/**
 * 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.image.indexing;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.IOException;
import java.util.List;

import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.filecache.DistributedCache;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import org.kohsuke.args4j.CmdLineException;
import org.kohsuke.args4j.CmdLineParser;
import org.kohsuke.args4j.Option;
import org.openimaj.feature.local.list.MemoryLocalFeatureList;
import org.openimaj.hadoop.mapreduce.TextBytesJobUtil;
import org.openimaj.hadoop.sequencefile.SequenceFileUtility;
import org.openimaj.image.feature.local.keypoints.Keypoint;
import org.openimaj.image.indexing.vlad.VLADIndexerData;

/**
 * Extractor for VLAD-PCA features. Consumes existing local-features and
 * requires a {@link VLADIndexerData} to provide the data.
 * 
 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
 */
public class HadoopPcaVladExtractor extends Configured implements Tool {
        private static final String VLAD_INDEXER_DATA_PATH_KEY = "openimaj.vlad.indexer.data";

        /**
         * {@link Mapper} for extracting PCA-VLAD features from sets of local
         * features
         * 
         * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
         */
        static class PcaVladMapper extends Mapper<Text, BytesWritable, Text, BytesWritable> {
                static enum COUNTERS {
                        EMIT, NULL;
                }

                private VLADIndexerData indexer;

                @Override
                protected void setup(Context context) throws IOException, InterruptedException
                {
                        indexer = VLADIndexerData.read(new File("./" + context.getConfiguration().get(VLAD_INDEXER_DATA_PATH_KEY)));
                }

                @Override
                protected void map(Text key, BytesWritable value, Context context)
                                throws IOException, InterruptedException
                {
                        final List<Keypoint> keys = MemoryLocalFeatureList.read(new ByteArrayInputStream(value.getBytes()),
                                        Keypoint.class);

                        final float[] vladData = indexer.extractPcaVlad(keys);

                        if (vladData == null) {
                                context.getCounter(COUNTERS.NULL).increment(1L);
                                return;
                        }

                        final ByteArrayOutputStream baos = new ByteArrayOutputStream();
                        final DataOutputStream dos = new DataOutputStream(baos);
                        for (final float f : vladData)
                                dos.writeFloat(f);

                        context.write(key, new BytesWritable(baos.toByteArray()));
                        context.getCounter(COUNTERS.EMIT).increment(1L);
                }
        }

        @Option(
                        name = "--dont-compress-output",
                        required = false,
                        usage = "Don't compress sequencefile records.",
                        metaVar = "BOOLEAN")
        private boolean dontcompress = false;

        @Option(
                        name = "--remove",
                        aliases = "-rm",
                        required = false,
                        usage = "Remove the existing output location if it exists.",
                        metaVar = "BOOLEAN")
        private boolean replace = false;

        @Option(name = "--input", aliases = "-i", required = true, usage = "Input local features file.", metaVar = "STRING")
        private String input;

        @Option(name = "--output", aliases = "-o", required = true, usage = "Output pca-vlad file.", metaVar = "STRING")
        private String output;

        @Option(name = "--indexer-data", aliases = "-id", required = true, usage = "Indexer data file.", metaVar = "STRING")
        private String indexerData;

        @Override
        public int run(String[] args) throws Exception {
                final CmdLineParser parser = new CmdLineParser(this);

                try {
                        parser.parseArgument(args);
                } catch (final CmdLineException e) {
                        System.err.println(e.getMessage());
                        System.err.println("Usage: hadoop jar HadoopImageIndexer.jar [options]");
                        parser.printUsage(System.err);
                        return -1;
                }

                final Path[] paths = SequenceFileUtility.getFilePaths(input, "part");
                final Path outputPath = new Path(output);

                if (outputPath.getFileSystem(this.getConf()).exists(outputPath) && replace)
                        outputPath.getFileSystem(this.getConf()).delete(outputPath, true);

                final Job job = TextBytesJobUtil.createJob(paths, outputPath, null, this.getConf());
                job.setJarByClass(this.getClass());
                job.setMapperClass(PcaVladMapper.class);
                job.setNumReduceTasks(0);

                DistributedCache.addFileToClassPath(new Path(indexerData), job.getConfiguration());
                job.getConfiguration().set(VLAD_INDEXER_DATA_PATH_KEY, new Path(indexerData).getName());

                SequenceFileOutputFormat.setCompressOutput(job, !dontcompress);
                job.waitForCompletion(true);

                return 0;
        }

        /**
         * Main method
         * 
         * @param args
         * @throws Exception
         */
        public static void main(String[] args) throws Exception {
                ToolRunner.run(new HadoopPcaVladExtractor(), args);
        }
}