/*
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2026, QOS.ch. All rights reserved.
    *
    * This program and the accompanying materials are dual-licensed under
    * either the terms of the Eclipse Public License v2.0 as published by
    * the Eclipse Foundation
    *
    *   or (per the licensee's choosing)
   *
   * under the terms of the GNU Lesser General Public License version 2.1
   * as published by the Free Software Foundation.
   */
  package ch.qos.logback.classic.net;
  
  import java.io.IOException;
  import java.net.ServerSocket;
  import java.net.Socket;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.concurrent.CountDownLatch;
  
  import javax.net.ServerSocketFactory;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import ch.qos.logback.classic.LoggerContext;
  import ch.qos.logback.classic.joran.JoranConfigurator;
  import ch.qos.logback.core.joran.spi.JoranException;
  
  /**
   * A simple {@link SocketNode} based server.
   * 
   * <pre>
   *      &lt;b&gt;Usage:&lt;/b&gt; java ch.qos.logback.classic.net.SimpleSocketServer port configFile
   * </pre>
   * 
   * where <em>port</em> is a port number where the server listens and
   * <em>configFile</em> is an XML configuration file fed to
   * {@link JoranConfigurator}.
   * 
   * </pre>
   * 
   * @author Ceki G&uuml;lc&uuml;
   * @author S&eacute;bastien Pennec
   * 
   * @since 0.8.4
   */
  public class SimpleSocketServer extends Thread {
  
      Logger logger = LoggerFactory.getLogger(SimpleSocketServer.class);
  
      private final int port;
      private final LoggerContext lc;
      private boolean closed = false;
      private ServerSocket serverSocket;
      private List<SocketNode> socketNodeList = new ArrayList<SocketNode>();
  
      // used for testing purposes
      private CountDownLatch latch;
  
      public static void main(String argv[]) throws Exception {
          doMain(SimpleSocketServer.class, argv);
      }
  
      protected static void doMain(Class<? extends SimpleSocketServer> serverClass, String argv[]) throws Exception {
          int port = -1;
          if (argv.length == 2) {
              port = parsePortNumber(argv[0]);
          } else {
              usage("Wrong number of arguments.");
          }
  
          String configFile = argv[1];
          LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
          configureLC(lc, configFile);
  
          SimpleSocketServer sss = new SimpleSocketServer(lc, port);
  
          // start the server in a separate thread
          sss.start();
      }
  
      public SimpleSocketServer(LoggerContext lc, int port) {
          this.lc = lc;
          this.port = port;
      }
  
      public void run() {
  
          final String oldThreadName = Thread.currentThread().getName();
  
          try {
  
              final String newThreadName = getServerThreadName();
              Thread.currentThread().setName(newThreadName);
  
              logger.info("Listening on port " + port);
             serverSocket = getServerSocketFactory().createServerSocket(port);
             while (!closed) {
                 logger.info("Waiting to accept a new client.");
                 signalAlmostReadiness();
                 Socket socket = serverSocket.accept();
                 logger.info("Connected to client at " + socket.getInetAddress());
                 logger.info("Starting new socket node.");
                 SocketNode newSocketNode = new SocketNode(this, socket, lc);
                 synchronized (socketNodeList) {
                     socketNodeList.add(newSocketNode);
                 }
                 final String clientThreadName = getClientThreadName(socket);
                 new Thread(newSocketNode, clientThreadName).start();
             }
         } catch (Exception e) {
             if (closed) {
                 logger.info("Exception in run method for a closed server. This is normal.");
             } else {
                 logger.error("Unexpected failure in run method", e);
             }
         }
 
         finally {
             Thread.currentThread().setName(oldThreadName);
         }
     }
 
     /**
      * Returns the name given to the server thread.
      */
     protected String getServerThreadName() {
         return String.format("Logback %s (port %d)", getClass().getSimpleName(), port);
     }
 
     /**
      * Returns a name to identify each client thread.
      */
     protected String getClientThreadName(Socket socket) {
         return String.format("Logback SocketNode (client: %s)", socket.getRemoteSocketAddress());
     }
 
     /**
      * Gets the platform default {@link ServerSocketFactory}.
      * <p>
      * Subclasses may override to provide a custom server socket factory.
      */
     protected ServerSocketFactory getServerSocketFactory() {
         return ServerSocketFactory.getDefault();
     }
 
     /**
      * Signal another thread that we have established a connection This is useful
      * for testing purposes.
      */
     void signalAlmostReadiness() {
         if (latch != null && latch.getCount() != 0) {
             // System.out.println("signalAlmostReadiness() with latch "+latch);
             latch.countDown();
         }
     }
 
     /**
      * Used for testing purposes
      * 
      * @param latch
      */
     void setLatch(CountDownLatch latch) {
         this.latch = latch;
     }
 
     /**
      * Used for testing purposes
      */
     public CountDownLatch getLatch() {
         return latch;
     }
 
     public boolean isClosed() {
         return closed;
     }
 
     public void close() {
         closed = true;
         if (serverSocket != null) {
             try {
                 serverSocket.close();
             } catch (IOException e) {
                 logger.error("Failed to close serverSocket", e);
             } finally {
                 serverSocket = null;
             }
         }
 
         logger.info("closing this server");
         synchronized (socketNodeList) {
             for (SocketNode sn : socketNodeList) {
                 sn.close();
             }
         }
         if (socketNodeList.size() != 0) {
             logger.warn("Was expecting a 0-sized socketNodeList after server shutdown");
         }
 
     }
 
     public void socketNodeClosing(SocketNode sn) {
         logger.debug("Removing {}", sn);
 
         // don't allow simultaneous access to the socketNodeList
         // (e.g. removal whole iterating on the list causes
         // java.util.ConcurrentModificationException)
         synchronized (socketNodeList) {
             socketNodeList.remove(sn);
         }
     }
 
     static void usage(String msg) {
         System.err.println(msg);
         System.err.println("Usage: java " + SimpleSocketServer.class.getName() + " port configFile");
         System.exit(1);
     }
 
     static int parsePortNumber(String portStr) {
         try {
             return Integer.parseInt(portStr);
         } catch (java.lang.NumberFormatException e) {
             e.printStackTrace();
             usage("Could not interpret port number [" + portStr + "].");
             // we won't get here
             return -1;
         }
     }
 
     static public void configureLC(LoggerContext lc, String configFile) throws JoranException {
         JoranConfigurator configurator = new JoranConfigurator();
         lc.reset();
         configurator.setContext(lc);
         configurator.doConfigure(configFile);
     }
 }