/*
 * 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.oodt.commons;

import org.apache.oodt.commons.io.Base64EncodingOutputStream;
import org.apache.oodt.commons.util.LogInit;
import org.apache.oodt.commons.util.XML;
import org.w3c.dom.DOMException;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentType;
import org.w3c.dom.Element;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;

import javax.naming.Context;
import javax.naming.NamingException;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.rmi.server.RemoteObject;
import java.rmi.server.RemoteRef;
import java.rmi.server.RemoteStub;
import java.util.Date;
import java.util.Iterator;

public class AvroExecServer {

    /** The configuration. */
    private static Configuration configuration;

    /** The servant. */
    private Object servant;


    /** Current binder, if any. */
    private static Binder binder;

    /** Object key name. */
    protected String name;

    /** Server's status document. */
    private Document statusDocument;

    /** The &lt;log&gt; element within the status document. */
    private Element logElement;

    /** Status DTD Document Type Definition formal public identifier. */
    public static final String STATUS_FPI = "-//JPL//DTD EDA Server Status 1.0";

    /** Status DTD system identifier. */
    public static final String STATUS_URL = "http://oodt.jpl.nasa.gov/edm-commons/xml/serverStatus.dtd";

    /** Name of the property that prints the server's IOR or RMI handle. */
    public static final String PRINT_IOR_PROPERTY = "org.apache.oodt.commons.ExecServer.printIOR";

    /** Name of the property that prevents binding of this object with the naming service. */
    public static final String DISABLE_BINDING = "org.apache.oodt.commons.ExecServer.disableBinding";

    /** How long to wait before bind attempts, in ms. */
    private static final long REBIND_PERIOD = Long.getLong("org.apache.oodt.commons.ExecServer.rebindPeriod", 30*60*1000).longValue();


    protected AvroExecServer(String name) {
        this.name = name;
    }

    /** Create a new executable server.
     *
     * @param name Name of the server
     * @param className Name of class that implements the server.
     * @throws ClassNotFoundException If the class for <var>className</var> can't be found.
     * @throws NoSuchMethodException If the constructor for <var>className</var> taking a single <code>ExecServer</code>
     *         can't be found.
     * @throws InstantiationException If the class for <var>className</var> is abstract or is an interface.
     * @throws IllegalAccessException If the class for <var>className</var> isn't public.
     * @throws InvocationTargetException If an exception occurs in the constructor for <var>className</var>.
     * @throws DOMException If the server's status document can't be created.
     * @throws UnknownHostException If the local host name can't be determined.
     */
    public AvroExecServer(String name, String className) throws ClassNotFoundException, NoSuchMethodException,
            InstantiationException, IllegalAccessException, InvocationTargetException, DOMException, UnknownHostException {
        this.name = name;

        // Find the class and the required constructor.
        Class clazz = Class.forName(className);
        Constructor ctor = clazz.getConstructor(new Class[]{ExecServer.class});

        // Invoke the constructor to create the servant.
        servant = ctor.newInstance(new Object[]{this});
        Date startDate = new Date();

        // Create the XML-RPC interface to this server.

        // I should create avro interface to this server

        /*Responder responder = new GenericResponder() {
            @Override
            public Object respond(Protocol.Message message, Object o) throws Exception {

                return null;
            }
        }*/
       /* server =new HttpServer();
        server.*/

//        xmlrpcServer = new XmlRpcServer();
//        xmlrpcServer.addHandler("server", this);

