/**
    * 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;
 	}
 
 }