/*
    * 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.lang.reflect.Field;
  import java.util.Arrays;
  import java.util.Comparator;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import org.apache.logging.log4j.Level;
  import org.apache.logging.log4j.Marker;
  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.message.Message;
  
  /**
   * This filter returns the onMatch result if the message matches the regular expression.
   *
   * The "useRawMsg" attribute can be used to indicate whether the regular expression should be applied to the result of
   * calling Message.getMessageFormat (true) or Message.getFormattedMessage() (false). The default is false.
   *
   */
  @Plugin(name = "RegexFilter", category = Node.CATEGORY, elementType = Filter.ELEMENT_TYPE, printObject = true)
  public final class RegexFilter extends AbstractFilter {
  
      private static final int DEFAULT_PATTERN_FLAGS = 0;
      private final Pattern pattern;
      private final boolean useRawMessage;
  
      private RegexFilter(final boolean raw, final Pattern pattern, final Result onMatch, final Result onMismatch) {
          super(onMatch, onMismatch);
          this.pattern = pattern;
          this.useRawMessage = raw;
      }
  
      @Override
      public Result filter(final Logger logger, final Level level, final Marker marker, final String msg,
              final Object... params) {
          return filter(msg);
      }
  
      @Override
      public Result filter(final Logger logger, final Level level, final Marker marker, final Object msg,
              final Throwable t) {
          if (msg == null) {
              return onMismatch;
          }
          return filter(msg.toString());
      }
  
      @Override
      public Result filter(final Logger logger, final Level level, final Marker marker, final Message msg,
              final Throwable t) {
          if (msg == null) {
              return onMismatch;
          }
          final String text = useRawMessage ? msg.getFormat() : msg.getFormattedMessage();
          return filter(text);
      }
  
      @Override
      public Result filter(final LogEvent event) {
          final String text = useRawMessage ? event.getMessage().getFormat() : event.getMessage().getFormattedMessage();
          return filter(text);
      }
  
      private Result filter(final String msg) {
          if (msg == null) {
              return onMismatch;
          }
          final Matcher m = pattern.matcher(msg);
          return m.matches() ? onMatch : onMismatch;
      }
  
      @Override
      public String toString() {
          final StringBuilder sb = new StringBuilder();
          sb.append("useRaw=").append(useRawMessage);
         sb.append(", pattern=").append(pattern.toString());
         return sb.toString();
     }
 
     /**
      * Creates a Filter that matches a regular expression.
      *
      * @param regex
      *        The regular expression to match.
      * @param patternFlags
      *        An array of Stirngs where each String is a {@link Pattern#compile(String, int)} compilation flag.
      * @param useRawMsg
      *        If true, the raw message will be used, otherwise the formatted message will be used.
      * @param match
      *        The action to perform when a match occurs.
      * @param mismatch
      *        The action to perform when a mismatch occurs.
      * @return The RegexFilter.
      * @throws IllegalAccessException
      * @throws IllegalArgumentException
      */
     // TODO Consider refactoring to use AbstractFilter.AbstractFilterBuilder
     @PluginFactory
     public static RegexFilter createFilter(
             //@formatter:off
             @PluginAttribute("regex") final String regex,
             @PluginElement("PatternFlags") final String[] patternFlags,
             @PluginAttribute("useRawMsg") final Boolean useRawMsg,
             @PluginAttribute("onMatch") final Result match,
             @PluginAttribute("onMismatch") final Result mismatch)
             //@formatter:on
             throws IllegalArgumentException, IllegalAccessException {
         if (regex == null) {
             LOGGER.error("A regular expression must be provided for RegexFilter");
             return null;
         }
         return new RegexFilter(useRawMsg, Pattern.compile(regex, toPatternFlags(patternFlags)), match, mismatch);
     }
 
     private static int toPatternFlags(final String[] patternFlags) throws IllegalArgumentException,
             IllegalAccessException {
         if (patternFlags == null || patternFlags.length == 0) {
             return DEFAULT_PATTERN_FLAGS;
         }
         final Field[] fields = Pattern.class.getDeclaredFields();
         final Comparator<Field> comparator = new Comparator<Field>() {
 
             @Override
             public int compare(final Field f1, final Field f2) {
                 return f1.getName().compareTo(f2.getName());
             }
         };
         Arrays.sort(fields, comparator);
         final String[] fieldNames = new String[fields.length];
         for (int i = 0; i < fields.length; i++) {
             fieldNames[i] = fields[i].getName();
         }
         int flags = DEFAULT_PATTERN_FLAGS;
         for (final String test : patternFlags) {
             final int index = Arrays.binarySearch(fieldNames, test);
             if (index >= 0) {
                 final Field field = fields[index];
                 flags |= field.getInt(Pattern.class);
             }
         }
         return flags;
     }
 }