/* 
 * 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 parquet.hadoop;

import org.apache.commons.io.FileUtils;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import parquet.hadoop.example.GroupWriteSupport;
import parquet.hadoop.metadata.CompressionCodecName;
import parquet.schema.MessageTypeParser;

import java.io.File;
import java.lang.management.ManagementFactory;
import java.util.Set;

/**
 * Verify MemoryManager could adjust its writers' allocated memory size.
 */
public class TestMemoryManager {

    Configuration conf = new Configuration();
    String writeSchema = "message example {\n" +
            "required int32 line;\n" +
            "required binary content;\n" +
            "}";
    long expectPoolSize;
    int rowGroupSize;
    ParquetOutputFormat parquetOutputFormat;
    CompressionCodecName codec;

    @Before
    public void setUp() {
        GroupWriteSupport.setSchema(MessageTypeParser.parseMessageType(writeSchema), conf);
        expectPoolSize = Math.round(ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().getMax
                () * MemoryManager.DEFAULT_MEMORY_POOL_RATIO);
        rowGroupSize = (int) Math.floor(expectPoolSize / 2);
        conf.setInt(ParquetOutputFormat.BLOCK_SIZE, rowGroupSize);
        codec = CompressionCodecName.UNCOMPRESSED;
    }

    @After
    public void tearDown() throws Exception {
        FileUtils.deleteDirectory(new File("target/test"));
    }

    @Test
    public void testMemoryManager() throws Exception {
        //Verify the adjusted rowGroupSize of writers
        RecordWriter writer1 = createWriter(1);
        verifyRowGroupSize(rowGroupSize);

        RecordWriter writer2 = createWriter(2);
        verifyRowGroupSize(rowGroupSize);

        RecordWriter writer3 = createWriter(3);
        verifyRowGroupSize((int) Math.floor(expectPoolSize / 3));

        writer1.close(null);
        verifyRowGroupSize(rowGroupSize);

        writer2.close(null);
        verifyRowGroupSize(rowGroupSize);

        writer3.close(null);

        //Verify the memory pool
        Assert.assertEquals("memory pool size is incorrect.", expectPoolSize,
                parquetOutputFormat.getMemoryManager().getTotalMemoryPool());
    }

    private RecordWriter createWriter(int index) throws Exception {
        Path file = new Path("target/test/", "parquet" + index);
        parquetOutputFormat = new ParquetOutputFormat(new GroupWriteSupport(null));
        return parquetOutputFormat.getRecordWriter(conf, file, codec);
    }

    private void verifyRowGroupSize(int expectRowGroupSize) {
        Set<InternalParquetRecordWriter> writers = parquetOutputFormat.getMemoryManager()
                .getWriterList().keySet();
        for (InternalParquetRecordWriter writer : writers) {
            Assert.assertEquals("wrong rowGroupSize", expectRowGroupSize,
                    writer.getRowGroupSizeThreshold(), 1);
        }
    }
}