package org.apache.lucene.index;

/**
 * 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.util.*;

import org.apache.lucene.analysis.MockAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.TermRangeQuery;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.MockDirectoryWrapper;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.LuceneTestCase;
import org.apache.lucene.util._TestUtil;

public class TestForTooMuchCloning extends LuceneTestCase {

  // Make sure we don't clone IndexInputs too frequently
  // during merging:
  public void test() throws Exception {
    final MockDirectoryWrapper dir = newDirectory();
    final TieredMergePolicy tmp = new TieredMergePolicy();
    tmp.setMaxMergeAtOnce(2);
    final RandomIndexWriter w = new RandomIndexWriter(random, dir,
                                                      newIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(random)).setMaxBufferedDocs(2).setMergePolicy(tmp));
    final int numDocs = 20;
    for(int docs=0;docs<numDocs;docs++) {
      StringBuilder sb = new StringBuilder();
      for(int terms=0;terms<100;terms++) {
        sb.append(_TestUtil.randomRealisticUnicodeString(random));
        sb.append(' ');
      }
      final Document doc = new Document();
      doc.add(newField("field", sb.toString(), Field.Store.NO, Field.Index.ANALYZED));
      w.addDocument(doc);
    }
    final IndexReader r = w.getReader();
    w.close();

    final int cloneCount = dir.getInputCloneCount();
    //System.out.println("merge clone count=" + cloneCount);
    assertTrue("too many calls to IndexInput.clone during merging: " + dir.getInputCloneCount(), cloneCount < 500);

    final IndexSearcher s = new IndexSearcher(r);

    // MTQ that matches all terms so the AUTO_REWRITE should
    // cutover to filter rewrite and reuse a single DocsEnum
    // across all terms;
    final TopDocs hits = s.search(new TermRangeQuery("field",
                                                     "",
                                                     "\uFFFF",
                                                     true,
                                                     true), 10);
    assertTrue(hits.totalHits > 0);
    final int queryCloneCount = dir.getInputCloneCount() - cloneCount;
    //System.out.println("query clone count=" + queryCloneCount);
    assertTrue("too many calls to IndexInput.clone during TermRangeQuery: " + queryCloneCount, queryCloneCount < 50);
    s.close();
    r.close();
    dir.close();
  }
}