/*
 * GML2Reader.java
 *
 * Created on 16 September 2001, 16:50
 */

package uk.ac.leeds.ccg.gml;

import org.w3c.dom.Document;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.apache.xerces.parsers.DOMParser;

import com.galdosinc.xml.XMLException;
import com.galdosinc.gml.util.*;
import com.galdosinc.gml.infoset.*;
import com.galdosinc.gml.dom.GMLDocument;

import uk.ac.leeds.ccg.geotools.*;

import java.net.*;
import java.io.*;

/**
 *
 * @author  James Macgill
 * @version
 */

public class GML2Reader implements uk.ac.leeds.ccg.geotools.FeatureReader {
    
    GMLDocument gmlDoc;
    private final static boolean DEBUG=true;
    
    /**
     * Build a list of features from GML.
     * There is a security
     * constraint in java applets which prevents an applet from accessing a
     * URL different to the server where the applet came from.  So if you want
     * to access a Web Feature Server from somewhere on the web, you need to set
     * up a local proxy.  A local proxy sits on the server where the applet
     * came from, it recieves calls from the applet, forwards them onto the
     * Web Feature Server, and then funnels the responses back to the applet.
     * <br>If you are not using an applet, or if the URL of the GML is on the
     * same server as the applet, then you can set <i>proxy</i> to null.
     * @param url URL of the GML features
     * @param proxy URL of the local proxy server.
     */
    public GML2Reader(URL url,URL proxy) {
        InputSource inputSource;
        try{
            DOMParser parser = new DOMParser();
            System.out.println("Parsing");
            if(DEBUG)System.out.println("GML2Reader: url="+url);
            
            if (proxy==null){
                inputSource = new InputSource(url.openStream());
                parser.parse(inputSource);
            }else{
                URL url2=new URL(
                    proxy.toString()
                    +"?ProxyURL="
                    +URLEncoder.encode(url.toString()));
                inputSource = new InputSource(url2.openStream());
                if(DEBUG)System.out.println("GML2Reader: url2="+url2);
            }
            Document document = parser.getDocument();
            
            gmlDoc = new GMLDocument(document);
            
            
        }
        catch(Exception e){
            System.err.println("GML inialization failed because of "+e);
            e.printStackTrace();
        }
    }
    

    public GML2Reader(URL url) {
        this(url,null);
    }

    
    public Layer getLayer() {
        MixedLayer layer=new MixedLayer();
        GMLConstructIterator iterator = gmlDoc.getGMLConstructIterator();
        GMLConstruct firstGMLConstruct = iterator.nextGMLConstruct();
        this.recursiveAddGeometry(layer,firstGMLConstruct);
        
        
        return layer;
    }
    
    
    public void recursiveAddGeometry(MixedLayer layer,GMLConstruct gmlConstruct) {
        GMLConstructIterator iterator = gmlConstruct.getGMLConstructIterator();
        while (iterator.hasNext()) {
            GMLConstruct nextGMLConstruct = (GMLConstruct) iterator.next();
            if (nextGMLConstruct instanceof Geometry) {
                
                Geometry candidate = (Geometry) nextGMLConstruct;
                System.out.println("Found geometry "+candidate+" "+candidate.getId());
                //String candidateGid = candidate.getId();
                //System.out.println("With attribute "+nextGMLConstruct.getAttribute(0));
                String type = candidate.getXMLDescriptor().getLocalName();
                System.out.println("Its a "+type);
                if(type.equalsIgnoreCase("linearring")){
                    System.out.println("found a linear ring, its owner was"+candidate.getOwner());
                }
                if(type.equalsIgnoreCase("polygon")){
                    System.out.println("Building polygon");
                    
                    GeoPolygon poly = new GeoPolygon();
                    
                    //candidate = candidate.getOuterBoundry();
                    Property outerRing = candidate.getPropertyIterator().nextProperty();
                    GeometryIterator parts = outerRing.getGeometryIterator();
                    
                    while(parts.hasNext()){
                        Geometry part = parts.nextGeometry();
                        System.out.println("part has id " +part.getId());
                        CoordinateTupleIterator coords = part.getCoordinateTupleIterator();
                        while(coords.hasNext()){
                            CoordinateTuple coord = coords.nextCoordinateTuple();
                            poly.addPoint(coord.getX().getValue().doubleValue(),coord.getY().getValue().doubleValue());
                        }
                    }
                    
                    
                    
                    layer.addGeoPolygon(poly);
                }
                System.out.println(candidate.getXMLDescriptor().getLocalName());
                
            }
            recursiveAddGeometry(layer,nextGMLConstruct);
            
        }
        
    }
    
    public GeoData readData(int colNumber) {
        return null;
    }
    
    public Theme getTheme() {
        return null;
    }
    
    public GeoData[] readData() {
        return null;
    }
    
    
    public static void main(String[] args) throws Exception{
        GML2Reader gmlReader = new GML2Reader(new URL("http://gemtun:8082/classpath/Schools.xml"));
        Layer layer = gmlReader.getLayer();
        java.awt.Frame f = new java.awt.Frame();
        f.setSize(400,400);
        Viewer view = new Viewer();
        f.add(view,"Center");
        view.addTheme(new Theme(layer));
        f.setVisible(true);
    }
    
}