content: package act.controller.captcha;
  
  /*-
   * #%L
   * ACT Framework
   * %%
   * Copyright (C) 2014 - 2018 ActFramework
   * %%
   * 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.
   * #L%
   */
  
  import act.Act;
  import act.act_messages;
  import act.i18n.I18n;
  import org.osgl.util.S;
  
  import java.io.Serializable;
  import java.util.Set;
  
  /**
   * A `CaptchaSession` is composed of a text (used to generate media)
   * , a corresponding answer and a media URL
   */
  public class CaptchaSession implements Serializable {
  
      private static final long serialVersionUID = 3648122710489336079L;
  
      private String caption;
      private String text;
      private String answer;
      private String mediaUrl;
      private String instruction;
      private Set<String> options;
  
  
      /**
       * Construct a CAPTCHA session with text, an answer and a media URL.
       *
       * @param text the text literal
       * @param answer
       *      the answer, optional. When omitted then the answer should be
       *      the text.
       * @param mediaUrl
       *      the media URL. When omitted, then the URL is /~/captcha/{encrypted-text}.
       * @param instruction
       *      the instruction to guide how end user should treat the CAPTCHA.
       * @param options
       *      the optional a set of option from which the answer could be selected.
       */
      public CaptchaSession(String text, String answer, String mediaUrl, String instruction, Set<String> options) {
          this.caption = I18n.i18n(act_messages.class, "act.captcha.caption");
          this.text = S.requireNotBlank(text);
          this.answer = answer;
          this.mediaUrl = ensureMediaUrl(mediaUrl, text);
          this.instruction = S.requireNotBlank(instruction);
          this.options = options;
      }
  
      public String getCaption() {
          return caption;
      }
  
      /**
       * Returns an encrypted token combined with answer.
       */
      public String getToken() {
          String id = null == answer ? text : answer;
          return Act.app().crypto().generateToken(id);
      }
  
      public String getMediaUrl() {
          return mediaUrl;
      }
  
      public String getInstruction() {
          return instruction;
      }
  
      public Set<String> getOptions() {
          return options;
      }
  
      private String ensureMediaUrl(String url, String text) {
          if (S.isBlank(url)) {
              String encrypted = Act.crypto().encrypt(text);
              return "/~/captcha/" + encrypted;
          }
          return url;
      }
  }
  