FTP Tchat by SpyLX

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;
using System.Net;

namespace FTP_Tchat_by_SpyLX
{
    public partial class Form1 : Form
    {
        private string localDirectory;
        private string filePath;
        private string fileNameToday;
        private string ftpFullPath;
        private string username;
        private string password;
        private string[] messages;
        private short tryAgainOrError;
        private long size;
        private long sizeChange;
        private WebClient request;
        private FtpWebRequest requestDir;
        private FtpWebResponse response;

        public Form1()
        {
            InitializeComponent();
            localDirectory = @"C:\ProgramData\cmd_tchat\";
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            up:
            string date = (DateTime.Now.Day + "." + DateTime.Now.Month + "." + DateTime.Now.Year);
            fileNameToday = localDirectory + date + ".txt";

            // Vérification si le fichier d'aujourd'hui existe, sinon le créer
            try
            {
                if (!File.Exists(fileNameToday))
                {
                    File.Create(fileNameToday).Close();
                    goto up;
                }
                else
                {
                    filePath = (fileNameToday);
                }
            }
            catch (DirectoryNotFoundException)
            {
                Directory.CreateDirectory(localDirectory.Remove(localDirectory.Length - 1));
                goto up;
            }

            string ftpHost;

            // Récupération des valeurs de ftp_settings
            try
            {
                ftpHost = File.ReadAllLines(localDirectory + "ftp_settings")[2];
                ftpFullPath = "ftp://" + ftpHost + "/" + date + ".txt";
                username = File.ReadAllLines(localDirectory + "ftp_settings")[3];
                password = File.ReadAllLines(localDirectory + "ftp_settings")[4];

                if (username == "-")
                    username = "";
                else if (password == "-")
                    password = "";

            }
            catch (FileNotFoundException)
            {
                File.Create(localDirectory + "ftp_settings").Close();
                using (StreamWriter writer = new StreamWriter(localDirectory + "ftp_settings", true))
                {
                    writer.WriteLine("# Line 3: IP Adress ; Line 4: FTP Username ; Line 5: FTP Password");
                    writer.WriteLine("# Put a '-' if the value is null");
                    writer.WriteLine("127.0.0.1");
                    writer.WriteLine("spylx");
                    writer.WriteLine("-");
                    writer.Close();
                }
                goto up;
            }
            catch (IndexOutOfRangeException)
            {
                MessageBox.Show("Une valeur est vide dans " + localDirectory + "ftp_settings");
                Application.Exit();
                goto up;
            }

            // Téléchargement du fichier d'aujourd'hui
            using (request = new WebClient())
            {
                request.Credentials = new NetworkCredential(username, password);

                TestSize();
                sizeChange = size;

                byte[] fileData;

                // Prendre le fichier d'aujourd'hui, si il n'existe pas, le créer sur le serveur FTP
                try
                {
                    fileData = request.DownloadData(ftpFullPath);
                }
                catch (WebException)
                {
                    try
                    {
                        request.UploadFile(ftpFullPath, filePath);
                        goto up;
                    }
                    catch (WebException)
                    {
                        tryAgainOrError++;
                        if (tryAgainOrError <= 100)
                        {
                            goto up;
                        } else
                        {
                            MessageBox.Show("Impossible d'accéder au serveur.");
                            Application.Exit();
                        }
                    }
                    return;
                }

                // Écriture du fichier téléchargé ci-dessus
                using (FileStream file = File.Create(filePath))
                {
                    file.Write(fileData, 0, fileData.Length);
                    file.Close();
                }
            }

            // Ajout du texte du fichier d'aujourd'hui dans RichTextBox1
            messages = File.ReadAllLines(filePath, Encoding.UTF8);
            richTextBox1.Lines = messages;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            using (StreamWriter writer = new StreamWriter(filePath, true))
                writer.WriteLine("[" + DateTime.Now.Hour.ToString().PadLeft(2, '0') + ':' + DateTime.Now.Minute.ToString().PadLeft(2, '0') + '.' + DateTime.Now.Second.ToString().PadLeft(2, '0') + "] " + textBox1.Text);

            request.UploadFile(ftpFullPath, filePath);

            textBox1.Text = null;
            Form1_Load(null, null);
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            if (textBox1.Text == "")
                button1.Enabled = false;
            else
                button1.Enabled = true;
        }

        private void richTextBox1_TextChanged(object sender, EventArgs e)
        {
            richTextBox1.SelectionStart = richTextBox1.Text.Length;
            richTextBox1.ScrollToCaret();
        }

        private void TestSize()
        {
            try
            {
                requestDir = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpFullPath));
                requestDir.Credentials = new NetworkCredential(username, password);
                requestDir.Method = WebRequestMethods.Ftp.GetFileSize;
                response = (FtpWebResponse)requestDir.GetResponse();
                size = response.ContentLength;
                response.Close();
            }
            catch
            {
                Form1_Load(null, null);
            }
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            TestSize();
            if (size != sizeChange)
            {
                Form1_Load(null, null);
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            MessageBox.Show(size.ToString());
            MessageBox.Show(sizeChange.ToString());
        }
    }
}