/*
 * 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.solr.spelling;

import java.util.Collection;
import org.apache.lucene.analysis.Analyzer;
import org.apache.solr.util.plugin.NamedListInitializedPlugin;

/**
 * The QueryConverter is an abstract base class defining a method for converting input "raw" queries
 * into a set of tokens for spell checking. It is used to "parse" the CommonParams.Q (the input
 * query) and converts it to tokens.
 *
 * <p>It is only invoked for the CommonParams.Q parameter, and <b>not</b> the "spellcheck.q"
 * parameter. Systems that use their own query parser or those that find issue with the basic
 * implementation should implement their own QueryConverter instead of using the provided
 * implementation (SpellingQueryConverter) by overriding the appropriate methods on the
 * SpellingQueryConverter and registering it in the solrconfig.xml
 *
 * <p>Refer to <a
 * href="https://solr.apache.org/guide/solr/latest/query-guide/spell-checking.html">https://solr.apache.org/guide/solr/latest/query-guide/spell-checking.html</a>
 * for more details
 *
 * @since solr 1.3
 */
public abstract class QueryConverter implements NamedListInitializedPlugin {
  protected Analyzer analyzer;

  /** This term is marked prohibited in the query with the minus sign. */
  public static final int PROHIBITED_TERM_FLAG = 16384;
  /** This term is marked required in the query with the plus sign. */
  public static final int REQUIRED_TERM_FLAG = 32768;
  /**
   * This term is directly followed by a boolean operator (AND/OR/NOT) and this operator differs
   * from the prior boolean operator in the query (this signifies this term is likely part of a
   * different query clause than the next term in the query)
   */
  public static final int TERM_PRECEDES_NEW_BOOLEAN_OPERATOR_FLAG = 65536;
  /** This term exists in a query that contains boolean operators (AND/OR/NOT) */
  public static final int TERM_IN_BOOLEAN_QUERY_FLAG = 131072;

  /**
   * Returns the Collection of {@link Token}s for the query. Offsets on the Token should correspond
   * to the correct offset in the origQuery
   */
  public abstract Collection<Token> convert(String original);

  /** Set the analyzer to use. Must be set before any calls to convert. */
  public void setAnalyzer(Analyzer analyzer) {
    this.analyzer = analyzer;
  }

  public Analyzer getAnalyzer() {
    return analyzer;
  }
}
