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/*
 * This is part of Geomajas, a GIS framework, http://www.geomajas.org/.
 *
 * Copyright 2008-2016 Geosparc nv, http://www.geosparc.com/, Belgium.
 *
 * The program is available in open source according to the GNU Affero
 * General Public License. All contributions in this program are covered
 * by the Geomajas Contributors License Agreement. For full licensing
 * details, see LICENSE.txt in the project root.
 */
package org.geomajas.command.geometry;

import java.util.ArrayList;
import java.util.List;

import org.geomajas.annotation.Api;
import org.geomajas.command.CommandHasRequest;
import org.geomajas.command.dto.GeometrySplitRequest;
import org.geomajas.command.dto.GeometrySplitResponse;
import org.geomajas.global.ExceptionCode;
import org.geomajas.global.GeomajasException;
import org.geomajas.service.DtoConverterService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.MultiPolygon;
import com.vividsolutions.jts.geom.Polygon;

/**
 * Command that splits up a given geometry using a splitting line. This command tries to return Polygons in the result.
 * 
 * @author Pieter De Graef
 * @since 1.11.0
 */
@Component
@Api
public class GeometrySplitCommand implements CommandHasRequest {

	public static final double DELTA = 0.00001;

	@Autowired
	private DtoConverterService converter;

	@Override
	public GeometrySplitRequest getEmptyCommandRequest() {
		return new GeometrySplitRequest();
	}

	@Override
	public GeometrySplitResponse getEmptyCommandResponse() {
		return new GeometrySplitResponse();
	}

	@Override
	public void execute(GeometrySplitRequest request, GeometrySplitResponse response) throws Exception {
		// Check the parameters:
		if (null == request.getGeometry()) {
			throw new GeomajasException(ExceptionCode.PARAMETER_MISSING, "geometry");
		}
		if (null == request.getSplitLine()) {
			throw new GeomajasException(ExceptionCode.PARAMETER_MISSING, "splittingLine");
		}

		// Convert geometries to JTS model:
		Geometry geometry = converter.toInternal(request.getGeometry());
		Geometry splittingLine = converter.toInternal(request.getSplitLine());
		Geometry buffered = splittingLine.buffer(DELTA);

		// Try to return polygons:
		List geometries = new ArrayList();
		if (org.geomajas.geometry.Geometry.POLYGON.equals(request.getGeometry().getGeometryType())) {
			Geometry diff = geometry.difference(buffered);
			if (diff instanceof Polygon) {
				geometries.add(converter.toDto(diff));
			} else if (diff instanceof MultiPolygon) {
				for (int i = 0; i < diff.getNumGeometries(); i++) {
					geometries.add(converter.toDto(diff.getGeometryN(i)));
				}
			}
		} else if (org.geomajas.geometry.Geometry.MULTI_POLYGON.equals(request.getGeometry().getGeometryType())) {
			for (int i = 0; i < geometry.getNumGeometries(); i++) {
				Polygon polygon = (Polygon) geometry.getGeometryN(i);
				Geometry diff = polygon.difference(buffered);
				if (diff instanceof Polygon) {
					geometries.add(converter.toDto(diff));
				} else if (diff instanceof MultiPolygon) {
					for (int j = 0; j < diff.getNumGeometries(); j++) {
						geometries.add(converter.toDto(diff.getGeometryN(j)));
					}
				}
			}
		}

		// Only support for Polygon and MultiPolygon, otherwise throw an exception...
		if (geometries.size() == 0) {
			throw new GeomajasException();
		}
		response.setGeometries(geometries);
	}
}