package eu.dnetlib.parthenos.virtuoso;

import eu.dnetlib.parthenos.publisher.ParthenosPublisherException;
import eu.dnetlib.parthenos.rdf.RecordParserHelper;
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.jena.datatypes.xsd.XSDDatatype;
import org.apache.jena.rdf.model.*;
import virtuoso.jena.driver.VirtModel;

/**
 * Created by Alessia Bardi on 12/07/2017.
 *
 * @author Alessia Bardi
 */
public class VirtuosoClient {

	private static final Log log = LogFactory.getLog(VirtuosoClient.class);

	public static final String PROVENANCE_NS = "http://www.d-net.research-infrastructures.eu/provenance/";
	public static final String PROVENANCE_GRAPH = PROVENANCE_NS+"graph";
	public static Property IS_API_OF = ResourceFactory.createProperty(PROVENANCE_NS, "isApiOf");
	public static Property COLL_FROM = ResourceFactory.createProperty(PROVENANCE_NS, "collectedFrom");
	public static Property COLL_IN_DATE = ResourceFactory.createProperty(PROVENANCE_NS, "collectedInDate");
	public static Property TRANS_IN_DATE = ResourceFactory.createProperty(PROVENANCE_NS, "transformedInDate");

	private RecordParserHelper recordParserHelper;

	private String connectionString;
	private String username;
	private String password;
	private String defaultBaseURI;

	protected VirtuosoClient(final String connectionString,
			final String username,
			final String password,
			final RecordParserHelper recordParserHelper,
			final String defaultBaseURI) {
		this.connectionString = connectionString;
		this.username = username;
		this.password = password;
		this.recordParserHelper = recordParserHelper;
		this.defaultBaseURI = defaultBaseURI;
	}

	//TODO: exploit new method eu.dnetlib.parthenos.publisher.SaxonHelper.Helper.parseXML() to avoid re-parsing the full record.

	public long feed(final String record) throws ParthenosPublisherException{
		Model md = null ;
		try {
			if (StringUtils.isBlank(record)) {
				log.warn("Got empty record");
				return 0;
			}
			String objIdentifier = recordParserHelper.getObjIdentifier(record);
			if (StringUtils.isBlank(objIdentifier)) {
				log.warn("Got record with no objIdentifier -- skipping");
				return 0;
			}
			String rdfBlock = recordParserHelper.getRDF(record);
			if (StringUtils.isBlank(rdfBlock)) {
				log.warn("Missing rdf:RDF in record with objIdentifier " + objIdentifier + " all triples in that named graph will be deleted");
			}
			String collectionDate = recordParserHelper.getCollectionDate(record);
			String transformationDate = recordParserHelper.getTransformationDate(record);
			String datasource = recordParserHelper.getDatasourceName(record);
			String dsInterface = recordParserHelper.getDatasourceApi(record);

			String namedGraph = getRecordDefaultURI(objIdentifier, dsInterface);
			log.debug("Trying to open the database model " + namedGraph+", connection string "+getConnectionString());

			md = VirtModel.openDatabaseModel(namedGraph, getConnectionString(), getUsername(), getPassword());
			log.debug("Opened virtuoso model for graph " + namedGraph);
			md.removeAll();
			log.debug("Removed all triples from graph " + namedGraph);
			md.read(IOUtils.toInputStream(rdfBlock, "UTF-8"), getDefaultBaseURI());
			long size = md.size();
			log.debug("Graph " + namedGraph + " now has " + size + " triples");

			long ntriples = feedProvenance(namedGraph, collectionDate, transformationDate, datasource, dsInterface);
			log.debug("provenance graph for " + namedGraph + " updated with " + ntriples + " triples");
			md.close();
			return size;
		}catch(Throwable e){
			if (md != null && !md.isClosed()) md.close();
			log.error(e);
			throw new ParthenosPublisherException(e);
		}
	}

