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

namespace Coolcat.De
{
	/// <summary>
	/// Simple session
	/// </summary>
	public class SmtpSession 
	{
		Socket _socket;
		private string	_sessionProtocol="";
		
		/// <summary>
		/// session protocol 
		/// </summary>
		public string SessionProtocol
		{
			get { return _sessionProtocol; }
			set { _sessionProtocol = value; }
		}



		/// <summary>
		/// process session
		/// </summary>
		public void Process ()
		{
			NetworkStream networkStream = new NetworkStream(_socket);
			StreamWriter streamWriter = new StreamWriter(networkStream);
			StreamReader streamReader = new StreamReader(networkStream);
			streamWriter.AutoFlush = true;

			try
			{
				streamWriter.WriteLine ("220 coolcat.de SMTP Mock Server Ready");
				bool datasent = false;

				while (_socket.Connected == true)
				{
					string line = streamReader.ReadLine();
					
					_sessionProtocol += line + "\n";

					if (line == String.Empty)
						continue;

					if (line.ToUpper().StartsWith ("QUIT"))
					{
						streamWriter.WriteLine("221 coolcat.de Service closing transmission channel");
						break;

					}
					if (line.ToUpper().StartsWith ("DATA"))
					{
						datasent=true;
						streamWriter.WriteLine("354 Immediate Reply");
					}
					else if (datasent && line.Trim() == ".")
					{
						datasent=false;
						streamWriter.WriteLine ("250 OK");
					}
					else if (!datasent)
					{
						streamWriter.WriteLine("250 OK");
					}
				}
			}
			catch (SocketException socketException)
			{
				Console.WriteLine (socketException.Message);
			}
			finally
			{
				streamReader.Close();
				streamWriter.Close ();
				networkStream.Close ();
				_socket.Close ();
			}
			
		}

		/// <summary>
		/// constructor
		/// </summary>
		/// <param name="socket"></param>
		public SmtpSession (Socket socket)
		{
			_socket = socket;
		}
		
	}
	/// <summary>
	/// Simple SMTP Mock server
	/// </summary>
	public class SmtpMock 
	{

		private TcpListener _smtpListener = null;
		private ArrayList _sessions = new ArrayList ();

		/// <summary>
		/// list of all smtp sessions
		/// </summary>
		public SmtpSession[] Sessions
		{
			get {  return (SmtpSession[]) _sessions.ToArray(typeof (SmtpSession)); }
		}


		/// <summary>
		/// start server
		/// </summary>
		public void Start ()
		{
			Thread smtpServerThread = new Thread (new ThreadStart (Run));
			smtpServerThread.Start ();
		}

		/// <summary>
		/// stop server
		/// </summary>
		public void Stop ()
		{
			if (_smtpListener != null)
				_smtpListener.Stop ();
		}


		/// <summary>
		/// run server
		/// </summary>
		private void Run ()
		{

			_smtpListener = new TcpListener (IPAddress.Any, 25); // open listener for port 
			_smtpListener.Start ();

			try
			{
				while (true)
				{
					Socket clientSocket = _smtpListener.AcceptSocket ();
					SmtpSession session = new SmtpSession (clientSocket);
					_sessions.Add (session);
					Thread sessionThread = new Thread (new ThreadStart (session.Process));
					sessionThread.Start ();
					/*sessionThread.Join (); // remove comment  for more sessions at the same time*/
				}
			}
			catch (InvalidOperationException) {}
			finally 
			{
				_smtpListener.Stop();
			}
			
		}
	}
}