/*
 * Copyright (c) 2010 by Intevation GmbH
 *
 * This program is free software under the LGPL (>=v2.1)
 * Read the file LGPL.txt coming with the software for details
 * or visit http://www.gnu.org/licenses/ if it does not exist.
 */

package de.intevation.gnv.raster;

import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.GeometryFactory;
import com.vividsolutions.jts.geom.LineString;
import com.vividsolutions.jts.geom.MultiLineString;
import com.vividsolutions.jts.geom.Polygon;
import com.vividsolutions.jts.geom.TopologyException;

import de.intevation.gnv.math.IJKey;

import de.intevation.gnv.raster.Vectorizer.Edge;

import de.intevation.gnv.utils.Pair;

import gnu.trove.TIntObjectHashMap;

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

import org.apache.log4j.Logger;

/**
 * Vectorizer backend to generated iso lines in form of
 * JTS multi linestrings.
 *
 * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a>
 */
public class JTSMultiLineStringProducer
extends      IsoProducer
{
    private static Logger log = Logger.getLogger(
        JTSMultiLineStringProducer.class);

    /**
     * The JTS geometry factory of this producer.
     */
    protected GeometryFactory geometryFactory;

    /**
     * The polygon used to clip the produced multe line strings.
     */
    protected Polygon clip;

    /**
     * Constructor to create a JTSMultiLineStringProducer with
     * a given clipping polygon and a world bounding box.
     * @param clip The clipping polygon.
     * @param minX Min x coord of the world.
     * @param minY Min y coord of the world.
     * @param maxX Max x coord of the world.
     * @param maxY Max y coord of the world.
     */
    public JTSMultiLineStringProducer(
        Polygon clip,
        double minX, double minY,
        double maxX, double maxY
    ) {
        this(
            clip,
            // XXX: Geotools crashes if only using a 2d packed data format!
            JTSMultiPolygonProducer.createDefaultGeometryFactory(3),
            minX, minY,
            maxX, maxY);
    }

    /**
     * Constructor to create a JTSMultiLineStringProducer with
     * a given clipping polygon, a geometry factory
     * and a world bounding box.
     * @param clip The clipping polygon.
     * @param geometryFactory The geometry factory.
     * @param minX Min x coord of the world.
     * @param minY Min y coord of the world.
     * @param maxX Max x coord of the world.
     * @param maxY Max y coord of the world.
     */
    public JTSMultiLineStringProducer(
        Polygon clip,
        GeometryFactory geometryFactory,
        double minX, double minY,
        double maxX, double maxY
    ) {
        super(minX, minY, maxX, maxY);
        this.clip = clip;
        this.geometryFactory = geometryFactory;
    }

    /**
     * Clips a given line string against the clippin polygon. The
     * result is stored in the given list of line strings.
     * @param lineString The line string to be clipped.
     * @param lineStrings The result line string list.
     */
    protected void clipLineString(
        LineString            lineString,
        ArrayList<LineString> lineStrings
    ) {
        if (clip == null) {
            lineStrings.add(lineString);
            return;
        }

        if (!lineString.intersects(clip)) {
            return;
        }

        try {
            Geometry result = lineString.intersection(clip);

            if (result instanceof LineString) {
                lineStrings.add((LineString)result);
            }
            else if (result instanceof MultiLineString) {
                MultiLineString mls = (MultiLineString)result;
                for (int i = 0, N = mls.getNumGeometries(); i < N; ++i) {
                    Geometry g = mls.getGeometryN(i);
                    if (g instanceof LineString) {
                        lineStrings.add((LineString)g);
                    }
                    else {
                        log.warn("cannot handle geometry " + g.getClass());
                    }
                }
            }
            else {
                log.warn("cannot handle " + result.getClass());
            }
        }
        catch (TopologyException te) {
            log.error(te.getLocalizedMessage(), te);
            lineStrings.add(lineString);
        }
    }

    /**
     * Returns a list of pairs attribute -&gt; multi line string.
     * All line strings produced are grouped by there attribute
     * which is generated with the given attribute generator.
     * @param attributeGenerator The attribute generator.
     * @return The list of attribute/multi line strings.
     */
    public List<Pair<Object, MultiLineString>> getMultiLineStrings(
        AttributeGenerator attributeGenerator
    ) {
        ArrayList<Pair<Object, MultiLineString>> multiLineStrings =
            new ArrayList<Pair<Object, MultiLineString>>();

        double b1 = minX;
        double m1 = width != 1
            ? (maxX - minX)/(width-1)
            : 0d;

         double b2 = minY;
         double m2 = height != 1
            ? (maxY - minY)/(height-1)
            : 0d;

        ArrayList<Coordinate> coordinates = new ArrayList<Coordinate>();

        for (IJKey key: joinPairs()) {
            ArrayList<LineString> lineStrings = new ArrayList<LineString>();

            // process complete
            ArrayList<Edge> completeList = complete.get(key);
            if (completeList != null) {
                for (Edge head: completeList) {
                    Edge current = head;
                    do {
                        coordinates.add(new Coordinate(
                            m1*(current.a % width) + b1,
                            m2*(current.a / width) + b2));
                    }
                    while ((current = current.next) != head);
                    // add head again to close shape
                    coordinates.add(new Coordinate(
                        m1*(head.a % width) + b1,
                        m2*(head.a / width) + b2));

                    clipLineString(
                        geometryFactory.createLineString(
                            coordinates.toArray(
                                new Coordinate[coordinates.size()])),
                        lineStrings);

                    coordinates.clear();
                }
            }

            // process open
            TIntObjectHashMap map = commonOpen.get(key);

            if (map != null) {
                for (Edge head: headList(map)) {

                    head = Vectorizer.simplify(head, width);
                    Edge current = head, last = head;
                    do {
                        coordinates.add(new Coordinate(
                            m1*(current.a % width) + b1,
                            m2*(current.a / width) + b2));
                        last = current;
                    }
                    while ((current = current.next) != null);
                    // add b from tail
                    coordinates.add(new Coordinate(
                        m1*(last.b % width) + b1,
                        m2*(last.b / width) + b2));

                    clipLineString(
                        geometryFactory.createLineString(
                            coordinates.toArray(
                                new Coordinate[coordinates.size()])),
                        lineStrings);

                    coordinates.clear();
                } // for all in common open
            } // if map defined for key

			if (!lineStrings.isEmpty()) {
                MultiLineString multiLineString =
                    geometryFactory.createMultiLineString(
                        lineStrings.toArray(
                            new LineString[lineStrings.size()]));
                lineStrings.clear();
                Object attribute = attributeGenerator != null
                    ? attributeGenerator.generateAttribute(key.i, key.j)
                    : key;
                multiLineStrings.add(new Pair<Object, MultiLineString>(
                    attribute,
                    multiLineString));
			}
        } // for all pairs

        return multiLineStrings;
    }
}
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