//-----------------------------------------------------------------------
//  This file is part of the Microsoft .NET Framework SDK Code Samples.
// 
//  Copyright (C) Microsoft Corporation.  All rights reserved.
// 
//This source code is intended only as a supplement to Microsoft
//Development Tools and/or on-line documentation.  See these other
//materials for detailed information regarding Microsoft code samples.
// 
//THIS CODE AND INFORMATION ARE PROVIDED AS IS WITHOUT WARRANTY OF ANY
//KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
//IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
//PARTICULAR PURPOSE.
//-----------------------------------------------------------------------

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

namespace Microsoft.Samples.QuickStart.HowTo.Net.TcpUdp
{
    static public class Chat 
    {

        private static UdpClient m_Client;

        private static int ListenerPort = 8080;
        private static int SenderPort = 8080;
        private static int LocalPort;
        private static int RemotePort;

        private static string m_szHostName;

        private static IPAddress m_GroupAddress;
        private static IPHostEntry m_LocalHost;
        private static IPEndPoint m_RemoteEP;

        private static bool m_Done = false;

        public static void Usage() 
        {
            Console.WriteLine("UDP Multicast Chat Utility");
            Console.WriteLine("\nUsage:");
            Console.WriteLine("chat.exe");
        }

        public static void Main( String [] args ) 
        {

            LocalPort = SenderPort;
            RemotePort = ListenerPort;

            if( args.Length > 0 ) 
            {
                //
                // print help message, as this utility doesnt take any arguments
                //
                Usage();
                return;
            }

            m_szHostName = Dns.GetHostName();

            m_LocalHost = Dns.GetHostEntry(m_szHostName);

            Console.WriteLine("Local Port: {0}, Remote: {1}", LocalPort, RemotePort);

            Console.WriteLine("Initializing...");

            if (!Initialize())
                Environment.Exit(0);

            Console.WriteLine("Starting Listener thread...");

            Thread t = new Thread(new ThreadStart(Listener));
            t.Start();

            Byte [] buffer = null;

            Encoding ASCII = Encoding.ASCII;

            bool m_ShuttingDown = false;

            while(!m_ShuttingDown) 
            {
                String s = Console.ReadLine();

                if( s.Length == 0 )
                    continue;

                if(String.Compare(s,0,"@",0,1,true,CultureInfo.InvariantCulture) == 0) 
                {
                    m_Done = true;
                    //
                    // send a terminator to ourselves,
                    // so that the receiving thread can shut down
                    //
                    s = m_szHostName + ":@";
                    m_ShuttingDown = true;
                } 
                else 
                {
                    s = m_szHostName + ":" + s;
                }


                buffer = new Byte[s.Length + 1];
                //
                // send data to remote peer
                //

                int len = ASCII.GetBytes( s.ToCharArray(), 0, s.Length, buffer, 0);

                int ecode = m_Client.Send(buffer, len, m_RemoteEP);

                if(ecode <= 0) 
                {
                    Console.WriteLine("Error in send : " + ecode);
                }

            }

            t.Abort();
            t.Join();

            Console.WriteLine("Closing connection...");

            Terminate();

        } // Main

        public static void Terminate() 
        {
            m_Client.DropMulticastGroup(m_GroupAddress);
        }

        public static bool Initialize() 
        {

            //
            // instantiate UdpCLient
            //
            m_Client = new UdpClient(LocalPort);

            //
            // Create an object for Multicast Group
            //

            m_GroupAddress = IPAddress.Parse("224.0.0.1");

            //
            // Join Group
            //
            try 
            {
                m_Client.JoinMulticastGroup(m_GroupAddress, 100);
            } 
            catch(SocketException ex) 
            {
                Console.WriteLine(
                    "Unable to join multicast group: {0}", ex.Message);
                return false;
            }

            //
            // Create Endpoint for peer
            //
            m_RemoteEP = new IPEndPoint( m_GroupAddress, RemotePort );

            return true;
        }

        public static void Listener() 
        {

            //
            // The listener waits for data to come
            // and buffers it

            Thread.Sleep(2000); // make sure client2 is receiving

            Encoding    ASCII = Encoding.ASCII;

            while(!m_Done) 
            {
                IPEndPoint endpoint = null;
                Byte[] data = m_Client.Receive(ref endpoint);

                String strData = ASCII.GetString(data);

                if( strData.IndexOf(":@") > 0 ) 
                {
                    //
                    // we received a termination indication
                    // now we have to decide if it is from
                    // our main thread shutting down, or
                    // from someone else
                    //
                    Char [] separators = {':'};
                    String [] vars = strData.Split(separators);

                    if( vars[0] == m_szHostName ) 
                    {
                        //
                        // this is from ourselves, therefore we
                        // end now
                        //
                        Console.WriteLine("shutting down Listener thread...");

                        //
                        // this should have been done by main thread, but we
                        // do it again for safety
                        //
                        m_Done = true;
                    }
                    else 
                    {
                        //
                        // this is from someone else
                        //
                        Console.WriteLine("{0} has left the conversation", vars[0]);
                    }
                }
                else 
                {
                    //
                    // this is normal data received from others
                    // as well as ourselves
                    // check to see if it is from ourselves before
                    // we print
                    //
                    if(strData.IndexOf(":") > 0) 
                    {
                        Char [] separators = {':'};
                        String [] vars = strData.Split(separators);

                        if( vars[0] != m_szHostName ) 
                        {
                            Console.WriteLine(strData);
                        }
                    }
                }
            }

            Console.WriteLine("Listener thread finished...");
            return;
        }
    }
}