/*
 * 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.uima.ducc.sampleapps;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;

import org.apache.uima.cas.CAS;
import org.apache.uima.cas.CASException;
import org.apache.uima.collection.CollectionException;
import org.apache.uima.collection.CollectionReader_ImplBase;
import org.apache.uima.ducc.Workitem;
import org.apache.uima.jcas.JCas;
import org.apache.uima.resource.ResourceConfigurationException;
import org.apache.uima.resource.ResourceInitializationException;
import org.apache.uima.util.Level;
import org.apache.uima.util.Logger;
import org.apache.uima.util.Progress;
import org.apache.uima.util.ProgressImpl;

/**
 * A DUCC Job collection reader that segments a collection text files from a directory 
 * in the filesystem into separate Work Items for a DUCC job.
 * In order to facilitate processing scale out, an optional blocksize parameter can be 
 * specified that will be used to break larger files into multiple Work Items.
 * 
 * By default any previously completed output files found in the output directory are preserved,
 * but a configuration parameter is available to ignore previous output. 

 * This CR can be configured with the following parameters:
 * <ul>
 * <li><code>InputDirectory</code> - path to directory containing input files</li>
 * <li><code>OutputDirectory</code> - path to directory for output files</li>
 * <li><code>IgnorePreviousOutput</code> (optional) - flag to ignore previous output files</li>
 * <li><code>Encoding</code> (optional) - character encoding of the input files</li>
 * <li><code>Language</code> (optional) - language of the input documents</li>
 * <li><code>BlockSize</code> (optional) - Block size used to process input files</li>
 * <li><code>SendToLast</code> (optional) - flag to route WorkItem CAS to last pipeline component. Only used for jobs with initial CM.</li>
 * <li><code>SendToAll</code> (optional) - flag to route WorkItem CAS to all pipeline components. Only used for jobs with initial CM.</li>
 * </ul>
 * 
 */
public class DuccJobTextCR extends CollectionReader_ImplBase {
  /**
   * Name of configuration parameter that must be set to the path of a directory containing input
   * files.
   */
  public static final String PARAM_INPUTDIR = "InputDirectory";

  /**
   * Name of configuration parameter that must be set to the path of the base directory 
   * where output files will be created.
   */
  public static final String PARAM_OUTPUTDIR = "OutputDirectory";

  /**
   * Name of configuration parameter that indicates if previous output should be ignored.
   */
  public static final String PARAM_IGNOREPREVIOUS = "IgnorePreviousOutput";

  /**
   * Name of configuration parameter that contains the character encoding used by the input files.
   * If not specified, the default system encoding will be used.
   */
  public static final String PARAM_ENCODING = "Encoding";

  /**
   * Name of optional configuration parameter that contains the language of the documents in the
   * input directory. If specified this information will be added to the CAS.
   */
  public static final String PARAM_LANGUAGE = "Language";

  /**
   * Name of configuration parameter specifying the block size used to break input files into work-items.
   * Output files will correspond to the input data found in each block.
   * If not specified, the entire file will be processed as a single work-item.
   */
  public static final String PARAM_BLOCKSIZE = "BlockSize";

  /**
   * Flag to route WorkItem CAS to last pipeline component. Used to flush any output data.
   * This string is ignored if the Job has a CM component.
   */
  public static final String PARAM_SENDTOLAST = "SendToLast";

  /**
   * Flag to route WorkItem CAS to all pipeline components.
   * If the Job has no CM component the WI CAS is already sent to AE and CC.
   */
  public static final String PARAM_SENDTOALL = "SendToAll";
  
  class WorkItem {
    public WorkItem(String absolutePathIn, String absolutePathOut, int i, long len, long off, boolean end) {
      filename=absolutePathIn;
      outname=absolutePathOut;
      index=i;
      length=(int)len;
      offset=(int)off;
      last=end;
    }
    String filename;
    String outname;
    int index;
    int offset;
    int length;
    boolean last;
  }

  private ArrayList<WorkItem> mWorkList; 

  private String mInputdirectory;

  private String mOutputdirectory;
  
  private Boolean mIgnorePrevious;

  private String mEncoding;

  private String mLanguage;

  private int mBlocksize;

  private int mCurrentIndex;

  private Boolean mSendToLast;

  private Boolean mSendToAll;

  private int mPreviouslyDone;

  private Logger logger;

  /**
   * @see org.apache.uima.collection.CollectionReader_ImplBase#initialize()
   */
  public void initialize() throws ResourceInitializationException {
	logger = getUimaContext().getLogger();
    mInputdirectory = ((String) getConfigParameterValue(PARAM_INPUTDIR)).trim();
    mOutputdirectory = ((String) getConfigParameterValue(PARAM_OUTPUTDIR)).trim();
    mIgnorePrevious = (Boolean) getConfigParameterValue(PARAM_IGNOREPREVIOUS);
    mEncoding  = (String) getConfigParameterValue(PARAM_ENCODING);
    mLanguage  = (String) getConfigParameterValue(PARAM_LANGUAGE);
    mSendToLast = (Boolean) getConfigParameterValue(PARAM_SENDTOLAST);
    mSendToAll = (Boolean) getConfigParameterValue(PARAM_SENDTOALL);

    if (null == mIgnorePrevious) {
    	mIgnorePrevious = Boolean.FALSE;
    }
    if (null == mSendToLast) {
    	mSendToLast = Boolean.FALSE;
    }
    if (null == mSendToAll) {
    	mSendToAll = Boolean.FALSE;
    }
    mCurrentIndex = 0;
    mPreviouslyDone = 0;

