/** tests the returned sort values are correct */
public void testSortValues() throws Exception {
  Expression expr = JavascriptCompiler.compile("sqrt(_score)");
  
  SimpleBindings bindings = new SimpleBindings();
  bindings.add("_score", DoubleValuesSource.SCORES);

  Sort sort = new Sort(expr.getSortField(bindings, true));
  Query query = new TermQuery(new Term("body", "contents"));
  TopFieldDocs td = searcher.search(query, 3, sort, true);
  for (int i = 0; i < 3; i++) {
    FieldDoc d = (FieldDoc) td.scoreDocs[i];
    float expected = (float) Math.sqrt(d.score);
    float actual = ((Double)d.fields[0]).floatValue();
    assertEquals(expected, actual, 0d);
  }
}
 

/** tests same binding used more than once in an expression */
public void testTwoOfSameBinding() throws Exception {
  Expression expr = JavascriptCompiler.compile("_score + _score");
  
  SimpleBindings bindings = new SimpleBindings();
  bindings.add("_score", DoubleValuesSource.SCORES);
  
  Sort sort = new Sort(expr.getSortField(bindings, true));
  Query query = new TermQuery(new Term("body", "contents"));
  TopFieldDocs td = searcher.search(query, 3, sort, true);
  for (int i = 0; i < 3; i++) {
    FieldDoc d = (FieldDoc) td.scoreDocs[i];
    float expected = 2*d.score;
    float actual = ((Double)d.fields[0]).floatValue();
    assertEquals(expected, actual, 0d);
  }
}
 

/** Uses variables with $ */
public void testDollarVariable() throws Exception {
  Expression expr = JavascriptCompiler.compile("$0+$score");
  
  SimpleBindings bindings = new SimpleBindings();
  bindings.add("$0", DoubleValuesSource.SCORES);
  bindings.add("$score", DoubleValuesSource.SCORES);

  Sort sort = new Sort(expr.getSortField(bindings, true));
  Query query = new TermQuery(new Term("body", "contents"));
  TopFieldDocs td = searcher.search(query, 3, sort, true);
  for (int i = 0; i < 3; i++) {
    FieldDoc d = (FieldDoc) td.scoreDocs[i];
    float expected = 2*d.score;
    float actual = ((Double)d.fields[0]).floatValue();
    assertEquals(expected, actual, 0d);
  }
}
 

/** tests expression referring to another expression */
public void testExpressionRefersToExpression() throws Exception {
  Expression expr1 = JavascriptCompiler.compile("_score");
  Expression expr2 = JavascriptCompiler.compile("2*expr1");
  
  SimpleBindings bindings = new SimpleBindings();
  bindings.add("_score", DoubleValuesSource.SCORES);
  bindings.add("expr1", expr1);
  
  Sort sort = new Sort(expr2.getSortField(bindings, true));
  Query query = new TermQuery(new Term("body", "contents"));
  TopFieldDocs td = searcher.search(query, 3, sort, true);
  for (int i = 0; i < 3; i++) {
    FieldDoc d = (FieldDoc) td.scoreDocs[i];
    float expected = 2*d.score;
    float actual = ((Double)d.fields[0]).floatValue();
    assertEquals(expected, actual, 0d);
  }
}
 

private void doTestLotsOfBindings(int n) throws Exception {
  SimpleBindings bindings = new SimpleBindings();    
  StringBuilder sb = new StringBuilder();
  for (int i = 0; i < n; i++) {
    if (i > 0) {
      sb.append("+");
    }
    sb.append("x" + i);
    bindings.add("x" + i, DoubleValuesSource.SCORES);
  }
  
  Expression expr = JavascriptCompiler.compile(sb.toString());
  Sort sort = new Sort(expr.getSortField(bindings, true));
  Query query = new TermQuery(new Term("body", "contents"));
  TopFieldDocs td = searcher.search(query, 3, sort, true);
  for (int i = 0; i < 3; i++) {
    FieldDoc d = (FieldDoc) td.scoreDocs[i];
    float expected = n*d.score;
    float actual = ((Double)d.fields[0]).floatValue();
    assertEquals(expected, actual, 0d);
  }
}
 

/** Utility method, to search and also collect all hits
 *  into the provided {@link Collector}. */
public static TopFieldDocs search(IndexSearcher searcher, Query q, int n, Sort sort, Collector fc) throws IOException {
  if (sort == null) {
    throw new IllegalArgumentException("sort must not be null");
  }
  return (TopFieldDocs) doSearch(searcher, null, q, n, sort, false, fc);
}
 

/** Utility method, to search and also collect all hits
 *  into the provided {@link Collector}. */
public static TopFieldDocs search(IndexSearcher searcher, Query q, int n, Sort sort, boolean doDocScores, Collector fc) throws IOException {
  if (sort == null) {
    throw new IllegalArgumentException("sort must not be null");
  }
  return (TopFieldDocs) doSearch(searcher, null, q, n, sort, doDocScores, fc);
}
 

public static TopFieldDocs nearest(IndexSearcher searcher, String field, int topN, float... origin) throws IOException {
  if (topN < 1) {
    throw new IllegalArgumentException("topN must be at least 1; got " + topN);
  }
  if (field == null) {
    throw new IllegalArgumentException("field must not be null");
  }
  if (searcher == null) {
    throw new IllegalArgumentException("searcher must not be null");
  }
  List<BKDReader> readers = new ArrayList<>();
  List<Integer> docBases = new ArrayList<>();
  List<Bits> liveDocs = new ArrayList<>();
  int totalHits = 0;
  for (LeafReaderContext leaf : searcher.getIndexReader().leaves()) {
    PointValues points = leaf.reader().getPointValues(field);
    if (points != null) {
      if (points instanceof BKDReader == false) {
        throw new IllegalArgumentException("can only run on Lucene60PointsReader points implementation, but got " + points);
      }
      totalHits += points.getDocCount();
      readers.add((BKDReader)points);
      docBases.add(leaf.docBase);
      liveDocs.add(leaf.reader().getLiveDocs());
    }
  }

