package com.sitech.ibnms.util;

import java.security.MessageDigest;
import java.security.SecureRandom;
import java.util.Random;

public class RandomGUID extends Object {

	public String valueBeforeMD5 = "";

	public String valueAfterMD5 = "";

	private static Random myRand;

	private static SecureRandom mySecureRand;

	public static String s_id;

	public static String s_name;

	private static final int PAD_BELOW = 0x10;

	private static final int TWO_BYTES = 0xFF;

	static {
		mySecureRand = new SecureRandom();
		long secureInitializer = mySecureRand.nextLong();
		myRand = new Random(secureInitializer);
	}

	public RandomGUID() {
		getRandomGUID(false);
	}

	public RandomGUID(boolean secure) {
		getRandomGUID(secure);
	}

	private void getRandomGUID(boolean secure) {
		MessageDigest md5 = null;
		StringBuffer sbValueBeforeMD5 = new StringBuffer(128);

		try {
			md5 = MessageDigest.getInstance("MD5");
			long time = System.currentTimeMillis();
			long rand = 0;

			if (secure) {
				rand = mySecureRand.nextLong();
			} else {
				rand = myRand.nextLong();
			}

			sbValueBeforeMD5.append(s_id);
			sbValueBeforeMD5.append(":");
			sbValueBeforeMD5.append(Long.toString(time));
			sbValueBeforeMD5.append(":");
			sbValueBeforeMD5.append(Long.toString(rand));

			valueBeforeMD5 = sbValueBeforeMD5.toString();
			md5.update(valueBeforeMD5.getBytes());

			byte[] array = md5.digest();
			StringBuffer sb = new StringBuffer(32);
			for (int j = 0; j < array.length; ++j) {
				int b = array[j] & TWO_BYTES;
				if (b < PAD_BELOW)
					sb.append('0');
				sb.append(Integer.toHexString(b));
			}

			valueAfterMD5 = sb.toString();

		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public String toString() {
		String raw = valueAfterMD5.toUpperCase();
		StringBuffer sb = new StringBuffer(64);
		sb.append(raw.substring(0, 8));
		sb.append("-");
		sb.append(raw.substring(8, 12));
		sb.append("-");
		sb.append(raw.substring(12, 16));
		sb.append("-");
		sb.append(raw.substring(16, 20));
		sb.append("-");
		sb.append(raw.substring(20));
		return sb.toString();
	}

	public static String getRandomGUID() {
		RandomGUID myGUID = new RandomGUID();
		return myGUID.toString();
	}

	public static void main(String args[]) {
		for (int i = 0; i < 100; i++) {
			RandomGUID myGUID = new RandomGUID();
			System.out.println(myGUID.toString());
		}
	}

}