/* Class    :  GameServer 
 * Author   :  Andrew Miller
 * Version  :  7/1/96  JAVA SDK 1.02
 * Notice   :  Copyright (C) 1996 Andrew Miller
 *
 * The central idea when designing this server was to make it as stupid as possible and yet
 * it must still be able to perform simple network duties.  The reason for this is that 
 * allowing the client have control and making it capable of determining game play makes 
 * the server more flexible.  You can be playing multiple games with multiple amounts of
 * people.  The server just doesnt care.  
 * 
 * It is responsible for:
 * 1:looking for connections 
 * 2:adding those connections to its global list (along with a unique ID number)
 * 3:broadcasting to all the connections the current list of users (and their unique IDs)
 * 4:support for name changing
 * 5:letting the other users know when a client has disconnected (so they can update their
 *   own user lists).
 * 6:looking for "directives" and distributing them to the correct clients.
 *
 * Any message received by the server is parsed to determine whether or not it is a special
 * instruction.  Directives are the most useful function that the server provides.  The 
 * server doesnt care what is contained in the server (usually game information), but it 
 * looks to the end of the directive for a list of clients to redistribute the directive to.
 * This allows for specific interaction among a selected group of clients.
 *
 *
 * Code and ideas for these classes comes in part from the following sources:
 *
 * - 'Java in a Nutshell' by David Flanagan
 * - 'Java Unleashed' by Sams Net
 * - 'Writing Java Applets' by John Rodley
 * - 'Simple Server' by Kyle Palmer
 * - 'Multiserver' by Jeff Breidenbach
 *  
 */

import java.net.*;
import java.io.*;
import java.lang.*;

//declaration of class GameServer
class GameServer {

  	static int users = 0;   	//the number of active users
  	static int unique_id = 1;  	//setup unique id number for users
  	static int DEFAULT_PORT = 7992;
  	static NetworkSocket clients[] = new NetworkSocket[29];
  
public static void main(String args[]) {

	

	ServerSocket serverSocket = null;

  	int i, port = 0, connectTest;

	boolean chatFlag = true;



  	if (args.length == 1) {

		try { port = Integer.parseInt (args[0]);}

		catch (NumberFormatException e) { port = 0;}

	}	

     if (port == 0) port = DEFAULT_PORT;



	try {

    	serverSocket = new ServerSocket(port);

  	} 

	catch (IOException e) {

    	System.out.println("Could not listen on port: " + e);

     	System.exit(1);

	}



	Socket clientSocket = null;

	Connection user = new Connection(serverSocket);



	if (users == 0)

	{  //if no users, wait for one

		try 

		{

    			clientSocket = serverSocket.accept();

    		} 

		catch (IOException e) 

		{

      		System.out.println("Accept failed: " + e);

      		System.exit(1);

		}

		add_client(new NetworkSocket(clientSocket)); //add the client

	}

        

	String inputStream;		//string for Input IO

	String outputStream;	//string for Output IO

        

//get the vector the write to

        

	user.start();  //start polling for new users

	try {

    	inputStream = "Connected! Double-click user to challenge";

     	i = users;

  		while (users >= 0) 

		{

        	if (users>0 && i<=users ){

             	connectTest = clients[i].is_readable();

                if (connectTest == -1){ 	//if Connection stale

                  	remove_client(i);  	//remove the client

                }

                else if (connectTest == 1){ 	//if there is a line to get

                  	inputStream = clients[i].read_stream();  	//get the string

         			chatFlag = process_line(inputStream,i); //process the line

                  	if (chatFlag){ 	//echo line if is plain text

                    	if (clients[i] != null)

							System.out.println(clients[i].name+": "+inputStream);

                      		write_all((clients[i].name).toUpperCase()+": "+inputStream);  //echo it

                  	}

               	}

         	}

        	try{

             	user.join(2); //give Connection testing some time

            } catch(InterruptedException e) {}

        	if (user.connected() == true){

                add_client(new NetworkSocket(user.get_socket()));

                user.resume();

			}

         	i++;

			if (i>users && users>=1) i=1;

     		if (i>users && users<1)	i=0;

		}

		serverSocket.close();

	}catch(IOException e){}

}



// sends all the names and IDs in the servers list to all the clients

static void send_names(){ 



    String names = new String("!!names!!"); //start with indicator

    int i;



    if (users < 1) return; // do nothing for a no users

    for (i=1;i<=users;i++)  //add all users

    	if (clients[i] != null) //if everthing is in order

        	names = names + Integer.toString(clients[i].id) +"~" + clients[i].name + "|";  //append names and delimiters

    write_all(names);  //echo the names to everyone

}



// process the incoming data stream and return a status flag

static boolean process_line (String line,int i){



    int next, usernum;

    String temp ;

    String directive = new String("!!directive!!");   //new indicator

    

    //false if don't echo line



    if (line.startsWith("!!directive!!")) {      //instruction to send directive to users

		line = line.substring(13);

		next = line.indexOf('|');  // get position of next delimeters

		directive = directive + line.substring(0, next)+","+clients[i].name;

 		line = line.substring(next+1);

		while (line.length() > 0) {    // send directive to players in list

			next = line.indexOf('|');

			if (next == -1) break;  // end of list

			temp = line.substring(0, next);  // check for range

			if ((Integer.parseInt(temp)) > users) break;

			clients[Integer.parseInt(temp)].write_stream(directive);

			line = line.substring(next+1);

    	}

    	return false;

    }

 	

    else if (line.startsWith("!!name!!")){  //instruction to change name

      	clients[i].name = line.substring(8);  //name is the rest of line

      	clients[i].write_stream("Name changed to "+line.substring(8)); 

		System.out.println (line.substring(8)+" enters");

      	send_names(); //send an updated names list

      	return false;  //don't echo this string

    }

    

	else if (line.equals("!!quit!!")){	  //instruction to quit 

      	write_all(clients[i].name+" is logging out."); //tell everyone

		System.out.println(clients[i].name+" logged out");

      	remove_client(i);

      	return false;

    }

    return true;



}



// writes the string to all the users contained in the server's list

static void write_all (String text) { //write to all the clients

    

	int i;

    

    for (i=1;i<=users;i++)

      	clients[i].write_stream(text);

}



// adds a client and assigns it a unique id, then updates client name lists

static  void add_client(NetworkSocket client) {

	synchronized(clients) {



		if (users >= 25){

			client.write_stream("Sorry, there already 25 users.");

			client.kill(); //don't allow too many

			return;

		}



		clients[++users] = client;  //add the client to the list

		clients[users].id = unique_id++;

		clients[users].write_stream("!!directive!!mssge,uid,"+Integer.toString(clients[users].id));

		clients[users].write_stream("Connected! Double-click user to challenge");

		send_names();  //update everyones names list

	}

}



// removes a client from the list and updates the client name lists

static  void remove_client(int client){  

	synchronized(clients) {



		clients[client].kill();  //close everything 

		clients[client]=clients[users];

		clients[users]=null;

		users--;

		if (users <= 0) unique_id = 1;

		send_names();  //update the names list

	}

}

  

}