in EnumerateFileSystemEntriesAsync(path,token))
            {
                if(token.IsCancellationRequested) yield break;
                if(await FileExistsAsync(item,token) && !await SymlinkExistsAsync(item,token))
                {
                    yield return await Task.FromResult(item);
                }
            }
        }
        public virtual async IAsyncEnumerable<UnixPath> EnumerateDirectoriesAsync(UnixPath path, [EnumeratorCancellation] CancellationToken token = default)
        {
            await foreach(var item in EnumerateFileSystemEntriesAsync(path,token))
            {
                if(token.IsCancellationRequested) yield break;
                if(await DirectoryExistsAsync(item,token) && !await SymlinkExistsAsync(item,token))
                {
                    yield return await Task.FromResult(item);
                }
            }
        }
        public virtual async IAsyncEnumerable<UnixPath> EnumerateSymlinksAsync(UnixPath path, [EnumeratorCancellation] CancellationToken token = default)
        {
            await foreach(var item in EnumerateFileSystemEntriesAsync(path,token))
            {
                if(token.IsCancellationRequested) yield break;
                if(await SymlinkExistsAsync(item,token))
                {
                    yield return await Task.FromResult(item);
                }
            }
        }


        public virtual bool FileExists(UnixPath path)
        {
            
            return Task.Run<bool>(async()=>await FileExistsAsync(path)).GetAwaiter().GetResult();
        }

        public abstract Task<bool> FileExistsAsync(UnixPath path, CancellationToken token = default);

        public virtual FileAttributes GetAttributes(UnixPath path)
        {
            return Task.Run<FileAttributes>(async()=>await GetAttributesAsync(path)).GetAwaiter().GetResult();
        }

        public virtual Task<FileAttributes> GetAttributesAsync(UnixPath path, CancellationToken token = default)
        {
            return Task.FromResult(FileAttributes.Normal);
        }

        public virtual DateTime GetCreationTime(UnixPath path)
        {
            return Task.Run<DateTime>(async()=>await GetCreationTimeAsync(path)).GetAwaiter().GetResult();
        }

        public abstract Task<DateTime> GetCreationTimeAsync(UnixPath path, CancellationToken token = default);

        public virtual DateTime GetLastAccessTime(UnixPath path)
        {
           return Task.Run<DateTime>(async()=>await GetLastAccessTimeAsync(path)).GetAwaiter().GetResult();
        }

        public abstract Task<DateTime> GetLastAccessTimeAsync(UnixPath path, CancellationToken token = default);

        public virtual DateTime GetLastWriteTime(UnixPath path)
        {
            return Task.Run<DateTime>(async()=>await GetLastWriteTimeAsync(path)).GetAwaiter().GetResult();
        }

        public abstract Task<DateTime> GetLastWriteTimeAsync(UnixPath path, CancellationToken token = default);
      

        public virtual void MoveDirectory(UnixPath src, UnixPath dest)
        {
            Task.Run(async()=>await MoveDirectoryAsync(src,dest)).Wait();
        }

        public abstract Task MoveDirectoryAsync(UnixPath src, UnixPath dest);

        public virtual void MoveFile(UnixPath src, UnixPath dest)
        { 
            Task.Run(async()=>await MoveFileAsync(src,dest)).Wait();
        }

        public abstract Task MoveFileAsync(UnixPath src, UnixPath dest);

        public Stream Open(UnixPath path, FileMode mode, FileAccess access, FileShare share)
        {
            return Task.Run<Stream>(async()=>await OpenAsync(path,mode,access,share)).GetAwaiter().GetResult();
        }

        public abstract Task<Stream> OpenAsync(UnixPath path, FileMode mode, FileAccess access, FileShare share, CancellationToken token = default);

        public virtual UnixPath ReadLink(UnixPath file)
        {
             return Task.Run<UnixPath>(async()=>await ReadLinkAsync(file)).GetAwaiter().GetResult();
        }

        public virtual async Task<UnixPath> ReadLinkAsync(UnixPath file, CancellationToken token = default)
        {
            return await Task.FromResult(file);
        }

        public virtual async Task<bool> SameFileSystemAsync(UnixPath src, UnixPath dest, CancellationToken token = default)
        {
            return await Task.FromResult(false);
        }

