/*
 *  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 "+this.hashCode()+
                           " created");
        this.handlers = new Vector<>();
    }

    @Override
    protected void finalize() {
        System.err.println("SimpleDaemon: instance "+this.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 "+this.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 "+this.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()) {}
        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 {
            final OutputStream file=new FileOutputStream(name,true);
            final PrintStream out=new PrintStream(file);
            final SimpleDateFormat fmt=new SimpleDateFormat();

            out.println(fmt.format(new Date()));
            out.close();
            file.close();
        }

        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 shutdown */
                        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=this.getDirectoryName()+
                                        "/SimpleDaemon."+
                                        this.getConnectionNumber()+
                                        ".tmp";
                            try {
                                this.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 "+
                                       this.getConnectionNumber());
                    return;
                }
            }
        }
    }
}
