/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2004-2008, Open Source Geospatial Foundation (OSGeo)
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation;
 *    version 2.1 of the License.
 *
 *    This library is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *    Lesser General Public License for more details.
 */
package org.geotools.validation.spatial;

import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.geotools.data.simple.SimpleFeatureCollection;
import org.geotools.data.simple.SimpleFeatureIterator;
import org.geotools.data.simple.SimpleFeatureSource;
import org.geotools.validation.ValidationResults;
import org.opengis.feature.simple.SimpleFeature;

import com.vividsolutions.jts.geom.CoordinateSequence;
import com.vividsolutions.jts.geom.Envelope;
import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.LineString;


/**
 * LineIntersectsLineWithNodeValidation purpose.
 * 
 * <p>
 * Ensures Line crosses the other Line at a node.
 * </p>
 *
 * @author dzwiers, Refractions Research, Inc.
 * @author $Author: jive $ (last modification)
 *
 * @source $URL$
 * @version $Id$
 */
public class LineIntersectsLineWithNodeValidation
    extends LineLineAbstractValidation {
    /**
     * LineIntersectsLineWithNodeValidation constructor.
     * 
     * <p>
     * Description
     * </p>
     */
    public LineIntersectsLineWithNodeValidation() {
        super();
    }

    /**
     * Ensure Line crosses the other Line at a node.
     * 
     * <p></p>
     *
     * @param layers a HashMap of key="TypeName" value="FeatureSource"
     * @param envelope The bounding box of modified features
     * @param results Storage for the error and warning messages
     *
     * @return True if no features intersect. If they do then the validation
     *         failed.
     *
     * @throws Exception DOCUMENT ME!
     *
     * @see org.geotools.validation.IntegrityValidation#validate(java.util.Map,
     *      com.vividsolutions.jts.geom.Envelope,
     *      org.geotools.validation.ValidationResults)
     */
    public boolean validate(Map layers, Envelope envelope,
        ValidationResults results) throws Exception {
    	boolean r = true;
    	
        SimpleFeatureSource fsLine = (SimpleFeatureSource) layers.get(getLineTypeRef());
        
        SimpleFeatureCollection fcLine = fsLine.getFeatures();
        SimpleFeatureIterator fLine = fcLine.features();
        
        SimpleFeatureSource fsRLine = (SimpleFeatureSource) layers.get(getRestrictedLineTypeRef());
        
        SimpleFeatureCollection fcRLine = fsRLine.getFeatures();
                
        while(fLine.hasNext()){
        	SimpleFeature line = fLine.next();
        	SimpleFeatureIterator fRLine = fcRLine.features();
        	Geometry lineGeom = (Geometry) line.getDefaultGeometry();
        	if(envelope.contains(lineGeom.getEnvelopeInternal())){
        		// 	check for valid comparison
        		if(LineString.class.isAssignableFrom(lineGeom.getClass())){
        			while(fRLine.hasNext()){
        				SimpleFeature rLine = fRLine.next();
        				Geometry rLineGeom = (Geometry) rLine.getDefaultGeometry(); 
        				if(envelope.contains(rLineGeom.getEnvelopeInternal())){
        					if(LineString.class.isAssignableFrom(rLineGeom.getClass())){
    							if(lineGeom.intersects(rLineGeom)){
    								if(!hasPair(((LineString)lineGeom).getCoordinateSequence(),((LineString)rLineGeom).getCoordinateSequence())){
    									results.error(rLine,"Line does not intersect line at node covered by the specified Line.");
    									r = false;
    								}
    							}else{
            						results.warning(rLine,"Does not intersect the LineString");	
    							}
                    		// do next.
        					}else{
        						fcRLine.remove(rLine);
        						results.warning(rLine,"Invalid type: this feature is not a derivative of a LineString");
        					}
        				}else{
        					fcRLine.remove(rLine);
        				}
        			}
        		}else{
        			results.warning(line,"Invalid type: this feature is not a derivative of a LineString");
        		}
        	}
        }
        return r;
    }
    
    /**
     * hasPair purpose.
     * <p>
     * finds a pair of points, assumes the sequence is sorted smallest to largest.
     * </p>
     * @param a1
     * @param a2
     */
    private boolean hasPair(CoordinateSequence a1, CoordinateSequence a2){
    	int i = 0;
    	CoordinateSequence c;
    	c = a1;
    	Set m = new HashSet();
    	while(i<c.size()){
    		m.add(c.getCoordinate(i));
    		i++;
    	}
    	i=0;c=a2;
    	while(i<c.size()){
    		if(!m.add(c.getCoordinate(i)))
    			return true;
    		i++;
    	}
    	return false;
    }
}