        public virtual bool SameFileSystem(UnixPath src, UnixPath dest)
        {
             return Task.Run<bool>(async()=>await SameFileSystemAsync(src,dest)).GetAwaiter().GetResult();
        }

        public virtual void SetAttributes(UnixPath path, FileAttributes attributes)
        {
             Task.Run(async()=>await SetAttributesAsync(path,attributes)).Wait();
        }

        public virtual async Task SetAttributesAsync(UnixPath path, FileAttributes attributes, CancellationToken token = default)
        {
            await Task.FromResult(0);
        }

        public virtual void SetCreationTime(UnixPath path, DateTime time)
        {
             Task.Run(async()=>await SetCreationTimeAsync(path,time)).Wait();
        }

        public abstract Task SetCreationTimeAsync(UnixPath path, DateTime time, CancellationToken token = default);

        public virtual void SetLastAccessTime(UnixPath path, DateTime time)
        {
            Task.Run(async()=>await SetLastAccessTimeAsync(path,time)).Wait();
        }

        public abstract Task SetLastAccessTimeAsync(UnixPath path, DateTime time, CancellationToken token = default);

        public virtual void SetLastWriteTime(UnixPath path, DateTime time)
        {
             Task.Run(async()=>await SetLastWriteTimeAsync(path,time)).Wait();
        }

        public abstract Task SetLastWriteTimeAsync(UnixPath path, DateTime time, CancellationToken token = default);

        public virtual async Task<bool> SymlinkExistsAsync(UnixPath file, CancellationToken token = default)
        {
            return await Task.FromResult(false);
        }

        public virtual bool SymlinkExists(UnixPath file)
        {
            return Task.Run<bool>(async()=>await SymlinkExistsAsync(file)).GetAwaiter().GetResult();
        }

        public virtual IVirtualWatcher WatchDirectory(UnixPath dir)
        {
           return null;
        }

        public IEnumerable<UnixPath> EnumerateFileSystemEntries(UnixPath path)
        {
            var enumerator = EnumerateFileSystemEntriesAsync(path).GetAsyncEnumerator();
            while(Task.Run<bool>(async()=>await enumerator.MoveNextAsync()).GetAwaiter().GetResult())
            {
                yield return enumerator.Current;
            }
            Task.Run(enumerator.DisposeAsync).Wait();
        }

        public IEnumerable<UnixPath> EnumerateSymlinks(UnixPath path)
        {
             var enumerator = EnumerateSymlinksAsync(path).GetAsyncEnumerator();
            while(Task.Run<bool>(async()=>await enumerator.MoveNextAsync()).GetAwaiter().GetResult())
            {
                yield return enumerator.Current;
            }
            Task.Run(enumerator.DisposeAsync).Wait();
        }

        

        public abstract IAsyncEnumerable<UnixPath> EnumerateFileSystemEntriesAsync(UnixPath path, CancellationToken token = default);
    }

    /*
    public sealed class MultiLayerFS : AsyncFileSystem
    {
        private delegate Task<Stream> OpenAsyncDel(UnixPath path, FileMode mode, FileAccess access, FileShare share, CancellationToken token = default);
        private class FileSystemWithCustomOpen : IVirtualFilesystem
        {

            public FileSystemWithCustomOpen(IVirtualFilesystem fs,OpenAsyncDel del)
            {
                this.del = del;
                this.fs = fs;
            }
            OpenAsyncDel del;
            public IVirtualFilesystem fs;

            public bool CanHandleSymlinks(UnixPath path)
            {
                return fs.CanHandleSymlinks(path);
            }

            public bool CanWatch(UnixPath path)
            {
                return fs.CanWatch(path);
            }

            public string ConvertPathFromUnixPath(UnixPath path)
            {
                return fs.ConvertPathFromUnixPath(path);
            }

            public UnixPath ConvertPathToUnixPath(string path)
            {
                return fs.ConvertPathToUnixPath(path);
            }

            public void CreateDirectory(UnixPath directory)
            {
                fs.CreateDirectory(directory);
            }

            public async Task CreateDirectoryAsync(UnixPath directory, CancellationToken token = default)
            {
                await fs.CreateDirectoryAsync(directory,token);
            }

            public void CreateHardlink(UnixPath src, UnixPath dest)
            {
                fs.CreateHardlink(src,dest);
            }

