//SERVER
using System;
using System.Net;
using System.Net.Sockets;
using System.Security.Cryptography;
using System.Text;



namespace server
{
    public class Program
    {
        #region Konstante
        const int STD_PORT = 1234; //standardni port na katerem bomo komunicirali
        const string STD_IP = "127.0.0.1";//local host
        const int STD_MSG_SIZE = 1024;//konstanta za velikost paketa (1KB)
        const int STD_HEAD_LEN = 1; //glava pa bo velika en bajt
        const string STD_CRYPTO_KEY = "mojKljuč";//zašifriramo

        static bool run = true;// to je za neskončno zanko, če bi jo zelel kasnje eprekiniti
        #endregion

        static string Receive(NetworkStream ns)
        {
            try
            {
                byte[] recv = new byte[STD_MSG_SIZE];
                int lenght = ns.Read(recv, 0, recv.Length);
                return Encoding.UTF8.GetString(recv, 0, lenght);
            }
            catch (Exception ex)
            {
                Console.WriteLine("Napaka pri prejemniku!\n" + ex.Message + "\n" + ex.StackTrace);
                return null;
            }
        }

        static void Send(NetworkStream ns, string message)
        {
            try
            {
                byte[] send = Encoding.UTF8.GetBytes(message.ToCharArray(), 0, message.Length);
                ns.Write(send, 0, send.Length);
            }
            catch (Exception ex)
            {
                Console.WriteLine("Napaka pri pošiljatelju!\n" + ex.Message + "\n" + ex.StackTrace);
            }
        }

        public static string Encrypt(string message)
        {
            return null;//samo začasno... tu se morem naret
        }

        static void Main(string[] args)
        {
            TcpListener listener = new TcpListener(IPAddress.Parse(STD_IP), STD_PORT);
            listener.Start();

            Console.WriteLine("Strežnik\n poslušam na naslovu " + STD_IP + ":" + STD_PORT.ToString());
            while (run)
            {
                TcpClient temp12 = listener.AcceptTcpClient();//tu sem odstrano using
                using (NetworkStream ns = temp12.GetStream())
                {
                    Console.WriteLine("Odjemalec se je povezal (" + temp12.Client.RemoteEndPoint.ToString() + ")");

                    string message = Receive(ns);

                    Console.WriteLine("Dobil sem sporočilo: " + message);
                    string response = "";

                    //protokol se morem napisat
                    string head = message[0].ToString();
                    string body = "";
                    if(message.Length > 1)
                    {
                        body = message.Substring(STD_HEAD_LEN, message.Length - 1);
                    }

                    switch (head)
                    {
                            case "A":
                            response = "Pozdravljen " + temp12.Client.RemoteEndPoint.ToString();
                            break;
                            case "B":
                            response ="Trenutni čas je: " + DateTime.Now.ToString("dd. MM. yyyy, H:mm");
                            break;
                            case "C":
                            response = Environment.CurrentDirectory;
                            break;
                            case "D":
                            response = body;
                            //sporocilo ki ga je pravkar prejel
                            break;
                            case "E":
                            response = Environment.MachineName + "\n" + Environment.OSVersion.ToString;
                            break;
                            case "F":
                            response = Environment.MachineName + "\n" + Environment.OSVersion.ToString;
                            break;

                    }

                    Send(ns, response);
                    Console.WriteLine("Odgovoril sem: " + response);

                }
                Console.WriteLine("Odjemalec se je odklopil\n");


            }
            listener.Stop();
            Console.WriteLine("Strežnik se je ustavil");
            Console.ReadKey();
        }
    }
}


//Console.WriteLine("Hello, World!");