/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements. See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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.apache.logging.log4j.core.filter;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.logging.log4j.Level;
  import org.apache.logging.log4j.Marker;
  import org.apache.logging.log4j.ThreadContext;
  import org.apache.logging.log4j.core.Filter;
  import org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.Logger;
  import org.apache.logging.log4j.core.config.Node;
  import org.apache.logging.log4j.core.config.plugins.Plugin;
  import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
  import org.apache.logging.log4j.core.config.plugins.PluginElement;
  import org.apache.logging.log4j.core.config.plugins.PluginFactory;
  import org.apache.logging.log4j.core.util.KeyValuePair;
  import org.apache.logging.log4j.message.Message;
  
  /**
   * Filter based on a value in the Thread Context Map (MDC).
   */
  @Plugin(name = "ThreadContextMapFilter", category = Node.CATEGORY, elementType = Filter.ELEMENT_TYPE, printObject = true)
  public class ThreadContextMapFilter extends MapFilter {
  
      private final String key;
      private final String value;
  
      private final boolean useMap;
  
      public ThreadContextMapFilter(final Map<String, List<String>> pairs, final boolean oper, final Result onMatch,
                                    final Result onMismatch) {
          super(pairs, oper, onMatch, onMismatch);
          if (pairs.size() == 1) {
              final Iterator<Map.Entry<String, List<String>>> iter = pairs.entrySet().iterator();
              final Map.Entry<String, List<String>> entry = iter.next();
              if (entry.getValue().size() == 1) {
                  this.key = entry.getKey();
                  this.value = entry.getValue().get(0);
                  this.useMap = false;
              } else {
                  this.key = null;
                  this.value = null;
                  this.useMap = true;
              }
          } else {
              this.key = null;
              this.value = null;
              this.useMap = true;
          }
      }
  
      @Override
      public Result filter(final Logger logger, final Level level, final Marker marker, final String msg,
                           final Object... params) {
          return filter();
      }
  
      @Override
      public Result filter(final Logger logger, final Level level, final Marker marker, final Object msg,
                           final Throwable t) {
          return filter();
      }
  
      @Override
      public Result filter(final Logger logger, final Level level, final Marker marker, final Message msg,
                           final Throwable t) {
          return filter();
      }
  
      private Result filter() {
          boolean match = false;
          if (useMap) {
              for (final Map.Entry<String, List<String>> entry : getMap().entrySet()) {
                  final String toMatch = ThreadContext.get(entry.getKey());
                  if (toMatch != null) {
                      match = entry.getValue().contains(toMatch);
                  } else {
                      match = false;
                  }
                 if ((!isAnd() && match) || (isAnd() && !match)) {
                     break;
                 }
             }
         } else {
             match = value.equals(ThreadContext.get(key));
         }
         return match ? onMatch : onMismatch;
     }
 
     @Override
     public Result filter(final LogEvent event) {
         return super.filter(event.getContextMap()) ? onMatch : onMismatch;
     }
 
     @PluginFactory
     public static ThreadContextMapFilter createFilter(
             @PluginElement("Pairs") final KeyValuePair[] pairs,
             @PluginAttribute("operator") final String oper,
             @PluginAttribute("onMatch") final Result match,
             @PluginAttribute("onMismatch") final Result mismatch) {
         if (pairs == null || pairs.length == 0) {
             LOGGER.error("key and value pairs must be specified for the ThreadContextMapFilter");
             return null;
         }
         final Map<String, List<String>> map = new HashMap<>();
         for (final KeyValuePair pair : pairs) {
             final String key = pair.getKey();
             if (key == null) {
                 LOGGER.error("A null key is not valid in MapFilter");
                 continue;
             }
             final String value = pair.getValue();
             if (value == null) {
                 LOGGER.error("A null value for key " + key + " is not allowed in MapFilter");
                 continue;
             }
             List<String> list = map.get(pair.getKey());
             if (list != null) {
                 list.add(value);
             } else {
                 list = new ArrayList<>();
                 list.add(value);
                 map.put(pair.getKey(), list);
             }
         }
         if (map.isEmpty()) {
             LOGGER.error("ThreadContextMapFilter is not configured with any valid key value pairs");
             return null;
         }
         final boolean isAnd = oper == null || !oper.equalsIgnoreCase("or");
         return new ThreadContextMapFilter(map, isAnd, match, mismatch);
     }
 }