/*
    * 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.extraction.demux;
  
  import java.io.IOException;
  import java.net.URI;
  import java.net.URISyntaxException;
  import java.text.SimpleDateFormat;
  import java.util.Date;
  
  import org.apache.hadoop.chukwa.conf.ChukwaConfiguration;
  import org.apache.hadoop.chukwa.extraction.CHUKWA_CONSTANT;
  import org.apache.hadoop.chukwa.util.NagiosHelper;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileStatus;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.fs.PathFilter;
  import org.apache.hadoop.util.ToolRunner;
  import org.apache.log4j.Logger;
  
  public class DemuxManager implements CHUKWA_CONSTANT {  
    static Logger log = Logger.getLogger(DemuxManager.class);
  
    int globalErrorcounter = 0;
    Date firstErrorTime = null;
  
    protected int ERROR_SLEEP_TIME = 60;
    protected int NO_DATASINK_SLEEP_TIME = 20;
  
    protected int DEFAULT_MAX_ERROR_COUNT = 6;
    protected int DEFAULT_MAX_FILES_PER_DEMUX = 500;
    protected int DEFAULT_REDUCER_COUNT = 8;
    
    protected int maxPermittedErrorCount = DEFAULT_MAX_ERROR_COUNT;
    protected int demuxReducerCount = 0;
    protected ChukwaConfiguration conf = null;
    protected FileSystem fs = null;
    protected int reprocess = 0;
    protected boolean sendAlert = true;
    
    protected SimpleDateFormat dayTextFormat = new java.text.SimpleDateFormat("yyyyMMdd");
    protected volatile boolean isRunning = true;
  
    final private static PathFilter DATA_SINK_FILTER = new PathFilter() {
      public boolean accept(Path file) {
        return file.getName().endsWith(".done");
      }     
    };
  
  
    public static void main(String[] args) throws Exception {
      
      DemuxManager manager = new DemuxManager();
      manager.start();
  
    }
  
    public DemuxManager() throws Exception {
      this.conf = new ChukwaConfiguration();
      init();
    }
  
    public DemuxManager(ChukwaConfiguration conf) throws Exception {
      this.conf = conf;
      init();
    }
  
    protected void init() throws IOException, URISyntaxException {
      String fsName = conf.get(HDFS_DEFAULT_NAME_FIELD);
      fs = FileSystem.get(new URI(fsName), conf);
    }
  
    public void shutdown() {
      this.isRunning = false;
    }
  
  
    public int getReprocess() {
      return reprocess;
    }
  
    /**
    * Start the Demux Manager daemon
    * @throws Exception
    */
   public void start() throws Exception {
 
      String chukwaRootDir = conf.get(CHUKWA_ROOT_DIR_FIELD, DEFAULT_CHUKWA_ROOT_DIR_NAME);
      if ( ! chukwaRootDir.endsWith("/") ) {
        chukwaRootDir += "/";
      }
      log.info("chukwaRootDir:" + chukwaRootDir);
 
      String demuxRootDir = chukwaRootDir + DEFAULT_DEMUX_PROCESSING_DIR_NAME;
      String demuxErrorDir = demuxRootDir + DEFAULT_DEMUX_IN_ERROR_DIR_NAME;
      String demuxInputDir = demuxRootDir + DEFAULT_DEMUX_MR_INPUT_DIR_NAME;
      String demuxOutputDir = demuxRootDir + DEFAULT_DEMUX_MR_OUTPUT_DIR_NAME;
 
      String dataSinkDir = conf.get(CHUKWA_DATA_SINK_DIR_FIELD, chukwaRootDir +DEFAULT_CHUKWA_LOGS_DIR_NAME);
      if ( ! dataSinkDir.endsWith("/") ) {
        dataSinkDir += "/";
      }
      log.info("dataSinkDir:" + dataSinkDir);
      
      String postProcessDir = conf.get(CHUKWA_POST_PROCESS_DIR_FIELD, chukwaRootDir +DEFAULT_CHUKWA_POSTPROCESS_DIR_NAME);
      if ( ! postProcessDir.endsWith("/") ) {
        postProcessDir += "/";
      }
      log.info("postProcessDir:" + postProcessDir);
      
      String archiveRootDir = conf.get(CHUKWA_ARCHIVE_DIR_FIELD, chukwaRootDir +DEFAULT_CHUKWA_DATASINK_DIR_NAME);
      if ( ! archiveRootDir.endsWith("/") ) {
        archiveRootDir += "/";
      }
      log.info("archiveRootDir:" + archiveRootDir);
      
      maxPermittedErrorCount = conf.getInt(CHUKWA_DEMUX_MAX_ERROR_COUNT_FIELD,
                                           DEFAULT_MAX_ERROR_COUNT);
      demuxReducerCount = conf.getInt(CHUKWA_DEMUX_REDUCER_COUNT_FIELD, DEFAULT_REDUCER_COUNT);
      log.info("demuxReducerCount:" + demuxReducerCount);
      
