package org.maltparser.core.feature.spec.reader;

import java.io.IOException;
import java.net.URL;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.maltparser.core.exception.MaltChainedException;
import org.maltparser.core.feature.FeatureException;
import org.maltparser.core.feature.spec.SpecificationModels;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;

/**
 *
 *
 * @author Johan Hall
 */
public class XmlReader implements FeatureSpecReader {

    public XmlReader() {
    }

    public void load(URL specModelURL, SpecificationModels featureSpecModels) throws MaltChainedException {
        try {
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            DocumentBuilder db = dbf.newDocumentBuilder();
            Element root = db.parse(specModelURL.openStream()).getDocumentElement();

            if (root == null) {
                throw new FeatureException("The feature specification file '" + specModelURL.getFile() + "' cannot be found. ");
            }

            readFeatureModels(root, featureSpecModels);
        } catch (IOException e) {
            throw new FeatureException("The feature specification file '" + specModelURL.getFile() + "' cannot be found. ", e);
        } catch (SAXParseException e) {
            throw new FeatureException("Problem parsing the feature specification XML-file " + specModelURL.getFile() + ". ", e);
        } catch (ParserConfigurationException e) {
            throw new FeatureException("Problem parsing the feature specification XML-file " + specModelURL.getFile() + ". ", e);
        } catch (SAXException e) {
            throw new FeatureException("Problem parsing the feature specification XML-file " + specModelURL.getFile() + ". ", e);
        }
    }

    private void readFeatureModels(Element featuremodels, SpecificationModels featureSpecModels) throws MaltChainedException {
        NodeList featureModelList = featuremodels.getElementsByTagName("featuremodel");
        for (int i = 0; i < featureModelList.getLength(); i++) {
            readFeatureModel((Element) featureModelList.item(i), featureSpecModels);
        }
    }

    private void readFeatureModel(Element featuremodel, SpecificationModels featureSpecModels) throws MaltChainedException {
        int specModelIndex = featureSpecModels.getNextIndex();
        NodeList submodelList = featuremodel.getElementsByTagName("submodel");
        if (submodelList.getLength() == 0) {
            NodeList featureList = featuremodel.getElementsByTagName("feature");
            for (int i = 0; i < featureList.getLength(); i++) {
                String featureText = ((Element) featureList.item(i)).getTextContent().trim();
                if (featureText.length() > 1) {
                    featureSpecModels.add(specModelIndex, featureText);
                }
            }
        } else {
            for (int i = 0; i < submodelList.getLength(); i++) {
                String name = ((Element) submodelList.item(i)).getAttribute("name");
                NodeList featureList = ((Element) submodelList.item(i)).getElementsByTagName("feature");
                for (int j = 0; j < featureList.getLength(); j++) {
                    String featureText = ((Element) featureList.item(j)).getTextContent().trim();
                    if (featureText.length() > 1) {
                        featureSpecModels.add(specModelIndex, name, featureText);
                    }
                }
            }
        }
    }
}