/*
    *  Licensed to the Apache Software Foundation (ASF) under one or more
    *  contributor license agreements.  See the NOTICE file distributed with
    *  this work for additional information regarding copyright ownership.
    *  The ASF licenses this file to You under the Apache License, Version 2.0
    *  (the "License"); you may not use this file except in compliance with
    *  the License.  You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   */
  
  package org.apache.commons.daemon;
  
  import java.io.*;
  import java.net.*;
  import java.text.SimpleDateFormat;
  import java.util.Date;
  import java.util.Enumeration;
  import java.util.Vector;
  
  public class SimpleDaemon implements Daemon, Runnable, DaemonUserSignal {
  
      private ServerSocket server;
      private Thread thread;
      private DaemonController controller;
      private volatile boolean stopping;
      private String directory;
      private final Vector<Handler> handlers;
      private boolean softReloadSignalled;
  
      public SimpleDaemon() {
          System.err.println("SimpleDaemon: instance " + hashCode() + " created");
          this.handlers = new Vector<>();
      }
  
      @Override
      protected void finalize() {
          System.err.println("SimpleDaemon: instance " + hashCode() + " garbage collected");
      }
  
      /**
       * init and destroy were added in jakarta-tomcat-daemon.
       */
      @Override
      public void init(final DaemonContext context) throws Exception {
          System.err.println("SimpleDaemon: instance " + hashCode() + " init");
  
          int port = 1200;
  
          final String[] a = context.getArguments();
  
          if (a.length > 0) {
              port = Integer.parseInt(a[0]);
          }
          if (a.length > 1) {
              this.directory = a[1];
          } else {
              this.directory = "/tmp";
          }
  
          // Dump a message
          System.err.println("SimpleDaemon: loading on port " + port);
  
          // Set up this simple daemon
          this.controller = context.getController();
          this.server = new ServerSocket(port);
          this.thread = new Thread(this);
      }
  
      @Override
      public void start() {
          // Dump a message
          System.err.println("SimpleDaemon: starting");
  
          // Start
          this.thread.start();
      }
  
      @Override
      public void stop() throws IOException, InterruptedException {
          // Dump a message
          System.err.println("SimpleDaemon: stopping");
  
          // Close the ServerSocket. This will make our thread to terminate
          this.stopping = true;
          this.server.close();
  
          // Wait for the main thread to exit and dump a message
          this.thread.join(5000);
          System.err.println("SimpleDaemon: stopped");
      }
  
      @Override
     public void destroy() {
         System.err.println("SimpleDaemon: instance " + hashCode() + " destroy");
     }
 
     @Override
     public void run() {
         int number = 0;
 
         System.err.println("SimpleDaemon: started acceptor loop");
         try {
             while (!this.stopping) {
                 checkForReload();
                 final Socket socket = this.server.accept();
                 checkForReload();
 
                 final Handler handler = new Handler(socket, this, this.controller);
                 handler.setConnectionNumber(number++);
                 handler.setDirectoryName(this.directory);
                 new Thread(handler).start();
             }
         } catch (final IOException e) {
             //
             // Don't dump any error message if we are stopping. A IOException is generated when the ServerSocket is closed in stop()
             //
             if (!this.stopping) {
                 e.printStackTrace(System.err);
             }
         }
 
         // Terminate all handlers that at this point are still open
         final Enumeration<Handler> openhandlers = this.handlers.elements();
         while (openhandlers.hasMoreElements()) {
             final Handler handler = openhandlers.nextElement();
             System.err.println("SimpleDaemon: dropping connection " + handler.getConnectionNumber());
             handler.close();
         }
 
