using System;
using System.Collections.Generic;
using System.Net.Sockets;
using System.Net;
using System.Threading;

namespace LocalhostProxy
{
    class Program
    {
        static void Main(string[] args)
        {
            const int DEFPORTNUM = 8081;
            int port2use = DEFPORTNUM;
            const int BACKLOG = 10; // maximum length of pending connections queue

            Socket listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

            // Establish the local endpoint for the socket
            IPAddress ipAddress = IPAddress.Loopback;
            IPEndPoint localEndPoint = new IPEndPoint(ipAddress, port2use);

            listener.Bind(localEndPoint);
            listener.Listen(BACKLOG);
            System.Console.WriteLine("Listening ... " + localEndPoint.ToString());

            while (true)
            {
                Socket sock = listener.Accept();
                //if(sock.Connected)
                //    System.Console.WriteLine("Connection established");
                RequestHandler rh = new RequestHandler(sock);
                Thread rhThread = new Thread(new ThreadStart(rh.DoRequest));
                rhThread.Start();
            }
        }
    }
    class RequestHandler
    {            
        public RequestHandler(Socket sock)
        {
            System.Text.Encoding utf8 = System.Text.Encoding.UTF8;
            List<byte> requestBytesList = new List<byte>();

            // Get the HTTP headers first
            Header = "";
            while (true)
            {
                RequestBytes = new byte[1];
                int bytesRec = sock.Receive(RequestBytes);
                requestBytesList.Add(RequestBytes[0]);
                Header += System.Text.Encoding.ASCII.GetString(RequestBytes, 0, bytesRec);
                if (Header.IndexOf("\r\n\r\n") > -1 || Header.IndexOf("\n\n") > -1)
                {
                    break;
                }
            }
            System.Console.WriteLine("*** Headers ***\n " + Header);

            // Break up the headers
            string[] headers = Header.Split(new char[] { '\n' });
            string requestLine = headers[0];
            string[] requestLineElements = requestLine.Split(new char[] { ' ' });

            RequestMethod = requestLineElements[0];
            Resource = requestLineElements[1];
            HttpVersion = requestLineElements[2];

            Uri uri = new Uri(Resource);

            Host = uri.Host;
            Port = uri.Port;

            for (int i = 1; i < headers.Length; i++)
            {
                RequestHeaders += headers[i] + "\r\n";
            }

            clientSock = sock;

            RequestBytes = requestBytesList.ToArray();
            /*
            Console.WriteLine("Request method:" + RequestMethod);
            Console.WriteLine("Resource: " + Resource);
            Console.WriteLine("HttpVersion:" + HttpVersion);
            Console.WriteLine("Host: " + Host);
            Console.WriteLine("Request Headers: \n" + RequestHeaders); 
                */
        }
        public void DoRequest()
        {
            System.Text.Encoding utf8 = System.Text.Encoding.UTF8;
            const int BUFSZ = 1024;

            try
            {
                // IPAddress and IPEndPoint represent the endpoint that will
                //   receive the request.
                // Get the first IPAddress in the list using