/*
 * Copyright (c) 2000, 2017 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

/*
 *  @(#)ConnectionRecover.java	1.43 04/03/08
 */

package com.sun.messaging.jmq.jmsclient;

import javax.jms.*;
//import com.sun.messaging.jmq.io.*;
import com.sun.messaging.*;
//import java.io.*;
import java.util.Enumeration;
import java.util.Vector;
import java.util.logging.Level;
import java.util.logging.Logger;
//import com.sun.messaging.jmq.jmsclient.notification.EventHandler;
//import com.sun.messaging.jms.notification.ConnectionReconnectedEvent;

import com.sun.messaging.jmq.jmsclient.resources.*;

/**
 *
 * This class provide a way for the client to recover itself if the connection goes away.
 *
 * <p>
 * The API user is transparent to the recovering attempt. All consumers are registered to the broker with their original
 * IDs. All producers are added with the same parameters.
 *
 */

public class ConnectionRecover implements Runnable {

    protected ConnectionImpl connection = null;
    // protected ProtocolHandler protocolHandler = null;

    protected final static String iMQConnectionRecover = "iMQConnectionRecover-";
    private boolean debug = Debug.debug;

    protected static final int RECOVER_INACTIVE = 0;
    protected static final int RECOVER_STOPPED = 1;
    protected static final int RECOVER_STARTED = 2;
    protected static final int RECOVER_IN_PROCESS = 3;
    protected static final int TRANSPORT_CONNECTED = 4;
    protected static final int RECOVER_SUCCEEDED = 5;
    protected static final int RECOVER_FAILED = 6;
    protected static final int RECOVER_ABORTED = 7;

    // string recover state -- used for logging
    private static final String STATES[] = { "RECOVER_INACTIVE", "RECOVER_STOPPED", "RECOVER_STARTED", "RECOVER_IN_PROCESS", "RECOVER_TRANSPORT_CONNECTED",
            "RECOVER_SUCCEEDED", "RECOVER_FAILED", "RECOVER_ABORTED" };

    // this flag is set to true when reconnected.
    private int recoverState = RECOVER_INACTIVE;

    private int maxRetries = 100;

    private int failedCount = 0;

    protected Thread recoverThread = null;

    // wait 3 secs and check status.
    private static final int WAIT_TIME = 3000;

    // total wait time out is 600 secs. This is the time for ReadChannel to
    // wait for this object to become inactive state.
    private static final int MAX_WAIT_COUNT = 200;

    // recover delay time.
    public int recoverDelay = 3000;

    private Logger connLogger = ConnectionImpl.connectionLogger;

    // enable connection consumer reconnect
    private boolean enableCCReconnect = true;

    public ConnectionRecover(ConnectionImpl connection) {
        this.connection = connection;

        String prop = connection.getTrimmedProperty("imq.recover.maxRetries");
        if (prop != null) {
            maxRetries = Integer.parseInt(prop);
        }

        prop = connection.getTrimmedProperty("imq.recover.delay");
        if (prop != null) {
            recoverDelay = Integer.parseInt(prop);

            if (connection.isConnectedToHABroker) {
                if (recoverDelay < ConnectionInitiator.HA_RECONNECT_DELAY) {
                    recoverDelay = ConnectionInitiator.HA_RECONNECT_DELAY;
                }
            }
        }

        // HACC
        // we can disable this just in case we breaks something unexpected.
        prop = connection.getTrimmedProperty("imq.recover.connectionConsumer");
        if (prop != null) {

            boolean flag = Boolean.getBoolean(prop);
            if (flag == false) {
                this.enableCCReconnect = false;
            }

        }

        logRecoverState(this.RECOVER_INACTIVE);

        // init();
    }

    protected void init() throws JMSException {
        // protocolHandler = connection.protocolHandler;

        Debug.println("*** in ConnectionRecover.init() ...");

        if (connection.isConnectedToHABroker) {

            if (recoverDelay < ConnectionInitiator.HA_RECONNECT_DELAY) {
                recoverDelay = ConnectionInitiator.HA_RECONNECT_DELAY;
            }

            sleep(recoverDelay);
        }

        // if ( connection.isConnectedToHABroker ) {
        // sleep (recoverDelay);
        // }

        closeProtocolHandler();

        connection.protocolHandler.init(true);

        logRecoverState(TRANSPORT_CONNECTED);

