/*
    * 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.chukwa.datacollection.adaptor;
  
  import java.io.BufferedInputStream;
  import java.io.IOException;
  import java.io.InterruptedIOException;
  import java.io.ObjectInputStream;
  import java.net.*;
  import java.nio.charset.Charset;
  
  import org.apache.hadoop.chukwa.*;
  import org.apache.hadoop.chukwa.util.ExceptionUtil;
  import org.apache.log4j.Logger;
  import org.apache.log4j.PatternLayout;
  import org.apache.log4j.spi.LoggingEvent;
  
  /**
   * SocketAdaptor reads TCP message from a port and convert the message to Chukwa
   * Chunk for transport from Chukwa Agent to Chukwa Collector.  Usage:
   * 
   * add SocketAdaptor [DataType] [Port] [SequenceNumber]
   * 
   */
  public class SocketAdaptor extends AbstractAdaptor {
    PatternLayout layout = new PatternLayout("%d{ISO8601} %p %c: %m%n");
  
    private final static Logger log = Logger.getLogger(SocketAdaptor.class);
    volatile boolean running = true;
    volatile long bytesReceived = 0;
    private int port = 9095;
    
    class Dispatcher extends Thread {
      private int port;
      private ServerSocket listener;
      
      public Dispatcher(int port) {
        this.port = port;
      }
      
      public void run() {
        try{
          listener = new ServerSocket();
          listener.setReuseAddress(true);
          bindWithExponentialBackoff(listener, port, 12000);
          log.info("SocketAdaptor bound successfully to port:" + port);
          
          Socket server;
  
          while(running){
            server = listener.accept();
            Worker connection = new Worker(server);
            Thread t = new Thread(connection);
            t.start();
          }
        } catch (IOException ioe) {
          log.error("SocketAdaptor Dispatcher problem:", ioe);
        } finally {
          try {
            listener.close();
          } catch (IOException e) {
            log.warn("IOException closing socket on port:" + port);
          }
        }
      }
      
      public void shutdown() {
        try {
          listener.close();
        } catch (IOException e) {
          log.debug(ExceptionUtil.getStackTrace(e));
        }
      }
      
      protected void bindWithExponentialBackoff(ServerSocket ss, int p,
          int maxDelay) throws IOException {
        int backoff = 1000;
        int waitedTime = 0;
        while (!ss.isBound()) {
          try {
            ss.bind(new InetSocketAddress(p));
          } catch (IOException bindEx) {
            backoff *= 2;
            log.warn("IOException in bind:" + bindEx);
           log.warn("Retrying bind to port " + p + " in milliseconds:" + backoff);
           try {
             Thread.sleep(backoff);
           } catch (InterruptedException e) {
             throw new IOException(
                 "Interrupted while trying to connect to port:" + p);
           }
         }
         waitedTime += backoff;
         if (waitedTime > maxDelay) {
           throw new IOException("Could not bind to port:" + p
               + " after waiting " + waitedTime
               + " milliseconds. Abandoning this SocketAdaptor.");
         }
       }
     }
   }
   
   class Worker implements Runnable {
     private ObjectInputStream ois;
     private Socket server;
     
     public Worker(Socket server) {
       this.server = server;
     }
     
     public void run() {
       LoggingEvent event;
 
       try {
         ois = new ObjectInputStream(
                            new BufferedInputStream(server.getInputStream()));
         if (ois != null) {
           while(running) {
             // read an event from the wire
             event = (LoggingEvent) ois.readObject();
             byte[] bytes = layout.format(event).getBytes(Charset.forName("UTF-8"));
             bytesReceived=bytes.length;
             Chunk c = new ChunkImpl(type, java.net.InetAddress.getLocalHost().getHostName(), bytesReceived, bytes, SocketAdaptor.this);
             dest.add(c);
           }
         }
       } catch(java.io.EOFException e) {
         log.debug("Caught java.io.EOFException:", e);
       } catch(java.net.SocketException e) {
         log.debug("Caught java.net.SocketException:", e);
       } catch(InterruptedIOException e) {
         Thread.currentThread().interrupt();
         log.debug("Caught java.io.InterruptedIOException: ", e);
       } catch(IOException e) {
         log.debug("Caught java.io.IOException: "+e);
       } catch(Exception e) {
         log.error("Unexpected exception. Closing conneciton.", e);
       } finally {
         if (ois != null) {
            try {
               ois.close();
            } catch(Exception e) {
               log.info("Could not close connection.", e);
            }
         }
         if (server != null) {
           try {
             server.close();
           } catch(InterruptedIOException e) {
             Thread.currentThread().interrupt();
           } catch(IOException ex) {
             log.debug(ExceptionUtil.getStackTrace(ex));
           }
         }
       }
     }
     
     public void shutdown() {
       try {
         ois.close();
         server.close();
       } catch (IOException e) {
         log.debug(ExceptionUtil.getStackTrace(e));
       }
     }
   }
   
   Dispatcher disp;
   
   @Override
   public String parseArgs(String s) {
     port = Integer.parseInt(s);
     return s;
   }
 
   @Override
   public void start(long offset) throws AdaptorException {
     try {
       disp = new Dispatcher(port);
       disp.setDaemon(true);
       disp.start();      
     } catch (Exception e) {
       throw new AdaptorException(ExceptionUtil.getStackTrace(e));
     }
   }
 
   @Override
   public String getCurrentStatus() {
     return type + " " + port;
   }
 
   @Override
   public long shutdown(AdaptorShutdownPolicy shutdownPolicy)
       throws AdaptorException {
     try {
       running = false;
       disp.shutdown();
     } catch(Exception e) {
       log.debug(ExceptionUtil.getStackTrace(e));
     }
     return 0;
   }
 
 }