/*
    * 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.pattern;
  
  import java.util.List;
  
  import org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.config.Configuration;
  import org.apache.logging.log4j.core.config.plugins.Plugin;
  import org.apache.logging.log4j.core.layout.PatternLayout;
  
  /**
   * Equals pattern converter.
   */
  @Plugin(name = "equals", category = PatternConverter.CATEGORY)
  @ConverterKeys({ "equals" })
  public final class EqualsReplacementConverter extends LogEventPatternConverter {
  
      /**
       * Gets an instance of the class.
       *
       * @param config  The current Configuration.
       * @param options pattern options, an array of three elements: pattern, testString, and substitution.
       * @return instance of class.
       */
      public static EqualsReplacementConverter newInstance(final Configuration config, final String[] options) {
          if (options.length != 3) {
              LOGGER.error("Incorrect number of options on equals. Expected 3 received " + options.length);
              return null;
          }
          if (options[0] == null) {
              LOGGER.error("No pattern supplied on equals");
              return null;
          }
          if (options[1] == null) {
              LOGGER.error("No test string supplied on equals");
              return null;
          }
          if (options[2] == null) {
              LOGGER.error("No substitution supplied on equals");
              return null;
          }
          final String p = options[1];
          final PatternParser parser = PatternLayout.createPatternParser(config);
          final List<PatternFormatter> formatters = parser.parse(options[0]);
          return new EqualsReplacementConverter(formatters, p, options[2], parser);
      }
  
      private final List<PatternFormatter> formatters;
  
      private final String substitution;
  
      private final String testString;
  
      private final PatternParser parser;
  
      /**
       * Construct the converter.
       *
       * @param formatters   The PatternFormatters to generate the text to manipulate.
       * @param testString   The test string.
       * @param substitution The substitution string.
       * @param parser       The PatternParser.
       */
      private EqualsReplacementConverter(final List<PatternFormatter> formatters, final String testString,
                                         final String substitution, final PatternParser parser) {
          super("equals", "equals");
          this.testString = testString;
          this.substitution = substitution;
          this.formatters = formatters;
          this.parser = parser;
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public void format(final LogEvent event, final StringBuilder toAppendTo) {
          final StringBuilder buf = new StringBuilder();
          for (final PatternFormatter formatter : formatters) {
              formatter.format(event, buf);
          }
          final String string = buf.toString();
          toAppendTo.append(testString.equals(string) ? parseSubstitution(event) : string);
      }
 
     /**
      * Returns the parsed substitution text.
      *
      * @param event the current log event
      * @return the parsed substitution text
      */
     String parseSubstitution(final LogEvent event) {
         final StringBuilder substitutionBuffer = new StringBuilder();
         // check if substitution needs to be parsed
         if (substitution.contains("%")) {
             // parse substitution pattern
             final List<PatternFormatter> substitutionFormatters = parser.parse(substitution);
             for (final PatternFormatter formatter : substitutionFormatters) {
                 formatter.format(event, substitutionBuffer);
             }
         } else {
             substitutionBuffer.append(substitution);
         }
         return substitutionBuffer.toString();
     }
 }