package xiphias3.util;

import javax.sound.sampled.AudioFormat;
import java.util.ArrayList;

/*
 * Author: Xiphias3
 * Date:   Oct 19, 2010
 * Time:   9:26:05 AM
 */

public class AudioUtil
{
    public static long millis2Bytes(long lMillis, AudioFormat format) {
        long lBytes = (long) (lMillis * format.getFrameRate()) / (1000 * format.getFrameSize());
        if (format.getFrameSize() > 1)
            lBytes -= (lBytes % format.getFrameSize());
        return lBytes;
    }

    public static long bytesToNanos(long lBytes, javax.media.format.AudioFormat format) {
        long lFrames = lBytes / (format.getSampleSizeInBits() / 8);
        double dSeconds = ((double) lFrames / format.getSampleRate());
        return (long) (dSeconds * 1000000000.0d);
    }

    public static byte[] mixPCM16(byte[] abOutput, int[] anCalcBuffer, ArrayList<byte[]> pcmStreams) {
        if (pcmStreams.size() == 1)
            return pcmStreams.get(0);

        int nMaxLen = -1;
        for (int i = 0; i < pcmStreams.size(); i++)
            if (pcmStreams.get(i).length > nMaxLen)
                nMaxLen = pcmStreams.get(i).length;

        if ((abOutput == null) || (abOutput.length < nMaxLen))
            abOutput = new byte[nMaxLen];

        if ((anCalcBuffer == null) || (anCalcBuffer.length != (nMaxLen / 2)))
            anCalcBuffer = new int[nMaxLen / 2];

        // Add a little amplification if to the mixed data
        float fAmp = 1.0f + (pcmStreams.size() / 10.0f);
        int nFactor = pcmStreams.size();
        for (int i = 0; i < pcmStreams.size(); i++) {
            byte[] abData = pcmStreams.get(i);
            for (int j = 0, k = 0; j < abData.length; j += 2, k += 1) {
                int nSample = (abData[j] & 0xFF) | (abData[j + 1] << 8);
                anCalcBuffer[k] += nSample;
            }
        }

        for (int i = 0; i < anCalcBuffer.length; i++) {
            anCalcBuffer[i] /= nFactor;
            abOutput[i * 2 + 0] = (byte) (anCalcBuffer[i] & 0xFF);
            abOutput[i * 2 + 1] = (byte) (anCalcBuffer[i] >>> 8);

            for (int j = 0; j < 2; j++) {
                int nVal = (int) (fAmp * abOutput[i * 2 + j]);
                if (nVal < Byte.MIN_VALUE)
                    nVal = Byte.MIN_VALUE;
                else if (nVal > Byte.MAX_VALUE)
                    nVal = Byte.MAX_VALUE;
                abOutput[i * 2 + j] = (byte) nVal;
            }
        }

        return abOutput;
    }
}