/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package utils;

import utils.ClassPathSearcher;
import java.io.IOException;
import java.io.InputStream;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Node;

import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import javax.xml.validation.Validator;

import org.xml.sax.SAXException;

/**
 *
 */
public class XmlUtils
{
    private final static Logger logger = Logger.getLogger(XmlUtils.class.getName());

    /*
     * from http://www.coderanch.com/how-to/java/DocumentToString
     */
    public static String xmlToString(Node node)
    {
        try
        {
            Source source = new DOMSource(node);
            StringWriter stringWriter = new StringWriter();
            Result result = new StreamResult(stringWriter);
            TransformerFactory factory = TransformerFactory.newInstance();
            Transformer transformer = factory.newTransformer();
            transformer.transform(source, result);
            return stringWriter.getBuffer().toString();
        }
        catch (TransformerConfigurationException e)
        {
            e.printStackTrace();
        }
        catch (TransformerException e)
        {
            e.printStackTrace();
        }

        return null;
    }

    public static boolean validateNodeAgainstSchema(Node n, String schemaFile)
    {
        if (n == null || schemaFile == null || schemaFile.isEmpty())
        {
            return false;
        }

        if (schemaFile.endsWith(".xsd"))
        {
            schemaFile = schemaFile.substring(0, schemaFile.length()-4);
        }

        try {
            ClassPathSearcher searcher = ClassPathSearcher.getInstance();
            Map<String, InputStream> schemas = searcher.findFilesInClassPath(
                    ".*"+schemaFile+"\\.xsd");

            if (schemas == null || schemas.keySet().isEmpty())
            {
                logger.log(Level.SEVERE, "Schema file {0} not found!", schemaFile);
                return false;
            }

            if (schemas.keySet().size()>1)
            {
                logger.log(Level.SEVERE, "Schema file {0} defined multiple times!", schemaFile);
                return false;
            }

            InputStream istream = schemas.get(schemas.keySet().iterator().next());

            String schemaLang = "http://www.w3.org/2001/XMLSchema";
            SchemaFactory factory = SchemaFactory.newInstance(schemaLang);
            Schema schema = factory.newSchema(new StreamSource(istream));

            Validator validator = schema.newValidator();

            logger.log(Level.INFO,"Node content to be validated: {0}",
                    xmlToString(n));

            StringReader r = new StringReader(xmlToString(n));
            validator.validate(new StreamSource(r));
        }
        catch (IOException ex)
        {
            logger.log(Level.SEVERE, null, ex);

            return false;
        }
        catch (SAXException ex)
        {
            logger.log(Level.SEVERE, null, ex);

            return false;
        }

        return true;
    }
}