/*
 * 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.lucene.index;


import org.apache.lucene.analysis.MockAnalyzer;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.MockTokenizer;
import org.apache.lucene.store.Directory;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.FieldType;
import org.apache.lucene.document.StringField;
import org.apache.lucene.index.IndexWriterConfig.OpenMode;
import org.apache.lucene.util.English;

import org.apache.lucene.util.LuceneTestCase;
import org.junit.BeforeClass;

import java.util.Random;

public class TestThreadedForceMerge extends LuceneTestCase {

  private static Analyzer ANALYZER;

  private final static int NUM_THREADS = 3;
  //private final static int NUM_THREADS = 5;

  private final static int NUM_ITER = 1;

  private final static int NUM_ITER2 = 1;

  private volatile boolean failed;

  @BeforeClass
  public static void setup() {
    ANALYZER = new MockAnalyzer(random(), MockTokenizer.SIMPLE, true);
  }

  private void setFailed() {
    failed = true;
  }

  public void runTest(Random random, Directory directory) throws Exception {

    IndexWriter writer = new IndexWriter(
        directory,
        newIndexWriterConfig(ANALYZER).
            setOpenMode(OpenMode.CREATE).
            setMaxBufferedDocs(2).
            setMergePolicy(newLogMergePolicy())
    );

    for(int iter=0;iter<NUM_ITER;iter++) {
      final int iterFinal = iter;

      ((LogMergePolicy) writer.getConfig().getMergePolicy()).setMergeFactor(1000);

      final FieldType customType = new FieldType(StringField.TYPE_STORED);
      customType.setOmitNorms(true);
      
      for(int i=0;i<200;i++) {
        Document d = new Document();
        d.add(newField("id", Integer.toString(i), customType));
        d.add(newField("contents", English.intToEnglish(i), customType));
        writer.addDocument(d);
      }

      ((LogMergePolicy) writer.getConfig().getMergePolicy()).setMergeFactor(4);

      Thread[] threads = new Thread[NUM_THREADS];
      
      for(int i=0;i<NUM_THREADS;i++) {
        final int iFinal = i;
        final IndexWriter writerFinal = writer;
        threads[i] = new Thread() {
          @Override
          public void run() {
            try {
              for(int j=0;j<NUM_ITER2;j++) {
                writerFinal.forceMerge(1, false);
                for(int k=0;k<17*(1+iFinal);k++) {
                  Document d = new Document();
                  d.add(newField("id", iterFinal + "_" + iFinal + "_" + j + "_" + k, customType));
                  d.add(newField("contents", English.intToEnglish(iFinal+k), customType));
                  writerFinal.addDocument(d);
                }
                for(int k=0;k<9*(1+iFinal);k++)
                  writerFinal.deleteDocuments(new Term("id", iterFinal + "_" + iFinal + "_" + j + "_" + k));
                writerFinal.forceMerge(1);
              }
            } catch (Throwable t) {
              setFailed();
              System.out.println(Thread.currentThread().getName() + ": hit exception");
              t.printStackTrace(System.out);
            }
          }
        };
      }

      for(int i=0;i<NUM_THREADS;i++)
        threads[i].start();

      for(int i=0;i<NUM_THREADS;i++)
        threads[i].join();

      assertTrue(!failed);

      final int expectedDocCount = (int) ((1+iter)*(200+8*NUM_ITER2*(NUM_THREADS/2.0)*(1+NUM_THREADS)));

      assertEquals("index=" + writer.segString() + " numDocs=" + writer.numDocs() + " maxDoc=" + writer.maxDoc() + " config=" + writer.getConfig(), expectedDocCount, writer.numDocs());
      assertEquals("index=" + writer.segString() + " numDocs=" + writer.numDocs() + " maxDoc=" + writer.maxDoc() + " config=" + writer.getConfig(), expectedDocCount, writer.maxDoc());

      writer.close();
      writer = new IndexWriter(directory, newIndexWriterConfig(ANALYZER)
          .setOpenMode(OpenMode.APPEND)
          .setMaxBufferedDocs(2));
      
      DirectoryReader reader = DirectoryReader.open(directory);
      assertEquals("reader=" + reader, 1, reader.leaves().size());
      assertEquals(expectedDocCount, reader.numDocs());
      reader.close();
    }
    writer.close();
  }

  /*
    Run above stress test against RAMDirectory and then
    FSDirectory.
  */
  public void testThreadedForceMerge() throws Exception {
    Directory directory = newDirectory();
    runTest(random(), directory);
    directory.close();
  }
}