package com.uas.sso.common.encrypt.base64;

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

/**
 * Convert binary data to and from UrlBase64 encoding. This is identical to
 * Base64 encoding, except that the padding character is "." and the other
 * non-alphanumeric characters are "-" and "_" instead of "+" and "/".
 * <p>
 * The purpose of UrlBase64 encoding is to provide a compact encoding of binary
 * data that is safe for use as an URL parameter. Base64 encoding does not
 * produce encoded values that are safe for use in URLs, since "/" can be
 * interpreted as a path delimiter; "+" is the encoded form of a space; and "="
 * is used to separate a name from the corresponding value in an URL parameter.
 */
public class UrlBase64 {

	private static final Encoder encoder = new UrlBase64Encoder();

	/**
	 * Encode the input data producing a URL safe base 64 encoded byte array.
	 *
	 * @return a byte array containing the URL safe base 64 encoded data.
	 */
	public static byte[] encode(byte[] data) {
		ByteArrayOutputStream bOut = new ByteArrayOutputStream();

		try {
			encoder.encode(data, 0, data.length, bOut);
		} catch (Exception e) {
			throw new IllegalStateException("exception encoding URL safe base64 data: " + e.getMessage(), e);
		}

		return bOut.toByteArray();
	}

	/**
	 * Encode the byte data writing it to the given output stream.
	 *
	 * @return the number of bytes produced.
	 */
	public static int encode(byte[] data, OutputStream out) throws IOException {
		return encoder.encode(data, 0, data.length, out);
	}

	/**
	 * Decode the URL safe base 64 encoded input data - white space will be
	 * ignored.
	 *
	 * @return a byte array representing the decoded data.
	 */
	public static byte[] decode(byte[] data) {
		ByteArrayOutputStream bOut = new ByteArrayOutputStream();

		try {
			encoder.decode(data, 0, data.length, bOut);
		} catch (Exception e) {
			throw new IllegalStateException("exception decoding URL safe base64 string: " + e.getMessage(), e);
		}

		return bOut.toByteArray();
	}

	/**
	 * decode the URL safe base 64 encoded byte data writing it to the given
	 * output stream, whitespace characters will be ignored.
	 *
	 * @return the number of bytes produced.
	 */
	public static int decode(byte[] data, OutputStream out) throws IOException {
		return encoder.decode(data, 0, data.length, out);
	}

	/**
	 * decode the URL safe base 64 encoded String data - whitespace will be
	 * ignored.
	 *
	 * @return a byte array representing the decoded data.
	 */
	public static byte[] decode(String data) {
		ByteArrayOutputStream bOut = new ByteArrayOutputStream();

		try {
			encoder.decode(data, bOut);
		} catch (Exception e) {
			throw new IllegalStateException("exception decoding URL safe base64 string: " + e.getMessage(), e);
		}

		return bOut.toByteArray();
	}

	/**
	 * Decode the URL safe base 64 encoded String data writing it to the given
	 * output stream, whitespace characters will be ignored.
	 *
	 * @return the number of bytes produced.
	 */
	public static int decode(String data, OutputStream out) throws IOException {
		return encoder.decode(data, out);
	}

}
