/**
 * 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.hcatalog.mapreduce;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import junit.framework.Assert;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.LocalFileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.metastore.MetaStoreUtils;
import org.apache.hadoop.hive.metastore.api.FieldSchema;
import org.apache.hadoop.hive.metastore.api.SerDeInfo;
import org.apache.hadoop.hive.metastore.api.StorageDescriptor;
import org.apache.hadoop.hive.metastore.api.Table;
import org.apache.hadoop.hive.ql.io.RCFileInputFormat;
import org.apache.hadoop.hive.ql.io.RCFileOutputFormat;
import org.apache.hadoop.hive.serde.serdeConstants;
import org.apache.hadoop.hive.serde2.columnar.ColumnarSerDe;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.JobStatus;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hcatalog.common.HCatConstants;
import org.apache.hcatalog.common.HCatUtil;
import org.apache.hcatalog.data.DefaultHCatRecord;
import org.apache.hcatalog.data.HCatRecord;
import org.apache.hcatalog.data.schema.HCatFieldSchema;
import org.apache.hcatalog.data.schema.HCatSchema;
import org.junit.After;
import org.junit.Before;
import org.junit.BeforeClass;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import static org.junit.Assert.assertTrue;

/**
 * Test for HCatOutputFormat. Writes a partition using HCatOutputFormat and reads
 * it back using HCatInputFormat, checks the column values and counts.
 */
public abstract class HCatMapReduceTest extends HCatBaseTest {

    private static final Logger LOG = LoggerFactory.getLogger(HCatMapReduceTest.class);
    protected static String dbName = MetaStoreUtils.DEFAULT_DATABASE_NAME;
    protected static String tableName = "testHCatMapReduceTable";

    protected String inputFormat = RCFileInputFormat.class.getName();
    protected String outputFormat = RCFileOutputFormat.class.getName();
    protected String serdeClass = ColumnarSerDe.class.getName();

    private static List<HCatRecord> writeRecords = new ArrayList<HCatRecord>();
    private static List<HCatRecord> readRecords = new ArrayList<HCatRecord>();

    protected abstract List<FieldSchema> getPartitionKeys();

    protected abstract List<FieldSchema> getTableColumns();

    private static FileSystem fs;

    @BeforeClass
    public static void setUpOneTime() throws Exception {
        fs = new LocalFileSystem();
        fs.initialize(fs.getWorkingDirectory().toUri(), new Configuration());

        HiveConf hiveConf = new HiveConf();
        hiveConf.setInt(HCatConstants.HCAT_HIVE_CLIENT_EXPIRY_TIME, 0);
        // Hack to initialize cache with 0 expiry time causing it to return a new hive client every time
        // Otherwise the cache doesn't play well with the second test method with the client gets closed() in the
        // tearDown() of the previous test
        HCatUtil.getHiveClient(hiveConf);

        MapCreate.writeCount = 0;
        MapRead.readCount = 0;
    }

    @After
    public void deleteTable() throws Exception {
        try {
            String databaseName = (dbName == null) ? MetaStoreUtils.DEFAULT_DATABASE_NAME : dbName;

            client.dropTable(databaseName, tableName);
        } catch (Exception e) {
            e.printStackTrace();
            throw e;
        }
    }

    @Before
    public void createTable() throws Exception {
        String databaseName = (dbName == null) ? MetaStoreUtils.DEFAULT_DATABASE_NAME : dbName;

        try {
            client.dropTable(databaseName, tableName);
        } catch (Exception e) {
        } //can fail with NoSuchObjectException


        Table tbl = new Table();
        tbl.setDbName(databaseName);
        tbl.setTableName(tableName);
        tbl.setTableType("MANAGED_TABLE");
        StorageDescriptor sd = new StorageDescriptor();

        sd.setCols(getTableColumns());
        tbl.setPartitionKeys(getPartitionKeys());

        tbl.setSd(sd);

        sd.setBucketCols(new ArrayList<String>(2));
        sd.setSerdeInfo(new SerDeInfo());
        sd.getSerdeInfo().setName(tbl.getTableName());
        sd.getSerdeInfo().setParameters(new HashMap<String, String>());
        sd.getSerdeInfo().getParameters().put(serdeConstants.SERIALIZATION_FORMAT, "1");
        sd.getSerdeInfo().setSerializationLib(serdeClass);
        sd.setInputFormat(inputFormat);
        sd.setOutputFormat(outputFormat);

        Map<String, String> tableParams = new HashMap<String, String>();
        tbl.setParameters(tableParams);

        client.createTable(tbl);
    }

    //Create test input file with specified number of rows
    private void createInputFile(Path path, int rowCount) throws IOException {

        if (fs.exists(path)) {
            fs.delete(path, true);
        }

        FSDataOutputStream os = fs.create(path);

        for (int i = 0; i < rowCount; i++) {
            os.writeChars(i + "\n");
        }

        os.close();
    }

    public static class MapCreate extends
            Mapper<LongWritable, Text, BytesWritable, HCatRecord> {

        static int writeCount = 0; //test will be in local mode

        @Override
        public void map(LongWritable key, Text value, Context context
        ) throws IOException, InterruptedException {
            {
                try {
                    HCatRecord rec = writeRecords.get(writeCount);
                    context.write(null, rec);
                    writeCount++;

