/**
    * 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.generation;
  
  import org.openimaj.audio.AudioFormat;
  import org.openimaj.audio.SampleChunk;
  import org.openimaj.audio.generation.Synthesizer.FMOptions;
  import org.openimaj.audio.generation.Synthesizer.OscillatorOptions;
  import org.openimaj.audio.samples.SampleBuffer;
  import org.openimaj.audio.samples.SampleBufferFactory;
  
  /**
   * 	The oscillator implementations for the synthesiser.
   *
   *  @author David Dupplaw (dpd@ecs.soton.ac.uk)
   *
   *	@created 2 May 2012
   */
  public interface Oscillator
  {
  	/**
  	 * 	Oscillator that produces pure sine waves.
  	 *
  	 *	@author David Dupplaw (dpd@ecs.soton.ac.uk)
  	 *  @created 21 Feb 2013
  	 *	@version $Author$, $Revision$, $Date$
  	 */
  	public static class SineOscillator implements Oscillator
  	{
  		@Override
          public SampleChunk getSampleChunk( final int length, final double time,
  				final double freq, final int gain, final AudioFormat format )
          {
  			// Work out how many samples per frequency wave
  			final double samplesPerWave = format.getSampleRateKHz()*1000d/freq;
  
  			// Phase offset in samples. (f*t)-floor(f*t) is the part number
  			// of waves at this point (assuming the first wave starts at a
  			// phase of zero).
  			final double p = 2*Math.PI*((freq*time)-Math.floor(freq*time));
  
  			// Create an appropriate sample buffer
  			final SampleBuffer sb = SampleBufferFactory.createSampleBuffer(
  					format, length );
  
  			// Fill it with sin waves
  			final double z = 2*Math.PI/samplesPerWave;
  			for( int i = 0; i < length; i++ )
  				sb.set( i, (float)(Math.sin( i*z+p )*gain) );
  
              return sb.getSampleChunk();
          }
  
  		@Override
  		public OscillatorOptions getOptions()
  		{
  			return null;
  		}
  	};
  
  	/**
  	 * 	Oscillator that produces pure square waves.
  	 *
  	 *	@author David Dupplaw (dpd@ecs.soton.ac.uk)
  	 *  @created 21 Feb 2013
  	 *	@version $Author$, $Revision$, $Date$
  	 */
  	public static class SquareOscillator implements Oscillator
  	{
  		@Override
          public SampleChunk getSampleChunk( final int length, final double time,
  				final double freq, final int gain, final AudioFormat format )
         {
 			final SampleBuffer sb = SampleBufferFactory.createSampleBuffer(
 					format, length );
 
 			final double samplesPerWave = format.getSampleRateKHz()*1000d/freq;
 
 			// phase offset in samples
 			final int p = (int)( samplesPerWave *
 				((freq*time)-Math.floor(freq*time)));
 
 			for( int i = 0; i < length; i++ )
 			{
 				final int x = (i+p) % (int)samplesPerWave;
 				if( x > samplesPerWave/2 )
 						sb.set( i, gain );
 				else	sb.set( i, -gain );
 			}
 
             return sb.getSampleChunk();
         }
 
 		@Override
 		public OscillatorOptions getOptions()
 		{
 			return null;
 		}
 	};
 
 	/**
 	 * 	Oscillator that produces saw waves.
 	 *
 	 *	@author David Dupplaw (dpd@ecs.soton.ac.uk)
 	 *  @created 21 Feb 2013
 	 *	@version $Author$, $Revision$, $Date$
 	 */
 	public static class SawOscillator implements Oscillator
 	{
 		@Override
         public SampleChunk getSampleChunk( final int length, final double time,
 				final double freq, final int gain, final AudioFormat format )
         {
 			final SampleBuffer sb = SampleBufferFactory.createSampleBuffer(
 					format, length );
 
 			final double samplesPerWave = format.getSampleRateKHz()*1000d/freq;
 
 			// phase offset in samples
 			final int p = (int)( samplesPerWave *
 				((freq*time)-Math.floor(freq*time)));
 
 			for( int i = 0; i < length; i++ )
 			{
 				final int x = (i+p) % (int)samplesPerWave;
 				sb.set( i, (float)(x*(gain/samplesPerWave)) );
 			}
 
             return sb.getSampleChunk();
         }
 
 		@Override
 		public OscillatorOptions getOptions()
 		{
 			return null;
 		}
 	};
 
 	/**
 	 * 	White noise generator
 	 *
 	 *	@author David Dupplaw (dpd@ecs.soton.ac.uk)
 	 *  @created 21 Feb 2013
 	 *	@version $Author$, $Revision$, $Date$
 	 */
 	public static class NoiseOscillator implements Oscillator
 	{
 		@Override
 		public SampleChunk getSampleChunk( final int length, final double time,
 				final double freq, final int gain, final AudioFormat format )
 		{
 			final SampleBuffer sb = SampleBufferFactory.createSampleBuffer(
 					format, length );
 			for( int i = 0; i < sb.size(); i++ )
 				sb.set( i, (float)(Math.random() * Integer.MAX_VALUE) );
 			return sb.getSampleChunk();
 		}
 
