/**
 ########################################################################
 # Copyright (C) 2013 Panagiotis Kritikakos <panoskrt@gmail.com>   	#
 # 																		#
 # This program is free software: you can redistribute it and/or modify #
 # it under the terms of the GNU General Public License as published by #
 # the Free Software Foundation, either version 3 of the License, or 	#
 # (at your option) any later version. 					#
 # 									#
 # This program is distributed in the hope that it will be useful, 	#
 # but WITHOUT ANY WARRANTY; without even the implied warranty of 	#
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 	#
 # GNU General Public License for more details. 			#
 # 									#
 # You should have received a copy of the GNU General Public License 	#
 # along with this program. If not, see <http://www.gnu.org/licenses/>. #
 ########################################################################
 **/

package com.panoskrt.javaencrypt;

import java.io.FileInputStream;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Encrypt {

	private FileInputStream fis;

	public Encrypt() {
		// Constructor
	}

	public String encryptString(String input, String salt, String algorithm) {
		String output = null;
		String fullInput = null;

		if (!salt.equals(null)) {
			fullInput = salt + input;
		} else {
			fullInput = input;
		}

		try {
			MessageDigest digest = MessageDigest.getInstance(algorithm);
			digest.update(fullInput.getBytes(), 0, fullInput.length());
			output = new BigInteger(1, digest.digest()).toString(16);
		} catch (NoSuchAlgorithmException ex) {
			ex.printStackTrace();
		}
		return output;
	}

	// Based on: http://www.mkyong.com/java/how-to-generate-a-file-checksum-value-in-java/
	public String calculateFingerprint(String fileName, String algorithm) {
		StringBuffer sb = new StringBuffer();
		try {
			MessageDigest md = MessageDigest.getInstance(algorithm);
			fis = new FileInputStream(fileName);
			byte[] dataBytes = new byte[1024];

			int nread = 0;
			while ((nread = fis.read(dataBytes)) != -1) {
				md.update(dataBytes, 0, nread);
			}

			byte[] mdbytes = md.digest();
			for (int i = 0; i < mdbytes.length; i++) {
				sb.append(Integer.toString((mdbytes[i] & 0xff) + 0x100, 16).substring(1));
			}
		} catch (Exception ex) {
			ex.printStackTrace();
		}
		return sb.toString();
	}
}