/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF 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.apache.syncope.core.spring.security;
  
  import com.fasterxml.uuid.Generators;
  import com.fasterxml.uuid.NoArgGenerator;
  import java.security.SecureRandom;
  import java.util.UUID;
  import org.apache.commons.text.RandomStringGenerator;
  import org.passay.PasswordGenerator;
  
  public final class SecureRandomUtils {
  
      private static final SecureRandom RANDOM = new SecureRandom();
  
      private static final PasswordGenerator PASSWORD_GENERATOR = new PasswordGenerator(RANDOM);
  
      private static final RandomStringGenerator FOR_PASSWORD = new RandomStringGenerator.Builder().
              usingRandom(RANDOM::nextInt).
              withinRange('0', 'z').
              filteredBy(Character::isLetterOrDigit).
              build();
  
      private static final RandomStringGenerator FOR_LETTERS = new RandomStringGenerator.Builder().
              usingRandom(RANDOM::nextInt).
              withinRange('a', 'z').
              build();
  
      private static final RandomStringGenerator FOR_NUMBERS = new RandomStringGenerator.Builder().
              usingRandom(RANDOM::nextInt).
              withinRange('0', '9').
              build();
  
      private static final NoArgGenerator UUID_GENERATOR = Generators.timeBasedEpochGenerator(RANDOM);
  
      public static String generateRandomPassword(final int tokenLength) {
          return FOR_PASSWORD.generate(tokenLength);
      }
  
      public static String generateRandomLetter() {
          return FOR_LETTERS.generate(1);
      }
  
      public static String generateRandomLetters(final int length) {
          return FOR_LETTERS.generate(length);
      }
  
      public static String generateRandomNumber() {
          return FOR_NUMBERS.generate(1);
      }
  
      public static String generateRandomNonAlphanumericChar(final char[] characters) {
          return new RandomStringGenerator.Builder().
                  usingRandom(RANDOM::nextInt).
                  filteredBy(codePoint -> {
                      boolean found = false;
                      for (int i = 0; i < characters.length && !found; i++) {
                          found = codePoint == Character.codePointAt(characters, i);
                      }
  
                      return found;
                  }).build().generate(1);
      }
  
      public static UUID generateRandomUUID() {
          return UUID_GENERATOR.generate();
      }
  
      public static PasswordGenerator passwordGenerator() {
          return PASSWORD_GENERATOR;
      }
  
      private SecureRandomUtils() {
          // private constructor for static utility class
      }
  }