/*
    * 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.log4j.bridge;
  
  import org.apache.log4j.Category;
  import org.apache.log4j.Level;
  import org.apache.log4j.spi.LocationInfo;
  import org.apache.log4j.spi.LoggingEvent;
  import org.apache.log4j.spi.ThrowableInformation;
  import org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.util.Loader;
  import org.apache.logging.log4j.core.util.Throwables;
  import org.apache.logging.log4j.spi.StandardLevel;
  import org.apache.logging.log4j.status.StatusLogger;
  import org.apache.logging.log4j.util.Strings;
  
  import java.lang.reflect.Method;
  import java.util.Map;
  import java.util.Set;
  
  /**
   * Converts a Log4j 2 LogEvent into the components needed by a Log4j 1.x LoggingEvent.
   * This class requires Log4j 2.
   */
  public class LogEventAdapter extends LoggingEvent {
  
      private static final long JVM_START_TIME = initStartTime();
  
      private final LogEvent event;
  
      public LogEventAdapter(LogEvent event) {
          this.event = event;
      }
  
      /**
       * Returns the time when the application started, in milliseconds
       * elapsed since 01.01.1970.
       * @return the time when the JVM started.
       */
      public static long getStartTime() {
          return JVM_START_TIME;
      }
  
      /**
       * Returns the result of {@code ManagementFactory.getRuntimeMXBean().getStartTime()},
       * or the current system time if JMX is not available.
       */
      private static long initStartTime() {
          // We'd like to call ManagementFactory.getRuntimeMXBean().getStartTime(),
          // but Google App Engine throws a java.lang.NoClassDefFoundError
          // "java.lang.management.ManagementFactory is a restricted class".
          // The reflection is necessary because without it, Google App Engine
          // will refuse to initialize this class.
          try {
              final Class<?> factoryClass = Loader.loadSystemClass("java.lang.management.ManagementFactory");
              final Method getRuntimeMXBean = factoryClass.getMethod("getRuntimeMXBean");
              final Object runtimeMXBean = getRuntimeMXBean.invoke(null);
  
              final Class<?> runtimeMXBeanClass = Loader.loadSystemClass("java.lang.management.RuntimeMXBean");
              final Method getStartTime = runtimeMXBeanClass.getMethod("getStartTime");
              return (Long) getStartTime.invoke(runtimeMXBean);
          } catch (final Throwable t) {
              StatusLogger.getLogger().error("Unable to call ManagementFactory.getRuntimeMXBean().getStartTime(), "
                      + "using system time for OnStartupTriggeringPolicy", t);
              // We have little option but to declare "now" as the beginning of time.
              return System.currentTimeMillis();
          }
      }
  
      public LogEvent getEvent() {
          return this.event;
      }
  
      /**
       * Set the location information for this logging event. The collected
       * information is cached for future use.
       */
      @Override
      public LocationInfo getLocationInformation() {
          return new LocationInfo(event.getSource());
      }
  
      /**
       * Return the level of this event. Use this form instead of directly
       * accessing the <code>level</code> field.
      */
     @Override
     public Level getLevel() {
         switch (StandardLevel.getStandardLevel(event.getLevel().intLevel())) {
             case TRACE:
                 return Level.TRACE;
             case DEBUG:
                 return Level.DEBUG;
             case INFO:
                 return Level.INFO;
             case WARN:
                 return Level.WARN;
             case FATAL:
                 return Level.FATAL;
             case OFF:
                 return Level.OFF;
             case ALL:
                 return Level.ALL;
             default:
                 return Level.ERROR;
         }
     }
 
     /**
      * Return the name of the logger. Use this form instead of directly
      * accessing the <code>categoryName</code> field.
      */
     @Override
     public String getLoggerName() {
         return event.getLoggerName();
     }
 
     @Override
     public long getTimeStamp() {
         return event.getTimeMillis();
     }
 
     /**
      * Gets the logger of the event.
      */
     @Override
     public Category getLogger() {
         return Category.getInstance(event.getLoggerName());
     }
 
     /*
      Return the message for this logging event.
     */
     @Override
     public Object getMessage() {
         return event.getMessage();
     }
 
     /*
      * This method returns the NDC for this event.
      */
     @Override
     public String getNDC() {
         return event.getContextStack().toString();
     }
 
     /*
      Returns the context corresponding to the <code>key</code> parameter.
      */
     @Override
     public Object getMDC(String key) {
         if (event.getContextData() != null) {
             return event.getContextData().getValue(key);
         }
         return null;
     }
 
     /**
      * Obtain a copy of this thread's MDC prior to serialization or
      * asynchronous logging.
      */
     @Override
     public void getMDCCopy() {
     }
 
     @Override
     public String getRenderedMessage() {
         return event.getMessage().getFormattedMessage();
     }
 
     @Override
     public String getThreadName() {
         return event.getThreadName();
     }
 
     /**
      * Returns the throwable information contained within this
      * event. May be <code>null</code> if there is no such information.
      *
      * <p>Note that the {@link Throwable} object contained within a
      * {@link ThrowableInformation} does not survive serialization.
      *
      * @since 1.1
      */
     @Override
     public ThrowableInformation getThrowableInformation() {
         if (event.getThrown() != null) {
             return new ThrowableInformation(event.getThrown());
         }
         return null;
     }
 
     /**
      * Return this event's throwable's string[] representaion.
      */
     @Override
     public String[] getThrowableStrRep() {
         if (event.getThrown() != null) {
             return Throwables.toStringList(event.getThrown()).toArray(Strings.EMPTY_ARRAY);
         }
         return null;
     }
 
     @Override
     public String getProperty(final String key) {
         return event.getContextData().getValue(key);
     }
 
     @Override
     public Set getPropertyKeySet() {
         return event.getContextData().toMap().keySet();
     }
 
     @Override
     public Map getProperties() {
         return event.getContextData().toMap();
     }
 }