/**
 * 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.demos.sandbox.audio;

import java.io.File;
import java.net.URL;

import org.openimaj.audio.AudioStream;
import org.openimaj.audio.SampleChunk;
import org.openimaj.audio.samples.SampleBuffer;
import org.openimaj.video.xuggle.XuggleAudio;

import edu.cmu.sphinx.frontend.BaseDataProcessor;
import edu.cmu.sphinx.frontend.Data;
import edu.cmu.sphinx.frontend.DataEndSignal;
import edu.cmu.sphinx.frontend.DataProcessingException;
import edu.cmu.sphinx.frontend.DataStartSignal;
import edu.cmu.sphinx.frontend.DoubleData;

/**
 *      A wrapper that allows OpenIMAJ audio objects to be used as input
 *      to a Sphinx4 speech recogniser.
 * 
 *      @author David Dupplaw (dpd@ecs.soton.ac.uk)
 *      @created 7 Jun 2012
 *      
 */
public class OpenIMAJAudioFileDataSource extends BaseDataProcessor
{
        /** Total number of values read */
        private long totalValuesRead = -1;
        
        /** The audio stream being used */
        private AudioStream audioStream = null;
        
        /** Set to true when we reach the end of the file */
        private boolean atEOF = false;

        /**
         *      Default constructor
         */
        public OpenIMAJAudioFileDataSource()
        {
        }
        
        /**
         *      Construct an OpenIMAJ audio wrapper for Sphinx
         *      @param as The audio stream to wrap
         */
        public OpenIMAJAudioFileDataSource( AudioStream as )
        {
                this.audioStream = as;
        }
        
        /**
         *      Reads data from the OpenIMAJ stream and creates Data packets for
         *      Sphinx. Creates a {@link DataStartSignal} and {@link DataEndSignal}
         *      at the beginning and end of the stream. 
         *
         *      @see edu.cmu.sphinx.frontend.util.AudioFileDataSource#getData()
         */
        @Override
        public Data getData() throws DataProcessingException
        {
                if( atEOF ) return null;
                
                getTimer().start();
                Data output = null;

                double sampleRate = audioStream.getFormat().
                                getSampleRateKHz() * 1000;

                // First time through?
                if( totalValuesRead == -1 )
                {
                        // If it's the first time through, we need to generate 
                        // a DataSignalStart packet
                        output = new DataStartSignal( (int)sampleRate );
                        totalValuesRead = 0;
                }
                else
                {
                        // Get some values we'll be needing
                long collectTime = System.currentTimeMillis();
                long firstSample = totalValuesRead;
        
                // Get the next sample chunk from the audio stream
                SampleChunk sc = audioStream.nextSampleChunk();
                
                // If we're at the end of the stream....
                if( sc == null )
                {
                        // Data End Signal (duration in milliseconds)
                        output = new DataEndSignal( (long)(totalValuesRead/sampleRate*1000) );
                        atEOF = true;
                }
                else
                {
                        // Get a sample buffer from the chunk
                        SampleBuffer b = sc.getSampleBuffer();
                        
                        // Keep a total of how many samples we've processed
                        totalValuesRead += b.size();
                                
                        // Create the data output packet
                        output = new DoubleData( b.asDoubleArray(), (int)sampleRate, 
                                        collectTime, firstSample );
                }
                }
        
                getTimer().stop();
                return output;
        }
        
        /**
         *      Set the audio file to read. Will instantiate a {@link XuggleAudio}
         *      to stream the data from.
         *      @param url The audio file location
         */
        public void setAudioFile( URL url )
        {
                this.audioStream = new XuggleAudio( url );
        }
        
        /**
         *      Set the audio file to read. Will instantiate a {@link XuggleAudio}
         *      to stream the data from.
         *      @param f The audio file location
         */
        public void setAudioFile( File f )
        {
                this.audioStream = new XuggleAudio( f );
        }
        
        /**
         *      Set the audio stream from which to read data.
         *      @param as The audio stream.
         */
        public void setAudioStream( AudioStream as )
        {
                this.audioStream = as;
        }
}