/**
    *
    * 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.hadoop.hbase.util;
  
  import java.io.OutputStreamWriter;
  import java.io.PrintStream;
  import java.io.PrintWriter;
  import java.lang.Thread.UncaughtExceptionHandler;
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  import java.nio.charset.StandardCharsets;
  import java.util.Set;
  import java.util.concurrent.LinkedBlockingQueue;
  import java.util.concurrent.ThreadFactory;
  import java.util.concurrent.ThreadPoolExecutor;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.util.ReflectionUtils;
  import org.apache.hadoop.util.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Thread Utility
   */
  @InterfaceAudience.Private
  public class Threads {
    private static final Logger LOG = LoggerFactory.getLogger(Threads.class);
    private static final AtomicInteger poolNumber = new AtomicInteger(1);
  
    public static final UncaughtExceptionHandler LOGGING_EXCEPTION_HANDLER =
      new UncaughtExceptionHandler() {
      @Override
      public void uncaughtException(Thread t, Throwable e) {
        LOG.warn("Thread:" + t + " exited with Exception:"
            + StringUtils.stringifyException(e));
      }
    };
  
    /**
     * Utility method that sets name, daemon status and starts passed thread.
     * @param t thread to run
     * @return Returns the passed Thread <code>t</code>.
     */
    public static Thread setDaemonThreadRunning(final Thread t) {
      return setDaemonThreadRunning(t, t.getName());
    }
  
    /**
     * Utility method that sets name, daemon status and starts passed thread.
     * @param t thread to frob
     * @param name new name
     * @return Returns the passed Thread <code>t</code>.
     */
    public static Thread setDaemonThreadRunning(final Thread t,
      final String name) {
      return setDaemonThreadRunning(t, name, null);
    }
  
    /**
     * Utility method that sets name, daemon status and starts passed thread.
     * @param t thread to frob
     * @param name new name
     * @param handler A handler to set on the thread.  Pass null if want to
     * use default handler.
     * @return Returns the passed Thread <code>t</code>.
     */
    public static Thread setDaemonThreadRunning(final Thread t,
      final String name, final UncaughtExceptionHandler handler) {
      t.setName(name);
      if (handler != null) {
        t.setUncaughtExceptionHandler(handler);
      }
      t.setDaemon(true);
      t.start();
      return t;
    }
  
    /**
     * Shutdown passed thread using isAlive and join.
     * @param t Thread to shutdown
    */
   public static void shutdown(final Thread t) {
     shutdown(t, 0);
   }
 
   /**
    * Shutdown passed thread using isAlive and join.
    * @param joinwait Pass 0 if we're to wait forever.
    * @param t Thread to shutdown
    */
   public static void shutdown(final Thread t, final long joinwait) {
     if (t == null) return;
     while (t.isAlive()) {
       try {
         t.join(joinwait);
       } catch (InterruptedException e) {
         LOG.warn(t.getName() + "; joinwait=" + joinwait, e);
       }
     }
   }
 
 
   /**
    * @param t Waits on the passed thread to die dumping a threaddump every
    * minute while its up.
    * @throws InterruptedException
    */
   public static void threadDumpingIsAlive(final Thread t)
   throws InterruptedException {
     if (t == null) {
       return;
     }
 
     while (t.isAlive()) {
       t.join(60 * 1000);
       if (t.isAlive()) {
         printThreadInfo(System.out,
             "Automatic Stack Trace every 60 seconds waiting on " +
             t.getName());
       }
     }
   }
 
   /**
    * If interrupted, just prints out the interrupt on STDOUT, resets interrupt and returns
    * @param millis How long to sleep for in milliseconds.
    */
   public static void sleep(long millis) {
     try {
       Thread.sleep(millis);
     } catch (InterruptedException e) {
       e.printStackTrace();
       Thread.currentThread().interrupt();
     }
   }
 
   /**
    * Sleeps for the given amount of time even if interrupted. Preserves
    * the interrupt status.
    * @param msToWait the amount of time to sleep in milliseconds
    */
   public static void sleepWithoutInterrupt(final long msToWait) {
     long timeMillis = System.currentTimeMillis();
     long endTime = timeMillis + msToWait;
     boolean interrupted = false;
     while (timeMillis < endTime) {
       try {
         Thread.sleep(endTime - timeMillis);
       } catch (InterruptedException ex) {
         interrupted = true;
       }
       timeMillis = System.currentTimeMillis();
     }
 
     if (interrupted) {
       Thread.currentThread().interrupt();
     }
   }
 
   /**
    * Create a new CachedThreadPool with a bounded number as the maximum
    * thread size in the pool.
    *
    * @param maxCachedThread the maximum thread could be created in the pool
    * @param timeout the maximum time to wait
    * @param unit the time unit of the timeout argument
    * @param threadFactory the factory to use when creating new threads
    * @return threadPoolExecutor the cachedThreadPool with a bounded number
    * as the maximum thread size in the pool.
    */
   public static ThreadPoolExecutor getBoundedCachedThreadPool(
       int maxCachedThread, long timeout, TimeUnit unit,
       ThreadFactory threadFactory) {
     ThreadPoolExecutor boundedCachedThreadPool =
       new ThreadPoolExecutor(maxCachedThread, maxCachedThread, timeout,
         unit, new LinkedBlockingQueue<Runnable>(), threadFactory);
     // allow the core pool threads timeout and terminate
     boundedCachedThreadPool.allowCoreThreadTimeOut(true);
     return boundedCachedThreadPool;
   }
 
