/*
 * Copyright (c) 2017, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
 *
 * WSO2 Inc. licenses this file to you under the Apache License,
 *  Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.wso2.carbon.user.mgt.common;

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

/**
 * This class is used to generate a random password of 8 characters length
 */
public class DefaultPasswordGenerator implements RandomPasswordGenerator {

    private static final int PASSWORD_LENGTH = 8;
    private static final Random RANDOM = new SecureRandom();


    @Override
    public char[] generatePassword() {
        // Pick from some letters that won't be easily mistaken for each
        // other. So, for example, omit o O and 0, 1 l and L.
        String letters = "abcdefghjkmnpqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ23456789+@";

        StringBuilder pw = new StringBuilder();
        for (int i = 0; i < PASSWORD_LENGTH; i++) {
            int index = (int) (RANDOM.nextDouble() * letters.length());
            pw.append(letters.substring(index, index + 1));
        }
        char[] password = new char[pw.length()];
        pw.getChars(0, pw.length(), password, 0);
        return password;
    }
}

@@ -1040,17 +1040,16 @@
 dom();%0A%0A
-%0A
     @Ove
@@ -1089,24 +1089,25 @@
 assword() %7B%0A
+%0A
         // P
@@ -1166,16 +1166,23 @@
 for each
+ other.
 %0A       
@@ -1184,23 +1184,16 @@
       //
- other.
  So, for
@@ -1241,83 +1241,491 @@
     
-String letters = %22abcdefghjkmnpqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ23456789+@%22
+// This will generate a random password which satisfy the following regex.%0A        // %5E((?=.*%5C%5Cd)(?=.*%5Ba-z%5D)(?=.*%5BA-Z%5D)(?=.*%5B!@#$%25&*%5D)).%7B0,100%7D$%7D%0A        String characters = %2223456789abcdefghjkmnpqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ!@#$%25&*%22;%0A        String digits = %2223456789%22;%0A        String lowercaseLetters = %22abcdefghjkmnpqrstuvwxyz%22;%0A        String uppercaseLetters = %22ABCDEFGHJKMNPQRSTUVWXYZ%22;%0A        String specialCharacters = %22!@#$%25&*%22;%0A        int mandatoryCharactersCount = 4
 ;%0A%0A 
@@ -1771,16 +1771,35 @@
 lder();%0A
+        int index;%0A
         
@@ -1837,71 +1837,404 @@
 NGTH
-; i++) %7B%0A            int index = (int) (RANDOM.nextDouble() * l
+ - mandatoryCharactersCount; i++) %7B%0A            index = RANDOM.nextInt(characters.length());%0A            pw.append(characters.charAt(index));%0A        %7D%0A%0A        index = RANDOM.nextInt(digits.length());%0A        pw.append(digits.charAt(index));%0A%0A        index = RANDOM.nextInt(lowercaseLetters.length());%0A        pw.append(lowercaseLetters.charAt(index));%0A%0A        index = RANDOM.nextInt(uppercaseL
 ette
@@ -2247,36 +2247,32 @@
 gth());%0A        
- 
-   
 pw.append(letter
@@ -2269,55 +2269,154 @@
 end(
-letters.substring(index, index + 1));%0A        %7D
+uppercaseLetters.charAt(index));%0A%0A        index = RANDOM.nextInt(specialCharacters.length());%0A        pw.append(specialCharacters.charAt(index));%0A
 %0A   

Improve default password generation logic