      String nagiosHost = conf.get(CHUKWA_NAGIOS_HOST_FIELD);
      int nagiosPort = conf.getInt(CHUKWA_NAGIOS_PORT_FIELD,0);
      String reportingHost = conf.get(CHUKWA_REPORTING_HOST_FIELD);
      
      log.info("Nagios information: nagiosHost:" + nagiosHost + ", nagiosPort:" 
          + nagiosPort + ", reportingHost:" + reportingHost);
      
      
      if (nagiosHost == null || nagiosHost.length() == 0 || nagiosPort == 0 || reportingHost == null || reportingHost.length() == 0) {
        sendAlert = false;
        log.warn("Alerting is OFF");
      }
      
      boolean demuxReady = false;
 
      
      while (isRunning) {
        try {
          demuxReady = false;
 
          if (maxPermittedErrorCount != -1 && globalErrorcounter >= maxPermittedErrorCount) {
            log.warn("==================\nToo many errors (" + globalErrorcounter +
                     "), Bail out!\n==================");
            break;
          }
          
          // Check for anomalies
          if (checkDemuxOutputDir(demuxOutputDir) == true) {
            // delete current demux output dir
            if ( deleteDemuxOutputDir(demuxOutputDir) == false ) {
              log.warn("Cannot delete an existing demux output directory!");
              throw new IOException("Cannot move demuxOutput to postProcess!");
            }
            continue;
          } else if (checkDemuxInputDir(demuxInputDir) == true) { // dataSink already there
            reprocess++;
 
            // Data has been processed more than 3 times ... move to InError directory
            if (reprocess > 3) {
              if (moveDataSinkFilesToDemuxErrorDirectory(demuxInputDir,demuxErrorDir) == false) {
                log.warn("Cannot move dataSink files to DemuxErrorDir!");
                throw new IOException("Cannot move dataSink files to DemuxErrorDir!");
              }
              reprocess = 0;
              continue;
            }
 
            log.error("Demux inputDir aready contains some dataSink files,"
                + " going to reprocess, reprocessCount=" + reprocess);
            demuxReady = true;
          } else { // standard code path
            reprocess = 0;
            // Move new dataSink Files
            if (moveDataSinkFilesToDemuxInputDirectory(dataSinkDir, demuxInputDir) == true) {
              demuxReady = true; // if any are available
            } else {
              demuxReady = false; // if none
            }
          }
 
          // start a new demux ?
          if (demuxReady == true) {
           boolean demuxStatus = processData(dataSinkDir, demuxInputDir, demuxOutputDir,
                postProcessDir, archiveRootDir);
           sendDemuxStatusToNagios(nagiosHost,nagiosPort,reportingHost,demuxErrorDir,demuxStatus,null);
 
           // if demux suceeds, then we reset these.
           if (demuxStatus) {
            globalErrorcounter = 0;
            firstErrorTime = null;
           }
          } else {
            log.info("Demux not ready so going to sleep ...");
            Thread.sleep(NO_DATASINK_SLEEP_TIME * 1000);
          }
        }catch(Throwable e) {
          globalErrorcounter ++;
          if (firstErrorTime == null) firstErrorTime = new Date();
 
          log.warn("Consecutive error number " + globalErrorcounter +
                   " encountered since " + firstErrorTime, e);
          sendDemuxStatusToNagios(nagiosHost,nagiosPort,reportingHost,demuxErrorDir,false, e.getMessage());
          try { Thread.sleep(ERROR_SLEEP_TIME * 1000); } 
          catch (InterruptedException e1) {/*do nothing*/ }
          init();
        }
      }
    }
 
 
    /**
     * Send NSCA status to Nagios
     * @param nagiosHost
     * @param nagiosPort
     * @param reportingHost
     * @param demuxInErrorDir
     * @param demuxStatus
     * @param exception
     */
   protected void sendDemuxStatusToNagios(String nagiosHost,int nagiosPort,String reportingHost,
         String demuxInErrorDir,boolean demuxStatus,String demuxException) {
       
      if (sendAlert == false) {
        return;
      }
       
      boolean demuxInErrorStatus = true;
      String demuxInErrorMsg = "";
      try {
        Path pDemuxInErrorDir = new Path(demuxInErrorDir);
        if ( fs.exists(pDemuxInErrorDir)) {
          FileStatus[] demuxInErrorDirs = fs.listStatus(pDemuxInErrorDir);
          if (demuxInErrorDirs.length == 0) {
            demuxInErrorStatus = false;
          }          
        }
      } catch (Throwable e) {
        demuxInErrorMsg = e.getMessage();
        log.warn(e);
      }
      
