/**
 * 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.apex.malhar.lib.io.fs;

import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.Map;

import org.junit.Assert;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.TestWatcher;
import org.junit.runner.Description;

import org.apache.apex.malhar.lib.io.block.AbstractBlockReader.ReaderRecord;
import org.apache.apex.malhar.lib.io.block.BlockWriter;
import org.apache.commons.io.FileUtils;

import com.google.common.collect.Lists;
import com.google.common.collect.Maps;

import com.datatorrent.api.Attribute;
import com.datatorrent.api.Context;
import com.datatorrent.api.DAG;
import com.datatorrent.netlet.util.Slice;

import static org.apache.apex.malhar.lib.helper.OperatorContextTestHelper.mockOperatorContext;

/**
 * Unit tests for {@link BlockWriter}
 */
public class BlockWriterTest
{

  public static final int BLOCK_SIZE = 5;

  public static final String[] FILE_CONTENTS = {"abcdefgh", "pqrst", "xyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
      "0123456789" };

  private class TestMeta extends TestWatcher
  {
    String outputPath;
    List<ReaderRecord<Slice>> blockDataList = Lists.newArrayList();
    Map<Long, String> blockIdToExpectedContent = Maps.newHashMap();

    BlockWriter underTest;
    File blocksDir;
    Context.OperatorContext context;

    /* (non-Javadoc)
     * @see org.junit.rules.TestWatcher#starting(org.junit.runner.Description)
     */
    @Override
    protected void starting(Description description)
    {
      super.starting(description);
      outputPath = new File("target/" + description.getClassName() + "/" + description.getMethodName()).getPath();

      underTest = new BlockWriter();
      String appDirectory = outputPath;

      Attribute.AttributeMap attributes = new Attribute.AttributeMap.DefaultAttributeMap();
      attributes.put(DAG.DAGContext.APPLICATION_ID, "PartitionWriterTest");
      attributes.put(DAG.DAGContext.APPLICATION_PATH, appDirectory);
      context = mockOperatorContext(1, attributes);

      underTest.setup(context);

      try {
        File outDir = new File(outputPath);
        FileUtils.forceMkdir(outDir);

        blocksDir = new File(context.getValue(Context.DAGContext.APPLICATION_PATH), BlockWriter.DEFAULT_BLOCKS_DIR);
        blocksDir.mkdirs();

        long blockID = 1000;

        for (int i = 0; i < FILE_CONTENTS.length; i++) {
          for (int offset = 0; offset < FILE_CONTENTS[i].length(); offset += BLOCK_SIZE, blockID++) {
            String blockContents;
            if (offset + BLOCK_SIZE < FILE_CONTENTS[i].length()) {
              blockContents = FILE_CONTENTS[i].substring(offset, offset + BLOCK_SIZE);
            } else {
              blockContents = FILE_CONTENTS[i].substring(offset);
            }

            ReaderRecord<Slice> readerRecord = new ReaderRecord<Slice>(blockID, new Slice(blockContents.getBytes()));
            blockIdToExpectedContent.put(blockID, blockContents);
            blockDataList.add(readerRecord);
          }
        }
      } catch (IOException e) {
        throw new RuntimeException(e);
      }
    }

    /* (non-Javadoc)
     * @see org.junit.rules.TestWatcher#finished(org.junit.runner.Description)
     */
    @Override
    protected void finished(Description description)
    {
      super.finished(description);

      try {
        FileUtils.deleteDirectory(new File(outputPath));
      } catch (IOException e) {
        throw new RuntimeException(e);
      }
    }
  }

  @Rule
  public TestMeta testMeta = new TestMeta();

  @Test
  public void testBlockWriting() throws IOException
  {

    testMeta.underTest.beginWindow(0);
    int i = 0;
    for (; i <= 5; i++) {
      testMeta.underTest.input.process(testMeta.blockDataList.get(i));
    }
    testMeta.underTest.endWindow();

    testMeta.underTest.beginWindow(1);
    for (; i <= 10; i++) {
      testMeta.underTest.input.process(testMeta.blockDataList.get(i));
    }
    testMeta.underTest.endWindow();

    testMeta.underTest.beginWindow(2);
    for (; i < testMeta.blockDataList.size(); i++) {
      testMeta.underTest.input.process(testMeta.blockDataList.get(i));
    }
    testMeta.underTest.endWindow();
    testMeta.underTest.committed(2);
    testMeta.underTest.teardown();

    File[] blockFileNames = testMeta.blocksDir.listFiles();
    for (File blockFile : blockFileNames) {
      Long blockId = Long.parseLong(blockFile.getName().split("\\.")[0]);
      String expected = testMeta.blockIdToExpectedContent.get(blockId);
      Assert.assertEquals(expected, FileUtils.readFileToString(blockFile));
    }
  }

}