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package com.badlogic.audio.io;

import java.io.FileInputStream;

import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.SourceDataLine;
import javax.sound.sampled.AudioFormat.Encoding;


/**
 * Class that allows directly passing PCM float mono
 * data to the sound card for playback. The sampling 
 * rate of the PCM data must be 44100Hz. 
 * 
 * @author mzechner
 *
 */
public class AudioDevice 
{
	/** the buffer size in samples **/
	private final static int BUFFER_SIZE = 1024;
	
	/** the java sound line we write our samples to **/
	private final SourceDataLine out;
	
	/** buffer for BUFFER_SIZE 16-bit samples **/
	private byte[] buffer = new byte[BUFFER_SIZE*2];
	
	/**
	 * Constructor, initializes the audio system for
	 * 44100Hz 16-bit signed mono output. 
	 * 
	 * @throws Exception in case the audio system could not be initialized
	 */
	public AudioDevice( ) throws Exception
	{
		AudioFormat format = new AudioFormat( Encoding.PCM_SIGNED, 44100, 16, 1, 2, 44100, false );
		out = AudioSystem.getSourceDataLine( format );
		out.open(format);	
		out.start();
	}
	
	/**
	 * Writes the given samples to the audio device. The samples
	 * have to be sampled at 44100Hz, mono and have to be in 
	 * the range [-1,1].
	 * 
	 * @param samples The samples.
	 */
	public void writeSamples( float[] samples )
	{
		fillBuffer( samples );
		out.write( buffer, 0, buffer.length );
	}
	
	private void fillBuffer( float[] samples )
	{
		for( int i = 0, j = 0; i < samples.length; i++, j+=2 )
		{
			short value = (short)(samples[i] * Short.MAX_VALUE);
			buffer[j] = (byte)(value | 0xff);
			buffer[j+1] = (byte)(value >> 8 );
		}
	}
	
	public static void main( String[] argv ) throws Exception
	{
		float[] samples = new float[1024];
		WaveDecoder reader = new WaveDecoder( new FileInputStream( "samples/sample.wav" ) );
		AudioDevice device = new AudioDevice( );
		
		while( reader.readSamples( samples ) > 0 )
		{
			device.writeSamples( samples );
		}
		
		Thread.sleep( 10000 );
	}
}