      // send Demux status
      if (demuxStatus == true) {
        NagiosHelper.sendNsca("Demux OK",NagiosHelper.NAGIOS_OK);
      } else {
        NagiosHelper.sendNsca("Demux failed. " + demuxException,NagiosHelper.NAGIOS_CRITICAL);
      }
      
      // send DemuxInErrorStatus
      if (demuxInErrorStatus == false) {
        NagiosHelper.sendNsca("DemuxInError OK",NagiosHelper.NAGIOS_OK);
      } else {
        NagiosHelper.sendNsca("DemuxInError not empty -" + demuxInErrorMsg,NagiosHelper.NAGIOS_CRITICAL);
      }
      
    }
    
    /**
     * Process Data, i.e. 
     * - run demux
     * - move demux output to postProcessDir
     * - move dataSink file to archiveDir
     * 
     * @param dataSinkDir
     * @param demuxInputDir
     * @param demuxOutputDir
     * @param postProcessDir
     * @param archiveDir
     * @return True iff succeed
     * @throws IOException
     */
     protected boolean processData(String dataSinkDir, String demuxInputDir,
        String demuxOutputDir, String postProcessDir, String archiveDir) throws IOException {
 
      boolean demuxStatus = false;
 
      long startTime = System.currentTimeMillis();
      demuxStatus = runDemux(demuxInputDir, demuxOutputDir);
      log.info("Demux Duration: " + (System.currentTimeMillis() - startTime));
 
      if (demuxStatus == false) {
        log.warn("Demux failed!");
      } else {
 
        // Move demux output to postProcessDir 
        if (checkDemuxOutputDir(demuxOutputDir)) {
          if (moveDemuxOutputDirToPostProcessDirectory(demuxOutputDir, postProcessDir) == false) {
            log.warn("Cannot move demuxOutput to postProcess! bail out!");
            throw new IOException("Cannot move demuxOutput to postProcess! bail out!");
          } 
        } else {
          log.warn("Demux processing OK but no output");
        }
 
        // Move DataSink Files to archiveDir
        if (moveDataSinkFilesToArchiveDirectory(demuxInputDir, archiveDir) == false) {
          log.warn("Cannot move datasinkFile to archive! bail out!");
          throw new IOException("Cannot move datasinkFile to archive! bail out!");
        }
      }
      
      return demuxStatus;
    }
 
 
    /**
     * Submit and Run demux Job 
     * @param demuxInputDir
     * @param demuxOutputDir
     * @return true id Demux succeed
     */
    protected boolean runDemux(String demuxInputDir, String demuxOutputDir) { 
      // to reload the configuration, and demux's reduce number
      Configuration tempConf = new Configuration(conf);
      tempConf.reloadConfiguration();
      demuxReducerCount = tempConf.getInt(CHUKWA_DEMUX_REDUCER_COUNT_FIELD, DEFAULT_REDUCER_COUNT);
      String[] demuxParams;
      int i=0;
      Demux.addParsers(tempConf);
      demuxParams = new String[4];
      demuxParams[i++] = "-r";
      demuxParams[i++] = "" + demuxReducerCount;
      demuxParams[i++] = demuxInputDir;
      demuxParams[i++] = demuxOutputDir;
      try {
        return ( 0 == ToolRunner.run(tempConf,new Demux(), demuxParams) );
      } catch (Throwable e) {
        e.printStackTrace();
        globalErrorcounter ++;
        if (firstErrorTime == null) firstErrorTime = new Date();
        log.error("Failed to run demux. Consecutive error number " +
                globalErrorcounter + " encountered since " + firstErrorTime, e);
      }
      return false;
    }
 
 
 
    /**
     * Move dataSink files to Demux input directory
     * @param dataSinkDir
     * @param demuxInputDir
     * @return true if there's any dataSink files ready to be processed
     * @throws IOException
     */
    protected boolean moveDataSinkFilesToDemuxInputDirectory(
        String dataSinkDir, String demuxInputDir) throws IOException {
      Path pDataSinkDir = new Path(dataSinkDir);
      Path pDemuxInputDir = new Path(demuxInputDir);
      log.info("dataSinkDir: " + dataSinkDir);
      log.info("demuxInputDir: " + demuxInputDir);
 
 
      boolean containsFile = false;
 
