import javax.sound.sampled.*;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;


public class ReadMP3 {


private ArrayList<Integer> bytes = new ArrayList<>();
private AudioFormat decodedFormat;

public ReadMP3() throws UnsupportedAudioFileException, IOException {

    String filename = new ReadFiles().getFile();
    File file = new File(filename);
    AudioInputStream in = AudioSystem.getAudioInputStream(file);
    AudioInputStream din = null;
    AudioFormat baseFormat = in.getFormat();
    AudioFormat decodedFormat = new
    AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
            baseFormat.getSampleRate(),
            16,
            baseFormat.getChannels(),
            baseFormat.getChannels() * 2,
            baseFormat.getSampleRate(),
            false);
    din = AudioSystem.getAudioInputStream(decodedFormat, in);
    this.decodedFormat = decodedFormat;

    int i = 0;
    while(true){
        int currentByte = din.read();
        if (currentByte == -1) {break;}
        bytes.add(i, currentByte);
        i++;
    }
    din.close();
    in.close();
}

public class AnalyzeMP3 {


//adds 4 bytes to offset[i][4], where each i represents 1hz,
//and 44100hz=1sec

public static int[][] calculate(ReadMP3 mp3) {

    //calculates and prints how long the song is
    double seconds = mp3.getBytes().size() /
    mp3.getDecodedFormat().getFrameRate() / 4;
    System.out.println("Length of song: " + (int)seconds + "s");

    //adds 4 values to i through the whole song
    int[][] offset  = new int[mp3.getBytes().size()/4][4];
    for(int i = 0; i < mp3.getBytes().size()/4; i++) {
        for(int j = 0; j < 4; j++) {
            offset[i][j] = mp3.getBytes().get(i+j);
        }
    }


    int skip = (int)((seconds-(offset.length/44100))* 44100);

    return cleanUp(offset, skip);
}

//Removes the header from the mp3 array, the amount to remove from the
//beginning is equal to skip
private static int[][] cleanUp(int[][] array, int skip) {
    int[][] newArray = new int[array.length-skip][4];
    int counter = 0;
    for(int i = skip; i < array.length;i++) {
        newArray[counter][0] = array[i][0];
        newArray[counter][1] = array[i][1];
        newArray[counter][2] = array[i][2];
        newArray[counter][3] = array[i][3];
        counter++;

    }

    return newArray;
}

}