package br.com.elotech.base.util;


import java.io.ByteArrayOutputStream;

import lombok.SneakyThrows;

public class EloPaddingUtils {

    private ByteArrayOutputStream data;
    private int blockSize;
    private static final int BLOCKSIZE_8 = 8;

    public EloPaddingUtils() {
        setBlockSize(BLOCKSIZE_8);
    }

    @SneakyThrows
    public void addData(byte[] data) {

        this.data.write(data);
    }

    public int getBlockSize() {
        return blockSize;
    }

    public void setBlockSize(int blockSize) {
        this.blockSize = blockSize;
        reset();
    }

    public int getPaddedSize() {
        return (data.size() / blockSize + 1) * blockSize;
    }

    public int getUnpaddedSize() {
        byte[] data = this.data.toByteArray();
        return data.length - data[data.length - 1];
    }

    @SneakyThrows
    public byte[] getPaddedData() {

        byte[] bfr = this.data.toByteArray();
        byte padSize = (byte) (getPaddedSize() - bfr.length);
        ByteArrayOutputStream data = new ByteArrayOutputStream();
        data.write(bfr);
        bfr = new byte[padSize];
        for (int i = 0; i < padSize - 1; i++) {
            bfr[i] = 0;
        }
        bfr[bfr.length - 1] = padSize;
        data.write(bfr);
        return data.toByteArray();
    }

    @SneakyThrows
    public byte[] getUnpaddedData() {

        byte[] bfr = this.data.toByteArray();
        byte padSize = bfr[bfr.length - 1];
        ByteArrayOutputStream data = new ByteArrayOutputStream();
        data.write(bfr, 0, bfr.length - padSize);
        return data.toByteArray();
    }

    public void reset() {
        data = new ByteArrayOutputStream();
    }

}