            public async Task CreateHardlinkAsync(UnixPath src, UnixPath dest, CancellationToken token = default)
            {
                await fs.CreateHardlinkAsync(src,dest,token);
            }

            public void CreateSymlink(UnixPath src, UnixPath dest)
            {
                fs.CreateSymlink(src,dest);
            }

            public async Task CreateSymlinkAsync(UnixPath src, UnixPath dest, CancellationToken token = default)
            {
               await fs.CreateSymlinkAsync(src,dest,token);
            }

            public void DeleteDirectory(UnixPath path)
            {
                fs.DeleteDirectory(path);
            }

            public async Task DeleteDirectoryAsync(UnixPath path, CancellationToken token = default)
            {
               await fs.DeleteDirectoryAsync(path,token);
            }

            public void DeleteFile(UnixPath path)
            {
                fs.DeleteFile(path);
            }

            public async Task DeleteFileAsync(UnixPath path, CancellationToken token = default)
            {
                await fs.DeleteFileAsync(path,token);
            }

            public bool DirectoryExists(UnixPath path)
            {
                return fs.DirectoryExists(path);
            }

            public async Task<bool> DirectoryExistsAsync(UnixPath path, CancellationToken token = default)
            {
                return await fs.DirectoryExistsAsync(path,token);
            }

            public void Dispose()
            {
                fs.Dispose();
            }

            public IEnumerable<UnixPath> EnumerateDirectories(UnixPath path)
            {
                foreach(var item in fs.EnumerateDirectories(path))
                {
                    yield return item;
                }
            }

            public async IAsyncEnumerable<UnixPath> EnumerateDirectoriesAsync(UnixPath path, [EnumeratorCancellation]CancellationToken token = default)
            {
                await foreach(var item in fs.EnumerateDirectoriesAsync(path,token))
                {
                    if(token.IsCancellationRequested) yield break;
                    yield return item;
                }
            }

            public IEnumerable<UnixPath> EnumerateFiles(UnixPath path)
            {
                foreach(var item in fs.EnumerateFiles(path))
                {
                    yield return item;
                }
            }

            public async IAsyncEnumerable<UnixPath> EnumerateFilesAsync(UnixPath path, [EnumeratorCancellation]CancellationToken token = default)
            {
                await foreach(var item in fs.EnumerateFilesAsync(path,token))
                {
                    if(token.IsCancellationRequested) yield break;
                    yield return path;
                }
            }

            public bool FileExists(UnixPath path)
            {
                return fs.FileExists(path);
            }

            public async Task<bool> FileExistsAsync(UnixPath path, CancellationToken token = default)
            {
                return await fs.FileExistsAsync(path,token);
            }

            public FileAttributes GetAttributes(UnixPath path)
            {
                return fs.GetAttributes(path);
            }

            public async Task<FileAttributes> GetAttributesAsync(UnixPath path, CancellationToken token = default)
            {
                return await fs.GetAttributesAsync(path,token);
            }

            public DateTime GetCreationTime(UnixPath path)
            {
                return fs.GetCreationTime(path);
            }

            public async Task<DateTime> GetCreationTimeAsync(UnixPath path, CancellationToken token = default)
            {
                return await fs.GetCreationTimeAsync(path,token);
            }

            public DateTime GetLastAccessTime(UnixPath path)
            {
                return fs.GetLastAccessTime(path);
            }

            public async Task<DateTime> GetLastAccessTimeAsync(UnixPath path, CancellationToken token = default)
            {
                return await fs.GetLastAccessTimeAsync(path,token);
            }

            public DateTime GetLastWriteTime(UnixPath path)
            {
                return fs.GetLastAccessTime(path);
            }

            public async Task<DateTime> GetLastWriteTimeAsync(UnixPath path, CancellationToken token = default)
            {
                return await fs.GetLastWriteTimeAsync(path,token);
            }

            public void MoveDirectory(UnixPath src, UnixPath dest)
            {
                fs.MoveDirectory(src,dest);
            }

            public async Task MoveDirectoryAsync(UnixPath src, UnixPath dest)
            {
                await fs.MoveDirectoryAsync(src,dest);
            }

            public void MoveFile(UnixPath src, UnixPath dest)
            {
                fs.MoveFile(src,dest);
            }

            public async Task MoveFileAsync(UnixPath src, UnixPath dest)
            {
                await fs.MoveFileAsync(src,dest);
            }

