package laudarch.utils;

import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * Created by laudarch on 16/12/13.
 */

public class EncryptionUtils {
    public static String sha1(String input) throws NoSuchAlgorithmException {
	MessageDigest mDigest = MessageDigest.getInstance("SHA1");
	byte[]        result  = mDigest.digest(input.getBytes());
	StringBuffer  sb      = new StringBuffer();

	for (int i = 0; i < result.length; i++) {
	    sb.append(Integer.toString((result[i] & 0xff) + 0x100, 16).substring(1));
	}

	return sb.toString();
    }

    public static String sha256(String input) throws NoSuchAlgorithmException {
	MessageDigest mDigest = MessageDigest.getInstance("SHA256");
	byte[]        result  = mDigest.digest(input.getBytes());
	StringBuffer  sb      = new StringBuffer();

	for (int i = 0; i < result.length; i++) {
	    sb.append(Integer.toString((result[i] & 0xff) + 0x100, 16).substring(1));
	}

	return sb.toString();
    }


    /**
     * Verifies SHA1 checksum
     * @param data to be verified
     * @param testChecksum the expected checksum
     * @return true if the SHA1 checksum of data matches the given SHA1 checksum; false otherwise.
     * @throws NoSuchAlgorithmException
     * @throws IOException
     */
    public static boolean verifySHA1Checksum(String data, String testChecksum) throws NoSuchAlgorithmException, IOException
    {
	String dataHash = EncryptionUtils.sha1(data);

	return dataHash.equals(testChecksum);
    }

    /**
     * Verifies SHA256 checksum
     * @param data  to be verified
     * @param testChecksum the expected checksum
     * @return true if the SHA256 checksum of the data matches the given SHA256 checksum; false otherwise.
     * @throws NoSuchAlgorithmException
     * @throws IOException
     */
    public static boolean verifyChecksum(String data, String testChecksum) throws NoSuchAlgorithmException, IOException
    {
	String dataHash = sha256(data);

	return dataHash.equals(testChecksum);
    }
}