package eu.dnetlib.ariadneplus.rdf;

import java.util.Map;

import javax.annotation.PostConstruct;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import com.google.common.collect.Maps;

import eu.dnetlib.ariadneplus.publisher.SaxonHelper;
import net.sf.saxon.s9api.SaxonApiException;
import net.sf.saxon.s9api.Serializer;
import net.sf.saxon.s9api.XPathSelector;

/**
 * @author enrico.ottonello
 *
 */

@Component
public class RecordParserHelper {

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

	public static final String OAI_NAMESPACE_URI = "http://www.openarchives.org/OAI/2.0/";
	public static final String DRI_NAMESPACE_URI = "http://www.driver-repository.eu/namespace/dri";
	public static final String RDF_NAMESPACE_URI = "http://www.w3.org/1999/02/22-rdf-syntax-ns#";

	@Autowired
	private SaxonHelper saxonHelper;

	private XPathSelector xpathSelectorObjIdentifier;
	private XPathSelector xpathSelectorCollectionDate;
	private XPathSelector xpathSelectorTransformationDate;
	private XPathSelector xpathSelectorDatasourceName;
	private XPathSelector xpathSelectorDatasourceApi;
	private XPathSelector xpathSelectorRDF;

	@PostConstruct
	public void init() throws SaxonApiException {
		prepareXpathSelectors();
	}

	public String getCollectionDate(final String record) {
		return extractFromRecord(record, xpathSelectorCollectionDate);
	}

	public String getTransformationDate(final String record) {
		return extractFromRecord(record, xpathSelectorTransformationDate);
	}

	public String getDatasourceName(final String record) {
		return extractFromRecord(record, xpathSelectorDatasourceName);
	}

	public String getDatasourceApi(final String record) {
		return extractFromRecord(record, xpathSelectorDatasourceApi);
	}

	public String getObjIdentifier(final String record) {
		return extractFromRecord(record, xpathSelectorObjIdentifier);
	}

	public String getRDF(final String record) {
		return extractFromRecord(record, xpathSelectorRDF);
	}

	private String extractFromRecord(final String record, final XPathSelector xPathSelector) {
		try {
			return this.saxonHelper.help().setSerializerProperty(Serializer.Property.OMIT_XML_DECLARATION, "yes").evaluateSingleAsString(record, xPathSelector);
		} catch (SaxonApiException e) {
			log.error(e);
			throw new RuntimeException("Cannot extract content from path "+ xPathSelector.toString(), e);
		}
	}

	private void prepareXpathSelectors() throws SaxonApiException {
		Map<String, String> namespaces = Maps.newHashMap();
		namespaces.put("oai", OAI_NAMESPACE_URI);
		namespaces.put("dri", DRI_NAMESPACE_URI);
		namespaces.put("rdf", RDF_NAMESPACE_URI);
		xpathSelectorObjIdentifier = this.saxonHelper.help().prepareXPathSelector("//oai:header/dri:objIdentifier/text()", namespaces);
		xpathSelectorCollectionDate = this.saxonHelper.help().prepareXPathSelector("//oai:header/dri:dateOfCollection/text()", namespaces);
		xpathSelectorTransformationDate = this.saxonHelper.help().prepareXPathSelector("//oai:header/dri:dateOfTransformation/text()", namespaces);
		xpathSelectorDatasourceName = this.saxonHelper.help().prepareXPathSelector("//oai:header/dri:datasourcename/text()", namespaces);
		xpathSelectorDatasourceApi = this.saxonHelper.help().prepareXPathSelector("//oai:header/dri:datasourceapi/text()", namespaces);
		xpathSelectorRDF = this.saxonHelper.help().prepareXPathSelector("//oai:metadata/rdf:RDF", namespaces);
	}

	public SaxonHelper getSaxonHelper() {
		return saxonHelper;
	}

	public void setSaxonHelper(final SaxonHelper saxonHelper) {
		this.saxonHelper = saxonHelper;
	}
}