/*
    * 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 org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.config.plugins.Plugin;
  
  import java.text.SimpleDateFormat;
  import java.util.Date;
  import java.util.TimeZone;
  
  
  /**
   * Convert and format the event's date in a StringBuffer.
   */
  @Plugin(name = "DatePatternConverter", type = "Converter")
  @ConverterKeys({"d", "date" })
  public final class DatePatternConverter extends LogEventPatternConverter implements ArrayPatternConverter {
      /**
       * ABSOLUTE string literal.
       */
      private static final String ABSOLUTE_FORMAT = "ABSOLUTE";
      /**
       * SimpleTimePattern for ABSOLUTE.
       */
      private static final String ABSOLUTE_TIME_PATTERN = "HH:mm:ss,SSS";
  
  
      /**
       * DATE string literal.
       */
      private static final String DATE_AND_TIME_FORMAT = "DATE";
      /**
       * SimpleTimePattern for DATE.
       */
      private static final String DATE_AND_TIME_PATTERN = "dd MMM yyyy HH:mm:ss,SSS";
  
      /**
       * ISO8601 string literal.
       */
      private static final String ISO8601_FORMAT = "ISO8601";
      /**
       * SimpleTimePattern for ISO8601.
       */
      private static final String ISO8601_PATTERN = "yyyy-MM-dd HH:mm:ss,SSS";
      /**
       * Date format.
       */
      private String cachedDate;
  
      private long lastTimestamp;
  
      private SimpleDateFormat simpleFormat;
  
      /**
       * Private constructor.
       *
       * @param options options, may be null.
       */
      private DatePatternConverter(final String[] options) {
          super("Date", "date");
  
          String patternOption;
  
          if ((options == null) || (options.length == 0)) {
              // the branch could be optimized, but here we are making explicit
              // that null values for patternOption are allowed.
              patternOption = null;
          } else {
              patternOption = options[0];
          }
  
          String pattern;
  
          if (patternOption == null || patternOption.equalsIgnoreCase(ISO8601_FORMAT)) {
              pattern = ISO8601_PATTERN;
          } else if (patternOption.equalsIgnoreCase(ABSOLUTE_FORMAT)) {
              pattern = ABSOLUTE_TIME_PATTERN;
          } else if (patternOption.equalsIgnoreCase(DATE_AND_TIME_FORMAT)) {
              pattern = DATE_AND_TIME_PATTERN;
          } else {
              pattern = patternOption;
          }
  
          try {
             simpleFormat = new SimpleDateFormat(pattern);
         } catch (IllegalArgumentException e) {
             LOGGER.warn("Could not instantiate SimpleDateFormat with pattern " + patternOption, e);
 
             // default to the ISO8601 format
             simpleFormat = new SimpleDateFormat(ISO8601_PATTERN);
         }
 
         // if the option list contains a TZ option, then set it.
         if ((options != null) && (options.length > 1)) {
             TimeZone tz = TimeZone.getTimeZone(options[1]);
             simpleFormat.setTimeZone(tz);
         }
     }
 
     /**
      * Obtains an instance of pattern converter.
      *
      * @param options options, may be null.
      * @return instance of pattern converter.
      */
     public static DatePatternConverter newInstance(final String[] options) {
         return new DatePatternConverter(options);
     }
 
     /**
      * {@inheritDoc}
      */
     public void format(final LogEvent event, final StringBuilder output) {
         long timestamp = event.getMillis();
 
         synchronized (this) {
             if (timestamp != lastTimestamp) {
                 lastTimestamp = timestamp;
                 cachedDate = simpleFormat.format(timestamp);
             }
         }
         output.append(cachedDate);
     }
 
     public void format(Object[] objects, final StringBuilder toAppendTo) {
         for (Object obj : objects) {
             if (obj instanceof Date) {
                 format(obj, toAppendTo);
                 break;
             }
         }
     }
 
     /**
      * {@inheritDoc}
      */
     public void format(final Object obj, final StringBuilder output) {
         if (obj instanceof Date) {
             format((Date) obj, output);
         }
 
         super.format(obj, output);
     }
 
     /**
      * Append formatted date to string buffer.
      *
      * @param date       date
      * @param toAppendTo buffer to which formatted date is appended.
      */
     public void format(final Date date, final StringBuilder toAppendTo) {
         synchronized (this) {
             toAppendTo.append(simpleFormat.format(date.getTime()));
         }
     }
 
     public String getPattern() {
         return simpleFormat.toPattern();
     }
 
 }