/*
    * 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.HashMap;
  import java.util.Locale;
  import java.util.Map;
  
  import org.apache.logging.log4j.Level;
  import org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.config.plugins.Plugin;
  import org.apache.logging.log4j.core.util.Patterns;
  
  /**
   * Returns the event's level in a StringBuilder.
   */
  @Plugin(name = "LevelPatternConverter", category = PatternConverter.CATEGORY)
  @ConverterKeys({ "p", "level" })
  public final class LevelPatternConverter extends LogEventPatternConverter {
      private static final String OPTION_LENGTH = "length";
      private static final String OPTION_LOWER = "lowerCase";
  
      /**
       * Singleton.
       */
      private static final LevelPatternConverter INSTANCE = new LevelPatternConverter(null);
  
      private final Map<Level, String> levelMap;
  
      /**
       * Private constructor.
       */
      private LevelPatternConverter(final Map<Level, String> map) {
          super("Level", "level");
          this.levelMap = map;
      }
  
      /**
       * Obtains an instance of pattern converter.
       *
       * @param options
       *            options, may be null. May contain a list of level names and The value that should be displayed for the
       *            Level.
       * @return instance of pattern converter.
       */
      public static LevelPatternConverter newInstance(final String[] options) {
          if (options == null || options.length == 0) {
              return INSTANCE;
          }
          final Map<Level, String> levelMap = new HashMap<Level, String>();
          int length = Integer.MAX_VALUE; // More than the longest level name.
          boolean lowerCase = false;
          final String[] definitions = options[0].split(Patterns.COMMA_SEPARATOR);
          for (final String def : definitions) {
              final String[] pair = def.split("=");
              if (pair == null || pair.length != 2) {
                  LOGGER.error("Invalid option {}", def);
                  continue;
              }
              final String key = pair[0].trim();
              final String value = pair[1].trim();
              if (OPTION_LENGTH.equalsIgnoreCase(key)) {
                  length = Integer.parseInt(value);
              } else if (OPTION_LOWER.equalsIgnoreCase(key)) {
                  lowerCase = Boolean.parseBoolean(value);
              } else {
                  final Level level = Level.toLevel(key, null);
                  if (level == null) {
                      LOGGER.error("Invalid Level {}", key);
                  } else {
                      levelMap.put(level, value);
                  }
              }
          }
          if (levelMap.isEmpty() && length == Integer.MAX_VALUE && !lowerCase) {
              return INSTANCE;
          }
          for (final Level level : Level.values()) {
              if (!levelMap.containsKey(level)) {
                  final String left = left(level, length);
                  levelMap.put(level, lowerCase ? left.toLowerCase(Locale.US) : left);
              }
          }
          return new LevelPatternConverter(levelMap);
      }
 
     /**
      * Returns the leftmost chars of the level name for the given level.
      *
      * @param level
      *            The level
      * @param length
      *            How many chars to return
      * @return The abbreviated level name, or the whole level name if the {@code length} is greater than the level name
      *         length,
      */
     private static String left(final Level level, final int length) {
         final String string = level.toString();
         if (length >= string.length()) {
             return string;
         }
         return string.substring(0, length);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void format(final LogEvent event, final StringBuilder output) {
         output.append(levelMap == null ? event.getLevel().toString() : levelMap.get(event.getLevel()));
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String getStyleClass(final Object e) {
         if (e instanceof LogEvent) {
             return "level " + ((LogEvent) e).getLevel().name().toLowerCase(Locale.ENGLISH);
         }
 
         return "level";
     }
 }