/*
 * JBoss, Home of Professional Open Source.
 * See the COPYRIGHT.txt file distributed with this work for information
 * regarding copyright ownership.  Some portions may be licensed
 * to Red Hat, Inc. under one or more contributor license agreements.
 *
 * 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; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA.
 */

package org.teiid.query.function;

import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
import java.io.PushbackReader;
import java.io.Reader;
import java.io.StringReader;
import java.sql.Blob;
import java.sql.SQLException;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.teiid.CommandContext;
import org.teiid.UserDefinedAggregate;
import org.teiid.api.exception.query.FunctionExecutionException;
import org.teiid.core.types.BlobImpl;
import org.teiid.core.types.BlobType;
import org.teiid.core.types.ClobImpl;
import org.teiid.core.types.ClobType;
import org.teiid.core.types.ClobType.Type;
import org.teiid.core.types.GeometryType;
import org.teiid.core.types.InputStreamFactory;
import org.teiid.query.QueryPlugin;
import org.wololo.geojson.GeoJSON;
import org.wololo.jts2geojson.GeoJSONReader;
import org.wololo.jts2geojson.GeoJSONWriter;
import org.xml.sax.Attributes;
import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

import com.vividsolutions.jts.geom.*;
import com.vividsolutions.jts.io.ByteOrderValues;
import com.vividsolutions.jts.io.InputStreamInStream;
import com.vividsolutions.jts.io.ParseException;
import com.vividsolutions.jts.io.WKBReader;
import com.vividsolutions.jts.io.WKBWriter;
import com.vividsolutions.jts.io.WKTReader;
import com.vividsolutions.jts.io.WKTWriter;
import com.vividsolutions.jts.io.gml2.GMLHandler;
import com.vividsolutions.jts.io.gml2.GMLWriter;
import com.vividsolutions.jts.precision.GeometryPrecisionReducer;
import com.vividsolutions.jts.simplify.DouglasPeuckerSimplifier;
import com.vividsolutions.jts.simplify.TopologyPreservingSimplifier;

/**
 * Utility methods for geometry
 * TODO: determine if we should use buffermanager to minimize memory footprint
 */
public class GeometryUtils {
    
    public static enum Ordinate {
        X, Y, Z
    }
	
	private static GeometryFactory GEOMETRY_FACTORY = new GeometryFactory();
	
    private static final int SRID_4326 = 4326;

	public static ClobType geometryToClob(GeometryType geometry, 
                                          boolean withSrid) 
            throws FunctionExecutionException {
        Geometry jtsGeometry = getGeometry(geometry);
        int srid = jtsGeometry.getSRID();
        StringBuilder geomText = new StringBuilder(); 
        if (withSrid && srid != GeometryType.UNKNOWN_SRID) {
            geomText.append("SRID=").append(jtsGeometry.getSRID()).append(";"); //$NON-NLS-1$ //$NON-NLS-2$
        }
        geomText.append(jtsGeometry.toText());
        return new ClobType(new ClobImpl(geomText.toString()));
    }

    public static GeometryType geometryFromClob(ClobType wkt)
            throws FunctionExecutionException {
        return geometryFromClob(wkt, GeometryType.UNKNOWN_SRID, false);
    }

