package de.intevation.flys.client.server.features;

import java.io.FileInputStream;
import java.io.IOException;

import java.util.Hashtable;
import java.util.List;
import java.util.LinkedList;

import javax.xml.xpath.XPathConstants;

import org.apache.log4j.Logger;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import de.intevation.artifacts.common.utils.XMLUtils;

public class XMLFileFeatures implements Features {

    private static final Logger logger = Logger.getLogger(XMLFileFeatures.class);

    private Hashtable<String, List<String>> featuremap = new Hashtable<String, List<String>>();

    public XMLFileFeatures(String filename) throws IOException {
        FileInputStream finput = new FileInputStream(filename);
        Document doc = XMLUtils.parseDocument(finput);

        String XPATH_FEATURES = "ftr:feature/child::text()";
        String XPATH_ROLES    = "/ftr:features/ftr:role";

        NodeList roles = (NodeList) XMLUtils.xpath(
            doc,
            XPATH_ROLES,
            XPathConstants.NODESET,
            FeaturesNamespaceContext.INSTANCE);

        for(int i=0; i < roles.getLength(); i++) {
            Node rolenode = roles.item(i);

            String name = XMLUtils.xpathString(
                rolenode, "@name", FeaturesNamespaceContext.INSTANCE);

            logger.debug("Found role: " + name);

            NodeList features = (NodeList) XMLUtils.xpath(
                rolenode,
                XPATH_FEATURES,
                XPathConstants.NODESET,
                FeaturesNamespaceContext.INSTANCE);

            if (features.getLength() > 0) {
                List<String> allowed = new LinkedList<String>();
                for (int j=0; j < features.getLength(); j++) {
                    Node featurenode = features.item(j);
                    String featurename = featurenode.getNodeValue();

                    logger.debug("found feature: " + featurename);

                    allowed.add(featurename);
                }
                featuremap.put(name, allowed);
            }
        }
        logger.debug("Loaded all features");

        finput.close();
    }

    @Override
    public List<String> getFeatures(List<String> roles) {
        List<String> features = new LinkedList<String>();

        for (String role: roles) {
            List<String> allowed = this.featuremap.get(role);
            if (!allowed.isEmpty()) {
                features.addAll(allowed);
            }
        }
        return features;
    }
}