package eu.dnetlib.dhp.oa.graph.dump.complete;

import java.io.*;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
import java.util.Optional;
import java.util.function.Consumer;
import java.util.function.Function;

import org.apache.commons.io.IOUtils;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.fasterxml.jackson.databind.ObjectMapper;

import eu.dnetlib.dhp.application.ArgumentApplicationParser;
import eu.dnetlib.dhp.oa.graph.dump.UtilCommunityAPI;
import eu.dnetlib.dhp.oa.graph.dump.Utils;
import eu.dnetlib.dhp.oa.graph.dump.exceptions.MyRuntimeException;
import eu.dnetlib.dhp.oa.graph.dump.subset.MasterDuplicate;
import eu.dnetlib.dhp.oa.model.graph.*;

/**
 * Writes the set of new Relation between the context and datasources. At the moment the relation between the context
 * and the project is not created because of a low coverage in the profiles of openaire ids related to projects
 */
public class CreateContextRelation implements Serializable {
	private static final Logger log = LoggerFactory.getLogger(CreateContextRelation.class);
	private final transient Configuration conf;
	private final transient BufferedWriter writer;

	public static void main(String[] args) throws Exception {
		String jsonConfiguration = IOUtils
			.toString(
				Objects
					.requireNonNull(
						CreateContextRelation.class
							.getResourceAsStream(
								"/eu/dnetlib/dhp/oa/graph/dump/input_entity_parameter.json")));

		final ArgumentApplicationParser parser = new ArgumentApplicationParser(jsonConfiguration);
		parser.parseArgument(args);

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

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

		final String hdfsNameNode = parser.get("nameNode");
		log.info("hdfsNameNode: {}", hdfsNameNode);

		final CreateContextRelation cce = new CreateContextRelation(hdfsPath, hdfsNameNode);

		log.info("Creating relation for datasources and projects...");
		cce
			.execute(
				Process::getRelation);

		cce.close();

	}

	private void close() throws IOException {
		writer.close();
	}

	public CreateContextRelation(String hdfsPath, String hdfsNameNode)
		throws IOException {
		this.conf = new Configuration();
		this.conf.set("fs.defaultFS", hdfsNameNode);

		FileSystem fileSystem = FileSystem.get(this.conf);
		Path hdfsWritePath = new Path(hdfsPath);
		FSDataOutputStream fsDataOutputStream = null;
		if (fileSystem.exists(hdfsWritePath)) {
			fsDataOutputStream = fileSystem.append(hdfsWritePath);
		} else {
			fsDataOutputStream = fileSystem.create(hdfsWritePath);
		}

		this.writer = new BufferedWriter(new OutputStreamWriter(fsDataOutputStream, StandardCharsets.UTF_8));

	}

	public void execute(final Function<ContextInfo, List<Relation>> producer) throws IOException {

		final Consumer<ContextInfo> consumer = ci -> producer.apply(ci).forEach(this::writeEntity);

		UtilCommunityAPI queryCommunityAPI = new UtilCommunityAPI();
		queryCommunityAPI.getContextRelation().forEach(ci -> consumer.accept(ci));
	}

	protected void writeEntity(final Relation r) {
		try {
			writer.write(Utils.OBJECT_MAPPER.writeValueAsString(r));
			writer.newLine();
		} catch (final Exception e) {
			throw new MyRuntimeException(e);
		}
	}

}