/**
    * 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;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.openimaj.audio.analysis.FourierTransform;
  import org.openimaj.audio.processor.AudioProcessor;
  import org.openimaj.util.pair.IndependentPair;
  import org.openimaj.util.pair.Pair;
  
  /**
   * {@link AudioProcessor} that provides frequency information.
   * 
   * @author David Dupplaw (dpd@ecs.soton.ac.uk)
   *
   */
  public class FrequencyAudioSource extends AudioProcessor implements Runnable {
  	
  	/**
  	 * Interface for classes that listen to the frequency information
  	 * extracted by the {@link FrequencyAudioSource}.
  	 * 
  	 * @author David Dupplaw (dpd@ecs.soton.ac.uk)
  	 *
  	 */
  	public static interface Listener {
  
  		/**
  		 * Called when new frequency data is available.
  		 * 
  		 * @param fftReal real fft values
  		 * @param fftImag imaginary fft values
  		 * @param low
  		 * @param high
  		 */
  		public void consumeFrequency(float[] fftReal, float[] fftImag, int low, int high);
  		
  	}
  
  	private final FourierTransform fftProc;
  	private final List<IndependentPair<Listener, Pair<Integer>>> listeners;
  	private float[] fftReal;
  	private float[] fftImag;
  	
  	
  	/**
  	 * Construct on top of given stream
  	 * @param stream the stream
  	 */
  	public FrequencyAudioSource(final AudioStream stream) {
  		super(stream);
  		this.fftProc = new FourierTransform();
  		this.listeners = new ArrayList<IndependentPair<Listener, Pair<Integer>>>();
  		new Thread(this).start();
  	}
  	
  	@Override
  	public SampleChunk process(final SampleChunk sample) throws Exception {
  		this.fftProc.process(sample);
  		final float[] fft = this.fftProc.getLastFFT()[0];
  		this.fireFrequencyEvent(fft,sample);
  		return sample;
  	}
  
  	private void fireFrequencyEvent(final float[] fft,final SampleChunk sample) {
  		final double binSize = (sample.getFormat().getSampleRateKHz()*1000) / (fft.length/2);
  		if(this.fftReal == null || fft.length/4 != this.fftReal.length){
  			this.fftReal = new float[fft.length/4];
  			this.fftImag = new float[fft.length/4];
  		}
 		// Extract the spectra
 		for( int i = 0; i < fft.length/4; i++ )
 		{
 			final float re = fft[i*2];
 			final float im = fft[i*2+1];
 			this.fftReal[i] = re;
 			this.fftImag[i] = im;
 		}
 		for(final IndependentPair<Listener,Pair<Integer>> l : this.listeners){
 			final Pair<Integer> range = l.secondObject();
 			final int low = (int) (range.firstObject()/binSize);
 			final int high = (int) (range.secondObject()/binSize);
 			l.firstObject().consumeFrequency(this.fftReal,this.fftImag,low,high);
 		}
 	}
 
 	@Override
 	public void run() {
 //		while(true){
 			try
 	        {
 		        Thread.sleep( 500 );
 		        SampleChunk s = null;
 		        while( (s = this.nextSampleChunk()) != null ) {
 		        	this.process( s );
 		        }
 	        }
 	        catch( final InterruptedException e )
 	        {
 	        	e.printStackTrace();
 	        } 
 	        catch (final Exception e) 
 	        {
 	        	e.printStackTrace();
 	        }
 	        
 //		}
 	}
 
 	/**
 	 * Add a listener
 	 * @param l the listener
 	 */
 	public void addFrequencyListener(final Listener l) {
 		final Pair<Integer> range = null;
 		this.listeners.add(IndependentPair.pair(l,range));
 	}
 	
 	/**
 	 * Add a listener
 	 * @param l the listener
 	 * @param requestFrequencyRange the range
 	 */
 	public void addFrequencyListener(final Listener l, final Pair<Integer> requestFrequencyRange) {
 		this.listeners.add(IndependentPair.pair(l,requestFrequencyRange));
 	}
 }