            public Stream Open(UnixPath path, FileMode mode, FileAccess access, FileShare share)
            {
                return Task.Run<Stream>(async()=>await del(path,mode,access,share)).GetAwaiter().GetResult();
            }

            public async Task<Stream> OpenAsync(UnixPath path, FileMode mode, FileAccess access, FileShare share, CancellationToken token = default)
            {
                return await del(path,mode,access,share,token);
            }

            public UnixPath ReadLink(UnixPath file)
            {
                return fs.ReadLink(file);
            }

            public async Task<UnixPath> ReadLinkAsync(UnixPath file, CancellationToken token = default)
            {
                return await fs.ReadLinkAsync(file,token);
            }

            public bool SameFileSystem(UnixPath src, UnixPath dest)
            {
                return fs.SameFileSystem(src,dest);
            }

            public async Task<bool> SameFileSystemAsync(UnixPath src, UnixPath dest, CancellationToken token = default)
            {
                return await fs.SameFileSystemAsync(src,dest,token);
            }

            public void SetAttributes(UnixPath path, FileAttributes attributes)
            {
                fs.SetAttributes(path,attributes);
            }

            public async Task SetAttributesAsync(UnixPath path, FileAttributes attributes, CancellationToken token = default)
            {
                await fs.SetAttributesAsync(path,attributes,token);
            }

            public void SetCreationTime(UnixPath path, DateTime time)
            {
                fs.SetCreationTime(path,time);
            }

            public async Task SetCreationTimeAsync(UnixPath path, DateTime time, CancellationToken token = default)
            {
                await fs.SetCreationTimeAsync(path,time,token);
            }

            public void SetLastAccessTime(UnixPath path, DateTime time)
            {
                fs.SetLastAccessTime(path,time);
            }

            public async Task SetLastAccessTimeAsync(UnixPath path, DateTime time, CancellationToken token = default)
            {
                await fs.SetLastAccessTimeAsync(path,time,token);
            }

            public void SetLastWriteTime(UnixPath path, DateTime time)
            {
                fs.SetLastWriteTime(path,time);
            }

            public async Task SetLastWriteTimeAsync(UnixPath path, DateTime time, CancellationToken token = default)
            {
                await fs.SetLastWriteTimeAsync(path,time,token);
            }

            public bool SymlinkExists(UnixPath file)
            {
                return fs.SymlinkExists(file);
            }

            public async Task<bool> SymlinkExistsAsync(UnixPath file, CancellationToken token = default)
            {
                return await fs.SymlinkExistsAsync(file,token);
            }

            public UnixPath UpPath(UnixPath path)
            {
                return fs.UpPath(path);
            }

            public IVirtualWatcher WatchDirectory(UnixPath dir)
            {
                return fs.WatchDirectory(dir);
            }
        }
        IVirtualFilesystem root;
        public MultiLayerFS(IVirtualFilesystem root)
        {
            this.root=root;
        }
        public class CloseEvtStream : Stream
        {
            Stream parent;
            Action cstrm;
            bool destroyParent;
            public CloseEvtStream(Stream parent,Action closed,bool destroyParent=true)
            {
                this.destroyParent=destroyParent;
                this.parent = parent;
                this.cstrm = closed;
            }
            public override bool CanRead => parent.CanRead;

            public override bool CanSeek => parent.CanSeek;

            public override bool CanWrite => parent.CanWrite;

            public override long Length => parent.Length;

            public override long Position { get => parent.Position; set => parent.Position = value; }

            public override void Flush()
            {
                parent.Flush();
            }

            public override int Read(byte[] buffer, int offset, int count)
            {
                return parent.Read(buffer,offset,count);
            }

            public override long Seek(long offset, SeekOrigin origin)
            {
                return parent.Seek(offset,origin);
            }

            public override void SetLength(long value)
            {
                parent.SetLength(value);
            }

            public override void Write(byte[] buffer, int offset, int count)
            {
                parent.Write(buffer,offset,count);
            }
            public override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
            {
                return parent.BeginRead(buffer, offset, count, callback, state);
            }
            public override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
            {
                return parent.BeginWrite(buffer, offset, count, callback, state);
            }
            public override bool CanTimeout => parent.CanTimeout;
            public override void Close()
            {
                if(destroyParent)
                parent.Close();
                cstrm();
            }
            protected override void Dispose(bool disposing)
            {
                if(disposing && destroyParent)
                parent.Dispose();
                cstrm();
            }
            public override void EndWrite(IAsyncResult asyncResult)
            {
                parent.EndWrite(asyncResult);
            }
            
