/**
 * 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.audio.features;

import org.openimaj.audio.AudioStream;
import org.openimaj.audio.SampleChunk;
import org.openimaj.audio.processor.AudioProcessor;
import org.openimaj.audio.samples.SampleBuffer;
import org.openimaj.feature.DoubleFV;
import org.openimaj.feature.FeatureExtractor;
import org.openimaj.util.array.ArrayUtils;

/**
 *      This class provides an OpenIMAJ wrapper for the JAudio library of feature extractors.
 *      It provides the marshalling of data from the OpenIMAJ audio streams into
 *      the data structures necessary for the jAudio FeatureExtractor interface.
 *
 *      @author David Dupplaw (dpd@ecs.soton.ac.uk)
 *  @created 23 May 2013
 *      @version $Author$, $Revision$, $Date$
 */
public abstract class JAudioFeatureExtractor extends AudioProcessor
        implements FeatureExtractor<DoubleFV, SampleChunk>
{
        /** The jaudio feature extractor */
        protected jAudioFeatureExtractor.AudioFeatures.FeatureExtractor featureExtractor;

        /** The feature that was last calculated */
        private double[][] lastCalculatedFeature;

        /**
         *      Default constructor for ad-hoc processing.
         */
        public JAudioFeatureExtractor()
        {
        }

        /**
         *      Chainable constructor
         *      @param as The audio stream to chain to.
         */
        public JAudioFeatureExtractor( final AudioStream as )
        {
                super( as );
        }

        /**
         *      Process the given sample buffer.
         *      @param sb The sample buffer
         *      @return The sample buffer
         */
        public SampleBuffer process( final SampleBuffer sb )
        {
                final double[][] chanSamples = sb.asDoubleChannelArray();
                this.lastCalculatedFeature = new double[chanSamples.length][];
                for( int c = 0; c < sb.getFormat().getNumChannels(); c++ )
                        this.lastCalculatedFeature[c] = this.process( chanSamples[c], sb.getFormat().getSampleRateKHz()*1000d );
                return sb;
        }

        /**
         *      Process the given sample data.
         *      @param samples The samples
         *      @param sampleRate The sample rate of the data
         *      @return The features
         */
        public double[][] process( final double[][] samples, final double sampleRate )
        {
                final double[][] featureVectors = new double[samples.length][];
                for( int i = 0; i < samples.length; i++ )
                        featureVectors[i] = this.process( samples[i], sampleRate );
                return featureVectors;
        }

        /**
         *      Process the given sample array for a single channel
         *      @param samples The samples for a single channel
         *      @param sampleRate The sample rate of the data
         *      @return The feature for the single channel
         */
        public double[] process( final double[] samples, final double sampleRate )
        {
                // Process the feature
                try
                {
                        final double[] f = this.featureExtractor.extractFeature( samples, sampleRate,
                                        this.getExtraInputs( samples, sampleRate ) );
                        return f;
                }
                catch( final Exception e )
                {
                        e.printStackTrace();
                }

                // If an exception occurs we return null
                return null;
        }

        /**
         *      Returns the extra inputs required by a specific feature extractor
         *      @param samples The samples for a single channel
         *      @param sampleRate The sample rate of the data
         *      @return The extra input
         */
        public abstract double[][] getExtraInputs( double[] samples, double sampleRate );

        /**
         *      {@inheritDoc}
         *      @see org.openimaj.audio.processor.AudioProcessor#process(org.openimaj.audio.SampleChunk)
         */
        @Override
        public SampleChunk process( final SampleChunk sample ) throws Exception
        {
                this.process( sample.getSampleBuffer() );
                return sample;
        }

        /**
         *      Calculates the feature for each channel, then flattens the channel arrays
         *      into a single {@link DoubleFV}.
         *
         *      {@inheritDoc}
         *      @see org.openimaj.feature.FeatureExtractor#extractFeature(java.lang.Object)
         */
        @Override
        public DoubleFV extractFeature( final SampleChunk sc )
        {
                // Calculate the feature vector for this frame.
                this.process( sc.getSampleBuffer() );
                return new DoubleFV( ArrayUtils.reshape( this.lastCalculatedFeature ) );
        }

        /**
         *      @return the lastCalculatedFeature
         */
        public double[][] getLastCalculatedFeature()
        {
                return this.lastCalculatedFeature;
        }

        /**
         *      @param lastCalculatedFeature the lastCalculatedFeature to set
         */
        public void setLastCalculatedFeature( final double[][] lastCalculatedFeature )
        {
                this.lastCalculatedFeature = lastCalculatedFeature;
        }

}