/*
    * Copyright 2012-2025 CodeLibs Project and the Others.
    *
    * Licensed 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.codelibs.fess.helper;
  
  import java.security.SecureRandom;
  import java.util.Random;
  
  import org.apache.commons.lang3.RandomStringUtils;
  import org.codelibs.core.lang.StringUtil;
  import org.codelibs.fess.exception.InvalidAccessTokenException;
  import org.codelibs.fess.util.ComponentUtil;
  
  import jakarta.servlet.http.HttpServletRequest;
  
  /**
   * The helper for access token.
   */
  public class AccessTokenHelper {
  
      /**
       * Default constructor.
       */
      public AccessTokenHelper() {
          // nothing
      }
  
      /**
       * The bearer string.
       */
      protected static final String BEARER = "Bearer";
  
      /**
       * The random instance.
       */
      protected Random random = new SecureRandom();
  
      /**
       * Generate the access token.
       * @return The access token.
       */
      public String generateAccessToken() {
          return RandomStringUtils.random(ComponentUtil.getFessConfig().getApiAccessTokenLengthAsInteger(), 0, 0, true, true, null, random);
      }
  
      /**
       * Get the access token from the request.
       * @param request The request.
       * @return The access token.
       */
      public String getAccessTokenFromRequest(final HttpServletRequest request) {
          final String token = request.getHeader("Authorization");
          if (token != null) {
              final String[] values = token.trim().split(" ");
              if (values.length == 2 && BEARER.equals(values[0])) {
                  return values[1];
              }
              if (values.length == 1 && !BEARER.equals(values[0])) {
                  return values[0];
              }
              throw new InvalidAccessTokenException("invalid_request", "Invalid format: " + token);
          }
          final String name = ComponentUtil.getFessConfig().getApiAccessTokenRequestParameter();
          if (StringUtil.isNotBlank(name)) {
              return request.getParameter(name);
          }
          return null;
      }
  
      /**
       * Set the random instance.
       * @param random The random instance.
       */
      public void setRandom(final Random random) {
          this.random = random;
      }
  }