            public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
            {
                return parent.WriteAsync(buffer, offset, count, cancellationToken);
            }
            public override Task FlushAsync(CancellationToken cancellationToken)
            {
                return parent.FlushAsync(cancellationToken);
            }
            public override void WriteByte(byte value)
            {
                parent.WriteByte(value);
            }
            public override int EndRead(IAsyncResult asyncResult)
            {
                return parent.EndRead(asyncResult);
            }
            public override Task CopyToAsync(Stream destination, int bufferSize, CancellationToken cancellationToken)
            {
                return parent.CopyToAsync(destination, bufferSize, cancellationToken);
            }
        }
        
        List<IVirtualFilesystem> fs2=new List<IVirtualFilesystem>();
        Dictionary<IVirtualFilesystem,(List<Stream> StreamList,Action2Event Destroy)> streams = new Dictionary<IVirtualFilesystem, (List<Stream> StreamList,Action2Event Destroy)>();
        Dictionary<string,IVirtualFilesystem> fs=new Dictionary<string, IVirtualFilesystem>();
        public override UnixPath UpPath(UnixPath path)
        {
            var unixPathLs = path as UnixPathList;
            if(unixPathLs != null)
            {
                return unixPathLs.ParentPL;
            }else{
                return path.Parent;
            }
        }
        Dictionary<string,IVirtualFileSystemCreator> _creators=new Dictionary<string,IVirtualFileSystemCreator>();
        public void Register(string scheme,IVirtualFileSystemCreator fs)
        {
            _creators.Add(scheme,fs);
        }
        public void Register(IVirtualFileSystemCreator fs)
        {
            _creators.Add(fs.Scheme,fs);
        }
        public override void Dispose()
        {
            while(fs2.Count>0 && streams.Count > 0)
            {
                if(streams.ContainsKey(fs2[0]))
                {
                    var strm = streams[fs2[0]];
                    foreach(var strm0 in strm.StreamList)
                    {
                        strm0.Dispose();
                    }
                    strm.StreamList.Clear();
                    CloseFileSystemIfNoStreams(fs2[0]);
                    streams.Remove(fs2[0]);
                    fs2.Remove(fs2[0]);
                }
            }
            streams.Clear();
            fs.Clear();

        }
      

        public override async Task CreateDirectoryAsync(UnixPath directory, CancellationToken token = default)
        {   
            var fs=await OpenTillAsync(directory,token);
                await fs.CreateDirectoryAsync(Last(directory));
                CloseFileSystemIfNoStreams(fs);
        }   
        private async Task<IVirtualFilesystem> OpenTillAsync(UnixPath path,CancellationToken token=default)
        {
            UnixPathList pathLs = path as UnixPathList;
            if(pathLs != null && pathLs.Count > 1)
            {
                return await OpenTillAsync(pathLs,token);
            }
            return root;
        }

        private async Task<IVirtualFilesystem> OpenTillAsync(UnixPathList path,CancellationToken token=default)
        {
            
            IVirtualFilesystem fs=root;
            List<UnixPath> paths=new List<UnixPath>();
            for(int i = 0;i<path.Count-1;i++)
            {
                paths.Add(path[i]);
                var curP = new UnixPathList(paths);
                
                fs=await OpenFileSystemAsync(fs,curP,token);
                if(token.IsCancellationRequested) {this.CloseFileSystemIfNoStreams(fs); return null;}
            }
            return fs;
        }
        Mutex mtx=new Mutex();
        
        private async Task<Stream> OpenStreamOnBehalf(IVirtualFilesystem fs,UnixPath p,FileMode mode,FileAccess access,FileShare share,CancellationToken token=default(CancellationToken))
        {
            
            Stream strm = await fs.OpenAsync(p,mode,access,share);
            CloseEvtStream strmI=new CloseEvtStream(strm,()=>{
                mtx.WaitOne();
                if(streams.ContainsKey(fs))
                {
                    var strmItem = streams[fs];
                    if(strmItem.StreamList.Contains(strm))
                    {
                        strmItem.StreamList.Remove(strm);
                        
