/**
 *                    BioJava development code
 *
 * This code may be freely distributed and modified under the
 * terms of the GNU Lesser General Public Licence.  This should
 * be distributed with the code.  If you do not have a copy,
 * see:
 *
 *      http://www.gnu.org/copyleft/lesser.html
 *
 * Copyright for this code is held jointly by the individual
 * authors.  These should be listed in @author doc comments.
 *
 * For more information on the BioJava project and its aims,
 * or to join the biojava-l mailing list, visit the home page
 * at:
 *
 *      http://www.biojava.org/
 *
 * Created on 19.03.2004
 * @author Andreas Prlic
 *
 */
package org.biojava.dasobert.das;


import java.net.URL                         ;
import java.io.InputStream                  ;
import org.xml.sax.InputSource              ;
import org.xml.sax.XMLReader                ;
import javax.xml.parsers.*                  ;
import org.xml.sax.*                        ;
import java.util.ArrayList                  ;
import java.util.List;
import java.util.logging.*                  ;
import java.net.HttpURLConnection           ;
import java.io.IOException;
import java.net.ConnectException;
import java.lang.reflect.Method;




/**
 * A class to perform a DAS features request
 *
 * @author Andreas Prlic
 *
 */
public class DAS_FeatureRetrieve {

    List features ;
    Logger logger     ;
    int comeBackLater;
    URL url;
    /**
     * @param url the URL the features should be downloaded from
     *
     */
    public DAS_FeatureRetrieve(URL url) {
        super();

        logger = Logger.getLogger("org.biojava.spice");
        features = new ArrayList() ;
        comeBackLater = -1;
        this.url=url;
        reload();
    }


    /** contact the DAS-feature server again. Usually
     * it is not necessary to call this again, because the constructor already does, but
     * if comeBackLater > -1 this should be called again.
     *
     */
    public void reload(){

        try {

            InputStream dasInStream = null;
            try {
                dasInStream	= open(url);
            } catch (Exception e ){
                comeBackLater = -1;
                logger.log(Level.FINE,"could not open connection to " + url,e);
                return ;
            }


            SAXParserFactory spfactory =
                SAXParserFactory.newInstance();

            spfactory.setValidating(false);

            SAXParser saxParser = null ;

            try{
                saxParser =
                    spfactory.newSAXParser();
            } catch (ParserConfigurationException e) {
                e.printStackTrace();
            }



            String vali = System.getProperty("XMLVALIDATION");

            boolean validation = false ;
            if ( vali != null )
                if ( vali.equals("true") )
                    validation = true ;


            XMLReader xmlreader = saxParser.getXMLReader();

            //XMLReader xmlreader = XMLReaderFactory.createXMLReader();
            try {
                xmlreader.setFeature("http://xml.org/sax/features/validation", validation);
            } catch (SAXException e) {
                logger.log(Level.FINE,"Cannot set validation " + validation);
            }

            try {
                xmlreader.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd",validation);
            } catch (SAXNotRecognizedException e){
                e.printStackTrace();
                logger.log(Level.FINE,"Cannot set load-external-dtd "+validation);

            }

            DAS_Feature_Handler cont_handle = new DAS_Feature_Handler() ;
            cont_handle.setDASCommand(url.toString());
            xmlreader.setContentHandler(cont_handle);
            xmlreader.setErrorHandler(new org.xml.sax.helpers.DefaultHandler());
            InputSource insource = new InputSource() ;
            insource.setByteStream(dasInStream);

            try {
                xmlreader.parse(insource);
                features = cont_handle.get_features();
                comeBackLater = cont_handle.getComBackLater();
            }
            catch ( Exception e){
                e.printStackTrace();
                logger.log(Level.FINE,"error while parsing response from "+ url);
                comeBackLater = -1;
                features = new ArrayList();
            }
        }
        catch (Exception ex) {
            ex.printStackTrace();
            comeBackLater = -1;
        }
    }


    /** open HttpURLConnection. Recommended way to open
     * HttpURLConnections, since this take care of setting timeouts
     * properly for java 1.4 and 1.5*/
    public static HttpURLConnection openHttpURLConnection(URL url)
    throws IOException, ConnectException {
    HttpURLConnection huc = null;
    huc = (HttpURLConnection) url.openConnection();

    String os_name    = java.lang.System.getProperty("os.name");
    String os_version = java.lang.System.getProperty("os.version");
    String os_arch    = java.lang.System.getProperty("os.arch");
    String VERSION = "1.0";

    String userAgent = "Jalview " + VERSION + "("+os_name+"; "+os_arch + " ; "+ os_version+")";
    //e.g. "Mozilla/5.0 (Windows; U; Win98; en-US; rv:1.7.2) Gecko/20040803"
     huc.addRequestProperty("User-Agent", userAgent);
    //logger.finest("opening "+url);


    // use reflection to determine if get and set timeout methods for urlconnection are available
        // seems java 1.5 does not watch the System properties any longer...
        // and java 1.4 did not provide these...
    // for 1.4 see setSystemProperties
    int timeout = 15000;
    try {
        // try to use reflection to set timeout property
        Class urlconnectionClass = Class.forName("java.net.HttpURLConnection");

            Method setconnecttimeout = urlconnectionClass.getMethod (
                                     "setConnectTimeout", new Class [] {int.class}
                                     );
        setconnecttimeout.invoke(huc,new Object[] {new Integer(timeout)});

        Method setreadtimeout = urlconnectionClass.getMethod (
                                  "setReadTimeout", new Class[] {int.class}
                                  );
        setreadtimeout.invoke(huc,new Object[] {new Integer(timeout)});
        //System.out.println("successfully set java 1.5 timeout");
    } catch (Exception e) {
        //e.printStackTrace();
        // most likely it was a NoSuchMEthodException and we are running java 1.4.
    }
    return huc;
    }


    private InputStream open(URL url)
    throws java.io.IOException, java.net.ConnectException
    {
        InputStream inStream = null;


        HttpURLConnection huc = openHttpURLConnection(url);

        inStream = huc.getInputStream();

        return inStream;

    }

    /** returns a List of Features
     * @return a List of Maps containing the features*/
    public List get_features() {

        return features;
    }

    /** returns the comeBackLater value - if a server returned suchh -
     *
     * @return comeBackLater in seconds, or -1 if not provided by server
     */
    public int getComeBackLater(){

        return comeBackLater;

    }


}