    public static GeometryType geometryFromClob(ClobType wkt, Integer srid, boolean allowEwkt) 
            throws FunctionExecutionException {
    	Reader r = null;
        try {
            WKTReader reader = new WKTReader(GEOMETRY_FACTORY);
            r = wkt.getCharacterStream();
            if (allowEwkt) {
            	PushbackReader pbr = new PushbackReader(r, 1);
            	r = pbr;
            	char[] expected = new char[] {'s', 'r', 'i', 'd','='};
            	int expectedIndex = 0;
            	StringBuilder sridBuffer = null;
            	for (int i = 0; i < 100000; i++) {
            		int charRead = pbr.read();
            		if (charRead == -1) {
            			break;
            		}
            		if (expectedIndex == expected.length) {
            			//parse srid
            			if (sridBuffer == null) {
            				sridBuffer = new StringBuilder(4);
            			}
            			if (charRead == ';') {
            				if (sridBuffer.length() == 0) {
            					pbr.unread(charRead);
            				}
            				break;
            			}
            			sridBuffer.append((char)charRead);
            			continue;
            		}
            		if (expectedIndex == 0 && Character.isWhitespace(charRead)) {
            			continue;
            		}
            		if (expected[expectedIndex] != Character.toLowerCase(charRead)) {
    					pbr.unread(charRead);
            			break;
            		}
            		expectedIndex++;	
            	}
            	if (sridBuffer != null) {
            		srid = Integer.parseInt(sridBuffer.toString());
            	}
            }
            Geometry jtsGeometry = reader.read(r);
            if (jtsGeometry == null) {
            	//for some reason io and parse exceptions are caught in their logic if they occur on the first word, then null is returned
            	throw new FunctionExecutionException(QueryPlugin.Util.gs(QueryPlugin.Event.TEIID31203));
            }
            if (!allowEwkt && (jtsGeometry.getSRID() != GeometryType.UNKNOWN_SRID || (jtsGeometry.getCoordinate() != null && !Double.isNaN(jtsGeometry.getCoordinate().z)))) {
            	//don't allow ewkt that requires a specific function
            	throw new FunctionExecutionException(QueryPlugin.Util.gs(QueryPlugin.Event.TEIID31160, "EWKT")); //$NON-NLS-1$
            }
            if (srid == null) {
            	srid = jtsGeometry.getSRID();
            }
            return getGeometryType(jtsGeometry, srid);
        } catch (ParseException e) {
            throw new FunctionExecutionException(e);
        } catch (SQLException e) {
            throw new FunctionExecutionException(e);
        } catch (IOException e) {
        	throw new FunctionExecutionException(e);
		} finally {
        	if (r != null) {
        		try {
					r.close();
				} catch (IOException e) {
				}
        	}
        }
    }
    
    public static ClobType geometryToGeoJson(GeometryType geometry) 
            throws FunctionExecutionException {        
        Geometry jtsGeometry = getGeometry(geometry);
        GeoJSONWriter writer = new GeoJSONWriter();
        try {
            GeoJSON geoJson = writer.write(jtsGeometry);
            ClobType result = new ClobType(new ClobImpl(geoJson.toString()));
            result.setType(Type.JSON);
            return result;
        } catch (Exception e) {
            throw new FunctionExecutionException(e);
        }
    }
    
    public static GeometryType geometryFromGeoJson(ClobType json) 
            throws FunctionExecutionException {
        return geometryFromGeoJson(json, GeometryType.UNKNOWN_SRID);
    }
    
    public static GeometryType geometryFromGeoJson(ClobType json, int srid) 
            throws FunctionExecutionException {
        try {
            GeoJSONReader reader = new GeoJSONReader();
            String jsonText = ClobType.getString(json);
            Geometry jtsGeometry = reader.read(jsonText);
            return getGeometryType(jtsGeometry, srid);
        } catch (SQLException e) {
            throw new FunctionExecutionException(e);            
        } catch (IOException e) {
            throw new FunctionExecutionException(e);            
        }
    }    
    
    public static ClobType geometryToGml(CommandContext ctx, GeometryType geometry, 
                                         boolean withGmlPrefix) 
            throws FunctionExecutionException {        
        Geometry jtsGeometry = getGeometry(geometry);
        GMLWriter writer = new GMLWriter();
        