                    }
                    if(strmItem.StreamList.Count == 0)
                    {
                        strmItem.Destroy.Invoke();
                        streams.Remove(fs);
                        string key = "";
                        foreach(var i in this.fs)
                        {
                            if(i.Value == fs)
                            {
                                key = i.Key;
                                break;
                            }
                        }
                        if(this.fs.ContainsKey(key))
                        {
                            this.fs.Remove(key);
                        }
                    }
                }
                mtx.ReleaseMutex();
            });
            mtx.WaitOne();
            if(streams.ContainsKey(fs))
            {
                  var strmItem = streams[fs];
                    if(!strmItem.StreamList.Contains(strm))
                    {
                        strmItem.StreamList.Add(strm);
                       
                    }

            }
            mtx.ReleaseMutex();

            return strmI;
        }
        public UnixPath ExceptLast(UnixPath p)
        {
            UnixPathList pl =  p as UnixPathList;
            if(pl != null && pl.Count > 0)
            {
                List<UnixPath> paths=new List<UnixPath>();
                for(int i = 0;i<pl.Count-1;i++)
                {
                    paths.Add(pl[i]);
                }
                return new UnixPathList(paths);
            }
            
            return p;
        }
        private UnixPath Last(UnixPath p)
        {
            UnixPathList pl=p as UnixPathList;
            if(pl!=null && pl.Count >0)
            {
                
                return pl[pl.Count-1];
            }
            return p;
        }
        private async Task<IVirtualFilesystem> OpenFileSystemAsync(IVirtualFilesystem parent,UnixPath p,CancellationToken token=default)
        {
            if(string.IsNullOrWhiteSpace(p.Scheme)) return parent;
            mtx.WaitOne();
            var last=Last(p);
            if(!_creators.ContainsKey(last.Scheme)){ mtx.ReleaseMutex();return null;}
            if(parent == root)
            {
                if(fs.ContainsKey(p.AsText))
                {
                   var res0= fs[p.AsText];
                    mtx.ReleaseMutex();
                    return res0;
                }
                var res=_creators[p.Scheme];
                if(res.IsDirectoryOrganizer)
                {
                    var c = res.Open(root,last);
                    fs.Add(p.AsText,c);

                    return c;
                }else{
                var strm = await OpenAsync(last,FileMode.Open,FileAccess.ReadWrite,FileShare.None,token);
                var c = res.Open(strm);
                Action a =()=>{
                    c.Dispose();
                    strm.Dispose();
                   
                };
                streams.Add(c,(new List<Stream>(),a));
                fs.Add(p.AsText,c);
                 return c;
                }
               
            }else{mtx.ReleaseMutex();
                if(fs.ContainsKey(p.AsText))
                {
                   var res0= fs[p.AsText];
                     mtx.ReleaseMutex();
                   return res0;
                }
                var res=_creators[p.Scheme];
                 if(res.IsDirectoryOrganizer)
                {
                    var parent2 = new FileSystemWithCustomOpen(parent,async(path,mode,access,share,token)=>{
                        return await OpenStreamOnBehalf(parent,path,mode,access,share,token);
                    });
                    var c = res.Open(parent2,last);
                    streams[parent].Destroy.Add(c.Dispose);
                     fs2.Insert(0,c);
                    fs.Add(p.AsText,c);
                    return c;
                }else{
                var res0=await OpenStreamOnBehalf(parent,last,FileMode.Open,FileAccess.ReadWrite,FileShare.None,token);
                var c = res.Open(res0);
                Action a =()=>{
                    if(fs2.Contains(c))
                    fs2.Remove(c);
                    c.Dispose();
                    res0.Dispose();
                    
                };
                
                streams.Add(c,(new List<Stream>(),a));
                fs.Add(p.AsText,c);
                fs2.Insert(0,c);
                 mtx.ReleaseMutex();
                return c;
                }
            }
        }
        private void CloseFileSystemIfNoStreams(IVirtualFilesystem fs)
        {
            if(fs == root) return;
            mtx.WaitOne();
              if(streams.ContainsKey(fs))
                {
                    var strmItem = streams[fs];
                    
                    if(strmItem.StreamList.Count == 0)
                    {
                        strmItem.Destroy.Invoke();
                    }
                }
             mtx.ReleaseMutex();
        }

        public override async Task DeleteDirectoryAsync(UnixPath path, CancellationToken token = default)
        {
            
                var fs=await OpenTillAsync(path,token);
                await fs.DeleteDirectoryAsync(Last(path),token);
                CloseFileSystemIfNoStreams(fs);
            