 
   /**
    * Returns a {@link java.util.concurrent.ThreadFactory} that names each created thread uniquely,
    * with a common prefix.
    * @param prefix The prefix of every created Thread's name
    * @return a {@link java.util.concurrent.ThreadFactory} that names threads
    */
   public static ThreadFactory getNamedThreadFactory(final String prefix) {
     SecurityManager s = System.getSecurityManager();
     final ThreadGroup threadGroup = (s != null) ? s.getThreadGroup() : Thread.currentThread()
         .getThreadGroup();
 
     return new ThreadFactory() {
       final AtomicInteger threadNumber = new AtomicInteger(1);
       private final int poolNumber = Threads.poolNumber.getAndIncrement();
       final ThreadGroup group = threadGroup;
 
       @Override
       public Thread newThread(Runnable r) {
         final String name = prefix + "-pool" + poolNumber + "-t" + threadNumber.getAndIncrement();
         return new Thread(group, r, name);
       }
     };
   }
 
   /**
    * Same as {#newDaemonThreadFactory(String, UncaughtExceptionHandler)},
    * without setting the exception handler.
    */
   public static ThreadFactory newDaemonThreadFactory(final String prefix) {
     return newDaemonThreadFactory(prefix, null);
   }
 
   /**
    * Get a named {@link ThreadFactory} that just builds daemon threads.
    * @param prefix name prefix for all threads created from the factory
    * @param handler unhandles exception handler to set for all threads
    * @return a thread factory that creates named, daemon threads with
    *         the supplied exception handler and normal priority
    */
   public static ThreadFactory newDaemonThreadFactory(final String prefix,
       final UncaughtExceptionHandler handler) {
     final ThreadFactory namedFactory = getNamedThreadFactory(prefix);
     return new ThreadFactory() {
       @Override
       public Thread newThread(Runnable r) {
         Thread t = namedFactory.newThread(r);
         if (handler != null) {
           t.setUncaughtExceptionHandler(handler);
         } else {
           t.setUncaughtExceptionHandler(LOGGING_EXCEPTION_HANDLER);
         }
         if (!t.isDaemon()) {
           t.setDaemon(true);
         }
         if (t.getPriority() != Thread.NORM_PRIORITY) {
           t.setPriority(Thread.NORM_PRIORITY);
         }
         return t;
       }
 
     };
   }
 
   /** Sets an UncaughtExceptionHandler for the thread which logs the
    * Exception stack if the thread dies.
    */
   public static void setLoggingUncaughtExceptionHandler(Thread t) {
     t.setUncaughtExceptionHandler(LOGGING_EXCEPTION_HANDLER);
   }
 
   private static Method PRINT_THREAD_INFO_METHOD = null;
   private static boolean PRINT_THREAD_INFO_METHOD_WITH_PRINTSTREAM = true;
 
   /**
    * Print all of the thread's information and stack traces. Wrapper around Hadoop's method.
    *
    * @param stream the stream to
    * @param title a string title for the stack trace
    */
   public static synchronized void printThreadInfo(PrintStream stream, String title) {
     if (PRINT_THREAD_INFO_METHOD == null) {
       try {
         // Hadoop 2.7+ declares printThreadInfo(PrintStream, String)
         PRINT_THREAD_INFO_METHOD = ReflectionUtils.class.getMethod("printThreadInfo",
           PrintStream.class, String.class);
       } catch (NoSuchMethodException e) {
         // Hadoop 2.6 and earlier declares printThreadInfo(PrintWriter, String)
         PRINT_THREAD_INFO_METHOD_WITH_PRINTSTREAM = false;
         try {
           PRINT_THREAD_INFO_METHOD = ReflectionUtils.class.getMethod("printThreadInfo",
             PrintWriter.class, String.class);
         } catch (NoSuchMethodException e1) {
           throw new RuntimeException("Cannot find method. Check hadoop jars linked", e1);
         }
       }
       PRINT_THREAD_INFO_METHOD.setAccessible(true);
     }
 
     try {
       if (PRINT_THREAD_INFO_METHOD_WITH_PRINTSTREAM) {
         PRINT_THREAD_INFO_METHOD.invoke(null, stream, title);
       } else {
         PRINT_THREAD_INFO_METHOD.invoke(null,
           new PrintWriter(new OutputStreamWriter(stream, StandardCharsets.UTF_8)), title);
       }
     } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
       throw new RuntimeException(e.getCause());
     }
   }
 
   /**
    * Checks whether any non-daemon thread is running.
    * @return true if there are non daemon threads running, otherwise false
    */
   public static boolean isNonDaemonThreadRunning() {
     AtomicInteger nonDaemonThreadCount = new AtomicInteger();
     Set<Thread> threads =  Thread.getAllStackTraces().keySet();
     for (Thread t: threads) {
       // Exclude current thread
       if (t.getId() != Thread.currentThread().getId() && !t.isDaemon()) {
         nonDaemonThreadCount.getAndIncrement();
         LOG.info("Non daemon thread {} is still alive", t.getName());
         LOG.info(printStackTrace(t));
       }
     }
     return nonDaemonThreadCount.get() > 0;
   }
 
   /*
     Print stack trace of the passed thread
    */
   public static String printStackTrace(Thread t) {
     StringBuilder sb = new StringBuilder();
     for (StackTraceElement frame: t.getStackTrace()) {
       sb.append("\n").append("    ").append(frame.toString());
     }
     return sb.toString();
   }
 }