import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Vector;


class Serveur {
	int port = 8080;
	ServerSocket socketServeur;
    Vector<String> idClients;
    Vector<Socket> socketsClients;
    
    public Serveur() throws Exception {
        socketServeur = new ServerSocket(port);
        idClients = new Vector<String>();
        socketsClients = new Vector<Socket>();
        while (true) {    
            Socket socketClient = socketServeur.accept();        
            new GestionnaireClient(socketClient);
        }
    }
	
    public static void main(String args[]) throws Exception { 
        new Serveur();
    }

	class GestionnaireClient extends Thread {
		Socket socket;
		BufferedReader entree;
		PrintWriter sortie;
		String id;
		String message;
		int position;
		int i;
		PrintWriter diffusion;
		
		public GestionnaireClient(Socket socketClient) throws Exception {
			socket = socketClient;
			socket.setKeepAlive(true);
			entree = new BufferedReader(new InputStreamReader(socket.getInputStream()));	   
			sortie = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())));
			start();
		}

		public void run() {
			try {
				while (true) {
					id = entree.readLine();
					message = entree.readLine();
					if (message.equals("NOUVEAU_CLIENT")) {							
						if (idClients.contains(id)) {
							/////////////////////////////////////////////////////////////
							System.out.println("Demande de connexion rejetée, le client '" + id + "' est déjà connecté.");
							/////////////////////////////////////////////////////////////
							sortie.println("CLIENT_EXISTE_DEJA");
							sortie.flush();
							break;
						}
						else {
							/////////////////////////////////////////////////////////////
							System.out.println("Demande de connexion acceptée, le client '" + id + "' est maintenant connecté.");
							/////////////////////////////////////////////////////////////
							idClients.add(id);
							socketsClients.add(socket);
							sortie.println("CLIENT_ACCEPTE");
							sortie.flush();
						}			       
					}
					else if (message.equals("DECONNECTER_CLIENT")) {
						/////////////////////////////////////////////////////////////
						System.out.println("Demande de déconnexion acceptée, le client '" + id + "' est maintenant déconnecté.");
						/////////////////////////////////////////////////////////////
						position = idClients.indexOf(id);
						idClients.removeElementAt(position);
						socketsClients.removeElementAt(position);
						sortie.println("DECONNECTER_CLIENT");
						sortie.flush();
						break;
					}
					else if (message.equals("MESSAGE_CLIENT")) {
						message = entree.readLine();
						message = id + " : " + message;
						/////////////////////////////////////////////////////////////
						System.out.println(message);
						/////////////////////////////////////////////////////////////
						for (i = 0; i < socketsClients.size(); i ++) {
							diffusion = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socketsClients.elementAt(i).getOutputStream())));
							diffusion.println("DIFFUSION_MESSAGE");
							diffusion.println(message);
							diffusion.flush();
							diffusion.close();
						}
						/////////////////////////////////////////////////////////////
						System.out.println("Message diffusé à " + socketsClients.size() + " client(s).");
						/////////////////////////////////////////////////////////////						
					}
				}
				entree.close();
				sortie.close();	
				socket.close();
			}
			catch(Exception exception) {
				exception.printStackTrace();
			}				        
		}
	}
}