using System;
using System.Text;
using System.Net;
using System.IO;
using System.Net.Sockets;
using System.Collections;
using System.Diagnostics;

namespace NntpTools {
 /// <summary>
 /// Class1 的摘要說明。
 /// </summary>
 class Debug {
  /// <summary>
  /// 應用程序的主入口點。
  /// </summary>
  [STAThread]
  static void Main(string[] args) {
   NNTPClass nc=new NNTPClass();
   nc.Connect("msnews.microsoft.com");
   ArrayList grouplist=nc.GetNewsgroups();
   for(int i=0;i<grouplist.Count;i++){
    Console.WriteLine(grouplist[i].ToString());
   }
   ArrayList cardlist=nc.GetNews("microsoft.public.cn.dotnet.framework");
   Console.WriteLine("=============================================================");
   StreamWriter sw=File.CreateText("c://news.txt");
   for(int i=0;i<cardlist.Count;i++){
    Console.WriteLine(cardlist[i].ToString());
    sw.WriteLine(cardlist[i].ToString());
    sw.WriteLine("=============================================================");
   }
   sw.Flush();
   sw.Close();
   nc.Disconnect();
  
   Console.ReadLine();
  }
 }

 class NNTPClass:System.Net.Sockets.TcpClient{
  public void Connect(string server){
   string response;

   Connect(server, 119);

   response = Response();

   if (response.Substring( 0, 3) != "200") {

    throw new Exception(response);

   }
  

  }

  public void Disconnect() {

   string message;

   string response;

   message = "QUIT/r/n";

   Write(message);

   response = Response();

   if (response.Substring( 0, 3) != "205") {

    throw new Exception(response);

   }

  }
  public ArrayList GetNewsgroups() {

   string message;

   string response;

   ArrayList retval = new ArrayList();

   message = "LIST/r/n";

   Write(message);

   response = Response();

   if (response.Substring( 0, 3) != "215") {

    throw new Exception(response);

   }

   while (true) {

    response = Response();

    if (response == "./r/n" ||

     response == "./n") {

     return retval;

    }

    else {

     char[] seps = { ' ' };

     string[] values = response.Split(seps);

     retval.Add(values[0]);

     continue;

    }

   }

  }
  public void Post(string newsgroup, string subject, string from,

   string content) {

   string message;

   string response;

   message = "POST " + newsgroup + "/r/n";

   Write(message);

   response = Response();

   if (response.Substring( 0, 3) != "340") {

    throw new Exception(response);

   }

   message = "From: " + from + "/r/n"

    + "Newsgroups: " + newsgroup + "/r/n"

    + "Subject: " + subject + "/r/n/r/n"

    + content + "/r/n./r/n";

   Write(message);

   response = Response();

   if (response.Substring( 0, 3) != "240") {

    throw new Exception(response);

   }

  }

  public ArrayList GetNews(string newsgroup) {

   string message;

   string response;

   ArrayList retval = new ArrayList();

   message = "GROUP " + newsgroup + "/r/n";

   Write(message);

   response = Response();

   if (response.Substring( 0, 3) != "211") {

    throw new Exception(response);

   }

   char[] seps = { ' ' };

   string[] values = response.Split(seps);

   long start = Int32.Parse(values[2]);

   long end = Int32.Parse(values[3]);

   if (start+100 < end && end > 100) {

    start = end-100;

   }

   for (long i=start;i<end;i++) {

    message = "ARTICLE " + i + "/r/n";

    Write(message);

    response = Response();

    if (response.Substring( 0, 3) == "423") {

     continue;

    }

    if (response.Substring( 0, 3) != "220") {

     throw new Exception(response);

    }

    string article = "";

    while (true) {

     response = Response();

     if (response == "./r/n") {

      break;

     }

     if (response == "./n") {

      break;

     }

     if (article.Length < 1024) {

      article += response;

     };

    }

    retval.Add(article);

   }

   return retval;

  }

  PRivate string Response() {

   //System.Text.ASCIIEncoding enc = new System.Text.ASCIIEncoding();
   System.Text.Encoding enc=Encoding.Default;
   byte []serverbuff = new Byte[1024];

   NetworkStream stream = GetStream();

   int count = 0;

   while (true) {

    byte []buff = new Byte[2];

    int bytes = stream.Read( buff, 0, 1 );

    if (bytes == 1) {

     serverbuff[count] = buff[0];

     count++;

     if (buff[0] == '/n') {

      break;

     }

    }

    else {

     break;

    };

   };

   string retval = enc.GetString( serverbuff, 0, count );

   System.Diagnostics.Debug.WriteLine("READ:" + retval);

   return retval;

  }

  private void Write(string message) {

   System.Text.ASCIIEncoding en = new System.Text.ASCIIEncoding() ;

   byte[] WriteBuffer = new byte[1024] ;

   WriteBuffer = en.GetBytes(message) ;

   NetworkStream stream = GetStream() ;

   stream.Write(WriteBuffer,0,WriteBuffer.Length);

   System.Diagnostics.Debug.WriteLine("WRITE:" + message);
  
  
  }

 }

 }
}