package org.apache.lucene.analysis.core;

/*
 * 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.
 */

import org.apache.lucene.analysis.util.*;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.core.StopAnalyzer;
import org.apache.lucene.analysis.core.StopFilter;

import java.util.Map;
import java.io.IOException;

/**
 * Factory for {@link StopFilter}.
 * <pre class="prettyprint" >
 * <fieldType name="text_stop" class="solr.TextField" positionIncrementGap="100" autoGeneratePhraseQueries="true">
 *   <analyzer>
 *     <tokenizer class="solr.WhitespaceTokenizerFactory"/>
 *     <filter class="solr.StopFilterFactory" ignoreCase="true"
 *             words="stopwords.txt" enablePositionIncrements="true"/>
 *   </analyzer>
 * </fieldType></pre>
 *
 */
public class StopFilterFactory extends TokenFilterFactory implements ResourceLoaderAware {

  @Override
  public void init(Map<String,String> args) {
    super.init(args);
    assureMatchVersion();
  }

  @Override
  public void inform(ResourceLoader loader) throws IOException {
    String stopWordFiles = args.get("words");
    ignoreCase = getBoolean("ignoreCase",false);
    enablePositionIncrements = getBoolean("enablePositionIncrements",false);

    if (stopWordFiles != null) {
      if ("snowball".equalsIgnoreCase(args.get("format"))) {
        stopWords = getSnowballWordSet(loader, stopWordFiles, ignoreCase);
      } else {
        stopWords = getWordSet(loader, stopWordFiles, ignoreCase);
      }
    } else {
      stopWords = new CharArraySet(luceneMatchVersion, StopAnalyzer.ENGLISH_STOP_WORDS_SET, ignoreCase);
    }
  }

  private CharArraySet stopWords;
  private boolean ignoreCase;
  private boolean enablePositionIncrements;

  public boolean isEnablePositionIncrements() {
    return enablePositionIncrements;
  }

  public boolean isIgnoreCase() {
    return ignoreCase;
  }

  public CharArraySet getStopWords() {
    return stopWords;
  }

  @Override
  public TokenStream create(TokenStream input) {
    StopFilter stopFilter = new StopFilter(luceneMatchVersion,input,stopWords);
    stopFilter.setEnablePositionIncrements(enablePositionIncrements);
    return stopFilter;
  }
}