/*
    * 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.logging.log4j.core.jmx;
  
  import java.io.IOException;
  import java.util.List;
  import java.util.concurrent.Executor;
  import java.util.concurrent.atomic.AtomicLong;
  
  import javax.management.MBeanNotificationInfo;
  import javax.management.Notification;
  import javax.management.NotificationBroadcasterSupport;
  import javax.management.ObjectName;
  
  import org.apache.logging.log4j.Level;
  import org.apache.logging.log4j.status.StatusData;
  import org.apache.logging.log4j.status.StatusListener;
  import org.apache.logging.log4j.status.StatusLogger;
  
  /**
   * Implementation of the {@code StatusLoggerAdminMBean} interface.
   */
  public class StatusLoggerAdmin extends NotificationBroadcasterSupport implements StatusListener, StatusLoggerAdminMBean {
  
      private final AtomicLong sequenceNo = new AtomicLong();
      private final ObjectName objectName;
      private final String contextName;
      private Level level = Level.WARN;
  
      /**
       * Constructs a new {@code StatusLoggerAdmin} with the {@code Executor} to
       * be used for sending {@code Notification}s asynchronously to listeners.
       *
       * @param contextName name of the LoggerContext under which to register this
       *            StatusLoggerAdmin. Note that the StatusLogger may be
       *            registered multiple times, once for each LoggerContext. In web
       *            containers, each web application has its own LoggerContext and
       *            by associating the StatusLogger with the LoggerContext, all
       *            associated MBeans can be unloaded when the web application is
       *            undeployed.
       * @param executor used to send notifications asynchronously
       */
      public StatusLoggerAdmin(final String contextName, final Executor executor) {
          super(executor, createNotificationInfo());
          this.contextName = contextName;
          try {
              final String mbeanName = String.format(PATTERN, Server.escape(contextName));
              objectName = new ObjectName(mbeanName);
          } catch (final Exception e) {
              throw new IllegalStateException(e);
          }
          removeListeners(contextName);
          StatusLogger.getLogger().registerListener(this);
      }
  
      /**
       * Add listener to StatusLogger for this context, or replace it if it already exists.
       *
       * @param ctxName
       */
      private void removeListeners(final String ctxName) {
          final StatusLogger logger = StatusLogger.getLogger();
          final Iterable<StatusListener> listeners = logger.getListeners();
          // Remove any StatusLoggerAdmin listeners already registered for this context
          for (final StatusListener statusListener : listeners) {
              if (statusListener instanceof StatusLoggerAdmin) {
                  final StatusLoggerAdmin adminListener = (StatusLoggerAdmin) statusListener;
                  if (ctxName != null && ctxName.equals(adminListener.contextName)) {
                      logger.removeListener(adminListener);
                  }
              }
          }
      }
  
      private static MBeanNotificationInfo createNotificationInfo() {
          final String[] notifTypes = new String[] {
                  NOTIF_TYPE_DATA,
                  NOTIF_TYPE_MESSAGE };
          final String name = Notification.class.getName();
          final String description = "StatusLogger has logged an event";
          return new MBeanNotificationInfo(notifTypes, name, description);
      }
  
      @Override
      public String[] getStatusDataHistory() {
         final List<StatusData> data = getStatusData();
         final String[] result = new String[data.size()];
         for (int i = 0; i < result.length; i++) {
             result[i] = data.get(i).getFormattedStatus();
         }
         return result;
     }
 
     @Override
     public List<StatusData> getStatusData() {
         return StatusLogger.getLogger().getStatusData();
     }
 
     @Override
     public String getLevel() {
         return this.level.name();
     }
 
     @Override
     public Level getStatusLevel() {
         return this.level;
     }
 
     @Override
     public void setLevel(final String level) {
         this.level = Level.toLevel(level, Level.ERROR);
     }
 
     @Override
     public String getContextName() {
         return contextName;
     }
 
     /*
      * (non-Javadoc)
      *
      * @see
      * org.apache.logging.log4j.status.StatusListener#log(org.apache.logging
      * .log4j.status.StatusData)
      */
     @Override
     public void log(final StatusData data) {
         final Notification notifMsg = new Notification(NOTIF_TYPE_MESSAGE, getObjectName(), nextSeqNo(), nowMillis(),
                 data.getFormattedStatus());
         sendNotification(notifMsg);
 
         final Notification notifData = new Notification(NOTIF_TYPE_DATA, getObjectName(), nextSeqNo(), nowMillis());
         notifData.setUserData(data);
         sendNotification(notifData);
     }
 
     /**
      * Returns the {@code ObjectName} of this mbean.
      *
      * @return the {@code ObjectName}
      * @see StatusLoggerAdminMBean#PATTERN
      */
     @Override
     public ObjectName getObjectName() {
         return objectName;
     }
 
     private long nextSeqNo() {
         return sequenceNo.getAndIncrement();
     }
 
     private long nowMillis() {
         return System.currentTimeMillis();
     }
 
     @Override
     public void close() throws IOException {
         // nothing to close here
     }
 }