/*
  * TeleStax, Open Source Cloud Communications
  * Copyright 2011-2016, TeleStax Inc. and individual contributors
  * by the @authors tag.
  *
  * This program is free software: you can redistribute it and/or modify
  * under the terms of the GNU Affero General Public License as
  * published by the Free Software Foundation; either version 3 of
  * the License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU Affero General Public License for more details.
  *
  * You should have received a copy of the GNU Affero General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>
  *
  * This file incorporates work covered by the following copyright and
  * permission notice:
  *
  *   JBoss, Home of Professional Open Source
  *   Copyright 2007-2011, Red Hat, Inc. and individual contributors
  *   by the @authors tag. See the copyright.txt in the distribution for a
  *   full listing of individual contributors.
  *
  *   This is free software; you can redistribute it and/or modify it
  *   under the terms of the GNU Lesser General Public License as
  *   published by the Free Software Foundation; either version 2.1 of
  *   the License, or (at your option) any later version.
  *
  *   This software is distributed in the hope that it will be useful,
  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  *   Lesser General Public License for more details.
  *
  *   You should have received a copy of the GNU Lesser General Public
  *   License along with this software; if not, write to the Free
  *   Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  *   02110-1301 USA, or see the FSF site: http://www.fsf.org.
  */

package org.jdiameter.common.impl.app.s6a;
import java.io.Serializable;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

import org.jdiameter.api.NetworkReqListener;
import org.jdiameter.api.app.StateChangeListener;
import org.jdiameter.api.app.StateMachine;
import org.jdiameter.client.api.ISessionFactory;
import org.jdiameter.common.api.app.s6a.IS6aMessageFactory;
import org.jdiameter.common.api.app.s6a.IS6aSessionData;
import org.jdiameter.common.impl.app.AppSessionImpl;

/**
 *
 * @author <a href="mailto:brainslog@gmail.com"> Alexandre Mendonca </a>
 * @author <a href="mailto:richard.good@smilecoms.com"> Richard Good </a>
 * @author <a href="mailto:paul.carter-brown@smilecoms.com"> Paul Carter-Brown </a>
 */
public abstract class S6aSession extends AppSessionImpl implements NetworkReqListener, StateMachine {

  public static final int _TX_TIMEOUT = 30 * 1000;

  protected Lock sendAndStateLock = new ReentrantLock();

  protected transient List<StateChangeListener> stateListeners = new CopyOnWriteArrayList<StateChangeListener>();
  protected transient IS6aMessageFactory messageFactory;

  protected static final String TIMER_NAME_MSG_TIMEOUT = "MSG_TIMEOUT";
  protected IS6aSessionData sessionData;

  public S6aSession(ISessionFactory sf, IS6aSessionData sessionData) {
    super(sf, sessionData);
    this.sessionData = sessionData;
  }

  @Override
  public void addStateChangeNotification(StateChangeListener listener) {
    if (!stateListeners.contains(listener)) {
      stateListeners.add(listener);
    }
  }

  @Override
  public void removeStateChangeNotification(StateChangeListener listener) {
    stateListeners.remove(listener);
  }

  @Override
  public boolean isStateless() {
    return true;
  }

  @Override
  public boolean isReplicable() {
    return false;
  }

  protected void startMsgTimer() {
    try {
      sendAndStateLock.lock();
      sessionData.setTsTimerId(super.timerFacility.schedule(getSessionId(), TIMER_NAME_MSG_TIMEOUT, _TX_TIMEOUT));
    }
    finally {
      sendAndStateLock.unlock();
    }
  }

  protected void cancelMsgTimer() {
    try {
      sendAndStateLock.lock();
      final Serializable timerId = this.sessionData.getTsTimerId();
      if (timerId == null) {
        return;
      }
      super.timerFacility.cancel(timerId);
      this.sessionData.setTsTimerId(null);
    }
    finally {
      sendAndStateLock.unlock();
    }
  }

  @Override
  public int hashCode() {
    final int prime = 31;
    int result = super.hashCode();
    result = prime * result + ((sessionData == null) ? 0 : sessionData.hashCode());
    return result;
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    }
    if (!super.equals(obj)) {
      return false;
    }
    if (getClass() != obj.getClass()) {
      return false;
    }
    S6aSession other = (S6aSession) obj;
    if (sessionData == null) {
      if (other.sessionData != null) {
        return false;
      }
    }
    else if (!sessionData.equals(other.sessionData)) {
      return false;
    }

    return true;
  }

}