        if (!withGmlPrefix) {
        	if (geometry.getSrid() != SRID_4326) {
        		if (geometry.getSrid() == GeometryType.UNKNOWN_SRID) {
        			throw new FunctionExecutionException(QueryPlugin.Util.gs(QueryPlugin.Event.TEIID31161));
        		}
        		jtsGeometry = GeometryTransformUtils.transform(ctx, jtsGeometry, SRID_4326);
        	}
            writer.setPrefix(null);
        } else if (geometry.getSrid() != GeometryType.UNKNOWN_SRID) {
        	//TODO: should include the srsName
        	//writer.setSrsName(String.valueOf(geometry.getSrid()));
        }
        String gmlText = writer.write(jtsGeometry);
        return new ClobType(new ClobImpl(gmlText));
    }
        
    public static GeometryType geometryFromGml(ClobType gml, Integer srid) 
            throws FunctionExecutionException {
        try {
			return geometryFromGml(gml.getCharacterStream(), srid);
		} catch (SQLException e) {
			throw new FunctionExecutionException(e);
		}
    }
    
    /**
     * Custom SAX handler extending GMLHandler to handle parsing SRIDs.
     * 
     * The default JTS logic only handles srsName=int or srsName=uri/int
     * whereas other systems commonly use srsName=name:int
     */
    private static class GmlSridHandler extends GMLHandler {
        private int srid = GeometryType.UNKNOWN_SRID;
        
        public GmlSridHandler(GeometryFactory gf, ErrorHandler delegate) {
            super(gf, delegate);
        }

        @Override
        public void startElement(String uri, String localName, String qName, Attributes attributes) 
                throws SAXException {
            String srsName = attributes.getValue("srsName"); //$NON-NLS-1$
            if (srsName != null) {
                String[] srsParts = srsName.split(":"); //$NON-NLS-1$
                try {
                	if (srsParts.length == 2) {
                		srid = Integer.parseInt(srsParts[1]);
                	}
                } catch (NumberFormatException e) {
                    // ignore
                }
            }            
            super.startElement(uri, localName, qName, attributes);
        }

        public int getSrid() {
            return srid;
        } 
    }
    
    public static GeometryType geometryFromGml(Reader reader, Integer srid) 
            throws FunctionExecutionException {
        Geometry jtsGeometry = null;
        try {            
            SAXParserFactory factory = SAXParserFactory.newInstance();
            factory.setNamespaceAware(false);
            factory.setValidating(false);            
            SAXParser parser = factory.newSAXParser();            
            
            GmlSridHandler handler = new GmlSridHandler(GEOMETRY_FACTORY, null);
            parser.parse(new InputSource(reader), handler);
            
            jtsGeometry = handler.getGeometry();
        
            if (srid == null) { 
        		if (jtsGeometry.getSRID() == GeometryType.UNKNOWN_SRID) {
        			srid = handler.getSrid();
        		} else {
        			srid = jtsGeometry.getSRID();
        		}
            }
        } catch (IOException e) {
            throw new FunctionExecutionException(e);
        } catch (SAXException e) {
            throw new FunctionExecutionException(e);
        } catch (ParserConfigurationException e) {
            throw new FunctionExecutionException(e);
        } finally {
            if (reader != null) {
                try {
                    reader.close();
                } catch (Exception e) {
                    // Nothing
                }
            }
        }
        return getGeometryType(jtsGeometry, srid);
    }
    
    public static GeometryType geometryFromBlob(BlobType wkb)
            throws FunctionExecutionException {
        return geometryFromBlob(wkb, GeometryType.UNKNOWN_SRID);
    }
    
    //TODO: should allow an option to assume well formed
    public static GeometryType geometryFromBlob(BlobType wkb, int srid) throws FunctionExecutionException {
        //return as geometry
        GeometryType gt = new GeometryType(wkb.getReference(), srid);
        
