DearFTP/DearFTP/Connection/Commands/RenameCommand.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

namespace DearFTP.Connection.Commands
{
    class RenameCommand : ICommand
    {
        public string[] Aliases { get; } = new string[]
        {
            "RNFR"
        };

        public void Execute(Session session, FtpStream stream, string alias, string argument)
        {
            var sourceFile = session.NavigablePath.GetSystemFilePath(argument);

            if (sourceFile.navigablePath == null)
            {
                stream.Send(ResponseCode.FileUnavailable, "File does not exist.");
                return;
            }

            if (sourceFile.navigablePath.CurrentDirectory == "/")
            {
                stream.Send(ResponseCode.FileUnavailable, "Operation not allowed: can't remove a share.");
                return;
            }

            if (!session.WritablesShares.Contains(sourceFile.navigablePath.CurrentShare))
            {
                stream.Send(ResponseCode.FileUnavailable, "You don't have write access to this file.");
                return;
            }

            stream.Send(ResponseCode.PendingFurtherInformation, "Waiting destination.");

            (string command, string destination) = stream.Receive();

            if (command.ToUpper() != "RNTO")
            {
                stream.Send(ResponseCode.BadSequence, "Expected a RNTO command.");
                return;
            }

            var destinationPath = session.NavigablePath.GetNewSystemFilePath(destination);

            if (destinationPath.realPath == null)
            {
                stream.Send(ResponseCode.FileUnavailable, "Invalid destination path.");
                return;
            }

            if (File.Exists(destinationPath.realPath) || Directory.Exists(destinationPath.realPath))
            {
                stream.Send(ResponseCode.FileUnavailable, "Destination path already exists.");
                return;
            }

            if (!session.WritablesShares.Contains(destinationPath.navigablePath.CurrentShare))
            {
                stream.Send(ResponseCode.FileUnavailable, "You don't have write access to this file.");
                return;
            }

            if (sourceFile.isDirectory)
            {
                Directory.Move(sourceFile.realPath, destinationPath.realPath);
            }
            else
            {
                File.Move(sourceFile.realPath, destinationPath.realPath);
            }

            stream.Send(ResponseCode.FileActionOK, "File successfully renamed.");
        }
    }
}