package com.basinc.golfminus.util;



import java.io.ByteArrayOutputStream;

import java.security.Provider;

import java.security.Security;

import java.util.StringTokenizer;



import javax.crypto.Cipher;

import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;

import javax.crypto.spec.SecretKeySpec;



import org.apache.log4j.Logger;



/**

 * Utility class for encrypting and decrypting data using currently the AES

 * routines.

 * 

 */

public class EncryptionUtils {



	private static Logger log = Logger.getLogger(EncryptionUtils.class);

	private static final String ALGORITHM = "AES";

	private static final String AES_KEY = "138-250-228-149-209-13-189-103-145-215-42-99-30-105-7-59";



	public static String encrypt(String source) {

		// Check for null

		if (source == null || "".equalsIgnoreCase(source.trim())) {

			return "";

		}



		if (isEncrypted(source)) {

			return source;

		}



		try {

			// Get our secret key

			// Key key = getKey();

			// KeyGenerator keyGen = KeyGenerator.getInstance(ALGORITHM);

			// SecretKey key = keyGen.generateKey();

			SecretKey key = new SecretKeySpec(getBytes(AES_KEY), ALGORITHM);



			// Create the cipher

			Cipher cipher = Cipher.getInstance(ALGORITHM);



			// Initialize the cipher for encryption

			cipher.init(Cipher.ENCRYPT_MODE, key);



			// Our cleartext as bytes

			byte[] cleartext = source.getBytes();



			// Encrypt the cleartext

			byte[] ciphertext = cipher.doFinal(cleartext);



			// Return a String representation of the cipher text

			return getString(ciphertext);

		} catch (Exception e) {

			log.error("Error encrypting data.", e);

			return null;

		}

	}



	public static String generateKey() {

		try {

			KeyGenerator keyGen = KeyGenerator.getInstance(ALGORITHM);

			SecretKey key = keyGen.generateKey();

			byte[] bytes = key.getEncoded();

			return getString(bytes);

		} catch (Exception e) {

			log.error("Error generating encryption key.", e);

			return null;

		}

	}



	public static String decrypt(String source) {

		try {

			if (source == null || "".equalsIgnoreCase(source.trim())) {

				return "";

			}



			// If the source is not encrypted, simply return it.

			if (!isEncrypted(source)) {

				return source;

			}



			// Get our secret key

			// Key key = getKey();

			// KeyGenerator keyGen = KeyGenerator.getInstance(ALGORITHM);

			// SecretKey key = keyGen.generateKey();

			SecretKey key = new SecretKeySpec(getBytes(AES_KEY), ALGORITHM);



			// Create the cipher

			Cipher cipher = Cipher.getInstance(ALGORITHM);



			// Encrypt the cleartext

			byte[] ciphertext = getBytes(source);



			// Initialize the same cipher for decryption

			cipher.init(Cipher.DECRYPT_MODE, key);



			// Decrypt the ciphertext

			byte[] cleartext = cipher.doFinal(ciphertext);



			// Return the clear text

			return new String(cleartext);

		} catch (Exception e) {

			log.error("Error decrypting data.", e);

			return null;

		}

	}



	// private static Key getKey()

	// {

	// try

	// {

	// byte[] bytes = getBytes(KEY_STRING);

	// DESKeySpec pass = new DESKeySpec(bytes);

	// SecretKeyFactory skf = SecretKeyFactory.getInstance(ALGORITHM);

	// SecretKey s = skf.generateSecret(pass);

	// return s;

	// }

	// catch (Exception e)

	// {

	// e.printStackTrace();

	// }

	// return null;

	// }



	/**

	 * Returns true if the specified text is encrypted, false otherwise

	 * 

	 * @param text

	 * @return boolean

	 */

	public static boolean isEncrypted(String text) {

		// Check for null

		if (text == null) {

			return false;

		}



		// If the string does not have any separators then it is not encrypted

		if (text.indexOf('-') == -1) {

			return false;

		}



		StringTokenizer st = new StringTokenizer(text, "-", false);

		while (st.hasMoreTokens()) {

			String token = st.nextToken();

			if (token.length() > 3) {

				return false;

			}

			for (int i = 0; i < token.length(); i++) {

				if (!Character.isDigit(token.charAt(i))) {

					return false;

				}

			}

		}

		return true;

	}



	private static String getString(byte[] bytes) {

		StringBuffer sb = new StringBuffer();

		for (int i = 0; i < bytes.length; i++) {

			byte b = bytes[i];

			sb.append((int) (0x00FF & b));

			if (i + 1 < bytes.length) {

				sb.append("-");

			}

		}

		return sb.toString();

	}



	private static byte[] getBytes(String str) {

		if (str == null) {

			return null;

		}



		ByteArrayOutputStream bos = new ByteArrayOutputStream();

		StringTokenizer st = new StringTokenizer(str, "-", false);

		while (st.hasMoreTokens()) {

			int i = Integer.parseInt(st.nextToken());

			bos.write((byte) i);

		}

		return bos.toByteArray();

	}



	// private static String generateBlowfishKey() {

	// try {

	// KeyGenerator kgen = KeyGenerator.getInstance("Blowfish");

	// SecretKey skey = kgen.generateKey();

	// byte[] raw = skey.getEncoded();

	// return getString(raw);

	// } catch (Exception e) {

	// log.error("Error generating encryption key.", e);

	// return null;

	// }

	// }



	public static void main(String[] args) {

		showProviders();

		if (args.length < 1) {

			System.out.println("Usage: EncryptionUtils <command> < args > ");

			System.out.println("\t<command>: encrypt, decrypt, generate - key");

			System.exit(0);



		}

		String command = args[0];

		if (command.equalsIgnoreCase("generate-key")) {

			System.out.println("New key: " + generateKey());

		} else if (command.equalsIgnoreCase("encrypt")) {

			String plaintext = args[1];

			String cipherText = encrypt(plaintext);

			System.out.println(plaintext + " = " + cipherText);

			System.out.println(cipherText + " = " + decrypt(cipherText));

		} else if (command.equalsIgnoreCase("decrypt")) {

			String ciphertext = args[1];

			System.out.println(ciphertext + " = " + decrypt(ciphertext));

		}

	}



	public static void showProviders() {

		try {

			Provider[] providers = Security.getProviders();

			for (int i = 0; i < providers.length; i++) {

				System.out.println("Provider: " + providers[i].getName() + ", " + providers[i].getInfo());

				for (Object o : providers[i].keySet()) {

					String key = (String) o;

					String value = (String) providers[i].get(key);

					System.out.println("\t" + key + " = " + value);

				}

			}

		} catch (Exception e) {

			log.error("Error listing security providers.", e);

		}

	}

}