package com.FitBank.common;

import java.io.ByteArrayOutputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;

/**
 * Clase que codifica un stream.
 * 
 * @author FitBank
 * @version 1.0
 */
public class Base64OutputStream extends FilterOutputStream {

	private static final char[] BASE_64 = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
    	 	  'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
              'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p',
              'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
              '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' };

    private int   col   = 0;
    private int   i     = 0;
    private int[] inbuf = new int[4];

    /**
     * Crea un nuevo objeto Base64OutputStream.
     * 
     * @param out Salida
     */
    public Base64OutputStream(OutputStream out) {
        super(out);
    }

    /**
     * Decodifica un array de bytes codificado.
     * 
     * @param contenido Array de bytes
     * 
     * @return array de bytes decodificado
     */
    public static String codificar(byte[] contenido) {
        ByteArrayOutputStream o   = new ByteArrayOutputStream();
        Base64OutputStream    out = new Base64OutputStream(o);

        try {
            out.write(contenido);
            out.flush();
        } catch (IOException e) {
            Debug.imprimirError(e);
        }

        return o.toString();
    }

    /**
     * Escribe un caracter.
     * 
     * @param c Caracter
     * 
     * @throws IOException en caso de error
     */
    @Override
    public void write(int c) throws IOException {
        inbuf[i++] = c;

        if (i == 3) {
            super.write(BASE_64[(inbuf[0] & 0xFC) >> 2]);
            super.write(BASE_64[(inbuf[0] & 0x03) << 4 | (inbuf[1] & 0xF0) >> 4]);
            super.write(BASE_64[(inbuf[1] & 0x0F) << 2 | (inbuf[2] & 0xC0) >> 6]);
            super.write(BASE_64[(inbuf[2] & 0x3F)]);

            col += 4;
            i    = 0;

            if (col >= 76) {
                super.write('\n');
                col = 0;
            }
        }
    }

    /**
     * Concluye el flujo y limpia los buffers temporales.
     * 
     * @throws IOException en caso de error.
     */
    @Override
    public void flush() throws IOException {
        if (i == 1) {
            super.write(BASE_64[(inbuf[0] & 0xFC) >> 2]);
            super.write(BASE_64[(inbuf[0] & 0x03) << 4]);
            super.write('=');
            super.write('=');
        } else if (i == 2) {
            super.write(BASE_64[(inbuf[0] & 0xFC) >> 2]);
            super.write(BASE_64[(inbuf[0] & 0x03) << 4 | (inbuf[1] & 0xF0) >> 4]);
            super.write(BASE_64[(inbuf[1] & 0x0F) << 2]);
            super.write('=');
        }
    }
}