/**
 *
 */
package de.intevation.gnv.artifactdatabase.client;

import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerFactoryConfigurationError;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.apache.log4j.Logger;
import org.restlet.Client;
import org.restlet.data.Method;
import org.restlet.data.Protocol;
import org.restlet.data.Request;
import org.restlet.data.Response;
import org.restlet.representation.Representation;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import de.intevation.gnv.artifactdatabase.client.exception.ArtifactDatabaseClientException;
import de.intevation.gnv.artifactdatabase.objects.ArtifactFactory;
import de.intevation.gnv.artifactdatabase.objects.ArtifactObject;
import de.intevation.gnv.util.XMLUtils;

/**
 * @author Tim Englich <tim.englich@intevation.de>
 *
 */
public class DefaultArtifactDatabaseClient implements ArtifactDatabaseClient {
    /**
     * the logger, used to log exceptions and additonaly information
     */
    private static Logger log = Logger.getLogger(DefaultArtifactDatabaseClient.class);
    
    // TODO Container for ArtifactDatabases should be used.
    private static Map<String, String> artifactDatabases = null;
    
    private static boolean initialized = false;
    
    /**
     * Constructor
     */
    public DefaultArtifactDatabaseClient() {
        super();
    }

    /**
     * @see de.intevation.gnv.artifactdatabase.client.ArtifactDatabaseClient#getArtifactFactories()
     */
    public Collection<ArtifactObject> getArtifactFactories() throws ArtifactDatabaseClientException {
        Collection<ArtifactObject> resultValues = null;
        if (!initialized){
            this.initialize();
        }
        try {
           XMLUtils xmlUtils = new XMLUtils();
            log.debug("DefaultArtifactDatabaseClient.getArtifactFactories");
            Iterator<String> it = artifactDatabases.values().iterator();
            while (it.hasNext()){
                String server = it.next();
                String url =  server+ "/factories";
                InputStream inputStream = this.doGetRequest(url);
                Document document = xmlUtils.readDocument(inputStream);
                log.debug(xmlUtils.writeDocument2String(document));
                if (resultValues == null){
                    resultValues = this.getArtifactFactories(document,server);
                }else{
                    resultValues.addAll(this.getArtifactFactories(document,server));
                }
            }
        } catch (IOException e) {
            log.error(e,e);
        }
        return resultValues;
    }

    private Collection<ArtifactObject>  getArtifactFactories(Document document, String server){
        XMLUtils xmlUtils = new XMLUtils();
        NodeList artifactFactories = xmlUtils.getNodeSetXPath(document, "/result/factories/factory");
        Collection<ArtifactObject> resultValues = new ArrayList<ArtifactObject>(artifactFactories.getLength());
        if (artifactFactories != null){
            for (int i = 0; i < artifactFactories.getLength(); i++){
                Node  artifactFactoryNode = artifactFactories.item(i);
                String name = xmlUtils.getStringXPath(artifactFactoryNode, "@name");
                String description = xmlUtils.getStringXPath(artifactFactoryNode, "@description");
                ArtifactFactory artifactFactory = new ArtifactFactory(name, description, server);
                resultValues.add(artifactFactory);
            }
        }
        return resultValues;
    }
    
    /**
     * @throws IOException
     */
    private InputStream doGetRequest(String requestUrl) throws IOException {
        Client client = new Client(Protocol.HTTP);
        Request request = new Request(Method.GET, requestUrl);  
        Response response = client.handle(request);
        Representation output = response.getEntity();
        return output.getStream();
    }
    
    private synchronized void initialize(){
        if (!initialized){
            this.artifactDatabases = new HashMap<String, String>();
            this.artifactDatabases.put("test", "http://localhost:8181");            // TODO Read from Config
            initialized = true;
        }
        
    }
    
   
}