package org.apache.lucene.search.similar;

/**
 * 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 java.io.IOException;
import java.io.StringReader;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;

import org.apache.lucene.analysis.MockAnalyzer;
import org.apache.lucene.analysis.MockTokenizer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.RandomIndexWriter;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.store.Directory;
import org.apache.lucene.util.LuceneTestCase;

public class TestMoreLikeThis extends LuceneTestCase {
  private Directory directory;
  private IndexReader reader;
  private IndexSearcher searcher;
  
  @Override
  protected void setUp() throws Exception {
    super.setUp();
    Random random = newRandom();
    directory = newDirectory(random);
    RandomIndexWriter writer = new RandomIndexWriter(random, directory);
    
    // Add series of docs with specific information for MoreLikeThis
    addDoc(writer, "lucene");
    addDoc(writer, "lucene release");

    reader = writer.getReader();
    writer.close();
    searcher = new IndexSearcher(reader);
  }
  
  @Override
  protected void tearDown() throws Exception {
    reader.close();
    searcher.close();
    directory.close();
    super.tearDown();
  }
  
  private void addDoc(RandomIndexWriter writer, String text) throws IOException {
    Document doc = new Document();
    doc.add(new Field("text", text, Field.Store.YES, Field.Index.ANALYZED));
    writer.addDocument(doc);
  }
  
  public void testBoostFactor() throws Throwable {
    Map<String,Float> originalValues = getOriginalValues();
    
    MoreLikeThis mlt = new MoreLikeThis(reader);
    mlt.setAnalyzer(new MockAnalyzer(MockTokenizer.WHITESPACE, false));
    mlt.setMinDocFreq(1);
    mlt.setMinTermFreq(1);
    mlt.setMinWordLen(1);
    mlt.setFieldNames(new String[] {"text"});
    mlt.setBoost(true);
    
    // this mean that every term boost factor will be multiplied by this
    // number
    float boostFactor = 5;
    mlt.setBoostFactor(boostFactor);
    
    BooleanQuery query = (BooleanQuery) mlt.like(new StringReader(
        "lucene release"));
    List<BooleanClause> clauses = query.clauses();
    
    assertEquals("Expected " + originalValues.size() + " clauses.",
        originalValues.size(), clauses.size());
    
    for (int i = 0; i < clauses.size(); i++) {
      BooleanClause clause = clauses.get(i);
      TermQuery tq = (TermQuery) clause.getQuery();
      Float termBoost = originalValues.get(tq.getTerm().text());
      assertNotNull("Expected term " + tq.getTerm().text(), termBoost);
      
      float totalBoost = termBoost.floatValue() * boostFactor;
      assertEquals("Expected boost of " + totalBoost + " for term '"
          + tq.getTerm().text() + "' got " + tq.getBoost(), totalBoost, tq
          .getBoost(), 0.0001);
    }
  }
  
  private Map<String,Float> getOriginalValues() throws IOException {
    Map<String,Float> originalValues = new HashMap<String,Float>();
    MoreLikeThis mlt = new MoreLikeThis(reader);
    mlt.setAnalyzer(new MockAnalyzer(MockTokenizer.WHITESPACE, false));
    mlt.setMinDocFreq(1);
    mlt.setMinTermFreq(1);
    mlt.setMinWordLen(1);
    mlt.setFieldNames(new String[] {"text"});
    mlt.setBoost(true);
    BooleanQuery query = (BooleanQuery) mlt.like(new StringReader(
        "lucene release"));
    List<BooleanClause> clauses = query.clauses();
    
    for (int i = 0; i < clauses.size(); i++) {
      BooleanClause clause = clauses.get(i);
      TermQuery tq = (TermQuery) clause.getQuery();
      originalValues.put(tq.getTerm().text(), Float.valueOf(tq.getBoost()));
    }
    return originalValues;
  }
}