package eu.dnetlib.dhp.common;

import static eu.dnetlib.dhp.common.SparkSessionSupport.runWithSparkHiveSession;

import java.util.Optional;

import org.apache.commons.io.IOUtils;
import org.apache.spark.SparkConf;
import org.apache.spark.sql.SparkSession;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import eu.dnetlib.dhp.application.ArgumentApplicationParser;

public class ResetHiveDbApplication {

	private static final Logger log = LoggerFactory.getLogger(ResetHiveDbApplication.class);

	public static void main(final String[] args) throws Exception {
		final ArgumentApplicationParser parser = new ArgumentApplicationParser(
			IOUtils
				.toString(
					ResetHiveDbApplication.class
						.getResourceAsStream(
							"/eu/dnetlib/dhp/common/reset_hive_db_parameters.json")));
		parser.parseArgument(args);

		Boolean isSparkSessionManaged = Optional
			.ofNullable(parser.get("isSparkSessionManaged"))
			.map(Boolean::valueOf)
			.orElse(Boolean.TRUE);
		log.info("isSparkSessionManaged: {}", isSparkSessionManaged);

		final String dbName = Optional
			.ofNullable(parser.get("dbName"))
			.orElseThrow(() -> new IllegalArgumentException("missing DB name"));
		log.info("dbName: {}", dbName);

		String hiveMetastoreUris = parser.get("hiveMetastoreUris");
		log.info("hiveMetastoreUris: {}", hiveMetastoreUris);

		SparkConf conf = new SparkConf();
		conf.set("hive.metastore.uris", hiveMetastoreUris);

		runWithSparkHiveSession(
			conf,
			isSparkSessionManaged,
			spark -> {
				runSQL(spark, String.format("DROP DATABASE IF EXISTS %s CASCADE", dbName));
				runSQL(spark, String.format("CREATE DATABASE %s", dbName));
			});
	}

	protected static void runSQL(SparkSession spark, String sql) {
		log.info("running SQL '{}'", sql);
		spark.sqlContext().sql(sql);
	}

}