	long feedProvenance(final String namedGraphURI, final String collectionDate, final String transformationDate, final String datasource, final String api) {
		Model md = VirtModel.openDatabaseModel(PROVENANCE_GRAPH, getConnectionString(), getUsername(), getPassword());
		Resource rApi = ResourceFactory.createResource(defaultBaseURI + api);
		Resource r = ResourceFactory.createResource(namedGraphURI);
		Statement stmApi =
				ResourceFactory.createStatement(rApi, IS_API_OF, ResourceFactory.createPlainLiteral(datasource));
		Statement stmCollFrom =
				ResourceFactory.createStatement(r, COLL_FROM, rApi);
		Statement stmCollDate = ResourceFactory
				.createStatement(r, COLL_IN_DATE, ResourceFactory.createTypedLiteral(collectionDate, XSDDatatype.XSDdateTime));
		Statement stmTransDate = ResourceFactory
				.createStatement(r, TRANS_IN_DATE, ResourceFactory.createTypedLiteral(transformationDate, XSDDatatype.XSDdateTime));

		//let's remove previous provenance statements for this resource:
		md.removeAll(r, null, null);
		//and add the new ones
		md.add(stmApi).add(stmCollFrom).add(stmCollDate).add(stmTransDate);
		md.close();
		return 3;
	}

	public long feed(final Iterable<String> records) throws ParthenosPublisherException {
		//TODO: can we do it in parallel? if all records have different objIdentifier it is safe, and this must be the case anyway, because the source of records is a D-Net mdstore.
		long count = 0;
		for (String r : records) count += this.feed(r);
		return count;
	}

	/**
	 * Delete all triples in named graphs collected from the given api
	 * @param api the id of the API
	 * @return the number of triples deleted from the named graphs associated to the given api
	 */
	public long drop(final String api){
		Model prov = VirtModel.openDatabaseModel(PROVENANCE_GRAPH, getConnectionString(), getUsername(), getPassword());
		//look for all named graphs associated to the api
		Resource rApi = ResourceFactory.createResource(defaultBaseURI + api);
		long deletedTriples = 0;
		final ResIterator resIterator = prov.listSubjectsWithProperty(COLL_FROM, rApi);
		while (resIterator.hasNext()) {
			Resource namedGraphURI = resIterator.nextResource();
			//delete all triples belonging to the r named graph
			deletedTriples += dropNamedGraph(namedGraphURI.getURI());
			//delete the named graph from the provenance graph
			prov.removeAll(namedGraphURI, null, null);
		}
		//delete the api from the provenance graph
		prov.removeAll(null, null, rApi);
		prov.removeAll(rApi, null, null);
		prov.close();
		return deletedTriples;
	}

	private long dropNamedGraph(String namedGraphURI){
		Model namedGraph = VirtModel.openDatabaseModel(namedGraphURI, getConnectionString(), getUsername(), getPassword());
		long deletedTriples = namedGraph.size();
		namedGraph.removeAll();
		namedGraph.close();
		return deletedTriples;
	}

	private String getRecordDefaultURI(final String objIdentifier, final String datasourceApi) {
		return defaultBaseURI + datasourceApi + "/" + objIdentifier;
	}

	public String getConnectionString() {
		return connectionString;
	}

	public String getUsername() {
		return username;
	}

	public String getPassword() {
		return password;
	}

	public String getDefaultBaseURI() {
		return defaultBaseURI;
	}

	public RecordParserHelper getRecordParserHelper() {
		return recordParserHelper;
	}

	public void setRecordParserHelper(final RecordParserHelper recordParserHelper) {
		this.recordParserHelper = recordParserHelper;
	}

	public void setConnectionString(final String connectionString) {
		this.connectionString = connectionString;
	}

	public void setUsername(final String username) {
		this.username = username;
	}

	public void setPassword(final String password) {
		this.password = password;
	}

	public void setDefaultBaseURI(final String defaultBaseURI) {
		this.defaultBaseURI = defaultBaseURI;
	}
}