package org.jtheque.core.managers.lifecycle;

 /*

  * This file is part of JTheque.

  *

  * JTheque is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, either version 3 of the License.

  *

  * JTheque is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with JTheque.  If not, see <http://www.gnu.org/licenses/>.

  */

 import org.jtheque.core.managers.Managers;

 import org.jtheque.core.managers.log.ILoggingManager;

 import org.jtheque.utils.io.FileUtils;

 import org.jtheque.utils.io.SocketUtils;

 import org.slf4j.LoggerFactory;

 import java.io.IOException;

 import java.io.PrintStream;

 import java.net.ServerSocket;

 import java.net.Socket;

 import java.net.SocketException;

 import java.net.UnknownHostException;

 import java.util.ArrayList;

 import java.util.Collection;

 /**

  * This class permit to have only one launched instance of the application.

  *

  * @author Baptiste Wicht

  */

 final class Instances {

     private ServerSocket socket;

     private final Collection<Client> clients = new ArrayList<Client>(5);

     private Thread thread;

     private static final String LOCALHOST = "127.0.0.1";

     private static final int PORT = 12345;

     /**

      * Launch the application. If an other instance of the application is soon launched,

      * call it and exit the current instance.

      */

     @SuppressWarnings({"SocketOpenedButNotSafelyClosed"})

     public void launchApplication() {

         boolean canLaunch = true;

         try {

             socket = new ServerSocket(PORT);

             registerNewClient();

         } catch (IOException e) {

             LoggerFactory.getLogger(getClass()).error("Unable to register socket", e);

             canLaunch = false;

         }

         if (!canLaunch) {

             exit();

         }

     }

     /**

      * Register a new client.

      */

     private void registerNewClient() {

         thread = new ServerThread();

         thread.start();

     }

     /**

      * Exit.

      */

     private void exit() {

         callInstance();

         System.exit(1); //At this moment, nothing need to be released

     }

     /**

      * Call the another instance of JTheque.

      */

     @SuppressWarnings({"SocketOpenedButNotSafelyClosed", "IOResourceOpenedButNotSafelyClosed"})

     private void callInstance() {

         Socket clientSocket = null;

         PrintStream stream = null;

         try {

             clientSocket = new Socket(LOCALHOST, PORT);

             stream = new PrintStream(clientSocket.getOutputStream());

             stream.println("open");

         } catch (UnknownHostException e) {

             LoggerFactory.getLogger(getClass()).error("The host is unknown", e);

         } catch (IOException e) {

             LoggerFactory.getLogger(getClass()).error("I/O error", e);

         } finally {

             FileUtils.close(stream);

             SocketUtils.close(clientSocket);

         }

     }

     /**

      * Close definitively all the open flows.

      */

     public void closeInstance() {

         stopClients();

         stopServer();

         SocketUtils.close(socket);

     }

     /**

      * Stop all the clients.

      */

     private void stopClients() {

         for (Client client : clients) {

             client.interrupt();

         }

     }

     /**

      * Stop the server.

      */

     private void stopServer() {

         if (thread != null) {

             thread.interrupt();

         }

     }

     /**

      * A thread for a client.

      *

      * @author Baptiste Wicht

      */

     @SuppressWarnings({"SocketOpenedButNotSafelyClosed"})

     private final class ServerThread extends Thread {

         private boolean closing;

         @Override

         public void run() {

             while (!socket.isClosed() && socket != null) {

                 try {

                     Client client = new Client(socket.accept());

                     clients.add(client);

                     client.start();

                 } catch (SocketException e1) {

                     if (!closing) {

                         Managers.getManager(ILoggingManager.class).getLogger(getClass()).error(e1, "Socket closed");

                     }

                 } catch (IOException e2) {

                     Managers.getManager(ILoggingManager.class).getLogger(getClass()).error(e2);

                     interrupt();

                 }

             }

         }

         @Override

         public void interrupt() {

             closing = true;

             SocketUtils.close(socket);

             super.interrupt();

         }

     }

 }