/*
    * 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.Arrays;
  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;
  import org.apache.logging.log4j.core.util.Patterns;
  import org.apache.logging.log4j.util.PerformanceSensitive;
  
  /**
   * Style pattern converter. Adds ANSI color styling to the result of the enclosed pattern.
   *
   * <p>
   * To disable ANSI output unconditionally, specify an additional option <code>disableAnsi=true</code>, or to
   * disable ANSI output if no console is detected, specify option <code>noConsoleNoAnsi=true</code>.
   * </p>
   */
  @Plugin(name = "style", category = PatternConverter.CATEGORY)
  @ConverterKeys({ "style" })
  @PerformanceSensitive("allocation")
  public final class StyleConverter extends LogEventPatternConverter implements AnsiConverter {
  
      private final List<PatternFormatter> patternFormatters;
  
      private final boolean noAnsi;
  
      private final String style;
  
      private final String defaultStyle;
  
      /**
       * Constructs the converter.
       *
       * @param patternFormatters
       *            The PatternFormatters to generate the text to manipulate.
       * @param style
       *            The style that should encapsulate the pattern.
       * @param noAnsi
       *            If true, do not output ANSI escape codes.
       */
      private StyleConverter(final List<PatternFormatter> patternFormatters, final String style, final boolean noAnsi) {
          super("style", "style");
          this.patternFormatters = patternFormatters;
          this.style = style;
          this.defaultStyle = AnsiEscape.getDefaultStyle();
          this.noAnsi = noAnsi;
      }
  
      /**
       * Gets an instance of the class.
       *
       * @param config
       *            The current Configuration.
       * @param options
       *            pattern options, may be null. If first element is "short", only the first line of the throwable will
       *            be formatted.
       * @return instance of class.
       */
      public static StyleConverter newInstance(final Configuration config, final String[] options) {
          if (options == null) {
              return null;
          }
          if (options.length < 2) {
              LOGGER.error("Incorrect number of options on style. Expected at least 1, received " + options.length);
              return null;
          }
          if (options[0] == null) {
              LOGGER.error("No pattern supplied for style converter");
              return null;
          }
          if (options[1] == null) {
              LOGGER.error("No style attributes supplied for style converter");
              return null;
          }
          final PatternParser parser = PatternLayout.createPatternParser(config);
          final List<PatternFormatter> formatters = parser.parse(options[0]);
          final String style = AnsiEscape.createSequence(options[1].split(Patterns.COMMA_SEPARATOR));
          final boolean disableAnsi = Arrays.toString(options).contains(PatternParser.DISABLE_ANSI + "=true");
          final boolean noConsoleNoAnsi = Arrays.toString(options).contains(PatternParser.NO_CONSOLE_NO_ANSI + "=true");
          final boolean hideAnsi = disableAnsi || (noConsoleNoAnsi && System.console() == null);
         return new StyleConverter(formatters, style, hideAnsi);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void format(final LogEvent event, final StringBuilder toAppendTo) {
         int start = 0;
         int end = 0;
         if (!noAnsi) { // use ANSI: set prefix
             start = toAppendTo.length();
             toAppendTo.append(style);
             end = toAppendTo.length();
         }
 
         //noinspection ForLoopReplaceableByForEach
         for (int i = 0, size = patternFormatters.size(); i <  size; i++) {
             patternFormatters.get(i).format(event, toAppendTo);
         }
 
         // if we use ANSI we need to add the postfix or erase the unnecessary prefix
         if (!noAnsi) {
             if (toAppendTo.length() == end) {
                 toAppendTo.setLength(start); // erase prefix
             } else {
                 toAppendTo.append(defaultStyle); // add postfix
             }
         }
     }
 
     @Override
     public boolean handlesThrowable() {
         for (final PatternFormatter formatter : patternFormatters) {
             if (formatter.handlesThrowable()) {
                 return true;
             }
         }
         return false;
     }
 
     /**
      * Returns a String suitable for debugging.
      *
      * @return a String suitable for debugging.
      */
     @Override
     public String toString() {
         final StringBuilder sb = new StringBuilder();
         sb.append(super.toString());
         sb.append("[style=");
         sb.append(style);
         sb.append(", defaultStyle=");
         sb.append(defaultStyle);
         sb.append(", patternFormatters=");
         sb.append(patternFormatters);
         sb.append(", noAnsi=");
         sb.append(noAnsi);
         sb.append(']');
         return sb.toString();
     }
 
 }