    }

    /**
     * Start recover in a different thread.
     */
    public void start() {

        // create a new thread and start recover interests, etc
        recoverThread = new Thread(this);
        if (connection.hasDaemonThreads()) {
            recoverThread.setDaemon(true);
        }
        // thread.setName(iMQConnectionRecover + connection.getConnectionID());
        recoverThread.setName(iMQConnectionRecover + "-" + connection.getLocalID() + "-" + connection.getConnectionID());

        /**
         * fix for bug 6520902 - client runtime gave up reconnecting.
         *
         * The state must be set before the thread is started. This makes it impossible to have the recover thread to finish
         * before the state is set to STARTED again.
         */
        setRecoverState(RECOVER_STARTED);

        recoverThread.start();
        // recoverState = RECOVER_RUNNING;
        // logRecoverState(RECOVER_RUNNING);
    }

    /**
     * Connection recover implementation.
     *
     * The connection recover in HAWK has improved such that client runtime will continue to retry when the cocovery failed.
     *
     *
     *
     */
    @Override
    public void run() {

        // set the current thread reference.
        connection.protocolHandler.recoverThread = Thread.currentThread();

        try {

            // recoverState = RECOVER_IN_PROCESS;

            setRecoverState(RECOVER_IN_PROCESS);

            recover();

            // recoverState = RECOVER_SUCCEEDED;
            setRecoverState(RECOVER_SUCCEEDED);

            failedCount = 0;

        } catch (JMSException jmse) {

            setRecoverState(RECOVER_FAILED);

            // log exception
            connLogger.log(Level.WARNING, jmse.toString(), jmse);

            // XXX trigger connection recover failed event.
            connection.triggerConnectionReconnectFailedEvent(jmse);
            checkForMaxRetries();
            closeProtocolHandler();
        } finally {

            if (recoverState == RECOVER_SUCCEEDED) {
                connection.triggerConnectionReconnectedEvent();
            }

            connection.protocolHandler.recoverThread = null;

            // reset state
            setRecoverState(RECOVER_INACTIVE);
        }
    }

    /**
     * Recover the connection when it's broken. 1. Delete messages in the session queue and receive queue. 2. Delete unacked
     * messages. 3. Reconnect. 4. hello to broker. 5. Register interests.
     *
     * NOTE: We do not recover if any of the following conditions exists: 1. There are active temporary destinations
     * associated with the connection. 2. There are transacted sessions. 3. There are unacked messages for client acked
     * session.
     */
    protected void recover() throws JMSException {

        try {
            if (debug) {
                Debug.println("BEGIN ConnectionRecover.recover()...");
            }

            // set the current thread reference.
            // protocolHandler.recoverThread = Thread.currentThread();

            /**
             * Synchronized on protocolHandler so that message producers will be block if trying to produce messages during
             * connection recovery.
             *
             * Bug 6157462 -- no need to sync anymore. all pkt out is synced on the Connection.reconnectSyncObj obj.
             */
            // synchronized ( protocolHandler ) {

            if (connection.isCloseCalled) {
                connection.setReconnecting(false);
                return;
            }

            checkConnectionConsumers();

            // HACC -- clear readQs in each CC.
            resetConnectionConsumers();

            resetSessions();

            // hand shaking to the broker
            connection.hello(true);
            // this.hello();

            connection.protocolHandler.resetClientID();

            // XXX PROTOCOL3.5
            // Create sessions.
            addSessions();

            // register consumers
            addConsumers();

            releaseConnectionConsumers();

            // add producers
            addProducers();

            // HACC -- add connection consumer
            // addConnectionConsumers();

            // } //synchronized connection

            // if connection was started, restart the connection
            if ((connection.isStopped == false) && (connection.eventListener == null)) {
                connection.protocolHandler.start();
            }

            if (connection.getEventHandler() != null) {
                connection.getEventHandler().resendConsumerInfoRequests(connection.protocolHandler);
            }

            if (debug) {
                Debug.info("ConnectionRecover.recover() SUCCESS!!!");
            }

        } catch (JMSException e) {

            if (debug) {
                Debug.println("ConnectionRecover failed.");
                Debug.printStackTrace(e);
            }

            throw e;

