/**
    * Copyright (c) 2011, The University of Southampton and the individual contributors.
    * All rights reserved.
    *
    * Redistribution and use in source and binary forms, with or without modification,
    * are permitted provided that the following conditions are met:
    *
    *   * 	Redistributions of source code must retain the above copyright notice,
    * 	this list of conditions and the following disclaimer.
   *
   *   *	Redistributions in binary form must reproduce the above copyright notice,
   * 	this list of conditions and the following disclaimer in the documentation
   * 	and/or other materials provided with the distribution.
   *
   *   *	Neither the name of the University of Southampton nor the names of its
   * 	contributors may be used to endorse or promote products derived from this
   * 	software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
   * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
   * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  package org.openimaj.hadoop.tools.globalfeature;
  
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.hadoop.conf.Configured;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.io.BytesWritable;
  import org.apache.hadoop.io.SequenceFile;
  import org.apache.hadoop.io.Text;
  import org.apache.hadoop.mapreduce.Job;
  import org.apache.hadoop.mapreduce.Mapper;
  import org.apache.hadoop.util.Tool;
  import org.apache.hadoop.util.ToolRunner;
  import org.apache.log4j.Logger;
  import org.openimaj.feature.FeatureVector;
  import org.openimaj.hadoop.mapreduce.TextBytesJobUtil;
  import org.openimaj.hadoop.sequencefile.MetadataConfiguration;
  import org.openimaj.hadoop.tools.HadoopToolsUtil;
  import org.openimaj.image.ImageUtilities;
  import org.openimaj.image.MBFImage;
  import org.openimaj.io.IOUtils;
  
  /**
   * A Hadoop version of the GlobalFeaturesTool. Capable of extracting global
   * image features on very large scale corpora from images stored in
   * {@link SequenceFile}s.
   *
   * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
   */
  public class HadoopGlobalFeaturesTool extends Configured implements Tool
  {
  	private static final String ARGS_KEY = "globalfeatures.args";
  	private static Logger logger = Logger.getLogger(HadoopGlobalFeaturesTool.class);
  
  	static class GlobalFeaturesMapper extends Mapper<Text, BytesWritable, Text, BytesWritable> {
  		private HadoopGlobalFeaturesOptions options;
  
  		public GlobalFeaturesMapper() {
  		}
  
  		@Override
  		protected void setup(Mapper<Text, BytesWritable, Text, BytesWritable>.Context context) {
  			options = new HadoopGlobalFeaturesOptions(context.getConfiguration().getStrings(ARGS_KEY));
  		}
  
  		@Override
  		protected void
  				map(Text key, BytesWritable value, Mapper<Text, BytesWritable, Text, BytesWritable>.Context context)
  						throws InterruptedException
  		{
  			try {
  				final MBFImage img = ImageUtilities.readMBF(new ByteArrayInputStream(value.getBytes()));
  				final FeatureVector fv = options.featureOp.extract(img);
  
  				final ByteArrayOutputStream baos = new ByteArrayOutputStream();
  				if (options.binary)
  					IOUtils.writeBinary(baos, fv);
  				else
  					IOUtils.writeASCII(baos, fv);
  
  				context.write(key, new BytesWritable(baos.toByteArray()));
  			} catch (final Exception e) {
  				logger.warn("Problem processing image " + key + " (" + e + ")");
  			}
 		}
 	}
 
 	@Override
 	public int run(String[] args) throws Exception {
 		final HadoopGlobalFeaturesOptions options = new HadoopGlobalFeaturesOptions(args, true);
 
 		final Map<String, String> metadata = new HashMap<String, String>();
 		metadata.put(MetadataConfiguration.CONTENT_TYPE_KEY, "application/globalfeature-" + options.feature + "-"
 				+ (options.binary ? "bin" : "ascii"));
 
 		metadata.put("clusterquantiser.filetype", (options.binary ? "bin" : "ascii"));
 
 		final List<Path> allPaths = new ArrayList<Path>();
 		for (final String p : options.input) {
 			allPaths.addAll(Arrays.asList(HadoopToolsUtil.getInputPaths(p)));
 		}
 
 		final Job job = TextBytesJobUtil.createJob(allPaths, new Path(options.output), metadata, this.getConf());
 		job.setJarByClass(this.getClass());
 		job.setMapperClass(GlobalFeaturesMapper.class);
 		job.getConfiguration().setStrings(ARGS_KEY, args);
 		job.setNumReduceTasks(0);
 
 		job.waitForCompletion(true);
 
 		return 0;
 	}
 
 	/**
 	 * The main method for the tool.
 	 * 
 	 * @param args
 	 *            the command-line arguments
 	 * @throws Exception
 	 *             if an error occurs
 	 */
 	public static void main(String[] args) throws Exception
 	{
 		ToolRunner.run(new HadoopGlobalFeaturesTool(), args);
 	}
 }