/*
    * Copyright (C) 2013 4th Line GmbH, Switzerland
    *
    * The contents of this file are subject to the terms of either the GNU
    * Lesser General Public License Version 2 or later ("LGPL") or the
    * Common Development and Distribution License Version 1 or later
    * ("CDDL") (collectively, the "License"). You may not use this file
    * except in compliance with the License. See LICENSE.txt for more
    * information.
   *
   * This program 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.
   */
  
  package org.fourthline.cling.model.profile;
  
  import org.fourthline.cling.model.meta.DeviceDetails;
  
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.regex.Pattern;
  
  /**
   * Selects device details based on a regex and the client's HTTP headers.
   * <p>
   * This provider will lookup and match a {@link DeviceDetails} entry in a
   * given map that is keyed by HTTP header name and a regular expression pattern.
   * If the control point sent an HTTP header that matches an entry's name,
   * and the value of the control points header matches the pattern of the entry,
   * the value of the entry is applied. This is a case-insensitive pattern match.
   * </p>
   *
   * @author Mario Franco
   * @author Christian Bauer
   */
  public class HeaderDeviceDetailsProvider implements DeviceDetailsProvider {
  
      public static class Key {
  
          final String headerName;
          final String valuePattern;
          final Pattern pattern;
  
          public Key(String headerName, String valuePattern) {
              this.headerName = headerName;
              this.valuePattern = valuePattern;
              this.pattern = Pattern.compile(valuePattern, Pattern.CASE_INSENSITIVE);
          }
  
          public String getHeaderName() {
              return headerName;
          }
  
          public String getValuePattern() {
              return valuePattern;
          }
  
          public boolean isValuePatternMatch(String value) {
              return pattern.matcher(value).matches();
          }
      }
  
  
      final private DeviceDetails defaultDeviceDetails;
      final private Map<Key, DeviceDetails> headerDetails;
  
      public HeaderDeviceDetailsProvider(DeviceDetails defaultDeviceDetails) {
          this(defaultDeviceDetails, null);
      }
  
      public HeaderDeviceDetailsProvider(DeviceDetails defaultDeviceDetails,
                                         Map<Key, DeviceDetails> headerDetails) {
          this.defaultDeviceDetails = defaultDeviceDetails;
          this.headerDetails = headerDetails != null ? headerDetails : new HashMap();
      }
  
      public DeviceDetails getDefaultDeviceDetails() {
          return defaultDeviceDetails;
      }
  
      public Map<Key, DeviceDetails> getHeaderDetails() {
          return headerDetails;
      }
  
      public DeviceDetails provide(RemoteClientInfo info) {
          if (info == null || info.getRequestHeaders().isEmpty()) return getDefaultDeviceDetails();
  
          for (Key key : getHeaderDetails().keySet()) {
              List<String> headerValues;
              if ((headerValues = info.getRequestHeaders().get(key.getHeaderName())) == null) continue;
              for (String headerValue : headerValues) {
                  if (key.isValuePatternMatch(headerValue))
                      return getHeaderDetails().get(key);
              }
          }
          return getDefaultDeviceDetails();
      }
 
 }