        //validate
        getGeometry(gt);
        return gt;
    }
    
	public static Boolean intersects(GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
        Geometry g1 = getGeometry(geom1);
        Geometry g2 = getGeometry(geom2);
        return g1.intersects(g2);
	}
	
	public static Boolean contains(GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
        Geometry g1 = getGeometry(geom1);
        Geometry g2 = getGeometry(geom2);
        return g1.contains(g2);
	}
	
	public static Boolean disjoint(GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
        Geometry g1 = getGeometry(geom1);
        Geometry g2 = getGeometry(geom2);
        return g1.disjoint(g2);
	}
	
	public static Boolean crosses(GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
        Geometry g1 = getGeometry(geom1);
        Geometry g2 = getGeometry(geom2);
        return g1.crosses(g2);
	}
	
	public static Double distance(GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
        Geometry g1 = getGeometry(geom1);
        Geometry g2 = getGeometry(geom2);
        return g1.distance(g2);
	}
	
	public static Boolean touches(GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
        Geometry g1 = getGeometry(geom1);
        Geometry g2 = getGeometry(geom2);
        return g1.touches(g2);
	}
	
	public static Boolean overlaps(GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
        Geometry g1 = getGeometry(geom1);
        Geometry g2 = getGeometry(geom2);
        return g1.overlaps(g2);
	}
	
    public static GeometryType getGeometryType(Geometry jtsGeom) {
        return getGeometryType(jtsGeom, jtsGeom.getSRID());       
    }
    
    public static GeometryType getGeometryType(Geometry jtsGeom, int srid) {
        byte[] bytes = getBytes(jtsGeom, true);
        return new GeometryType(bytes, srid);
    }
    
    public static byte[] getBytes(Geometry jtsGeom, boolean bigEndian) {
        WKBWriter writer = new WKBWriter(2, bigEndian?ByteOrderValues.BIG_ENDIAN:ByteOrderValues.LITTLE_ENDIAN);
        return writer.write(jtsGeom);
    }
    
    public static Geometry getGeometry(GeometryType geom)
            throws FunctionExecutionException {
        try {
			return getGeometry(geom.getBinaryStream(), geom.getSrid(), false);
		} catch (SQLException e) {
			throw new FunctionExecutionException(e);
		}
    }

	public static Geometry getGeometry(InputStream is1, Integer srid, boolean allowEwkb) 
            throws FunctionExecutionException {
        try {
            WKBReader reader = new WKBReader();
            Geometry jtsGeom = reader.read(new InputStreamInStream(is1));
            if (!allowEwkb && (jtsGeom.getSRID() != GeometryType.UNKNOWN_SRID || (jtsGeom.getCoordinate() != null && !Double.isNaN(jtsGeom.getCoordinate().z)))) {
            	//don't allow ewkb - that needs an explicit function
            	throw new FunctionExecutionException(QueryPlugin.Util.gs(QueryPlugin.Event.TEIID31160, "EWKB")); //$NON-NLS-1$
            }
            if (srid != null) { 
            	jtsGeom.setSRID(srid);
            }
            return jtsGeom;
        } catch (ParseException e) {
            throw new FunctionExecutionException(e);
        } catch (IOException e) {
        	throw new FunctionExecutionException(e);
		} finally {
        	if (is1 != null) {
        		try {
					is1.close();
				} catch (IOException e) {
				}
        	}
        }
	}

	public static Boolean equals(GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
		return getGeometry(geom1).equalsTopo(getGeometry(geom2));
	}

	public static GeometryType geometryFromEwkb(InputStream is, Integer srid) throws FunctionExecutionException {
		Geometry geom = getGeometry(is, srid, true);
		return getGeometryType(geom);
	}

	public static GeometryType simplify(
			GeometryType geom, double tolerance) throws FunctionExecutionException {
	    DouglasPeuckerSimplifier douglasPeuckerSimplifier = new DouglasPeuckerSimplifier(getGeometry(geom));
	    douglasPeuckerSimplifier.setEnsureValid(false);
	    douglasPeuckerSimplifier.setDistanceTolerance(tolerance);
	    Geometry resultGeometry = douglasPeuckerSimplifier.getResultGeometry();
        return getGeometryType(resultGeometry);
	}
	
