package eu.dnetlib.common.utils;

import java.io.StringReader;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.dom4j.*;
import org.dom4j.io.SAXReader;

public class XMLUtils {

	private static final SAXReader reader = new SAXReader();
	private static Map<String, String> nsMap = new HashMap<String, String>();

	public static Document getDocument(String document) throws XMLException {
		try {
			return reader.read(new StringReader(document));
		} catch (DocumentException e) {
			throw new XMLException(e);
		}
	}

	public static void setNamespaces(Map<String, String> nsMap) {
		XMLUtils.nsMap = nsMap;
	}

	public static String evaluate(String document, String expression) throws XMLException {
		XPath xpath = DocumentHelper.createXPath(expression);
		xpath.setNamespaceURIs(XMLUtils.nsMap);
		return xpath.valueOf(getDocument(document));
	}

	public static String evaluate(Node document, String expression) throws XMLException {
		XPath xpath = DocumentHelper.createXPath(expression);
		xpath.setNamespaceURIs(XMLUtils.nsMap);
		return xpath.valueOf(document);
	}

	@SuppressWarnings("unchecked")
	public static List<Node> getNodes(Node document, String expression) throws XMLException {
		XPath xpath = DocumentHelper.createXPath(expression);
		xpath.setNamespaceURIs(XMLUtils.nsMap);
		return xpath.selectNodes(document, xpath);
	}

	public static Node getNode(Node document, String expression) {
		return document.selectSingleNode(expression);
	}
}