/*
 * TeleStax, Open Source Cloud Communications
 * Copyright 2011-2014, Telestax Inc and individual contributors
 * by the @authors tag.
 *
 * This program is free software: you can redistribute it and/or modify
 * under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation; either version 3 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */
package org.restcomm.connect.commons.util;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;

/**
 * @author ricardo.limonta@gmail.com (Ricardo Limonta)
 */
public class PcmToWavConverterUtils {

    public void rawToWave(final File rawFile, final File waveFile) throws IOException {

        byte[] rawData = new byte[(int) rawFile.length()];
        DataInputStream input = null;
        try {
            input = new DataInputStream(new FileInputStream(rawFile));
            input.read(rawData);
        } finally {
            if (input != null) {
                input.close();
            }
        }

        DataOutputStream output = null;
        try {
            output = new DataOutputStream(new FileOutputStream(waveFile));
            // WAVE header
            writeString(output, "RIFF"); // chunk id
            writeInt(output, 36 + rawData.length); // chunk size
            writeString(output, "WAVE"); // format
            writeString(output, "fmt "); // subchunk 1 id
            writeInt(output, 16); // subchunk 1 size
            writeShort(output, (short) 1); // audio format (1 = PCM)
            writeShort(output, (short) 1); // number of channels
            writeInt(output, 8000); // sample rate
            writeInt(output, 8 * 2); // byte rate
            writeShort(output, (short) 2); // block align
            writeShort(output, (short) 16); // bits per sample
            writeString(output, "data"); // subchunk 2 id
            writeInt(output, rawData.length); // subchunk 2 size
            // Audio data (conversion big endian -> little endian)
            short[] shorts = new short[rawData.length / 2];
            ByteBuffer.wrap(rawData).order(ByteOrder.LITTLE_ENDIAN).asShortBuffer().get(shorts);
            ByteBuffer bytes = ByteBuffer.allocate(shorts.length * 2);
            for (short s : shorts) {
                bytes.putShort(s);
            }

            output.write(fullyReadFileToBytes(rawFile));
        } finally {
            if (output != null) {
                output.close();
            }
        }
    }

    byte[] fullyReadFileToBytes(File f) throws IOException {
        int size = (int) f.length();
        byte[] bytes = new byte[size];
        byte[] tmpBuff = new byte[size];
        FileInputStream fis = new FileInputStream(f);
        try {

            int read = fis.read(bytes, 0, size);
            if (read < size) {
                int remain = size - read;
                while (remain > 0) {
                    read = fis.read(tmpBuff, 0, remain);
                    System.arraycopy(tmpBuff, 0, bytes, size - remain, read);
                    remain -= read;
                }
            }
        } catch (IOException e) {
            throw e;
        } finally {
            fis.close();
        }

        return bytes;
    }

    private void writeInt(final DataOutputStream output, final int value) throws IOException {
        output.write(value >> 0);
        output.write(value >> 8);
        output.write(value >> 16);
        output.write(value >> 24);
    }

    private void writeShort(final DataOutputStream output, final short value) throws IOException {
        output.write(value >> 0);
        output.write(value >> 8);
    }

    private void writeString(final DataOutputStream output, final String value) throws IOException {
        for (int i = 0; i < value.length(); i++) {
            output.write(value.charAt(i));
        }
    }

}