            // If we catches any exception here, abort ...
            // connection.abort(e);
        } finally {
            releaseConnectionConsumers();

            if (debug) {
                Debug.println("END ConnectionRecover.recover()!!!");
            }

            // protocolHandler.recoverThread = null;

            // if (recoverState && connection.eventListener != null) {
            // connection.triggerConnectionReconnectedEvent();
            // } else {
            // connection.setReconnecting(false);
            // }
        }
    }

    /**
     * HACC -- clear cc read queue.
     */
    private void resetConnectionConsumers() {

        try {
            int size = this.connection.connectionConsumerTable.size();

            for (int i = 0; i < size; i++) {
                ConnectionConsumerImpl ccImpl = (ConnectionConsumerImpl) connection.connectionConsumerTable.get(i);

                ccImpl.setFailoverInprogress(true);
                ccImpl.getReadQueue().clear();
            }

        } catch (Exception e) {
            this.connLogger.log(Level.WARNING, e.getMessage(), e);
        }
    }

    private void releaseConnectionConsumers() {

        try {
            int size = this.connection.connectionConsumerTable.size();

            for (int i = 0; i < size; i++) {
                try {
                    ConnectionConsumerImpl ccImpl = (ConnectionConsumerImpl) connection.connectionConsumerTable.get(i);

                    ccImpl.setFailoverInprogress(false);
                } catch (Exception e) {
                    this.connLogger.log(Level.WARNING, e.getMessage(), e);
                }
            }

        } catch (Exception e) {
            this.connLogger.log(Level.WARNING, e.getMessage(), e);
        }
    }

    protected void checkConnectionConsumers() throws JMSException {

        // from 4.2, by default we enable reconnect for CC.
        // so no more checking for the table size below.
        // HACC
        if (this.enableCCReconnect) {
            return;
        }

        if (connection.connectionConsumerTable.size() > 0) {
            String errorString = AdministeredObject.cr.getKString(AdministeredObject.cr.X_CONNECT_RECOVER);

            JMSException jmse = new com.sun.messaging.jms.IllegalStateException(errorString, AdministeredObject.cr.X_CONNECT_RECOVER);

            ExceptionHandler.throwJMSException(jmse);
        }

    }

    // XXX chiaming REVISIT: handle connectionConsumer?
    protected void resetSessions() throws JMSException {
        Enumeration enum2 = connection.sessionTable.elements();
        while (enum2.hasMoreElements()) {
            SessionImpl session = (SessionImpl) enum2.nextElement();

            // HACC -- sine 4.2, we allow reconnect for connection consumer
            if ((enableCCReconnect == false) && session.getMessageListener() != null) {
                String errorString = AdministeredObject.cr.getKString(AdministeredObject.cr.X_CONNECT_RECOVER);

                JMSException jmse = new com.sun.messaging.jms.IllegalStateException(errorString, AdministeredObject.cr.X_CONNECT_RECOVER);

                ExceptionHandler.throwJMSException(jmse);
            }

            session.reset();
        }
    }

    protected void addSessions() throws JMSException {
        Enumeration enum2 = connection.sessionTable.elements();
        while (enum2.hasMoreElements()) {
            SessionImpl session = (SessionImpl) enum2.nextElement();
            session.recreateSession();
        }
    }

    /**
     * Reregister all consumers.
     */
    protected void addConsumers() throws JMSException {
        Object tmp[] = connection.interestTable.toArray();

        Vector v = new Vector();

        for (int i = 0; i < tmp.length; i++) {

            if (((Consumer) tmp[i]).isClosed == false) {
                connection.protocolHandler.addInterest((Consumer) tmp[i]);
            } else {
                v.add(tmp[i]);
            }

        }

        // clean up closed consumer
        while (v.isEmpty() == false) {
            Object o = v.firstElement();
            connection.interestTable.remove(o);
            v.remove(o);
        }

    }

    /**
     * Reregister all producers in a connection
     */
    protected void addProducers() throws JMSException {
        Enumeration enum2 = connection.sessionTable.elements();
        while (enum2.hasMoreElements()) {
            SessionImpl session = (SessionImpl) enum2.nextElement();
            addSessionProducers(session);
        }
    }

