package eu.dnetlib.dhp.oa.graph.raw;

import com.fasterxml.jackson.databind.ObjectMapper;
import eu.dnetlib.dhp.application.ArgumentApplicationParser;
import eu.dnetlib.dhp.common.HdfsSupport;
import eu.dnetlib.dhp.schema.oaf.*;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.io.compress.GzipCodec;
import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.api.java.function.FilterFunction;
import org.apache.spark.api.java.function.MapFunction;
import org.apache.spark.sql.Encoders;
import org.apache.spark.sql.SaveMode;
import org.apache.spark.sql.SparkSession;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Optional;

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

public class DispatchEntitiesApplication {

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

	private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();

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

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

		final String sourcePath = parser.get("sourcePath");
		final String targetPath = parser.get("graphRawPath");

		SparkConf conf = new SparkConf();
		runWithSparkSession(conf, isSparkSessionManaged, spark -> {
			removeOutputDir(spark, targetPath);

			processEntity(spark, Publication.class, sourcePath, targetPath);
			processEntity(spark, Dataset.class, sourcePath, targetPath);
			processEntity(spark, Software.class, sourcePath, targetPath);
			processEntity(spark, OtherResearchProduct.class, sourcePath, targetPath);
			processEntity(spark, Datasource.class, sourcePath, targetPath);
			processEntity(spark, Organization.class, sourcePath, targetPath);
			processEntity(spark, Project.class, sourcePath, targetPath);
			processEntity(spark, Relation.class, sourcePath, targetPath);
		});
	}

	private static <T extends Oaf> void processEntity(final SparkSession spark, final Class<T> clazz, final String sourcePath, final String targetPath) {
		final String type = clazz.getSimpleName().toLowerCase();

		log.info(String.format("Processing entities (%s) in file: %s", type, sourcePath));

		spark.read()
				.textFile(sourcePath)
				.filter((FilterFunction<String>) value -> isEntityType(value, type))
				.map((MapFunction<String, String>) value -> StringUtils.substringAfter(value, "|"), Encoders.STRING())
				.map((MapFunction<String, T>) value -> OBJECT_MAPPER.readValue(value, clazz), Encoders.bean(clazz))
				.write()
				.mode(SaveMode.Overwrite)
				.parquet(targetPath + "/" + type);

		/*
		JavaSparkContext.fromSparkContext(spark.sparkContext())
				.textFile(sourcePath)
				.filter(l -> isEntityType(l, type))
				.map(l -> StringUtils.substringAfter(l, "|"))
				.saveAsTextFile(targetPath + "/" + type, GzipCodec.class); // use repartition(XXX) ???

		 */
	}

	private static boolean isEntityType(final String line, final String type) {
		return StringUtils.substringBefore(line, "|").equalsIgnoreCase(type);
	}

	private static void removeOutputDir(SparkSession spark, String path) {
		HdfsSupport.remove(path, spark.sparkContext().hadoopConfiguration());
	}

}