	public static GeometryType simplifyPreserveTopology(
            GeometryType geom, double tolerance) throws FunctionExecutionException {
        return getGeometryType(TopologyPreservingSimplifier.simplify(getGeometry(geom), tolerance));
    }
	
	public static boolean boundingBoxIntersects(
			GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
		Geometry g1 = getGeometry(geom1);
        Geometry g2 = getGeometry(geom2);
		return g1.getEnvelope().intersects(g2.getEnvelope());
	}

	public static GeometryType envelope(GeometryType geom) throws FunctionExecutionException {
		return getGeometryType(getGeometry(geom).getEnvelope());
	}

	public static Boolean within(GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
		Geometry g1 = getGeometry(geom1);
        Geometry g2 = getGeometry(geom2);
		return g1.within(g2);
	}
	
	public static Boolean dwithin(GeometryType geom1, GeometryType geom2, double distance) throws FunctionExecutionException {
		return distance(geom1, geom2) < distance;
	}
	
	public static class Extent implements UserDefinedAggregate<GeometryType> {
		
		private Envelope e;
		
		public Extent() {
		}
		
		@Override
		public void reset() {
			e = null;
		}
		
		public void addInput(GeometryType geom) throws FunctionExecutionException {
			Geometry g1 = getGeometry(geom);
			if (e == null) {
				e = new Envelope();
			} 
		    e.expandToInclude(g1.getEnvelopeInternal());
		}
		
		@Override
		public GeometryType getResult(CommandContext commandContext) {
			if (e == null) {
				return null;
			}
			//created a closed polygon box result
			return getGeometryType(GEOMETRY_FACTORY.createPolygon(new Coordinate[] {
			        new Coordinate(e.getMinX(), e.getMinY()),
			        new Coordinate(e.getMinX(), e.getMaxY()),
			        new Coordinate(e.getMaxX(), e.getMaxY()),
			        new Coordinate(e.getMaxX(), e.getMinY()),
			        new Coordinate(e.getMinX(), e.getMinY())}));
		}

	}

	/**
	 * We'll take the wkb format and add the extended flag/srid
	 * @param geometry
	 * @return
	 */
	public static BlobType geometryToEwkb(final GeometryType geometry) {
		final Blob b = geometry.getReference();
    	BlobImpl blobImpl = new BlobImpl(new InputStreamFactory() {
			
			@Override
			public InputStream getInputStream() throws IOException {
				PushbackInputStream pbis;
				try {
					pbis = new PushbackInputStream(b.getBinaryStream(), 9);
				} catch (SQLException e) {
					throw new IOException(e);
				}
				int byteOrder = pbis.read();
				if (byteOrder == -1) {
					return pbis;
				}
				byte[] typeInt = new byte[4];
				int bytesRead = pbis.read(typeInt);
				if (bytesRead == 4) {
					int srid = geometry.getSrid();
					byte[] sridInt = new byte[4];
					ByteOrderValues.putInt(srid, sridInt, byteOrder==0?ByteOrderValues.BIG_ENDIAN:ByteOrderValues.LITTLE_ENDIAN);
					pbis.unread(sridInt);
					typeInt[byteOrder==0?0:3] |= 0x20;
				}
				pbis.unread(typeInt, 0, bytesRead);
				pbis.unread(byteOrder);
				return pbis;
			}
		});
    	return new BlobType(blobImpl);
	}

	public static double area(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		return g.getArea();
	}

	public static GeometryType boundary(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		return getGeometryType(g.getBoundary());
	}
	
	public static GeometryType buffer(GeometryType geom, double distance)  throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		return getGeometryType(g.buffer(distance));
	}
	
	public static GeometryType buffer(GeometryType geom, double distance, int quadrantSegments)  throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		return getGeometryType(g.buffer(distance, quadrantSegments));
	}

