/*
    * 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.message;
  
  import java.io.InvalidObjectException;
  import java.io.ObjectInputStream;
  import java.io.Serializable;
  import java.lang.management.ManagementFactory;
  import java.lang.management.ThreadInfo;
  import java.lang.management.ThreadMXBean;
  import java.lang.reflect.Method;
  import java.util.HashMap;
  import java.util.Map;
  
  import org.apache.logging.log4j.util.Strings;
  
  /**
   * Captures information about all running Threads.
   */
  public class ThreadDumpMessage implements Message {
  
      private static final long serialVersionUID = -1103400781608841088L;
  
      private static final ThreadInfoFactory FACTORY;
  
      private volatile Map<ThreadInformation, StackTraceElement[]> threads;
  
      private final String title;
  
      private String formattedMessage;
  
      static {
          final Method[] methods = ThreadInfo.class.getMethods();
          boolean basic = true;
          for (final Method method : methods) {
              if (method.getName().equals("getLockInfo")) {
                  basic = false;
                  break;
              }
          }
          FACTORY = basic ? new BasicThreadInfoFactory() : new ExtendedThreadInfoFactory();
      }
  
      /**
       * Generate a ThreadDumpMessage with a title.
       * @param title The title.
       */
      public ThreadDumpMessage(final String title) {
          this.title = title == null ? Strings.EMPTY : title;
          threads = FACTORY.createThreadInfo();
      }
  
      private ThreadDumpMessage(final String formattedMsg, final String title) {
          this.formattedMessage = formattedMsg;
          this.title = title == null ? Strings.EMPTY : title;
      }
  
      @Override
      public String toString() {
          final StringBuilder sb = new StringBuilder("ThreadDumpMessage[");
          if (this.title.length() > 0) {
              sb.append("Title=\"").append(this.title).append('"');
          }
          sb.append(']');
          return sb.toString();
      }
  
      /**
       * Returns the ThreadDump in printable format.
       * @return the ThreadDump suitable for logging.
       */
      @Override
      public String getFormattedMessage() {
          if (formattedMessage != null) {
              return formattedMessage;
          }
          final StringBuilder sb = new StringBuilder(title);
          if (title.length() > 0) {
              sb.append('\n');
          }
          for (final Map.Entry<ThreadInformation, StackTraceElement[]> entry : threads.entrySet()) {
              final ThreadInformation info = entry.getKey();
              info.printThreadInfo(sb);
              info.printStack(sb, entry.getValue());
              sb.append('\n');
         }
         return sb.toString();
     }
 
     /**
      * Returns the title.
      * @return the title.
      */
     @Override
     public String getFormat() {
         return title == null ? Strings.EMPTY : title;
     }
 
     /**
      * Returns an array with a single element, a Map containing the ThreadInformation as the key.
      * and the StackTraceElement array as the value;
      * @return the "parameters" to this Message.
      */
     @Override
     public Object[] getParameters() {
         return null;
     }
 
         /**
      * Creates a ThreadDumpMessageProxy that can be serialized.
      * @return a ThreadDumpMessageProxy.
      */
     protected Object writeReplace() {
         return new ThreadDumpMessageProxy(this);
     }
 
     private void readObject(final ObjectInputStream stream)
         throws InvalidObjectException {
         throw new InvalidObjectException("Proxy required");
     }
 
     /**
      * Proxy pattern used to serialize the ThreadDumpMessage.
      */
     private static class ThreadDumpMessageProxy implements Serializable {
 
         private static final long serialVersionUID = -3476620450287648269L;
         private final String formattedMsg;
         private final String title;
 
         public ThreadDumpMessageProxy(final ThreadDumpMessage msg) {
             this.formattedMsg = msg.getFormattedMessage();
             this.title = msg.title;
         }
 
         /**
          * Returns a ThreadDumpMessage using the data in the proxy.
          * @return a ThreadDumpMessage.
          */
         protected Object readResolve() {
             return new ThreadDumpMessage(formattedMsg, title);
         }
     }
 
     /**
      * Factory to create Thread information.
      */
     private interface ThreadInfoFactory {
         Map<ThreadInformation, StackTraceElement[]> createThreadInfo();
     }
 
     /**
      * Factory to create basic thread information.
      */
     private static class BasicThreadInfoFactory implements ThreadInfoFactory {
         @Override
         public Map<ThreadInformation, StackTraceElement[]> createThreadInfo() {
             final Map<Thread, StackTraceElement[]> map = Thread.getAllStackTraces();
             final Map<ThreadInformation, StackTraceElement[]> threads =
                 new HashMap<ThreadInformation, StackTraceElement[]>(map.size());
             for (final Map.Entry<Thread, StackTraceElement[]> entry : map.entrySet()) {
                 threads.put(new BasicThreadInformation(entry.getKey()), entry.getValue());
             }
             return threads;
         }
     }
 
     /**
      * Factory to create extended thread information.
      */
     private static class ExtendedThreadInfoFactory implements ThreadInfoFactory {
         @Override
         public Map<ThreadInformation, StackTraceElement[]> createThreadInfo() {
             final ThreadMXBean bean = ManagementFactory.getThreadMXBean();
             final ThreadInfo[] array = bean.dumpAllThreads(true, true);
 
             final Map<ThreadInformation, StackTraceElement[]>  threads =
                 new HashMap<ThreadInformation, StackTraceElement[]>(array.length);
             for (final ThreadInfo info : array) {
                 threads.put(new ExtendedThreadInformation(info), info.getStackTrace());
             }
             return threads;
         }
     }
 
     /**
      * Always returns null.
      *
      * @return null
      */
     @Override
     public Throwable getThrowable() {
         return null;
     }
 }