/**
 * 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 java.util.Arrays;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
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.data.schema.HCatSchema;
import org.apache.hcatalog.mapreduce.HCatInputFormat;
import org.apache.hcatalog.mapreduce.InputJobInfo;

/**
 * This is a map reduce test for testing hcat that checks that the columns
 * handed by hcat have the right type and right values. It achieves the first
 * objective by checking the type of the Objects representing the columns against
 * the schema provided as a cmdline arg. It achieves the second objective by
 * writing the data as Text to be compared against golden results.
 *
 * The schema specification consists of the types as given by "describe <table>"
 * with each column's type separated from the next column's type by a '+'
 *
 * Can be used against "numbers" and "complex" tables.
 *
 * Usage: hadoop jar testudf.jar typedatacheck <serveruri> <tablename> 
 * <hive types of cols + delimited> <output dir> <tab|ctrla> <-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 TypeDataCheck implements Tool {

    static String SCHEMA_KEY = "schema";
    static String DELIM = "delim";
    private static Configuration conf = new Configuration();

    public static class TypeDataCheckMapper
        extends Mapper<WritableComparable, HCatRecord, Long, Text> {

        Long dummykey = null;
        String[] types;
        String delim = "\u0001";

        @Override
        protected void setup(org.apache.hadoop.mapreduce.Mapper<WritableComparable, HCatRecord, Long, Text>.Context context)
            throws IOException, InterruptedException {
            String typesStr = context.getConfiguration().get(SCHEMA_KEY);
            delim = context.getConfiguration().get(DELIM);
            if (delim.equals("tab")) {
                delim = "\t";
            } else if (delim.equals("ctrla")) {
                delim = "\u0001";
            }
            types = typesStr.split("\\+");
            for (int i = 0; i < types.length; i++) {
                types[i] = types[i].toLowerCase();
            }


        }

        String check(HCatRecord r) throws IOException {
            String s = "";
            for (int i = 0; i < r.size(); i++) {
                s += Util.check(types[i], r.get(i));
                if (i != r.size() - 1) {
                    s += delim;
                }
            }
            return s;
        }

        @Override
        protected void map(WritableComparable key, HCatRecord value,
                           org.apache.hadoop.mapreduce.Mapper<WritableComparable, HCatRecord, Long, Text>.Context context)
            throws IOException, InterruptedException {
            context.write(dummykey, new Text(check(value)));
        }
    }

    public static void main(String[] args) throws Exception {
        TypeDataCheck self = new TypeDataCheck();
        System.exit(ToolRunner.run(conf, self, args));
    }

    public int run(String[] args) {
        try {
            args = new GenericOptionsParser(conf, args).getRemainingArgs();
            String[] otherArgs = new String[5];
            int j = 0;
            for (int i = 0; i < args.length; i++) {
                if (args[i].equals("-libjars")) {
                    conf.set("tmpjars", args[i + 1]);
                    i = i + 1; // skip it , the for loop will skip its value
                } else {
                    otherArgs[j++] = args[i];
                }
            }
            if (otherArgs.length != 5) {
                System.err.println("Other args:" + Arrays.asList(otherArgs));
                System.err.println("Usage: hadoop jar testudf.jar typedatacheck " +
                    "<serveruri> <tablename> <hive types of cols + delimited> " +
                    "<output dir> <tab|ctrla> <-libjars hive-hcat jar>\n" +
                    "The <tab|ctrla> argument controls the output delimiter.\n" +
                    "The hcat jar location should be specified as file://<full path to jar>\n");
                System.err.println(" The <tab|ctrla> argument controls the output delimiter.");
                System.exit(2);
            }
            String serverUri = otherArgs[0];
            String tableName = otherArgs[1];
            String schemaStr = otherArgs[2];
            String outputDir = otherArgs[3];
            String outputdelim = otherArgs[4];
            if (!outputdelim.equals("tab") && !outputdelim.equals("ctrla")) {
                System.err.println("ERROR: Specify 'tab' or 'ctrla' for output delimiter");
            }
            String dbName = "default";

            String principalID = System.getProperty(HCatConstants.HCAT_METASTORE_PRINCIPAL);
            if (principalID != null) {
                conf.set(HCatConstants.HCAT_METASTORE_PRINCIPAL, principalID);
            }
            Job job = new Job(conf, "typedatacheck");
            // initialize HCatInputFormat
            HCatInputFormat.setInput(job, InputJobInfo.create(
                dbName, tableName, null));
            HCatSchema s = HCatInputFormat.getTableSchema(job);
            job.getConfiguration().set(SCHEMA_KEY, schemaStr);
            job.getConfiguration().set(DELIM, outputdelim);
            job.setInputFormatClass(HCatInputFormat.class);
            job.setOutputFormatClass(TextOutputFormat.class);
            job.setJarByClass(TypeDataCheck.class);
            job.setMapperClass(TypeDataCheckMapper.class);
            job.setNumReduceTasks(0);
            job.setOutputKeyClass(Long.class);
            job.setOutputValueClass(Text.class);
            FileOutputFormat.setOutputPath(job, new Path(outputDir));
            System.exit(job.waitForCompletion(true) ? 0 : 1);
            return 0;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public Configuration getConf() {
        return conf;
    }

    @Override
    public void setConf(Configuration conf) {
        TypeDataCheck.conf = conf;
    }

}