	public static GeometryType centroid(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		return getGeometryType(g.getCentroid());
	}
	
	public static GeometryType convexHull(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		return getGeometryType(g.convexHull());
	}

	public static Integer coordDim(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		Coordinate c = g.getCoordinate();
		if (c != null && !Double.isNaN(c.z)) {
			return 3;
		}
		return 2;
	}

	public static GeometryType difference(GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
		Geometry g1 = getGeometry(geom1);
        Geometry g2 = getGeometry(geom2);
		return getGeometryType(g1.difference(g2));
	}

	public static GeometryType intersection(GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
		Geometry g1 = getGeometry(geom1);
		Geometry g2 = getGeometry(geom2);
		return getGeometryType(g1.intersection(g2));
	}

	public static int dimension(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		return g.getDimension();
	}

	public static GeometryType startEndPoint(GeometryType geom, boolean start) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		if (g instanceof LineString) {
			LineString lineString = (LineString)g;
			Geometry p = null;
			if (start) {
				p = lineString.getStartPoint();
			} else {
				p = lineString.getEndPoint();
			}
			if (p == null) {
				//can be empty
				return null;
			}
			return getGeometryType(p);
		}
		return null;
	}
	
	public static GeometryType exteriorRing(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		if (!(g instanceof Polygon)) {
			return null;
		}
		return getGeometryType(((Polygon)g).getExteriorRing());
	}
	
	public static GeometryType geometryN(GeometryType geom, int index) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		int num = g.getNumGeometries();
		if (index < 0 || index >= num) {
			return null;
		}
		Geometry n = g.getGeometryN(index);
		return getGeometryType(n);
	}

	public static String geometryType(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		return "ST_" + g.getGeometryType(); //$NON-NLS-1$
	}

	public static Boolean isClosed(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		if (!(g instanceof LineString)) {
			return false;
		}
		LineString lineString = ((LineString)g);
		return lineString.isClosed();
	}
	
	public static Boolean isEmpty(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		return g.isEmpty();
	}
	
	public static Boolean isRing(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		if (!(g instanceof LineString)) {
			return false;
		}
		LineString lineString = ((LineString)g);
		return lineString.isClosed() && lineString.isSimple();
	}

	public static Boolean isSimple(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		return g.isSimple();
	}
	
	public static Boolean isValid(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		return g.isValid();
	}
	
	public static Double length(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		if (g instanceof LineString || g instanceof MultiLineString) {
			return g.getLength();
		}
		return 0.0;
	}
	
	public static Integer numInteriorRings(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		if (!(g instanceof Polygon)) {
			return null;
		}
		return ((Polygon)g).getNumInteriorRing();
	}

	public static int numGeometries(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		return g.getNumGeometries();
	}

	public static int numPoints(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		return g.getNumPoints();
	}

	public static GeometryType interiorRingN(GeometryType geom, int i) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		if (!(g instanceof Polygon)) {
			return null;
		}
		Polygon g2 = (Polygon)g;
		if (i < 0 || i >= g2.getNumInteriorRing()) {
			return null;
		}
		return getGeometryType(g2.getInteriorRingN(i));
	}

	public static Boolean orderingEquals(GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
		return getGeometry(geom1).equalsExact(getGeometry(geom2));
	}

	public static GeometryType point(double x, double y) {
		return getGeometryType(GEOMETRY_FACTORY.createPoint(new Coordinate(x, y)));
	}

	public static GeometryType pointN(GeometryType geom, int i) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		if (!(g instanceof LineString)) {
			return null;
		}
		LineString g2 = (LineString)g;
		if (i < 0 || i >= g2.getNumPoints()) {
			return null;
		}
		return getGeometryType(g2.getPointN(i));
	}
	
	public static Double perimeter(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		if (g instanceof Polygon || g instanceof MultiPolygon) {
			return g.getLength();
		}
		return 0.0;
	}

