package eu.dnetlib.dhp.graph;

import org.apache.commons.io.IOUtils;
import org.apache.hadoop.io.Text;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.sql.Encoders;
import org.apache.spark.sql.SaveMode;
import org.apache.spark.sql.SparkSession;

import com.fasterxml.jackson.databind.ObjectMapper;

import eu.dnetlib.dhp.application.ArgumentApplicationParser;
import scala.Tuple2;

public class SparkGraphImporterJob {

	public static void main(final String[] args) throws Exception {

		final ArgumentApplicationParser parser = new ArgumentApplicationParser(
				IOUtils.toString(SparkGraphImporterJob.class.getResourceAsStream("/eu/dnetlib/dhp/graph/input_graph_parameters.json")));
		parser.parseArgument(args);
		final SparkSession spark = SparkSession
				.builder()
				.appName(SparkGraphImporterJob.class.getSimpleName())
				.master(parser.get("master"))
				.config("hive.metastore.uris", parser.get("hive_metastore_uris"))
				.enableHiveSupport()
				.getOrCreate();

		final JavaSparkContext sc = new JavaSparkContext(spark.sparkContext());
		final String inputPath = parser.get("sourcePath");
		final String hiveDbName = parser.get("hive_db_name");

		spark.sql(String.format("CREATE DATABASE IF NOT EXISTS %s", hiveDbName));

		// Read the input file and convert it into RDD of serializable object
		GraphMappingUtils.types.forEach((name, clazz) -> {
			final JavaRDD<Tuple2<String, String>> inputRDD = sc.sequenceFile(inputPath + "/" + name, Text.class, Text.class)
					.map(item -> new Tuple2<>(item._1.toString(), item._2.toString()));

			spark.createDataset(inputRDD
					.filter(s -> s._1().equals(clazz.getName()))
					.map(Tuple2::_2)
					.map(s -> new ObjectMapper().readValue(s, clazz))
					.rdd(), Encoders.bean(clazz))
					.write()
					.mode(SaveMode.Overwrite)
					.saveAsTable(hiveDbName + "." + name);
		});

	}
}