package org.apache.lucene.store;

/**
 * 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.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.MockAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.RandomIndexWriter;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.util.LineFileDocs;
import org.apache.lucene.util.LuceneTestCase;
import org.apache.lucene.util.Version;
import org.apache.lucene.util._TestUtil;

public class TestNRTCachingDirectory extends LuceneTestCase {

  public void testNRTAndCommit() throws Exception {
    Directory dir = newDirectory();
    NRTCachingDirectory cachedDir = new NRTCachingDirectory(dir, 2.0, 25.0);
    IndexWriterConfig conf = newIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(random));
    conf.setMergeScheduler(cachedDir.getMergeScheduler());
    RandomIndexWriter w = new RandomIndexWriter(random, cachedDir, conf);
    w.w.setInfoStream(VERBOSE ? System.out : null);
    final LineFileDocs docs = new LineFileDocs(random);    
    final int numDocs = _TestUtil.nextInt(random, 100, 400);

    if (VERBOSE) {
      System.out.println("TEST: numDocs=" + numDocs);
    }

    final List<String> ids = new ArrayList<String>();
    IndexReader r = null;
    for(int docCount=0;docCount<numDocs;docCount++) {
      final Document doc = docs.nextDoc();
      ids.add(new String(doc.get("docid")));
      w.addDocument(doc);
      if (random.nextInt(20) == 17) {
        if (r == null) {
          r = IndexReader.open(w.w, false);
        } else {
          final IndexReader r2 = IndexReader.openIfChanged(r);
          if (r2 != null) {
            r.close();
            r = r2;
          }
        }
        assertEquals(1+docCount, r.numDocs());
        final IndexSearcher s = new IndexSearcher(r);
        // Just make sure search can run; we can't assert
        // totHits since it could be 0
        TopDocs hits = s.search(new TermQuery(new Term("body", "the")), 10);
        // System.out.println("tot hits " + hits.totalHits);
      }
    }

    if (r != null) {
      r.close();
    }

    // Close should force cache to clear since all files are sync'd
    w.close();

    final String[] cachedFiles = cachedDir.listCachedFiles();
    for(String file : cachedFiles) {
      System.out.println("FAIL: cached file " + file + " remains after sync");
    }
    assertEquals(0, cachedFiles.length);
    
    r = IndexReader.open(dir);
    for(String id : ids) {
      assertEquals(1, r.docFreq(new Term("docid", id)));
    }
    r.close();
    cachedDir.close();
  }

  // NOTE: not a test; just here to make sure the code frag
  // in the javadocs is correct!
  public void verifyCompiles() throws Exception {
    Analyzer analyzer = null;

    Directory fsDir = FSDirectory.open(new File("/path/to/index"));
    NRTCachingDirectory cachedFSDir = new NRTCachingDirectory(fsDir, 2.0, 25.0);
    IndexWriterConfig conf = new IndexWriterConfig(Version.LUCENE_32, analyzer);
    conf.setMergeScheduler(cachedFSDir.getMergeScheduler());
    IndexWriter writer = new IndexWriter(cachedFSDir, conf);
  }

  public void testDeleteFile() throws Exception {
    Directory dir = new NRTCachingDirectory(newDirectory(), 2.0, 25.0);
    dir.createOutput("foo.txt").close();
    dir.deleteFile("foo.txt");
    assertEquals(0, dir.listAll().length);
    dir.close();
  }
  
  // LUCENE-3382 -- make sure we get exception if the directory really does not exist.
  public void testNoDir() throws Throwable {
    Directory dir = new NRTCachingDirectory(newFSDirectory(_TestUtil.getTempDir("doesnotexist")), 2.0, 25.0);
    try {
      IndexReader.open(dir, true);
      fail("did not hit expected exception");
    } catch (NoSuchDirectoryException nsde) {
      // expected
    }
    dir.close();
  }
  
  // LUCENE-3382 test that we can add a file, and then when we call list() we get it back
  public void testDirectoryFilter() throws IOException {
    Directory dir = new NRTCachingDirectory(newFSDirectory(_TestUtil.getTempDir("foo")), 2.0, 25.0);
    String name = "file";
    try {
      dir.createOutput(name).close();
      assertTrue(dir.fileExists(name));
      assertTrue(Arrays.asList(dir.listAll()).contains(name));
    } finally {
      dir.close();
    }
  }
  
  /** Creates a file of the specified size with sequential data. The first
   *  byte is written as the start byte provided. All subsequent bytes are
   *  computed as start + offset where offset is the number of the byte.
   */
  private void createSequenceFile(Directory dir, String name, byte start, int size) throws IOException {
      IndexOutput os = dir.createOutput(name);
      for (int i=0; i < size; i++) {
          os.writeByte(start);
          start ++;
      }
      os.close();
  }
}