using System;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Configuration;
using System.Net.Mail;
using System.Net.Security;
using System.Net.Sockets;
using System.Security.Cryptography;
using System.Text;

namespace Program
{
    class Test
    {
        static void Main(string[] args)
        {
            int k;
            string response, username, pass, checkAnswer;
            byte[] receivedMessage=new byte[100];
            TcpClient client = new TcpClient("smtp.gmail.com", 465);
            //NetworkStream networkStream = client.GetStream();
            //string firstFivChar = new string(yourStringVariable.Take(5).ToArray());
            //Stream stm = client.GetStream();
            SslStream ssl = new SslStream(client.GetStream());
            ssl.AuthenticateAsClient("smtp.gmail.com");


            //string login = Base64Encode(username, pass);
            //Console.WriteLine(login);

            k = ssl.Read(receivedMessage, 0, 100);
            response = BytesToString(receivedMessage, k);
            Console.WriteLine(response);
            ASCIIEncoding asen = new ASCIIEncoding();
            checkAnswer = new string(response.Take(3).ToArray());
            Console.WriteLine(checkAnswer);

            if (checkAnswer == "220")
            {
                byte[] ba = asen.GetBytes("HELO gmail \r\n");
                ssl.Write(ba, 0, ba.Length);

                k = ssl.Read(receivedMessage, 0, 100);
                response = BytesToString(receivedMessage, k);
                Console.WriteLine(response);

                checkAnswer = new string(response.Take(3).ToArray());
                Console.WriteLine(checkAnswer);

                if (checkAnswer == "250")
                {
                    Console.WriteLine("Iveskite el.pasta ir slaptazodi:");
                    username = Console.ReadLine();
                    pass = Console.ReadLine();

                    var command = "AUTH LOGIN";
                    ba = asen.GetBytes(command + " \r\n");
                    ssl.Write(ba, 0, ba.Length);

                    k = ssl.Read(receivedMessage, 0, 100);
                    response = BytesToString(receivedMessage, k);
                    Console.WriteLine(response);

                    var login64 = Base64Encode(username);
                    ba = asen.GetBytes(login64 + "\r\n");
                    ssl.Write(ba, 0, ba.Length);
                    Console.WriteLine(login64);

                    k = ssl.Read(receivedMessage, 0, 100);
                    response = BytesToString(receivedMessage, k);
                    Console.WriteLine(response);

                    var pass64 = Base64Encode(pass);
                    ba = asen.GetBytes(pass64 + "\r\n");
                    ssl.Write(ba, 0, ba.Length);
                    Console.WriteLine(pass64);

                    k = ssl.Read(receivedMessage, 0, 100);
                    response = BytesToString(receivedMessage, k);
                    Console.WriteLine(response);

                    Console.WriteLine("Iveskite siuntejo el.pasta:");
                    var mailFrom = Console.ReadLine();
                    command = "MAIL FROM:<" + mailFrom + ">";
                    ba = asen.GetBytes(command + " \r\n");
                    ssl.Write(ba, 0, ba.Length);

                    k = ssl.Read(receivedMessage, 0, 100);
                    response = BytesToString(receivedMessage, k);
                    Console.WriteLine(response);

                    Console.WriteLine("Iveskite adresato el.pasta:");

                    var rcptTo = Console.ReadLine();
                    command = "rcpt to:<" + rcptTo + ">";
                    ba = asen.GetBytes(command + " \r\n");
                    ssl.Write(ba, 0, ba.Length);

                    k = ssl.Read(receivedMessage, 0, 100);
                    response = BytesToString(receivedMessage, k);
                    Console.WriteLine(response);

                    while (true)
                    {
                        Console.WriteLine("1-Prideti dar viena adresata\n2-Neprideti\n");
                        int choice = Int32.Parse(Console.ReadLine());
                        if (choice == 1)
                        {
                            Console.WriteLine("Iveskite adresato el.pasta:");
                            rcptTo = Console.ReadLine();
                            command = "rcpt to:<" + rcptTo + ">";
                            ba = asen.GetBytes(command + " \r\n");
                            ssl.Write(ba, 0, ba.Length);

                            k = ssl.Read(receivedMessage, 0, 100);
                            response = BytesToString(receivedMessage, k);
                            Console.WriteLine(response);
                        }

                        if (choice == 2)
                        {
                            break;
                        }

                    }

                    ba = asen.GetBytes("DATA \r\n");
                    ssl.Write(ba, 0, ba.Length);

                    k = ssl.Read(receivedMessage, 0, 100);
                    response = BytesToString(receivedMessage, k);
                    Console.WriteLine(response);

                    Console.WriteLine("Iveskite laisko tema:");
                    string sbj = Console.ReadLine();

                    Console.WriteLine("Rasykite laiska:");
                    string message = Console.ReadLine();
                    ba = asen.GetBytes("Subject: " + sbj + "\n" + message + "\r\n.\r\n");
                    ssl.Write(ba, 0, ba.Length);

                    /* ba = asen.GetBytes("\r\n.\r\n");
            ssl.Write(ba, 0, ba.Length);*/

                    k = ssl.Read(receivedMessage, 0, 100);
                    response = BytesToString(receivedMessage, k);
                    Console.WriteLine(response);

                    ba = asen.GetBytes("QUIT \r\n");
                    ssl.Write(ba, 0, ba.Length);

                    k = ssl.Read(receivedMessage, 0, 100);
                    response = BytesToString(receivedMessage, k);
                    Console.WriteLine(response);
                }
            }
            else
            {
                Console.WriteLine("Klaida prisijungiant i serveri!");
            }
        }

        public static string BytesToString(byte[] bytes, int k)
        {
            var str = new StringBuilder();
            for (int i = 0; i < k; i++)
                if (bytes[i] != 13 && bytes[i] != 10)
                    str.Append(Convert.ToChar(bytes[i]));

            return str.ToString();
        }

        public static string Base64Encode(string info)
        {
            var plainTextBytes = System.Text.Encoding.UTF8.GetBytes(info);
            return System.Convert.ToBase64String(plainTextBytes);
        }
    }
}