/*
    * Copyright (c) 2002-2025 Gargoyle Software Inc.
    *
    * 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
    * https://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.htmlunit.util;
  
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import org.htmlunit.HttpHeader;
  import org.htmlunit.WebResponse;
  
  /**
   * @author Anton Demydenko
   * @author Lai Quang Duong
   */
  public final class HeaderUtils {
  
      private static final String CACHE_CONTROL_PRIVATE = "private";
      private static final String CACHE_CONTROL_PUBLIC = "public";
      private static final String CACHE_CONTROL_NO_STORE = "no-store";
      private static final String CACHE_CONTROL_NO_CACHE = "no-cache";
      private static final String CACHE_CONTROL_MAX_AGE = "max-age";
      private static final String CACHE_CONTROL_S_MAXAGE = "s-maxage";
      private static final Pattern MAX_AGE_HEADER_PATTERN = Pattern.compile("^.*max-age=(\\d+).*$");
      private static final Pattern S_MAXAGE_HEADER_PATTERN = Pattern.compile("^.*s-maxage=(\\d+).*$");
  
      private HeaderUtils() {
          // utility class
      }
  
      /**
       * @param response {@code WebResponse}
       * @return if 'Cache-Control' header is present and contains 'private' value
       */
      public static boolean containsPrivate(final WebResponse response) {
          return containsCacheControlValue(response, CACHE_CONTROL_PRIVATE);
      }
  
      /**
       * @param response {@code WebResponse}
       * @return if 'Cache-Control' header is present and contains 'public' value
       */
      public static boolean containsPublic(final WebResponse response) {
          return containsCacheControlValue(response, CACHE_CONTROL_PUBLIC);
      }
  
      /**
       * @param response {@code WebResponse}
       * @return if 'Cache-Control' header is present and contains 'no-store' value
       */
      public static boolean containsNoStore(final WebResponse response) {
          return containsCacheControlValue(response, CACHE_CONTROL_NO_STORE);
      }
  
      /**
       * @param response {@code WebResponse}
       * @return if 'Cache-Control' header is present and contains 'no-cache' value@return
       */
      public static boolean containsNoCache(final WebResponse response) {
          return containsCacheControlValue(response, CACHE_CONTROL_NO_CACHE);
      }
  
      /**
       * @param response {@code WebResponse}
       * @return if 'Etag' header is present
       */
      public static boolean containsETag(final WebResponse response) {
          return response.getResponseHeaderValue(HttpHeader.ETAG) != null;
      }
  
      /**
       * @param response {@code WebResponse}
       * @return if 'Last-Modified' header is present
       */
      public static boolean containsLastModified(final WebResponse response) {
          return response.getResponseHeaderValue(HttpHeader.LAST_MODIFIED) != null;
      }
  
      /**
       * @param response {@code WebResponse}
       * @return if 'Cache-Control' header is present and contains 's-maxage' value
       */
      public static boolean containsSMaxage(final WebResponse response) {
          return containsCacheControlValue(response, CACHE_CONTROL_S_MAXAGE);
      }
  
      /**
       * @param response {@code WebResponse}
      * @return if 'Cache-Control' header is present and contains 'max-age' value
      */
     public static boolean containsMaxAge(final WebResponse response) {
         return containsCacheControlValue(response, CACHE_CONTROL_MAX_AGE);
     }
 
     /**
      * @param response {@code WebResponse}
      * @return if 'Cache-Control' header is present and contains 'max-age' value
      */
     public static boolean containsMaxAgeOrSMaxage(final WebResponse response) {
         final String cacheControl = response.getResponseHeaderValue(HttpHeader.CACHE_CONTROL);
         if (StringUtils.containsIgnoreCase(cacheControl, CACHE_CONTROL_MAX_AGE)) {
             return true;
         }
         return StringUtils.containsIgnoreCase(cacheControl, CACHE_CONTROL_S_MAXAGE);
     }
 
     /**
      * @param response {@code WebResponse}
      * @return value of 's-maxage' directive and 0 if it is absent
      */
     public static long sMaxage(final WebResponse response) {
         if (containsCacheControlValue(response, CACHE_CONTROL_S_MAXAGE)) {
             return directiveValue(response, S_MAXAGE_HEADER_PATTERN);
         }
         return 0;
     }
 
     /**
      * @param response {@code WebResponse}
      * @return value of 'max-age' directive and 0 if it is absent
      */
     public static long maxAge(final WebResponse response) {
         if (containsCacheControlValue(response, CACHE_CONTROL_MAX_AGE)) {
             return directiveValue(response, MAX_AGE_HEADER_PATTERN);
         }
 
         return 0;
     }
 
     private static long directiveValue(final WebResponse response, final Pattern pattern) {
         final String value = response.getResponseHeaderValue(HttpHeader.CACHE_CONTROL);
         if (value != null) {
             final Matcher matcher = pattern.matcher(value);
             if (matcher.matches()) {
                 return Long.parseLong(matcher.group(1));
             }
         }
 
         return 0;
     }
 
     private static boolean containsCacheControlValue(final WebResponse response, final String value) {
         final String cacheControl = response.getResponseHeaderValue(HttpHeader.CACHE_CONTROL);
         return StringUtils.containsIgnoreCase(cacheControl, value);
     }
 }