        // Create the server status document.
        DocumentType docType = XML.getDOMImplementation().createDocumentType("server", STATUS_FPI, STATUS_URL);
        statusDocument = XML.getDOMImplementation().createDocument(/*namespaceURI*/null, "server", docType);
        Element serverElement = statusDocument.getDocumentElement();
        XML.add(serverElement, "name", name);
        XML.add(serverElement, "class", className);
        XML.add(serverElement, "state", "up");
        Element startElement = statusDocument.createElement("start");
        serverElement.appendChild(startElement);
        Element userElement = statusDocument.createElement("user");
        startElement.appendChild(userElement);
        XML.add(userElement, "name", System.getProperty("user.name", "UNKNOWN"));
        XML.add(userElement, "cwd", System.getProperty("user.dir", "UNKNOWN"));
        XML.add(userElement, "home", System.getProperty("user.home", "UNKNOWN"));
        Element dateElement = statusDocument.createElement("date");
        startElement.appendChild(dateElement);
        dateElement.setAttribute("ms", String.valueOf(startDate.getTime()));
        dateElement.appendChild(statusDocument.createTextNode(startDate.toString()));
        XML.add(startElement, "config", System.getProperty("org.apache.oodt.commons.Configuration.url", "UNKNOWN"));
        Element hostElement = statusDocument.createElement("host");
        serverElement.appendChild(hostElement);
        XML.add(hostElement, "name", InetAddress.getLocalHost().getHostName());
        Element osElement = statusDocument.createElement("os");
        hostElement.appendChild(osElement);
        XML.add(osElement, "name", System.getProperty("os.name", "UNKNOWN"));
        XML.add(osElement, "version", System.getProperty("os.version", "UNKNOWN"));
        XML.add(osElement, "arch", System.getProperty("os.arch", "UNKNOWN"));
        Element vmElement = statusDocument.createElement("vm");
        serverElement.appendChild(vmElement);
        XML.add(vmElement, "name", System.getProperty("java.vm.name", "UNKNOWN"));
        XML.add(vmElement, "version", System.getProperty("java.version", "UNKNOWN"));
        XML.add(vmElement, "classpath", System.getProperty("java.class.path", "UNKNOWN"));
        XML.add(vmElement, "extdirs", System.getProperty("java.ext.dirs", "UNKNOWN"));
        logElement = statusDocument.createElement("log");
        serverElement.appendChild(logElement);
    }


    public static void runInitializers() throws EDAException {
        String initList = System.getProperty("org.apache.oodt.commons.initializers",
                System.getProperty("org.apache.oodt.commons.ExecServer.initializers", System.getProperty("initializers", "")));
        for (Iterator i = org.apache.oodt.commons.util.Utility.parseCommaList(initList); i.hasNext();) {
            String iname = (String) i.next();
            try {
                Class initClass = Class.forName(iname);
                Initializer init = (Initializer) initClass.newInstance();
                init.initialize();
            } catch (ClassNotFoundException ex) {
                System.err.println("Initializer \"" + iname + "\" not found; aborting");
                throw new EDAException(ex);
            } catch (InstantiationException ex) {
                System.err.println("Initializer \"" + iname + "\" is abstract; aborting");
                throw new EDAException(ex);
            } catch (IllegalAccessException ex) {
                System.err.println("Initializer \"" + iname + "\" isn't public; aborting");
                throw new EDAException(ex);
            } 
        }
    }

    public static void main(String[] argv) {
        if (argv.length < 2) {
            System.err.println("Usage: class-name-of-server object-name");
            System.exit(1);
        }

        String className = argv[0];
        String name = argv[1];

        // Enable support of our special URLs, like stdin:
        System.setProperty("java.protocol.handler.pkgs", "org.apache.oodt.commons.net.protocol");

        try {
            // Get the configuration.
            configuration = Configuration.getConfiguration();
            configuration.mergeProperties(System.getProperties());

            // Set up the logger.
            LogInit.init(System.getProperties(), name);

            // Run initializers
            try {
                runInitializers();
            } catch (EDAException ex) {
                ex.printStackTrace();
                System.exit(1);
            }

            // Create it.
            final AvroExecServer server = new AvroExecServer(name, className);