  NearestHit[] hits = nearest(readers, liveDocs, docBases, topN, origin);

  // Convert to TopFieldDocs:
  ScoreDoc[] scoreDocs = new ScoreDoc[hits.length];
  for(int i=0;i<hits.length;i++) {
    NearestHit hit = hits[i];
    scoreDocs[i] = new FieldDoc(hit.docID, 0.0f, new Object[] { (float)Math.sqrt(hit.distanceSquared) });
  }
  return new TopFieldDocs(new TotalHits(totalHits, TotalHits.Relation.EQUAL_TO), scoreDocs, null);
}
 

public void testMultipleUpdatesSameDoc() throws Exception {

    Directory dir = newDirectory();
    IndexWriterConfig conf = newIndexWriterConfig(new MockAnalyzer(random()));
    
    conf.setMaxBufferedDocs(3); // small number of docs, so use a tiny maxBufferedDocs

    IndexWriter writer = new IndexWriter(dir, conf);

    writer.updateDocument       (new Term("id","doc-1"), doc(1, 1000000000L ));
    writer.updateNumericDocValue(new Term("id","doc-1"), "val", 1000001111L );
    writer.updateDocument       (new Term("id","doc-2"), doc(2, 2000000000L ));
    writer.updateDocument       (new Term("id","doc-2"), doc(2, 2222222222L ));
    writer.updateNumericDocValue(new Term("id","doc-1"), "val", 1111111111L );

    final DirectoryReader reader;
    if (random().nextBoolean()) {
      writer.commit();
      reader = DirectoryReader.open(dir);
    } else {
      reader = DirectoryReader.open(writer);
    }
    final IndexSearcher searcher = new IndexSearcher(reader);
    TopFieldDocs td;
    
    td = searcher.search(new TermQuery(new Term("id", "doc-1")), 1, 
                         new Sort(new SortField("val", SortField.Type.LONG)));
    assertEquals("doc-1 missing?", 1, td.scoreDocs.length);
    assertEquals("doc-1 value", 1111111111L, ((FieldDoc)td.scoreDocs[0]).fields[0]);
    
    td = searcher.search(new TermQuery(new Term("id", "doc-2")), 1, 
                        new Sort(new SortField("val", SortField.Type.LONG)));
    assertEquals("doc-2 missing?", 1, td.scoreDocs.length);
    assertEquals("doc-2 value", 2222222222L, ((FieldDoc)td.scoreDocs[0]).fields[0]);
    
    IOUtils.close(reader, writer, dir);
  }
 

@Override
protected List<Lookup.LookupResult> createResults(IndexSearcher searcher, TopFieldDocs hits, int num, CharSequence key,
                                                  boolean doHighlight, Set<String> matchedTokens, String prefixToken)
    throws IOException {

  TreeSet<Lookup.LookupResult> results = new TreeSet<>(LOOKUP_COMP);

  // we reduce the num to the one initially requested
  int actualNum = num / numFactor;

  for (int i = 0; i < hits.scoreDocs.length; i++) {
    FieldDoc fd = (FieldDoc) hits.scoreDocs[i];

    BinaryDocValues textDV = MultiDocValues.getBinaryValues(searcher.getIndexReader(), TEXT_FIELD_NAME);
    assert textDV != null;

    textDV.advance(fd.doc);

    final String text = textDV.binaryValue().utf8ToString();
    long weight = (Long) fd.fields[0];

    // This will just be null if app didn't pass payloads to build():
    // TODO: maybe just stored fields?  they compress...
    BinaryDocValues payloadsDV = MultiDocValues.getBinaryValues(searcher.getIndexReader(), "payloads");

    BytesRef payload;
    if (payloadsDV != null) {
      if (payloadsDV.advance(fd.doc) == fd.doc) {
        payload = BytesRef.deepCopyOf(payloadsDV.binaryValue());
      } else {
        payload = new BytesRef(BytesRef.EMPTY_BYTES);
      }
    } else {
      payload = null;
    }

    double coefficient;
    if (text.startsWith(key.toString())) {
      // if hit starts with the key, we don't change the score
      coefficient = 1;
    } else {
      coefficient = createCoefficient(searcher, fd.doc, matchedTokens, prefixToken);
    }
    if (weight == 0) {
      weight = 1;
    }
    if (weight < 1 / LINEAR_COEF && weight > -1 / LINEAR_COEF) {
      weight *= 1 / LINEAR_COEF;
    }
    long score = (long) (weight * coefficient);

    LookupResult result;
    if (doHighlight) {
      result = new LookupResult(text, highlight(text, matchedTokens, prefixToken), score, payload);
    } else {
      result = new LookupResult(text, score, payload);
    }

    boundedTreeAdd(results, result, actualNum);
  }

  return new ArrayList<>(results.descendingSet());
}