	public static GeometryType pointOnSurface(GeometryType geom) throws FunctionExecutionException {
		Geometry g = getGeometry(geom);
		Point point = g.getInteriorPoint();
		if (point == null) {
			return null;
		}
		point.setSRID(geom.getSrid());
		return getGeometryType(point);
	}
	
	public static GeometryType polygon(GeometryType geom, int srid) throws FunctionExecutionException {
        Geometry g = getGeometry(geom);
        if (!(g instanceof LineString)) {
            throw new FunctionExecutionException(QueryPlugin.Event.TEIID31207, QueryPlugin.Util.gs(QueryPlugin.Event.TEIID31207));
        }
        LineString ls = (LineString)g;
        Geometry result = GEOMETRY_FACTORY.createPolygon(ls.getCoordinateSequence());
        result.setSRID(srid);
        return getGeometryType(result);
    }

    public static Boolean relate(GeometryType geom1, GeometryType geom2, String intersectionPattern) throws FunctionExecutionException {
        Geometry g1 = getGeometry(geom1);
        Geometry g2 = getGeometry(geom2);
        return g1.relate(g2, intersectionPattern);
    }
    
    public static String relate(GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
        Geometry g1 = getGeometry(geom1);
        Geometry g2 = getGeometry(geom2);
        IntersectionMatrix im = g1.relate(g2);
        return im.toString();
    }
    
    public static GeometryType symDifference(GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
        Geometry g1 = getGeometry(geom1);
        Geometry g2 = getGeometry(geom2);
        return getGeometryType(g1.symDifference(g2));
    }
    
    public static GeometryType union(GeometryType geom1, GeometryType geom2) throws FunctionExecutionException {
        Geometry g1 = getGeometry(geom1);
        Geometry g2 = getGeometry(geom2);
        return getGeometryType(g1.union(g2));
    }
    
    public static Double ordinate(GeometryType geom, Ordinate ordinate) throws FunctionExecutionException {
        Geometry g = getGeometry(geom);
        if (!(g instanceof Point)) {
            throw new FunctionExecutionException(QueryPlugin.Event.TEIID31208, QueryPlugin.Util.gs(QueryPlugin.Event.TEIID31208));
        }
        Point p = (Point)g;
        Coordinate c = p.getCoordinate();
        if (c == null) {
            return null;
        }
        double value = c.getOrdinate(ordinate.ordinal());
        if (Double.isNaN(value)) {
            return null;
        }
        return value;
    }

    public static GeometryType makeEnvelope(double xmin, double ymin,
            double xmax, double ymax, Integer srid) {
        Geometry geom = GEOMETRY_FACTORY.createPolygon(new Coordinate[] {new Coordinate(xmin, ymin), new Coordinate(xmin, ymax), new Coordinate(xmax, ymax), new Coordinate(xmax, ymin), new Coordinate(xmin, ymin)});
        if (srid != null) {
            geom.setSRID(srid);
        }
        return getGeometryType(geom);
    }

    public static GeometryType snapToGrid(GeometryType geom, double size) throws FunctionExecutionException {
        if (size == 0) {
            return geom;
        }
        Geometry g1 = getGeometry(geom);
        PrecisionModel precisionModel = new PrecisionModel(1/size);
        GeometryPrecisionReducer reducer = new GeometryPrecisionReducer(precisionModel);
        reducer.setPointwise(true);
        reducer.setChangePrecisionModel(true);
        Geometry result = reducer.reduce(g1);
        //since the wkb writer doesn't consider precision, we have to first write/read through wkt
        WKTWriter writer = new WKTWriter();
        String val = writer.write(result);
        WKTReader reader = new WKTReader(GEOMETRY_FACTORY);
        try {
            result = reader.read(new StringReader(val));
        } catch (ParseException e) {
            throw new FunctionExecutionException(e);
        }
        result.setSRID(geom.getSrid());
        return getGeometryType(result);
    }

}
