/**
 * 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.utils;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import org.apache.hcatalog.common.HCatConstants;
import org.apache.hcatalog.data.HCatRecord;
import org.apache.hcatalog.mapreduce.HCatInputFormat;
import org.apache.hcatalog.mapreduce.InputJobInfo;

/**
 * This is a map reduce test for testing hcat which goes against the "numbers"
 * table. It performs a group by on the first column and a SUM operation on the
 * other columns. This is to simulate a typical operation in a map reduce program
 * to test that hcat hands the right data to the map reduce program
 *
 * Usage: hadoop jar sumnumbers <serveruri> <output dir> <-libjars hive-hcat jar>
 The <tab|ctrla> argument controls the output delimiter
 The hcat jar location should be specified as file://<full path to jar>
 */
public class SimpleRead extends Configured implements Tool {

    private static final String TABLE_NAME = "studenttab10k";
    private static final String TAB = "\t";

    public static class Map
        extends Mapper<WritableComparable, HCatRecord, Text, IntWritable> {

        String name;
        int age;
        double gpa;

        @Override
        protected void map(WritableComparable key, HCatRecord value,
                           org.apache.hadoop.mapreduce.Mapper<WritableComparable, HCatRecord,
                               Text, IntWritable>.Context context)
            throws IOException, InterruptedException {
            name = (String) value.get(0);
            age = (Integer) value.get(1);
            gpa = (Double) value.get(2);
            context.write(new Text(name), new IntWritable(age));

        }
    }

    public int run(String[] args) throws Exception {
        Configuration conf = getConf();
        args = new GenericOptionsParser(conf, args).getRemainingArgs();

        String serverUri = args[0];
        String tableName = args[1];
        String outputDir = args[2];
        String dbName = null;

        String principalID = System.getProperty(HCatConstants.HCAT_METASTORE_PRINCIPAL);
        if (principalID != null)
            conf.set(HCatConstants.HCAT_METASTORE_PRINCIPAL, principalID);
        Job job = new Job(conf, "SimpleRead");
        HCatInputFormat.setInput(job, InputJobInfo.create(
            dbName, tableName, null));
        // initialize HCatOutputFormat

        job.setInputFormatClass(HCatInputFormat.class);
        job.setOutputFormatClass(TextOutputFormat.class);
        job.setJarByClass(SimpleRead.class);
        job.setMapperClass(Map.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);
        FileOutputFormat.setOutputPath(job, new Path(outputDir));
        return (job.waitForCompletion(true) ? 0 : 1);
    }

    public static void main(String[] args) throws Exception {
        int exitCode = ToolRunner.run(new SimpleRead(), args);
        System.exit(exitCode);
    }
}