content: /*
   *  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.causeway.core.security.authentication.standard;
  
  import java.security.SecureRandom;
  
  import jakarta.annotation.Priority;
  import jakarta.inject.Named;
  
  import org.springframework.beans.factory.annotation.Qualifier;
  import org.springframework.stereotype.Component;
  
  import org.apache.causeway.applib.annotation.PriorityPrecedence;
  import org.apache.causeway.core.security.CausewayModuleCoreSecurity;
  
  @Component
  @Named(RandomCodeGeneratorDefault.LOGICAL_TYPE_NAME)
  @Priority(PriorityPrecedence.LATE)
  @Qualifier("Default")
  public class RandomCodeGeneratorDefault implements RandomCodeGenerator {
  
      public static final String LOGICAL_TYPE_NAME = CausewayModuleCoreSecurity.NAMESPACE + ".RandomCodeGenerator10Chars";
  
      private static final int NUMBER_CHARACTERS = 10;
      private static final String CHARACTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
  
      private final SecureRandom random = new SecureRandom(); // Compliant for security-sensitive use cases
  
      @Override
      public String generateRandomCode(final int numChars) {
          if(numChars < NUMBER_CHARACTERS) {
              throw new IllegalArgumentException("Must request at least %d characters".formatted(NUMBER_CHARACTERS));
          }
          final StringBuilder buf = new StringBuilder(numChars);
          for (int i = 0; i < numChars; i++) {
              final int pos = random.nextInt(CHARACTERS.length());
              buf.append(CHARACTERS.charAt(pos));
          }
          return buf.toString();
      }
  
  }
  