        }

        public override async Task DeleteFileAsync(UnixPath path, CancellationToken token = default)
        {
           
                var fs=await OpenTillAsync(path,token);
                await fs.DeleteFileAsync(Last(path),token);
                CloseFileSystemIfNoStreams(fs);
            
        }

        public override async Task<bool> DirectoryExistsAsync(UnixPath path, CancellationToken token = default)
        {
           
                 var fs=await OpenTillAsync(path,token);
                var res=await fs.DirectoryExistsAsync(Last(path));
                CloseFileSystemIfNoStreams(fs);
          
            return res;
        }

        public override async IAsyncEnumerable<UnixPath> EnumerateDirectoriesAsync(UnixPath path, [EnumeratorCancellation] CancellationToken token = default)
        {
            
            
                 var fs=await OpenTillAsync(path,token);
                using(var reg= token.Register(()=>{
                    CloseFileSystemIfNoStreams(fs);
                 })){
                await foreach(var item in fs.EnumerateDirectoriesAsync(Last(path)))
                {
                    yield return item;
                }
                CloseFileSystemIfNoStreams(fs);
            
                 }

            
        }

        public override async IAsyncEnumerable<UnixPath> EnumerateFilesAsync(UnixPath path, [EnumeratorCancellation] CancellationToken token = default)
        {
              var fs=await OpenTillAsync(path,token);
                using(var reg= token.Register(()=>{
                    CloseFileSystemIfNoStreams(fs);
                 })){
                await foreach(var item in fs.EnumerateFilesAsync(Last(path)))
                {
                    yield return item;
                }
                CloseFileSystemIfNoStreams(fs);
            
                 }

        }

        public override async Task<bool> FileExistsAsync(UnixPath path, CancellationToken token = default)
        {
           
                 var fs=await OpenTillAsync(path,token);
                bool res = await fs.FileExistsAsync(Last(path),token);

                CloseFileSystemIfNoStreams(fs);
                return res;
     
        }

        public override async Task<DateTime> GetCreationTimeAsync(UnixPath path, CancellationToken token = default)
        {
             
                 var fs=await OpenTillAsync(path,token);
                DateTime res = await fs.GetCreationTimeAsync(Last(path),token);

                CloseFileSystemIfNoStreams(fs);
                return res;
            
        }

        public override async Task<DateTime> GetLastAccessTimeAsync(UnixPath path, CancellationToken token = default)
        {
              
                 var fs=await OpenTillAsync(path,token);
                DateTime res = await fs.GetLastAccessTimeAsync(Last(path),token);

                CloseFileSystemIfNoStreams(fs);
                return res;
            
        }

        public override async Task<DateTime> GetLastWriteTimeAsync(UnixPath path, CancellationToken token = default)
        {
              
                 var fs=await OpenTillAsync(path,token);
                DateTime res = await fs.GetLastWriteTimeAsync(Last(path),token);

                CloseFileSystemIfNoStreams(fs);
                return res;
           
        }

        public override async Task MoveDirectoryAsync(UnixPath src, UnixPath dest)
        {
            if(ExceptLast(src).AsText == ExceptLast(dest).AsText)
            {
                
                var fs=await OpenTillAsync(src);
                await fs.MoveDirectoryAsync(Last(src),Last(dest));
                CloseFileSystemIfNoStreams(fs);
                
            }else{
                var fs=await OpenTillAsync(src);
                var fs2=await OpenTillAsync(dest);
                 await fs.MoveDirectoryAsync(fs2,Last(src),Last(dest));
                CloseFileSystemIfNoStreams(fs);
                CloseFileSystemIfNoStreams(fs2);
                
            }
            
        }

        public override async Task MoveFileAsync(UnixPath src, UnixPath dest)
        {
            if(ExceptLast(src).AsText == ExceptLast(dest).AsText)
            {
                
                var fs=await OpenTillAsync(src);
                await fs.MoveFileAsync(Last(src),Last(dest));
                CloseFileSystemIfNoStreams(fs);
                