         System.err.println("SimpleDaemon: exiting acceptor loop");
     }
 
     @Override
     public void signal() {
         //
         // In this example we are using soft reload on custom signal.
         //
         this.softReloadSignalled = true;
     }
 
     private void checkForReload() {
         if (this.softReloadSignalled) {
             System.err.println("SimpleDaemon: picked up reload, waiting for connections to finish...");
             while (!this.handlers.isEmpty()) {
                 // noop
             }
             System.err.println("SimpleDaemon: all connections have finished, pretending to reload");
             this.softReloadSignalled = false;
         }
     }
 
     protected void addHandler(final Handler handler) {
         synchronized (handler) {
             this.handlers.add(handler);
         }
     }
 
     protected void removeHandler(final Handler handler) {
         synchronized (handler) {
             this.handlers.remove(handler);
         }
     }
 
     public static class Handler implements Runnable {
 
         private final DaemonController controller;
         private final SimpleDaemon parent;
         private String directory;
         private final Socket socket;
         private int number;
 
         public Handler(final Socket s, final SimpleDaemon p, final DaemonController c) {
             this.socket = s;
             this.parent = p;
             this.controller = c;
         }
 
         @Override
         public void run() {
             this.parent.addHandler(this);
             System.err.println("SimpleDaemon: connection " + this.number + " opened from " + this.socket.getInetAddress());
             try {
                 final InputStream in = this.socket.getInputStream();
                 final OutputStream out = this.socket.getOutputStream();
                 handle(in, out);
                 this.socket.close();
             } catch (final IOException e) {
                 e.printStackTrace(System.err);
             }
             System.err.println("SimpleDaemon: connection " + this.number + " closed");
             this.parent.removeHandler(this);
         }
 
         public void close() {
             try {
                 this.socket.close();
             } catch (final IOException e) {
                 e.printStackTrace(System.err);
             }
         }
 
         public void setConnectionNumber(final int number) {
             this.number = number;
         }
 
         public int getConnectionNumber() {
             return this.number;
         }
 
         public void setDirectoryName(final String directory) {
             this.directory = directory;
         }
 
         public String getDirectoryName() {
             return this.directory;
         }
 
         public void log(final String name) throws IOException {
             try (final OutputStream file = new FileOutputStream(name, true);
                     final PrintStream out = new PrintStream(file)) {
                 out.println(new SimpleDateFormat().format(new Date()));
             }
         }
 
         public void handle(final InputStream in, final OutputStream os) {
             final PrintStream out = new PrintStream(os);
 
             while (true) {
                 try {
                     /*
                      * If we don't have data in the System InputStream, we want to ask to the user for an option.
                      */
                     if (in.available() == 0) {
                         out.println();
                         out.println("Please select one of the following:");
                         out.println("    1) Shutdown");
                         out.println("    2) Reload");
                         out.println("    3) Create a file");
                         out.println("    4) Disconnect");
                         out.println("    5) Soft reload");
                         out.print("Your choice: ");
                     }
 
                     /* Read an option from the client */
                     final int x = in.read();
 
                     switch (x) {
                     /* If the socket was closed, we simply return */
                     case -1:
                         return;
 
                     /* Attempt to shut down */
                     case '1':
                         out.println("Attempting a shutdown...");
                         try {
                             this.controller.shutdown();
                         } catch (final IllegalStateException e) {
                             out.println();
                             out.println("Can't shutdown now");
                             e.printStackTrace(out);
                         }
                         break;
 
                     /* Attempt to reload */
                     case '2':
                         out.println("Attempting a reload...");
                         try {
                             this.controller.reload();
                         } catch (final IllegalStateException e) {
                             out.println();
                             out.println("Can't reload now");
                             e.printStackTrace(out);
                         }
                         break;
 
                     /* Disconnect */
                     case '3':
                         final String name = getDirectoryName() + "/SimpleDaemon." + getConnectionNumber() + ".tmp";
                         try {
                             log(name);
                             out.println("File '" + name + "' created");
                         } catch (final IOException e) {
                             e.printStackTrace(out);
                         }
                         break;
 
                     /* Disconnect */
                     case '4':
                         out.println("Disconnecting...");
                         return;
                     case '5':
                         out.println("Reloading configuration...");
                         this.parent.signal();
                         return;
 
                     /* Discard any carriage return / newline characters */
                     case '\r':
                     case '\n':
                         break;
 
                     /* We got something that we weren't supposed to get */
                     default:
                         out.println("Unknown option '" + (char) x + "'");
                         break;
 
                     }
 
                     /* If we get an IOException we return (disconnect) */
                 } catch (final IOException e) {
                     System.err.println("SimpleDaemon: IOException in " + "connection " + getConnectionNumber());
                     return;
                 }
             }
         }
     }
 }