/*
 * 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.lucene.analysis.charfilter;


import org.apache.lucene.analysis.util.CharFilterFactory;

import java.io.Reader;
import java.util.Map;
import java.util.Set;
import java.util.regex.Pattern;

/**
 * Factory for {@link HTMLStripCharFilter}. 
 * <pre class="prettyprint">
 * &lt;fieldType name="text_html" class="solr.TextField" positionIncrementGap="100"&gt;
 *   &lt;analyzer&gt;
 *     &lt;charFilter class="solr.HTMLStripCharFilterFactory" escapedTags="a, title" /&gt;
 *     &lt;tokenizer class="solr.WhitespaceTokenizerFactory"/&gt;
 *   &lt;/analyzer&gt;
 * &lt;/fieldType&gt;</pre>
 *
 * @since 3.1
 * @lucene.spi {@value #NAME}
 */
public class HTMLStripCharFilterFactory extends CharFilterFactory {

  /** SPI name */
  public static final String NAME = "htmlStrip";

  final Set<String> escapedTags;
  static final Pattern TAG_NAME_PATTERN = Pattern.compile("[^\\s,]+");
  
  /** Creates a new HTMLStripCharFilterFactory */
  public HTMLStripCharFilterFactory(Map<String,String> args) {
    super(args);
    escapedTags = getSet(args, "escapedTags");
    if (!args.isEmpty()) {
      throw new IllegalArgumentException("Unknown parameters: " + args);
    }
  }

  @Override
  public HTMLStripCharFilter create(Reader input) {
    HTMLStripCharFilter charFilter;
    if (null == escapedTags) {
      charFilter = new HTMLStripCharFilter(input);
    } else {
      charFilter = new HTMLStripCharFilter(input, escapedTags);
    }
    return charFilter;
  }
}