/**
 * 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;
	}

}