                } catch (Exception e) {

                    e.printStackTrace(System.err); //print since otherwise exception is lost
                    throw new IOException(e);
                }
            }
        }
    }

    public static class MapRead extends
            Mapper<WritableComparable, HCatRecord, BytesWritable, Text> {

        static int readCount = 0; //test will be in local mode

        @Override
        public void map(WritableComparable key, HCatRecord value, Context context
        ) throws IOException, InterruptedException {
            {
                try {
                    readRecords.add(value);
                    readCount++;
                } catch (Exception e) {
                    e.printStackTrace(); //print since otherwise exception is lost
                    throw new IOException(e);
                }
            }
        }
    }

    Job runMRCreate(Map<String, String> partitionValues,
                    List<HCatFieldSchema> partitionColumns, List<HCatRecord> records,
                    int writeCount, boolean assertWrite) throws Exception {
        return runMRCreate(partitionValues, partitionColumns, records, writeCount, assertWrite, true);
    }

    /**
     * Run a local map reduce job to load data from in memory records to an HCatalog Table
     * @param partitionValues
     * @param partitionColumns
     * @param records data to be written to HCatalog table
     * @param writeCount
     * @param assertWrite
     * @param asSingleMapTask
     * @return
     * @throws Exception
     */
    Job runMRCreate(Map<String, String> partitionValues,
                    List<HCatFieldSchema> partitionColumns, List<HCatRecord> records,
                    int writeCount, boolean assertWrite, boolean asSingleMapTask) throws Exception {

        writeRecords = records;
        MapCreate.writeCount = 0;

        Configuration conf = new Configuration();
        Job job = new Job(conf, "hcat mapreduce write test");
        job.setJarByClass(this.getClass());
        job.setMapperClass(HCatMapReduceTest.MapCreate.class);

        // input/output settings
        job.setInputFormatClass(TextInputFormat.class);

        if (asSingleMapTask) {
            // One input path would mean only one map task
            Path path = new Path(fs.getWorkingDirectory(), "mapred/testHCatMapReduceInput");
            createInputFile(path, writeCount);
            TextInputFormat.setInputPaths(job, path);
        } else {
            // Create two input paths so that two map tasks get triggered. There could be other ways
            // to trigger two map tasks.
            Path path = new Path(fs.getWorkingDirectory(), "mapred/testHCatMapReduceInput");
            createInputFile(path, writeCount / 2);

            Path path2 = new Path(fs.getWorkingDirectory(), "mapred/testHCatMapReduceInput2");
            createInputFile(path2, (writeCount - writeCount / 2));

            TextInputFormat.setInputPaths(job, path, path2);
        }

        job.setOutputFormatClass(HCatOutputFormat.class);

        OutputJobInfo outputJobInfo = OutputJobInfo.create(dbName, tableName, partitionValues);
        HCatOutputFormat.setOutput(job, outputJobInfo);

        job.setMapOutputKeyClass(BytesWritable.class);
        job.setMapOutputValueClass(DefaultHCatRecord.class);

        job.setNumReduceTasks(0);

        HCatOutputFormat.setSchema(job, new HCatSchema(partitionColumns));

        boolean success = job.waitForCompletion(true);

        // Ensure counters are set when data has actually been read.
        if (partitionValues != null) {
            assertTrue(job.getCounters().getGroup("FileSystemCounters")
                    .findCounter("FILE_BYTES_READ").getValue() > 0);
        }

        if (!HCatUtil.isHadoop23()) {
            // Local mode outputcommitter hook is not invoked in Hadoop 1.x
            if (success) {
                new FileOutputCommitterContainer(job, null).commitJob(job);
            } else {
                new FileOutputCommitterContainer(job, null).abortJob(job, JobStatus.State.FAILED);
            }
        }
        if (assertWrite) {
            // we assert only if we expected to assert with this call.
            Assert.assertEquals(writeCount, MapCreate.writeCount);
        }

        return job;
    }

    List<HCatRecord> runMRRead(int readCount) throws Exception {
        return runMRRead(readCount, null);
    }

    /**
     * Run a local map reduce job to read records from HCatalog table and verify if the count is as expected
     * @param readCount
     * @param filter
     * @return
     * @throws Exception
     */
    List<HCatRecord> runMRRead(int readCount, String filter) throws Exception {

        MapRead.readCount = 0;
        readRecords.clear();

        Configuration conf = new Configuration();
        Job job = new Job(conf, "hcat mapreduce read test");
        job.setJarByClass(this.getClass());
        job.setMapperClass(HCatMapReduceTest.MapRead.class);

        // input/output settings
        job.setInputFormatClass(HCatInputFormat.class);
        job.setOutputFormatClass(TextOutputFormat.class);

        HCatInputFormat.setInput(job, dbName, tableName).setFilter(filter);

        job.setMapOutputKeyClass(BytesWritable.class);
        job.setMapOutputValueClass(Text.class);

        job.setNumReduceTasks(0);

        Path path = new Path(fs.getWorkingDirectory(), "mapred/testHCatMapReduceOutput");
        if (fs.exists(path)) {
            fs.delete(path, true);
        }

        TextOutputFormat.setOutputPath(job, path);

        job.waitForCompletion(true);
        Assert.assertEquals(readCount, MapRead.readCount);

        return readRecords;
    }


    protected HCatSchema getTableSchema() throws Exception {

        Configuration conf = new Configuration();
        Job job = new Job(conf, "hcat mapreduce read schema test");
        job.setJarByClass(this.getClass());

        // input/output settings
        job.setInputFormatClass(HCatInputFormat.class);
        job.setOutputFormatClass(TextOutputFormat.class);

        HCatInputFormat.setInput(job, dbName, tableName);

        return HCatInputFormat.getTableSchema(job);
    }

}