/**
 * 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.filters;

import java.util.ArrayList;
import java.util.List;

import org.openimaj.audio.AudioFormat;
import org.openimaj.audio.SampleChunk;
import org.openimaj.audio.processor.AudioProcessor;
import org.openimaj.audio.util.WesternScaleNote;

/**
 *      A filter bank for musical note detection. Uses a set of comb filters
 *      tuned to the notes that are to be detected.
 *
 *  @author David Dupplaw <dpd@ecs.soton.ac.uk>
 *      @version $Author$, $Revision$, $Date$
 *      @created 30 Apr 2012
 */
public class MusicalNoteFilterBank extends AudioProcessor
{
        /** The start of the range as a MIDI note number */
        private int startOfRange = 0;
        
        /** The end of the range as a MIDI note number */
        private int endOfRange = 0;
        
        /** The filters we'll use */
        private List<FeedForwardCombFilter> filters = null;
        
        /** The audio format that will be processed */
        private AudioFormat format = null;
        
        /** The last calculated output power of the filter bank */
        private double outputPower = 0;
        
        /**
         *      Create a 12-deep filter bank for detecting notes
         *      between C4 and C5. The audio format may be null
         *      if not known in advance; in this case, the filter
         *      bank will be setup lazily during the processing loop. 
         * 
         *      @param af The audio format of the filter bank
         */
        public MusicalNoteFilterBank( final AudioFormat af )
    {
                this( 60, 72, af );
    }
        
        /**
         *      Create a filter bank for detecting notes between the start
         *      note given and the end note given. The audio format may be null
         *      if not known in advance; in this case, the filter
         *      bank will be setup lazily during the processing loop.
         * 
         *  @param startOfRange The start MIDI note number to detect
         *  @param endOfRange The end MIDI note number to detect.
         *  @param af The format
         */
        public MusicalNoteFilterBank( final int startOfRange, final int endOfRange, final AudioFormat af )
    {
                this.startOfRange = startOfRange;
                this.endOfRange = endOfRange;
                this.format = af;
                
                if( this.format != null )
                        this.setupFilters();
    }
        
        /**
         *      Setup the filters based on the settings of this class.
         */
        private void setupFilters()
        {
                this.filters = new ArrayList<FeedForwardCombFilter>();
                for( int i = this.startOfRange; i < this.endOfRange; i++ )
                {
                        // Get the frequency of the given note
                        final double f = WesternScaleNote.createNote( i ).frequency;
                        
                        // Add a feed-forward comb filter for that frequency
                        this.filters.add( new FeedForwardCombFilter( f, 
                                        this.format.getSampleRateKHz()*1000d, 1f ) );
                }
    }

        /**
         *      {@inheritDoc}
         *      @see org.openimaj.audio.processor.AudioProcessor#process(org.openimaj.audio.SampleChunk)
         */
        @Override
        public SampleChunk process( final SampleChunk sample ) throws Exception
        {
                if( this.filters == null )
                {
                        this.format = sample.getFormat();
                        this.setupFilters();
                }
                
                this.outputPower = 0;
                for( final FeedForwardCombFilter filter : this.filters )
                {
                        // Process the sample with each filter
                        filter.process( sample );
                        this.outputPower += filter.getOutputPower();
                }
                
                return sample;
        }
        
        /**
         *      Get the last calculated output power.
         *      @return The last calcualted output power
         */
        public double getOutputPower()
        {
                return this.outputPower;
        }
}