/*
    * 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.util;
  
  import org.apache.hadoop.chukwa.ChukwaArchiveKey;
  import org.apache.hadoop.chukwa.ChunkImpl;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.ChecksumException;
  import org.apache.hadoop.fs.FSDataOutputStream;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.io.SequenceFile;
  import org.apache.log4j.Logger;
  
  /**
   * This class is used by LocalToRemoteHDFSMover to
   * convert .chukwa files to .done before moving them. 
   * By creating a new sequence file and copying all valid chunks to it,
   * it makes sure that no corrupt sequence files get into HDFS.
   */
  public class CopySequenceFile {
    static Logger log = Logger.getLogger(CopySequenceFile.class);
    private static SequenceFile.Writer seqFileWriter = null;
    private static SequenceFile.Reader seqFileReader = null; 
    private static FSDataOutputStream newOutputStr = null;
    
    public static void createValidSequenceFile(Configuration conf,
  		                                     String originalFileDir, 
  		                                     String originalFileName,
  		                                     FileSystem localFs) {
      try {
        if (!originalFileDir.endsWith("/")) {
      	      originalFileDir += "/";
        }	
  	  String originalCompleteDir= originalFileDir + originalFileName;
  	  Path originalPath= new Path(originalCompleteDir);
  	  int extensionIndex= originalFileName.indexOf(".chukwa",0);
        
  	  String recoverFileName=originalFileName.substring(0, extensionIndex)+".recover";
  	  String recoverDir= originalFileDir + recoverFileName;
  	  Path recoverPath= new Path(recoverDir);
  	  String recoverDoneFileName=originalFileName.substring(0, extensionIndex)+".recoverDone";
   	  String recoverDoneDir= originalFileDir + recoverDoneFileName;
   	  Path recoverDonePath= new Path(recoverDoneDir);
  	  String doneFileName=originalFileName.substring(0, extensionIndex)+".done";
  	  String doneDir= originalFileDir + doneFileName;
  	  Path donePath= new Path(doneDir);
  	  
  	  ChukwaArchiveKey key = new ChukwaArchiveKey();
        ChunkImpl evt = ChunkImpl.getBlankChunk();
  
  	  newOutputStr = localFs.create(recoverPath);
        seqFileWriter = SequenceFile.createWriter(conf, newOutputStr,
                                                  ChukwaArchiveKey.class, ChunkImpl.class,
                                                  SequenceFile.CompressionType.NONE, null);
        seqFileReader = new SequenceFile.Reader(localFs, originalPath, conf);
          
        System.out.println("key class name is " + seqFileReader.getKeyClassName());
        System.out.println("value class name is " + seqFileReader.getValueClassName());
        try { 
          while (seqFileReader.next(key, evt)) {
            seqFileWriter.append(key, evt);
          }
         } catch (ChecksumException e) { //The exception occurs when we read a bad chunk while copying
             log.info("Encountered Bad Chunk while copying .chukwa file, continuing",e);	 
         }
         seqFileReader.close();
  	   seqFileWriter.close();
  	   newOutputStr.close();
         try {
  	     localFs.rename(recoverPath, recoverDonePath); //Rename the destination file from .recover to .recoverDone 
     	     localFs.delete(originalPath,false); //Delete Original .chukwa file
  	     localFs.rename(recoverDonePath, donePath); //rename .recoverDone to .done
         } catch (Exception e) {
             log.warn("Error occured while renaming .recoverDone to .recover or deleting .chukwa",e);		 
      	   e.printStackTrace();
         }
  
  	} catch(Exception e) {
  	    log.warn("Error during .chukwa file recovery",e);	 
  	    e.printStackTrace();
  	}	
   }
 }