    // if input directory does not exist or is not a directory, throw exception
    File inDirectory = new File(mInputdirectory);
    if (!inDirectory.exists() || !inDirectory.isDirectory()) {
      throw new ResourceInitializationException(ResourceConfigurationException.DIRECTORY_NOT_FOUND,
              new Object[] { PARAM_INPUTDIR, this.getMetaData().getName(), inDirectory.getPath() });
    }

    // if output directory is a file throw exception
    File outDirectory = new File(mOutputdirectory);
    if (outDirectory.exists() && !outDirectory.isDirectory()) {
      throw new ResourceInitializationException(new RuntimeException("Specified output directory "+mOutputdirectory+" is a file"));
    }

    mBlocksize = 0;
    logger.log(Level.INFO, "Processing input files from "+mInputdirectory);
    if (null != getConfigParameterValue(PARAM_BLOCKSIZE)) {
      mBlocksize  = (Integer) getConfigParameterValue(PARAM_BLOCKSIZE);
      logger.log(Level.INFO, "Using blocksize "+ mBlocksize);
    }
    if (null != mIgnorePrevious && mIgnorePrevious) {
      logger.log(Level.INFO, "Overwriting previous outfiles");
    }

    // get list of files or file-parts in the specified directory
    mWorkList = new ArrayList<WorkItem>();
    addFilesFromDir(inDirectory);
    if (0 < mPreviouslyDone) {
      logger.log(Level.INFO, "Preserving "+mPreviouslyDone+" output files in "+mOutputdirectory);
    }
    logger.log(Level.INFO, "Processing "+mWorkList.size()+" output files in "+mOutputdirectory);
  }
  
  /**
   * This method adds files or file-chunks in the input directory,
   * if the respective output file does not exist,
   * or if mIgnorePrevious = true.
   * 
   * @param dir
   */
  private void addFilesFromDir(File dir) {
    File[] files = dir.listFiles();
    for (int i = 0; files != null && i < files.length; i++) {
      if (!files[i].isDirectory()) {
        String outfilename = files[i].getAbsolutePath();
        outfilename = outfilename.substring(mInputdirectory.length());
        outfilename = mOutputdirectory+outfilename;
        if (mBlocksize == 0) {
          File outFile = new File(outfilename+"_processed.zip");
          if (!mIgnorePrevious && outFile.exists()) {
        	  mPreviouslyDone++;
          }
          if (mIgnorePrevious || !outFile.exists()) {
            mWorkList.add(new WorkItem(files[i].getAbsolutePath(),outfilename+"_processed.zip",0,files[i].length(),0,true));
            logger.log(Level.FINE, "adding "+outfilename);
          }
        }
        // use blocksize
        else {
          long fsize = files[i].length();
          long offset=0;
          int j=0;
          while (fsize > 0) {
            String outfilechunk = outfilename+"_"+j;
            long length = (fsize < mBlocksize) ? fsize : mBlocksize;
            File outFile = new File(outfilechunk+"_processed.zip");
            if (!mIgnorePrevious && outFile.exists()) {
          	  mPreviouslyDone++;
            }
            if (mIgnorePrevious || !outFile.exists()) {
              mWorkList.add(new WorkItem(files[i].getAbsolutePath(),outfilechunk+"_processed.zip",j,length,offset,fsize==length));
              logger.log(Level.FINE, "adding "+outfilechunk);
            }
            j++;
            fsize -= length;
            offset += length;
          }
        }
      }
    }
  }

  /**
   * @see org.apache.uima.collection.CollectionReader#hasNext()
   */
  public boolean hasNext() {
    return mCurrentIndex < mWorkList.size();
  }

  /**
   * @see org.apache.uima.collection.CollectionReader#getNext(org.apache.uima.cas.CAS)
   */
  public void getNext(CAS aCAS) throws IOException, CollectionException {
    JCas jcas;
    try {
      jcas = aCAS.getJCas();
      Workitem wi = new Workitem(jcas);
      wi.setInputspec(mWorkList.get(mCurrentIndex).filename);
      wi.setOutputspec(mWorkList.get(mCurrentIndex).outname);
      wi.setBlockindex(mWorkList.get(mCurrentIndex).index);
      wi.setBlocksize(mBlocksize);
      wi.setBytelength(mWorkList.get(mCurrentIndex).length);
      if (null != mEncoding) {
    	  wi.setEncoding(mEncoding);
      }
      if (null != mLanguage) {
    	  wi.setLanguage(mLanguage);
      }
      wi.setSendToLast(mSendToLast);
      wi.setSendToAll(mSendToAll);
      wi.addToIndexes();
      wi.setLastBlock(mWorkList.get(mCurrentIndex).last);
      logger.log(Level.INFO, "Sending "+wi.getInputspec()+" index="+wi.getBlockindex()+" last="+wi.getLastBlock()+" length="+wi.getBytelength());
      mCurrentIndex++;
      jcas.setDocumentText(wi.getInputspec()+" index="+wi.getBlockindex()+" length="+wi.getBytelength());
    } catch (CASException e) {
      throw new CollectionException(e);
    }

    //create WorkItem info structure
  }

  /**
   * @see org.apache.uima.collection.base_cpm.BaseCollectionReader#close()
   */
  public void close() throws IOException {
  }

  /**
   * @see org.apache.uima.collection.base_cpm.BaseCollectionReader#getProgress()
   */
  public Progress[] getProgress() {
    return new Progress[] { new ProgressImpl(mCurrentIndex, mWorkList.size(), Progress.ENTITIES) };
  }

  /**
   * Gets the total number of documents that will be returned by this collection reader. This is not
   * part of the general collection reader interface.
   * 
   * @return the number of documents in the collection
   */
  public int getNumberOfDocuments() {
    return mWorkList.size();
  }

}