            // Print it.
            if (Boolean.getBoolean(PRINT_IOR_PROPERTY)) {
                if (server.getServant() instanceof RemoteObject) {
                    RemoteObject remoteObject = (RemoteObject) server.getServant();
                    RemoteStub remoteStub = (RemoteStub) RemoteObject.toStub(remoteObject);
                    RemoteRef ref = remoteStub.getRef();
                    System.out.print("RMI:");
                    System.out.flush();
                    ObjectOutputStream objOut
                            = new ObjectOutputStream(new Base64EncodingOutputStream(System.out));
                    objOut.writeObject(ref);
                    objOut.flush();
                    System.out.println();
                } else {
                    org.omg.PortableServer.Servant servant=(org.omg.PortableServer.Servant)server.getServant();
                    org.omg.CORBA.ORB orb = servant._orb();
                    System.out.println(orb.object_to_string(servant._this_object(orb)));
                }
                System.out.flush();
            }

            // Bind it.
            if (!Boolean.getBoolean(DISABLE_BINDING)) {
                binder = new Binder(name, server);
                binder.start();
            }

            // Prepare for the inevitable
            Runtime.getRuntime().addShutdownHook(new Thread() {
                public void run() {
                    server.shutdown0();
                }
            });

            // We're done here.
            for (;;) try {
                Thread.currentThread().join();
            } catch (InterruptedException ignore) {}
        } catch (IOException ex) {
            System.err.println("I/O error during initialization: " + ex.getMessage());
            ex.printStackTrace();
        } catch (SAXParseException ex) {
            System.err.println("Error in the configuration file at line " + ex.getLineNumber() + ", column "
                    + ex.getColumnNumber() + ": " + ex.getMessage());
        } catch (SAXException ex) {
            System.err.println("Error " + ex.getClass().getName() + " while attempting to parse the configuration"
                    + " file: " + ex.getMessage());
        } catch (java.lang.reflect.InvocationTargetException ex) {
            Throwable target = ex.getTargetException();
            System.err.println("Constructor for \"" + className + "\" threw " + target.getClass().getName() + ": "
                    + ex.getMessage());
            target.printStackTrace();
        } catch (RuntimeException ex) {
            throw ex;
        } catch (Exception ex) {
            System.err.println("Exception " + ex.getClass().getName() + " initializing server \"" + name
                    + "\" with class \"" + className + "\": " + ex.getMessage());
            ex.printStackTrace();
        }
        System.exit(1);
    }

    /**
     * Binding thread.
     */
    private static class Binder extends Thread {
        private boolean keepBinding;
        private String name;
        private AvroExecServer server;
        public Binder(String name, AvroExecServer server) {
            super("Binder for " + name);
            setDaemon(true);
            this.name = name;
            this.server = server;
            keepBinding = true;
        }
        public void run() {
            while (shouldKeepBinding()) try {
                Context objectContext = configuration.getObjectContext();
                objectContext.rebind(name, server.getServant());
                objectContext.close();
            } catch (Throwable ex) {
                System.err.println("Exception binding at " + new Date() + "; will keep trying...");
                ex.printStackTrace();
            } finally {
                try {
                    Thread.sleep(REBIND_PERIOD);
                } catch (InterruptedException ignore) {}
            }
        }
        public synchronized void stopBinding() {
            keepBinding = false;
        }
        private synchronized boolean shouldKeepBinding() {
            return keepBinding;
        }

    }

    /** Return the servant for this executable server.
     *
     * @return The servant.
     */
    public Object getServant() {
        return servant;
    }

    private void shutdown0() {
        // Unbind.
        if (!Boolean.getBoolean(DISABLE_BINDING)) try {
            binder.stopBinding();
            Context objectContext = configuration.getObjectContext();
            objectContext.unbind(getName());
            objectContext.close();
        } catch (NamingException ignore) {}

        // Kill the ORB.  YEAH!  KILL IT, KILL IT, KIIIIIIIIIIIIIIL IIIIIIIIT!!!!!!!1
        try {
            if (servant instanceof org.omg.PortableServer.Servant) {
                org.omg.PortableServer.Servant s = (org.omg.PortableServer.Servant) servant;
                org.omg.CORBA.ORB orb = s._orb();
                orb.shutdown(false/*=>terminate without waiting for reqs to complete*/);
            }
        } catch (Throwable ignore) {}
    }

    /** Get my name.
     *
     * @return The name under which I'm registered in teh naming context.
     */
    public String getName() {
        return name;
    }


}