/*
    * This file is part of ***  M y C o R e  ***
    * See http://www.mycore.de/ for details.
    *
    * MyCoRe is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    *
   * MyCoRe is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with MyCoRe.  If not, see <http://www.gnu.org/licenses/>.
   */
  package org.mycore.restapi.v1.utils;
  
  import java.util.LinkedHashMap;
  import java.util.Map;
  import java.util.Optional;
  
  import org.glassfish.jersey.server.ServerProperties;
  
  import jakarta.ws.rs.core.Application;
  
  /**
   * This class contains some generic utility functions for the REST API
   * 
   * @author Thomas Scheffler (yagee)
   */
  public class MCRRestAPIUtil {
      public static String getWWWAuthenticateHeader(String s,
          Map<String, String> attributes, Application app) {
          LinkedHashMap<String, String> attrMap = new LinkedHashMap<>();
          String realm = app.getProperties()
              .getOrDefault(ServerProperties.APPLICATION_NAME, "REST API")
              .toString();
          attrMap.put("realm", realm);
          Optional.ofNullable(attributes).ifPresent(attrMap::putAll);
          StringBuilder b = new StringBuilder();
          attrMap.entrySet().stream()
              .forEach(e -> appendFieldValue(b, e.getKey(), e.getValue()));
          b.insert(0, " ");
          return Optional.ofNullable(s).orElse("Basic") + b;
      }
  
      private static void appendField(StringBuilder b, String field) {
          if (b.length() > 0) {
              b.append(", ");
          }
          b.append(field);
      }
  
      private static void appendValue(StringBuilder b, String value) {
          for (char c : value.toCharArray()) {
              if ((c < 0x20) || (c == 0x22) || (c == 0x5c) || (c > 0x7e)) {
                  b.append(' ');
              } else {
                  b.append(c);
              }
          }
      }
  
      private static void appendFieldValue(StringBuilder b, String field, String value) {
          appendField(b, field);
          if (value != null && !value.isEmpty()) {
              b.append("=\"");
              appendValue(b, value);
              b.append('\"');
          }
      }
  
  }