 		@Override
 		public OscillatorOptions getOptions()
 		{
 			return null;
 		}
 	};
 
 	/**
 	 * 	Generates an empty sample chunk
 	 *
 	 *	@author David Dupplaw (dpd@ecs.soton.ac.uk)
 	 *  @created 21 Feb 2013
 	 *	@version $Author$, $Revision$, $Date$
 	 */
 	public static class DummyOscillator implements Oscillator
 	{
 		@Override
 		public SampleChunk getSampleChunk( final int length, final double time,
 				final double freq, final int gain, final AudioFormat format )
 		{
 			final SampleBuffer sb = SampleBufferFactory.createSampleBuffer(
 					format, length );
 			return sb.getSampleChunk();
 		}
 
 		@Override
 		public OscillatorOptions getOptions()
 		{
 			return null;
 		}
 	};
 
 	/**
 	 * Frequency modulation of wave types. We use a carrier wave that generates a
 	 * tone at the required frequency and modulate with the wave that is the
 	 * modulation wave by altering the time (phase) offset of the carrier using
 	 * the modulation wave.
 	 *
 	 *	@author David Dupplaw (dpd@ecs.soton.ac.uk)
 	 *  @created 21 Feb 2013
 	 *	@version $Author$, $Revision$, $Date$
 	 */
 	public static class FrequencyModulatedOscillator implements Oscillator
 	{
 		/** The options for this synth */
 		private final FMOptions options = new FMOptions();
 
 		@Override
 		public SampleChunk getSampleChunk(final int length, final double time,
 				final double freq, final int gain, final AudioFormat format)
 		{
 //			System.out.println( "======================================================" );
 //			System.out.println( "Getting signal at time "+time );
 
 			// Get the modulator signal
 			final SampleBuffer sb = this.getOptions().modulator.nextSampleChunk().getSampleBuffer();
 
 			// work out the maximum and minimum time signal needed from the carrier
 			// so that we can retrieve the appropriate time chunk from it
 			double minTime = time;
 			double maxTime = time + length;
 			final double step = format.getSampleRateKHz();
 			final double amp = this.getOptions().modulatorAmplitude;
 			for( int i = 0; i < sb.size(); i++ )
 			{
 				final float f = sb.get(i);
 				final double t = time + step*i + f*amp;
 				minTime = Math.min( t, minTime );
 				maxTime = Math.max( t, maxTime );
 			}
 
 			// The start and length of the carrier signal required
 			final int cl = (int)(maxTime - minTime);
 			final double ct = minTime;
 
 //			System.out.println( "Carrier buffer: "+ct+" -> "+cl );
 
 			// Get the carrier signal
 			final SampleBuffer carrierBuffer = this.getOptions().carrier.getOscillator()
 					.getSampleChunk( cl, ct, freq, gain, format ).getSampleBuffer();
 
 			// We'll side-affect the modulator signal, as it's the right length already.
 			for( int i = 0; i < sb.size(); i++ )
 			{
 				// The time to retrieve in the carrier signal
 				final float f = sb.get(i);
 				final double t = time + step*i + f*amp;
 
 				// Convert the time back to an index into the carrier buffer
 				final int index = (int)((t - minTime)/step);
 
 				sb.set( i, carrierBuffer.get( index ) );
 
 //				System.out.println( "------ "+i+" ------");
 //				System.out.println( "Value in modulator: "+f+" (scaled to "+(f*amp)+")" );
 //				System.out.println( "Time at position: "+(time + step*i) );
 //				System.out.println( "Modulated time: "+t );
 //				System.out.println( "Index into carrier: "+index );
 //				System.out.println( "Value in carrier: "+carrierBuffer.get(index) );
 			}
 
 			return sb.getSampleChunk();
 		}
 
 		@Override
 		public FMOptions getOptions()
 		{
 			return this.options;
 		}
 	};
 
 	/**
 	 *
 	 *  @param length The length of the sample chunk to generate
 	 *  @param time The time at which the sample chunk should start
 	 *  @param freq The frequency of wave to generate
 	 *  @param gain The gain of the wave to generate (0 <= gain <= MAX_INT)
 	 *  @param format The format of the sample chunk
 	 *  @return The sample chunk
 	 */
 	public abstract SampleChunk getSampleChunk( int length, double time,
 			double freq, int gain, AudioFormat format );
 
 	/**
 	 * 	Returns the options for the particular oscillator type.
 	 *	@return The options object
 	 */
 	public abstract OscillatorOptions getOptions();
 }