            }else{
                var fs=await OpenTillAsync(src);
                var fs2=await OpenTillAsync(dest);
                 await fs.MoveFileAsync(fs2,Last(src),Last(dest));
                CloseFileSystemIfNoStreams(fs);
                CloseFileSystemIfNoStreams(fs2);
                
            }
        }

        public override async Task<Stream> OpenAsync(UnixPath path, FileMode mode, FileAccess access, FileShare share, CancellationToken token = default)
        {
            var fs = await OpenTillAsync(path,token);
            using(var t = token.Register(()=>{CloseFileSystemIfNoStreams(fs);}))
            {
               return await OpenStreamOnBehalf(fs,Last(path),mode,access,share,token);

            }
        }

        public override async Task SetCreationTimeAsync(UnixPath path, DateTime time, CancellationToken token = default)
        {
            var fs=await OpenTillAsync(path);
            await fs.SetCreationTimeAsync(Last(path),time,token);
            CloseFileSystemIfNoStreams(fs);
        }

        public override async Task SetLastAccessTimeAsync(UnixPath path, DateTime time, CancellationToken token = default)
        {
            var fs=await OpenTillAsync(path);
            await fs.SetLastAccessTimeAsync(Last(path),time,token);
            CloseFileSystemIfNoStreams(fs);
        }
        public override async Task SetAttributesAsync(UnixPath path, FileAttributes attributes, CancellationToken token = default)
        {
            var fs=await OpenTillAsync(path);
            await fs.SetAttributesAsync(Last(path),attributes,token);
            CloseFileSystemIfNoStreams(fs);
        }
        public override bool CanWatch(UnixPath path)
        {
           return false;
        }
        public override async Task<UnixPath> ReadLinkAsync(UnixPath file, CancellationToken token = default)
        {
           
            var fs=await OpenTillAsync(file);
            var rlink=await fs.ReadLinkAsync(Last(file));
            CloseFileSystemIfNoStreams(fs);
            return rlink;
        }
        public override async Task<bool> SameFileSystemAsync(UnixPath src, UnixPath dest, CancellationToken token = default)
        {
            return await Task.FromResult(ExceptLast(src).AsText == ExceptLast(dest).AsText);
        }
        public override Task<bool> SymlinkExistsAsync(UnixPath file, CancellationToken token = default)
        {
            return base.SymlinkExistsAsync(file, token);
        }
        public override async Task<FileAttributes> GetAttributesAsync(UnixPath path, CancellationToken token = default)
        {
            var fs=await OpenTillAsync(path);
            var res=await fs.GetAttributesAsync(Last(path));
            CloseFileSystemIfNoStreams(fs);
            return res;
        }
        public override async Task CreateSymlinkAsync(UnixPath src, UnixPath dest, CancellationToken token = default)
        {
            if(ExceptLast(src).AsText != ExceptLast(dest).AsText) return;
            var fs=await OpenTillAsync(src);
            await fs.CreateSymlinkAsync(Last(src),Last(dest));
            CloseFileSystemIfNoStreams(fs);
        }
        public override async Task CreateHardlinkAsync(UnixPath src, UnixPath dest, CancellationToken token = default)
        {
            if(ExceptLast(src).AsText != ExceptLast(dest).AsText) return;
            var fs=await OpenTillAsync(src);
            await fs.CreateHardlinkAsync(Last(src),Last(dest));
            CloseFileSystemIfNoStreams(fs);
        }
        public override bool CanHandleSymlinks(UnixPath path)
        {
            var fs=Task.Run<IVirtualFilesystem>(async()=>await OpenTillAsync(path)).GetAwaiter().GetResult();
            var can=fs.CanHandleSymlinks(Last(path));
            CloseFileSystemIfNoStreams(fs);
            return can;
        }
        public override async Task SetLastWriteTimeAsync(UnixPath path, DateTime time, CancellationToken token = default)
        {
            var fs=await OpenTillAsync(path);
            await fs.SetLastWriteTimeAsync(Last(path),time,token);
            CloseFileSystemIfNoStreams(fs);
        }
    }
    */
    public class Action2Event
    {
        public Action2Event(Action a)
        {
            Event+=a;
        }
        public void Add(Action a)
        {
            Event+=a;
        }
        public void Invoke()
        {
            Event?.Invoke();
        }
        public event Action Event;
        public static implicit operator Action2Event(Action a)
        {
            return new Action2Event(a);
        }

    }
}