    /**
     * Add producers in a session. Called by addProducers().
     */
    protected void addSessionProducers(SessionImpl session) throws JMSException {
        Enumeration enum2 = session.producers.elements();
        while (enum2.hasMoreElements()) {

            MessageProducerImpl producer = (MessageProducerImpl) enum2.nextElement();

            producer.recreateProducer();
        }
    }

    protected synchronized void setRecoverState(int state) {

        if (recoverState != RECOVER_ABORTED) {
            this.recoverState = state;
            logRecoverState(state);
        } else {
            logRecoverState(RECOVER_ABORTED);
        }

        notifyAll();
    }

    protected synchronized int getRecoverState() {
        return this.recoverState;
    }

    private void closeProtocolHandler() {

        try {
            connection.protocolHandler.close();
        } catch (Exception e) {
            if (debug) {
                Debug.printStackTrace(e);
            }
        }
    }

    /**
     * Check if we should continue to retry. JMS recover failure may consume broker resources and instability. We should
     * exit when it is not recoverable.
     */
    private void checkForMaxRetries() {

        failedCount++;

        if (maxRetries == -1) {
            return;
        }

        if (failedCount > maxRetries) {

            setRecoverState(RECOVER_ABORTED);

            if (debug) {
                Debug.println("*** reached max internal retry count: " + maxRetries);
            }

            String msg = AdministeredObject.cr.getKString(ClientResources.I_CONNECTION_RECOVER_ABORTED, this.connection.getBrokerAddressList(), maxRetries);

            this.connLogger.log(Level.SEVERE, msg);
        }
    }

    public synchronized void waitUntilInactive() throws JMSException {

        int wcounter = 0;

        int lctr = 0;

        if (recoverState == RECOVER_ABORTED) {
            JMSException jmse = new JMSException("ConnectionRecover aborted!");
            ExceptionHandler.throwJMSException(jmse);
        }

        while (recoverState != RECOVER_INACTIVE && (recoverState != RECOVER_ABORTED)) {

            try {

                wait(WAIT_TIME); // wake up every 3 secs.

                lctr++; // log counter
                if (lctr == 5) { // log every 15 secs.
                    String msg = AdministeredObject.cr.getKString(ClientResources.I_CONNECTION_RECOVER_STATE, STATES[getRecoverState()],
                            this.connection.getLastContactedBrokerAddress());

                    connLogger.log(Level.INFO, msg);
                    lctr = 0; // reset.
                }

            } catch (Exception e) {
                connLogger.log(Level.WARNING, e.toString(), e);
            }

            // don't wait if closed.
            if (connection.isCloseCalled) {
                setRecoverState(RECOVER_ABORTED);
                return;
            }

            connection.readChannel.closeIOAndNotify();

            wcounter++;

            // This should never happen. But we want to exit should this happen.
            if (wcounter > MAX_WAIT_COUNT) { // max wait is 10 minutes.

                // if ( debug ) {
                // Debug.getPrintStream().println("*** RUN AWAY THREAD: ConnectionRecover *** ");
                // recoverThread.dumpStack();
                // }

                // abort
                setRecoverState(RECOVER_ABORTED);

                JMSException jmse = new JMSException("Timeout on ConnectionRecover object.  Broker: " + connection.getLastContactedBrokerAddress());

                // throw jmse;
                ExceptionHandler.throwJMSException(jmse);
            }
        }

    }

    private void sleep(int sleepTime) {

        try {
            int count = sleepTime / WAIT_TIME;

            for (int i = 0; i < count; i++) {

                if (debug) {
                    Debug.println("*** ConnectionRecover, sleeping " + WAIT_TIME * (i + 1) + " milli secs");
                }

                Thread.sleep(WAIT_TIME);

                if (connection.isCloseCalled) {
                    return;
                }
            }

        } catch (InterruptedException e) {
            
        }
    }

    /**
     * log recover state.
     *
     * @param state the current recover state.
     */
    private void logRecoverState(int state) {

        if (connLogger.isLoggable(Level.INFO)) {

            String addr = this.connection.getLastContactedBrokerAddress();

            String msg = AdministeredObject.cr.getKString(ClientResources.I_CONNECTION_RECOVER_STATE, STATES[state], addr);

            connLogger.log(Level.INFO, msg);
        }
    }

}
