/*
 * $RCSfile$
 * $Revision: $
 * $Date: $
 *
 * Copyright (C) 2006 Jive Software. All rights reserved.
 *
 * Licensed 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.jivesoftware.multiplexer.starter;

import org.jivesoftware.util.Log;

import java.io.*;
import java.util.jar.Pack200;
import java.util.jar.JarOutputStream;

/**
 * Starts the core XMPP server. A bootstrap class that configures classloaders
 * to ensure easy, dynamic server startup.
 *
 * This class should be for standalone mode only. Connection managers launched
 * through a J2EE container (servlet/EJB) will use those environment's
 * classloading facilities to ensure proper startup.<p>
 *
 * Tasks:<ul>
 *      <li>Unpack any pack files in the lib directory (Pack200 encoded JAR files).</li>
 *      <li>Add all jars in the lib directory to the classpath.</li>
 *      <li>Add the config directory to the classpath for loadResource()</li>
 *      <li>Start the server</li>
 * </ul>
 *
 * Note: if the enviroment property <tt>cmanager.lib.dir</tt> is specified
 * ServerStarter will attempt to use this value as the value for Connection Manager's lib
 * directory. If the property is not specified the default value of ../lib will be used.
 *
 * @author Gaston Dombiak
 */
public class ServerStarter {

    /**
     * Default to this location if one has not been specified
     */
    private static final String DEFAULT_LIB_DIR = "../lib";

    public static void main(String [] args) {
        new ServerStarter().start();
    }

    /**
     * Starts the server by loading and instantiating the bootstrap
     * container. Once the start method is called, the server is
     * started and the server starter should not be used again.
     */
    private void start() {
        // Verify that Java 1.5 or later is being used
        if (System.getProperty("java.version").compareTo("1.5") < 0) {
            System.out.println("Connection Manager requires Java 1.5 or later");
            System.err.println("Connection Manager requires Java 1.5 or later");
            return;
        }

        // Setup the classpath using JiveClassLoader
        try {
            // Load up the bootstrap container
            final ClassLoader parent = findParentClassLoader();

            String libDirString = System.getProperty("cmanager.lib.dir");

            File libDir;
            if (libDirString != null) {
                // If the lib directory property has been specified and it actually
                // exists use it, else use the default
                libDir = new File(libDirString);
                if (!libDir.exists()) {
                    Log.warn("Lib directory " + libDirString +
                            " does not exist. Using default " + DEFAULT_LIB_DIR);
                    libDir = new File(DEFAULT_LIB_DIR);
                }
            }
            else {
                libDir = new File(DEFAULT_LIB_DIR);
            }

            // Unpack any pack files.
            unpackArchives(libDir);

            ClassLoader loader = new JiveClassLoader(parent, libDir);

            Thread.currentThread().setContextClassLoader(loader);
            Class containerClass = loader.loadClass(
                    "org.jivesoftware.multiplexer.ConnectionManager");
            containerClass.newInstance();
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * Locates the best class loader based on context (see class description).
     *
     * @return The best parent classloader to use
     */
    private ClassLoader findParentClassLoader() {
        ClassLoader parent = Thread.currentThread().getContextClassLoader();
        if (parent == null) {
            parent = this.getClass().getClassLoader();
            if (parent == null) {
                parent = ClassLoader.getSystemClassLoader();
            }
        }
        return parent;
    }

    /**
     * Converts any pack files in a directory into standard JAR files. Each
     * pack file will be deleted after being converted to a JAR. If no
     * pack files are found, this method does nothing.
     *
     * @param libDir the directory containing pack files.
     */
    private void unpackArchives(File libDir) {
        // Get a list of all packed files in the lib directory.
        File [] packedFiles = libDir.listFiles(new FilenameFilter() {
            public boolean accept(File dir, String name) {
                return name.endsWith(".pack");
            }
        });

        if (packedFiles == null) {
            // Do nothing since no .pack files were found
            return;
        }

        // Unpack each.
        boolean unpacked = false;
        for (File packedFile : packedFiles) {
            try {
                String jarName = packedFile.getName().substring(0,
                        packedFile.getName().length() - ".pack".length());
                // Delete JAR file with same name if it exists (could be due to upgrade
                // from old Openfire release).
                File jarFile = new File(libDir, jarName);
                if (jarFile.exists()) {
                    jarFile.delete();
                }

                InputStream in = new BufferedInputStream(new FileInputStream(packedFile));
                JarOutputStream out = new JarOutputStream(new BufferedOutputStream(
                        new FileOutputStream(new File(libDir, jarName))));
                Pack200.Unpacker unpacker = Pack200.newUnpacker();
                // Print something so the user knows something is happening.
                System.out.print(".");
                // Call the unpacker
                unpacker.unpack(in, out);

                in.close();
                out.close();
                packedFile.delete();
                unpacked = true;
            }
            catch (Exception e) {
                e.printStackTrace();
            }
        }
        // Print newline if unpacking happened.
        if (unpacked) {
            System.out.println();
        }
    }
}