      FileStatus[] dataSinkFiles = fs.listStatus(pDataSinkDir,DATA_SINK_FILTER);
      if (dataSinkFiles.length > 0) {
        setup(pDemuxInputDir);
      }
 
      int maxFilesPerDemux = 0;
      for (FileStatus fstatus : dataSinkFiles) {
        boolean rename = fs.rename(fstatus.getPath(),pDemuxInputDir);
        log.info("Moving " + fstatus.getPath() + " to " + pDemuxInputDir +", status is:" + rename);
        maxFilesPerDemux ++;
        containsFile = true;
        if (maxFilesPerDemux >= DEFAULT_MAX_FILES_PER_DEMUX) {
          log.info("Max File per Demux reached:" + maxFilesPerDemux);
          break;
        }
      }
      return containsFile;
    }
 
 
 
 
    /**
     * Move sourceFolder inside destFolder
     * @param dataSinkDir : ex chukwa/demux/inputDir
     * @param demuxErrorDir : ex /chukwa/demux/inError
     * @return true if able to move chukwa/demux/inputDir to /chukwa/demux/inError/<YYYYMMDD>/demuxInputDirXXX
     * @throws IOException
     */
    protected boolean moveDataSinkFilesToDemuxErrorDirectory(
        String dataSinkDir, String demuxErrorDir) throws IOException {
      demuxErrorDir += "/" + dayTextFormat.format(System.currentTimeMillis());
      return moveFolder(dataSinkDir,demuxErrorDir,"demuxInputDir");
    }
 
    /**
     * Move sourceFolder inside destFolder
     * @param demuxInputDir ex chukwa/demux/inputDir
     * @param archiveDirectory ex /chukwa/archives
     * @return true if able to move chukwa/demux/inputDir to /chukwa/archives/raw/<YYYYMMDD>/dataSinkDirXXX
     * @throws IOException
     */
    protected boolean moveDataSinkFilesToArchiveDirectory(
        String demuxInputDir, String archiveDirectory) throws IOException {
      archiveDirectory += "/" + dayTextFormat.format(System.currentTimeMillis());
      return moveFolder(demuxInputDir,archiveDirectory,"dataSinkDir");
    }
 
    /**
     * Move sourceFolder inside destFolder
     * @param demuxOutputDir ex chukwa/demux/outputDir 
     * @param postProcessDirectory ex /chukwa/postProcess
     * @return true if able to move chukwa/demux/outputDir to /chukwa/postProcess/demuxOutputDirXXX
     * @throws IOException 
     */
    protected  boolean moveDemuxOutputDirToPostProcessDirectory(
        String demuxOutputDir, String postProcessDirectory) throws IOException {
      return moveFolder(demuxOutputDir,postProcessDirectory,"demuxOutputDir");
    }
 
 
    /**
     * Test if demuxInputDir exists
     * @param demuxInputDir
     * @return true if demuxInputDir exists
     * @throws IOException
     */
    protected boolean checkDemuxInputDir(String demuxInputDir)
    throws IOException {
      return dirExists(demuxInputDir);
    }
 
    /**
     * Test if demuxOutputDir exists
     * @param demuxOutputDir
     * @return true if demuxOutputDir exists
     * @throws IOException
     */
    protected boolean checkDemuxOutputDir(String demuxOutputDir)
    throws IOException {
      return dirExists(demuxOutputDir);
    }
 
 
    /**
     * Delete DemuxOutput directory
     * @param demuxOutputDir
     * @return true if succeed
     * @throws IOException
     */
    protected boolean deleteDemuxOutputDir(String demuxOutputDir) throws IOException
    {
      return fs.delete(new Path(demuxOutputDir), true);
    }
 
    /**
     * Create directory if !exists
     * @param directory
     * @throws IOException
     */
    protected void setup(Path directory) throws IOException {
       if ( ! fs.exists(directory)) {
         fs.mkdirs(directory);
       }
     }
 
     /** 
      * Check if source exists and if source is a directory
      * @param f source file
      */
    protected boolean dirExists(String directory) throws IOException {
       Path pDirectory = new Path(directory);
       return (fs.exists(pDirectory) && fs.getFileStatus(pDirectory).isDir());
     }
 
     /**
      * Move sourceFolder inside destFolder
      * @param srcDir
      * @param destDir
      * @return
      * @throws IOException
      */ 
    protected boolean moveFolder(String srcDir,String destDir, String prefix) throws IOException {
       if (!destDir.endsWith("/")) {
         destDir +="/";
       }
       Path pSrcDir = new Path(srcDir);
       Path pDestDir = new Path(destDir );
       setup(pDestDir);
       destDir += prefix +"_" +System.currentTimeMillis();
       Path pFinalDestDir = new Path(destDir );
 
       return fs.rename(pSrcDir, pFinalDestDir);
     }
 }