package Microsoft.Samples.QuickStart.HowTo.Net.TcpUdp;
//-----------------------------------------------------------------------
//  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.
//-----------------------------------------------------------------------
import System.*;
import System.Globalization.*;
import System.Net.*;
import System.Net.Sockets.*;
import System.Threading.*;
import System.Text.*;

public class Chat
{
    private static UdpClient mClient;
    private static int listenerPort = 8080;
    private static int senderPort = 8080;
    private static int localPort;
    private static int remotePort;
    private static String mszHostName;

    private static IPAddress mGroupAddress;
    private static IPHostEntry mLocalHost;
    private static IPEndPoint mRemoteEP;
    private static boolean mDone = false;

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

    public static void main(String[] args)
    {
        localPort = senderPort;
        remotePort = listenerPort;

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

        mszHostName = Dns.GetHostName();
        mLocalHost = Dns.GetHostEntry(mszHostName);
        Console.WriteLine("Local Port: {0}, Remote: {1}", (Int32)localPort,
            (Int32)remotePort);

        Console.WriteLine("Initializing...");
        Initialize();
        Console.WriteLine("Starting Listener thread...");
        System.Threading.Thread t = new System.Threading.Thread(new 
            ThreadStart(Listener));
        t.Start();

        ubyte buffer[] = null;
        Encoding ascii = Encoding.get_ASCII();
        boolean mShuttingDown = false;

        while (!mShuttingDown) {
            String s = Console.ReadLine();
            if (s.get_Length() == 0) {
                continue;
            }

            if (String.Compare(s, 0, "@", 0, 1, true, CultureInfo.
                get_InvariantCulture()) == 0) {
                mDone = true;
                //
                // send a terminator to ourselves,
                // so that the receiving thread can shut down
                //
                s = mszHostName + ":@";
                mShuttingDown = true;
            }
            else {
                s = mszHostName + ":" + s;
            }
            buffer = new ubyte[s.get_Length() + 1];
            //
            // send data to remote peer
            //
            int len = ascii.GetBytes(s.ToCharArray(), 0, s.get_Length(), 
                buffer, 0);
            int eCode = mClient.Send(buffer, len, mRemoteEP);

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

        t.Abort();
        t.Join();
        Console.WriteLine("Closing connection...");
        Terminate();
    } //main

    public static void Terminate()
    {
        mClient.DropMulticastGroup(mGroupAddress);
    } //Terminate

    public static void Initialize()
    {
        //
        // instantiate UdpCLient
        //
        mClient = new UdpClient(localPort);
        //
        // Create an object for Multicast Group
        //
        mGroupAddress = IPAddress.Parse("224.0.0.1");
        //
        // Join Group
        //
        try {
            mClient.JoinMulticastGroup(mGroupAddress, 100);
        }
        catch (System.Exception exp) {
            Console.WriteLine("Unable to join multicast group");
        }
        //
        // Create Endpoint for peer
        mRemoteEP = new IPEndPoint(mGroupAddress, remotePort);
    } //Initialize

    public static void Listener()
    {
        //
        // The listener waits for data to come
        // and buffers it
        System.Threading.Thread.Sleep(2000); // make sure client2 is receiving
        Encoding ascii = Encoding.get_ASCII();

        while (!mDone) {
            IPEndPoint endPoint = null;
            ubyte data[] = mClient.Receive(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].Equals(mszHostName)) {
                    //
                    // 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
                    //
                    mDone = 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].Equals(mszHostName))) {
                        Console.WriteLine(strData);
                    }
                }
            }
        }
        Console.WriteLine("Listener thread finished...");
        return;
    } //Listener
} //Chat