/*
 * 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.examples.cpe;
/* 
 *******************************************************************************************
 * N O T E :     The XML format (XCAS) that this Cas Consumer outputs, is eventually 
 *               being superceeded by the more standardized and compact XMI format.  However
 *               it is used currently as the expected form for remote services, and there is
 *               existing tooling for doing stand-alone component development and debugging 
 *               that uses this format to populate an initial CAS.  So it is not 
 *               deprecated yet;  it is also being kept for compatibility with older versions.
 *               
 *               New code should consider using the XmiWriterCasConsumer where possible,
 *               which uses the current XMI format for XML externalizations of the CAS
 *******************************************************************************************               
 */

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.URL;

import org.apache.uima.cas.CAS;
import org.apache.uima.cas.CASException;
import org.apache.uima.cas.FSIterator;
import org.apache.uima.cas.impl.XCASSerializer;
import org.apache.uima.collection.CasConsumer_ImplBase;
import org.apache.uima.examples.SourceDocumentInformation;
import org.apache.uima.jcas.JCas;
import org.apache.uima.resource.ResourceInitializationException;
import org.apache.uima.resource.ResourceProcessException;
import org.apache.uima.util.XMLSerializer;
import org.xml.sax.SAXException;

/**
 * A simple CAS consumer that generates XCAS (XML representation of the CAS) files in the
 * filesystem.
 * <p>
 * This CAS Consumer takes one parameters:
 * <ul>
 * <li><code>OutputDirectory</code> - path to directory into which output files will be written</li>
 * </ul>
 * 
 * 
 */
public class XCasWriterCasConsumer extends CasConsumer_ImplBase {
  /**
   * Name of configuration parameter that must be set to the path of a directory into which the
   * output files will be written.
   */
  public static final String PARAM_OUTPUTDIR = "OutputDirectory";

  /** The m output dir. */
  private File mOutputDir;

  /** The m doc num. */
  private int mDocNum;

  /*
   * (non-Javadoc)
   * 
   * @see org.apache.uima.collection.CasConsumer_ImplBase#initialize()
   */
  @Override
  public void initialize() throws ResourceInitializationException {
    mDocNum = 0;
    mOutputDir = new File((String) getConfigParameterValue(PARAM_OUTPUTDIR));
    if (!mOutputDir.exists()) {
      mOutputDir.mkdirs();
    }
  }

  /**
   * Processes the CasContainer which was populated by the TextAnalysisEngines. <br>
   * In this case, the CAS is converted to XML and written into the output file .
   * 
   * @param aCAS
   *          CasContainer which has been populated by the TAEs
   * 
   * @throws ResourceProcessException
   *           if there is an error in processing the Resource
   * 
   * @see org.apache.uima.collection.base_cpm.CasObjectProcessor#processCas(org.apache.uima.cas.CAS)
   */
  @Override
  public void processCas(CAS aCAS) throws ResourceProcessException {
    JCas jcas;
    try {
      jcas = aCAS.getJCas();
    } catch (CASException e) {
      throw new ResourceProcessException(e);
    }

    // retrieve the filename of the input file from the CAS
    FSIterator it = jcas.getAnnotationIndex(SourceDocumentInformation.type).iterator();
    File outFile = null;
    if (it.hasNext()) {
      SourceDocumentInformation fileLoc = (SourceDocumentInformation) it.next();
      File inFile;
      try {
        inFile = new File(new URL(fileLoc.getUri()).getPath());
        String outFileName = inFile.getName();
        if (fileLoc.getOffsetInSource() > 0) {
          outFileName += fileLoc.getOffsetInSource();
        }
        outFile = new File(mOutputDir, outFileName);
      } catch (MalformedURLException e1) {
        // invalid URL, use default processing below
      }
    }
    if (outFile == null) {
      outFile = new File(mOutputDir, "doc" + mDocNum++);
    }
    // serialize XCAS and write to output file
    try {
      writeXCas(jcas.getCas(), outFile);
    } catch (IOException e) {
      throw new ResourceProcessException(e);
    } catch (SAXException e) {
      throw new ResourceProcessException(e);
    }
  }

  /**
   * Serialize a CAS to a file in XCAS format.
   *
   * @param aCas
   *          CAS to serialize
   * @param name
   *          output file
   * @throws IOException
   *           if an I/O failure occurs
   * @throws SAXException
   *           if an error occurs generating the XML text
   */
  private void writeXCas(CAS aCas, File name) throws IOException, SAXException {

    try (OutputStream out = new FileOutputStream(name)) {
      XCASSerializer ser = new XCASSerializer(aCas.getTypeSystem());
      XMLSerializer xmlSer = new XMLSerializer(out, false);
      ser.serialize(aCas, xmlSer.getContentHandler());
    }
  }
}
