FTP

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;

namespace ClientFTP
{
    class FTP
    {
        public string username { get; }
        public string password { get; }
        public string hostname { get; }
        public string currentDirectory { get; private set; }
        public string currentDirectoryAbsolute //tak samo jak public string getCurrentDirectoryAbsolute() {return hostname + currentDirectory;}
        {
            get { return hostname + currentDirectory; }
        }
        public int port { get; }

        public FTP(string username, string password, string hostname, int port)
        {
            this.username = username;
            this.password = password;
            this.port = port;

            int index = hostname.IndexOf('/');
            if (index == -1)
            {
                this.hostname = hostname + "/";
                currentDirectory = "";
            }
            else
            {
                this.hostname = hostname.Substring(0, index);
                currentDirectory = hostname.Substring(index, hostname.Length - index) + "/";
            }
        }

        string updatePath(string oldPath, string newPath)
        {
            string s = "/" + oldPath + "/" + newPath;

            while (s.Contains("//"))
                s = s.Replace("//", "/");

            while (s.Contains(".."))
            {
                int index = s.IndexOf("/..");
                string left = s.Substring(0, index);
                string right = "/" + s.Substring(index + 3, s.Length - (index + 3));

                index = left.LastIndexOf('/');
                left = left.Substring(0, index);
                s = left + right;
            }
            return s;
        }

        public void changeDirectory(string dir)
        {
            if (dir[0] == '/')
                currentDirectory = "%2f" + dir + "/";
            else
                currentDirectory = updatePath(currentDirectory, dir);

            while (currentDirectory.Contains("//"))
                currentDirectory = currentDirectory.Replace("//", "/");
        }

        public string getDirectoryContents(string path = null)
        {
            StringBuilder result = new StringBuilder();
            FtpWebRequest requestDir = (FtpWebRequest)WebRequest.Create("ftp://" + hostname + "/" + (path == null ? currentDirectory : path));
            requestDir.Method = WebRequestMethods.Ftp.ListDirectoryDetails;
            requestDir.Credentials = new NetworkCredential(username, password);
            FtpWebResponse responseDir = (FtpWebResponse)requestDir.GetResponse();
            StreamReader readerDir = new StreamReader(responseDir.GetResponseStream());

            string line = readerDir.ReadLine();
            while (line != null)
            {
                result.Append(line);
                result.Append(Environment.NewLine);
                line = readerDir.ReadLine();
            }

            responseDir.Close();
            return result.ToString();
        }

        public string printDirectoryTree(string path, bool first = true)
        {
            StringBuilder sb = new StringBuilder();
            while (path.Length > 1 && path[path.Length - 1] == '/')
                path = path.Substring(0, path.Length - 1);
            string[] contents = getDirectoryContents(path).Split('\n');

            foreach(string line in contents)
            {
                if (line.Trim() == "")
                    continue;

                string tmp = line.Substring(line.LastIndexOf(' '), line.Length - line.LastIndexOf(' ')).Trim();

                if (line[0] == 'd' && tmp != "." && tmp != "..")
                {
                    sb.Append((first ? "" : "\t") + tmp + "\n");
                    foreach (string l in printDirectoryTree(path + "/" + tmp, false).Split('\n'))
                        sb.Append((first ? "" : "\t") + l + "\n");
                }
                else if (tmp == "." || tmp == "..")
                {
                    continue;
                }
                else
                {
                    sb.Append((first ? "" : "\t") + tmp + "\n");
                }
            }

            return sb.ToString();
        }
    }
}