/*
 * 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.core;


import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.CharArraySet;
import org.apache.lucene.analysis.util.ResourceLoader;
import org.apache.lucene.analysis.util.ResourceLoaderAware;
import org.apache.lucene.analysis.util.TokenFilterFactory;

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

/**
 * Modified StopFilterFactory, because the 'wise' people of Lucene:
 *  - removed ability to 'not count' gaps
 *  - and also, in their infinite wisdom, made the option private
 *    (so the poor devs have not other chance then to fork)
 */

public class AqpStopFilterFactory extends TokenFilterFactory implements ResourceLoaderAware {
  public static final String FORMAT_WORDSET = "wordset";
  public static final String FORMAT_SNOWBALL = "snowball";
  
  private CharArraySet stopWords;
  private final String stopWordFiles;
  private final String format;
  private final boolean ignoreCase;
  private boolean ignorePosition;
  
  /** Creates a new StopFilterFactory */
  public AqpStopFilterFactory(Map<String,String> args) {
    super(args);
    stopWordFiles = get(args, "words");
    format = get(args, "format", (null == stopWordFiles ? null : FORMAT_WORDSET));
    ignoreCase = getBoolean(args, "ignoreCase", false);
    ignorePosition = getBoolean(args, "ignorePosition", true);
    if (!args.isEmpty()) {
      throw new IllegalArgumentException("Unknown parameters: " + args);
    }
  }

  @Override
  public void inform(ResourceLoader loader) throws IOException {
    if (stopWordFiles != null) {
      if (FORMAT_WORDSET.equalsIgnoreCase(format)) {
        stopWords = getWordSet(loader, stopWordFiles, ignoreCase);
      } else if (FORMAT_SNOWBALL.equalsIgnoreCase(format)) {
        stopWords = getSnowballWordSet(loader, stopWordFiles, ignoreCase);
      } else {
        throw new IllegalArgumentException("Unknown 'format' specified for 'words' file: " + format);
      }
    } else {
      if (null != format) {
        throw new IllegalArgumentException("'format' can not be specified w/o an explicit 'words' file: " + format);
      }
      stopWords = new CharArraySet(StopAnalyzer.ENGLISH_STOP_WORDS_SET, ignoreCase);
    }
  }

  public boolean isIgnoreCase() {
    return ignoreCase;
  }

  public CharArraySet getStopWords() {
    return stopWords;
  }

  @Override
  public TokenStream create(TokenStream input) {
    AqpStopFilter stopFilter = new AqpStopFilter(input, stopWords, ignorePosition);
    return stopFilter;
  }
}