package eu.dnetlib.dedup;

import java.util.ArrayList;
import java.util.List;

import org.apache.commons.io.IOUtils;
import org.apache.spark.api.java.JavaPairRDD;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.function.FlatMapFunction;
import org.apache.spark.api.java.function.MapFunction;
import org.apache.spark.api.java.function.PairFunction;
import org.apache.spark.graphx.Edge;
import org.apache.spark.rdd.RDD;
import org.apache.spark.sql.Dataset;
import org.apache.spark.sql.Encoders;
import org.apache.spark.sql.SparkSession;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.hash.Hashing;

import eu.dnetlib.dedup.graph.ConnectedComponent;
import eu.dnetlib.dedup.graph.GraphProcessor;
import eu.dnetlib.dhp.application.ArgumentApplicationParser;
import eu.dnetlib.dhp.schema.oaf.Oaf;
import eu.dnetlib.dhp.schema.oaf.Relation;
import eu.dnetlib.pace.config.DedupConfig;
import eu.dnetlib.pace.util.MapDocumentUtil;
import scala.Tuple2;

public class SparkCreateConnectedComponent {

	public static void main(String[] args) throws Exception {
		final ArgumentApplicationParser parser = new ArgumentApplicationParser(
			IOUtils
				.toString(
					SparkCreateConnectedComponent.class
						.getResourceAsStream(
							"/eu/dnetlib/dhp/sx/dedup/dedup_parameters.json")));
		parser.parseArgument(args);
		final SparkSession spark = SparkSession
			.builder()
			.appName(SparkCreateConnectedComponent.class.getSimpleName())
			.master(parser.get("master"))
			.getOrCreate();

		final String inputPath = parser.get("sourcePath");
		final String entity = parser.get("entity");
		final String targetPath = parser.get("targetPath");
		// final DedupConfig dedupConf =
		// DedupConfig.load(IOUtils.toString(SparkCreateConnectedComponent.class.getResourceAsStream("/eu/dnetlib/dhp/dedup/conf/org.curr.conf2.json")));
		final DedupConfig dedupConf = DedupConfig.load(parser.get("dedupConf"));

		final JavaPairRDD<Object, String> vertexes = spark
			.read()
			.load(inputPath + "/" + entity)
			.as(Encoders.kryo(Oaf.class))
			.map((MapFunction<Oaf, String>) p -> new ObjectMapper().writeValueAsString(p), Encoders.STRING())
			.javaRDD()
			.map(s -> MapDocumentUtil.getJPathString(dedupConf.getWf().getIdPath(), s))
			.mapToPair(
				(PairFunction<String, Object, String>) s -> new Tuple2<Object, String>(getHashcode(s), s));

		final Dataset<Relation> similarityRelations = spark
			.read()
			.load(DedupUtility.createSimRelPath(targetPath, entity))
			.as(Encoders.bean(Relation.class));
		final RDD<Edge<String>> edgeRdd = similarityRelations
			.javaRDD()
			.map(
				it -> new Edge<>(
					getHashcode(it.getSource()), getHashcode(it.getTarget()), it.getRelClass()))
			.rdd();
		final JavaRDD<ConnectedComponent> cc = GraphProcessor
			.findCCs(vertexes.rdd(), edgeRdd, dedupConf.getWf().getMaxIterations())
			.toJavaRDD();
		final Dataset<Relation> mergeRelation = spark
			.createDataset(
				cc
					.filter(k -> k.getDocIds().size() > 1)
					.flatMap(
						(FlatMapFunction<ConnectedComponent, Relation>) c -> c
							.getDocIds()
							.stream()
							.flatMap(
								id -> {
									List<Relation> tmp = new ArrayList<>();
									Relation r = new Relation();
									r.setSource(c.getCcId());
									r.setTarget(id);
									r.setRelClass("merges");
									tmp.add(r);
									r = new Relation();
									r.setTarget(c.getCcId());
									r.setSource(id);
									r.setRelClass("isMergedIn");
									tmp.add(r);
									return tmp.stream();
								})
							.iterator())
					.rdd(),
				Encoders.bean(Relation.class));
		mergeRelation
			.write()
			.mode("overwrite")
			.save(DedupUtility.createMergeRelPath(targetPath, entity));
	}

	public static long getHashcode(final String id) {
		return Hashing.murmur3_128().hashString(id).asLong();
	}
}