D-Net

package eu.dnetlib.data.utils;

import java.io.IOException;

import java.io.StringReader;

import java.io.StringWriter;

import java.io.Writer;

import java.util.List;

import java.util.stream.Collectors;

import org.apache.commons.lang3.StringUtils;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.dom4j.Document;

import org.dom4j.DocumentException;

import org.dom4j.Node;

import org.dom4j.io.SAXReader;

import org.jbibtex.BibTeXDatabase;

import org.jbibtex.BibTeXEntry;

import org.jbibtex.BibTeXFormatter;

import org.jbibtex.Key;

import org.jbibtex.StringValue;

import org.jbibtex.StringValue.Style;

public class BibTexConverter {

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

	public static String asBibTex(final String xml) {

		try {

			final Document doc = new SAXReader().read(new StringReader(xml));

			final BibTeXEntry dbEntry = new BibTeXEntry(

					findBibTexType(doc.valueOf("//*[local-name() = 'resourceType']")),

					new Key(doc.valueOf("//*[local-name() = 'identifier']")));

			addSimpleStringValue(dbEntry, BibTeXEntry.KEY_TITLE, doc, "//*[local-name() = 'title']");

			addMultipleStringValue(dbEntry, BibTeXEntry.KEY_AUTHOR, doc, "//*[local-name() = 'creator']");

			addSimpleStringValue(dbEntry, BibTeXEntry.KEY_YEAR, doc, "//*[local-name() = 'date']");

			final BibTeXFormatter formatter = new BibTeXFormatter();

			final Writer res = new StringWriter();

			final BibTeXDatabase db = new BibTeXDatabase();

			db.addObject(dbEntry);

			formatter.format(db, res);

			return res.toString();

		} catch (final DocumentException | IOException e) {

			log.warn("Error generating bibtex", e);

			return "";

		}

	}

	private static void addSimpleStringValue(final BibTeXEntry dbEntry, final Key key, final Document doc, final String xpath) {

		final String val = doc.valueOf(xpath).trim();

		if (StringUtils.isNotBlank(val)) {

			dbEntry.addField(key, new StringValue(val, Style.BRACED));

		}

	}

	@SuppressWarnings("unchecked")

	private static void addMultipleStringValue(final BibTeXEntry dbEntry, final Key key, final Document doc, final String xpath) {

		final String val = ((List<Node>) doc.selectNodes(xpath))

				.stream()

				.map(Node::getText)

				.map(String::trim)

				.filter(StringUtils::isNotEmpty)

				.collect(Collectors.joining(" and "));

		if (StringUtils.isNotBlank(val)) {

			dbEntry.addField(key, new StringValue(val, Style.BRACED));

		}

	}

	private static Key findBibTexType(final String resourceType) {

		switch (resourceType) {

		case "Conference object":

			return BibTeXEntry.TYPE_INPROCEEDINGS;

		case "Report":

			return BibTeXEntry.TYPE_TECHREPORT;

		case "Article":

			return BibTeXEntry.TYPE_ARTICLE;

		case "Other":

			return BibTeXEntry.TYPE_MISC;

		case "Part of book or chapter of book":

			return BibTeXEntry.TYPE_INBOOK;

		case "Book":

			return BibTeXEntry.TYPE_BOOK;

		case "Bachelor thesis":

			return BibTeXEntry.TYPE_MASTERSTHESIS;

		case "Doctoral thesis":

			return BibTeXEntry.TYPE_PHDTHESIS;

		case "Patent":

			return BibTeXEntry.TYPE_MISC;

		case "Master thesis":

			return BibTeXEntry.TYPE_MASTERSTHESIS;

		default:

			return BibTeXEntry.TYPE_MISC;

		}

	}

}