/*
   Copyright (C) 2002 MySQL AB

      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 2 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, write to the Free Software
      Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */
package com.mysql.jdbc;

import java.io.ObjectInputStream;
import java.io.PrintWriter;
import java.io.StringWriter;


/**
 * Various utility methods for the driver.
 *
 * @author Mark Matthews
 */
public class Util {
    private static Util enclosingInstance = new Util();

    /**
     * Given a ResultSet and an index into the columns of that ResultSet,
     * read binary data from the column which represents a serialized object,
     * and re-create the object.
     *
     * @param resultSet the ResultSet to use.
     * @param index an index into the ResultSet.
     * @return the object if it can be de-serialized
     * @throws Exception if an error occurs
     */
    public static Object readObject(java.sql.ResultSet resultSet, int index)
        throws Exception {
        ObjectInputStream objIn = new ObjectInputStream(resultSet
                .getBinaryStream(index));
        Object obj = objIn.readObject();
        objIn.close();

        return obj;
    }

    /**
     * DOCUMENT ME!
     *
     * @param message DOCUMENT ME!
     * @param password DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    public static String scramble(String message, String password) {
        long[] hashPass;
        long[] hashMessage;
        byte[] to = new byte[8];
        String val = "";

        message = message.substring(0, 8);

        if ((password != null) && (password.length() > 0)) {
            hashPass = newHash(password);
            hashMessage = newHash(message);

            RandStructcture randStruct = randomInit(hashPass[0]
                    ^ hashMessage[0], hashPass[1] ^ hashMessage[1]);

            int msgPos = 0;
            int msgLength = message.length();
            int toPos = 0;

            while (msgPos++ < msgLength) {
                to[toPos++] = (byte) (Math.floor(rnd(randStruct) * 31) + 64);
            }

            /* Make it harder to break */
            byte extra = (byte) (Math.floor(rnd(randStruct) * 31));

            for (int i = 0; i < to.length; i++) {
                to[i] ^= extra;
            }

            val = new String(to);
        }

        return val;
    }

    /**
     * Converts a nested exception into a nicer message
     *
     * @param ex the exception to expand into a message.
     *
     * @return a message containing the exception, the
     * message (if any), and a stacktrace.
     */
    public static String stackTraceToString(Throwable ex) {
        StringBuffer traceBuf = new StringBuffer();
        traceBuf.append("\n\n** BEGIN NESTED EXCEPTION ** \n\n");

        if (ex != null) {
            traceBuf.append(ex.getClass().getName());

            String message = ex.getMessage();

            if (message != null) {
                traceBuf.append("\nMESSAGE: ");
                traceBuf.append(message);
            }

            StringWriter out = new StringWriter();

            PrintWriter printOut = new PrintWriter(out);

            ex.printStackTrace(printOut);

            traceBuf.append("\n\nSTACKTRACE:\n\n");
            traceBuf.append(out.toString());
        }

        traceBuf.append("\n\n** END NESTED EXCEPTION **\n\n");

        return traceBuf.toString();
    }

    // Right from Monty's code
    static String newCrypt(String password, String seed) {
        byte b;
        double d;

        if ((password == null) || (password.length() == 0)) {
            return password;
        }

        long[] pw = newHash(seed);
        long[] msg = newHash(password);
        long max = 0x3fffffffL;
        long seed1 = (pw[0] ^ msg[0]) % max;
        long seed2 = (pw[1] ^ msg[1]) % max;
        char[] chars = new char[seed.length()];

        for (int i = 0; i < seed.length(); i++) {
            seed1 = ((seed1 * 3) + seed2) % max;
            seed2 = (seed1 + seed2 + 33) % max;
            d = (double) seed1 / (double) max;
            b = (byte) java.lang.Math.floor((d * 31) + 64);
            chars[i] = (char) b;
        }

        seed1 = ((seed1 * 3) + seed2) % max;
        seed2 = (seed1 + seed2 + 33) % max;
        d = (double) seed1 / (double) max;
        b = (byte) java.lang.Math.floor(d * 31);

        for (int i = 0; i < seed.length(); i++) {
            chars[i] ^= (char) b;
        }

        return new String(chars);
    }

    static long[] newHash(String password) {
        long nr = 1345345333L;
        long add = 7;
        long nr2 = 0x12345671L;
        long tmp;

        for (int i = 0; i < password.length(); ++i) {
            if ((password.charAt(i) == ' ') || (password.charAt(i) == '\t')) {
                continue; // skip spaces
            }

            tmp = (long) (0xff & password.charAt(i));
            nr ^= ((((nr & 63) + add) * tmp) + (nr << 8));
            nr2 += ((nr2 << 8) ^ nr);
            add += tmp;
        }

        long[] result = new long[2];
        result[0] = nr & 0x7fffffffL;
        result[1] = nr2 & 0x7fffffffL;

        return result;
    }

    static String oldCrypt(String password, String seed) {
        long hp;
        long hm;
        long s1;
        long s2;
        long max = 0x01FFFFFF;
        double d;
        byte b;

        if ((password == null) || (password.length() == 0)) {
            return password;
        }

        hp = oldHash(seed);
        hm = oldHash(password);

        long nr = hp ^ hm;
        nr %= max;
        s1 = nr;
        s2 = nr / 2;

        char[] chars = new char[seed.length()];

        for (int i = 0; i < seed.length(); i++) {
            s1 = ((s1 * 3) + s2) % max;
            s2 = (s1 + s2 + 33) % max;
            d = (double) s1 / max;
            b = (byte) java.lang.Math.floor((d * 31) + 64);
            chars[i] = (char) b;
        }

        return new String(chars);
    }

    static long oldHash(String password) {
        long nr = 1345345333;
        long nr2 = 7;
        long tmp;

        for (int i = 0; i < password.length(); i++) {
            if ((password.charAt(i) == ' ') || (password.charAt(i) == '\t')) {
                continue;
            }

            tmp = (long) password.charAt(i);
            nr ^= ((((nr & 63) + nr2) * tmp) + (nr << 8));
            nr2 += tmp;
        }

        return nr & (((long) 1L << 31) - 1L);
    }

    private static RandStructcture randomInit(long seed1, long seed2) {
        RandStructcture randStruct = enclosingInstance.new RandStructcture();

        randStruct.maxValue = 0x3FFFFFFFL;
        randStruct.maxValueDbl = (double) randStruct.maxValue;
        randStruct.seed1 = seed1 % randStruct.maxValue;
        randStruct.seed2 = seed2 % randStruct.maxValue;

        return randStruct;
    }

    private static double rnd(RandStructcture randStruct) {
        randStruct.seed1 = ((randStruct.seed1 * 3) + randStruct.seed2) % randStruct.maxValue;
        randStruct.seed2 = (randStruct.seed1 + randStruct.seed2 + 33) % randStruct.maxValue;

        return (((double) randStruct.seed1) / randStruct.maxValueDbl);
    }

    class RandStructcture {
        double maxValueDbl;
        long maxValue;
        long seed1;
        long seed2;
    }
}