using System;
using System.Text;
using System.Net;
using System.Net.Sockets;
using System.Threading;

namespace Lab20ServerMultiThread
{
    class Program
    {
        public static void Main(string[] args)
        {
            TcpListener server = null;
            try
            {
                // Threading..
                int maxThreadCount = Environment.ProcessorCount * 4;
                ThreadPool.SetMaxThreads(maxThreadCount, maxThreadCount);
                ThreadPool.SetMinThreads(2, 2);

                // Server creation
                int port = 9999;
                int counter = 0;
                IPAddress localAddr = IPAddress.Parse("127.0.0.1");
                server = new TcpListener(localAddr, port);
                server.Start();

                Console.WriteLine($"Server started on 127.0.0.1:{port}. Thread count: {maxThreadCount}");

                // Listining for clients
                while (true)
                {
                    Console.WriteLine("Waiting for connection...");
                    ThreadPool.QueueUserWorkItem(ClientProcessing, server.AcceptTcpClient());
                    Console.WriteLine($"Accepted connection #{counter}");
                    counter++;
                }
            }
            catch (SocketException exc)
            {
                Console.WriteLine($"Socket exception: {exc}");
            }
            finally
            {
                server.Stop();
            }
        }

        /// <summary>
        /// Processes accepted client
        /// </summary>
        /// <param name="state">State.</param>
        private static void ClientProcessing(object state)
        {
            byte[] bytes = new byte[256];
            string data = null;
            TcpClient tcpClient = state as TcpClient;

            // Get incoming info
            NetworkStream stream = tcpClient.GetStream();
            int i;
            while ((i = stream.Read(bytes, 0, bytes.Length)) != 0)
            {
                data = Encoding.ASCII.GetString(bytes, 0, i).ToUpper();

                // Echo uppered info
                byte[] msg = Encoding.ASCII.GetBytes(data);
                stream.Write(msg, 0, msg.Length);
            }
            tcpClient.Close();
        }
    }
}