package de.intevation.flys.utils;

import java.io.IOException;
import java.io.File;
import java.io.Serializable;
import java.net.MalformedURLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.log4j.Logger;

import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.Envelope;
import com.vividsolutions.jts.geom.Geometry;

import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.referencing.FactoryException;
import org.opengis.referencing.NoSuchAuthorityCodeException;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
import org.opengis.referencing.operation.MathTransform;
import org.opengis.referencing.operation.TransformException;

import org.geotools.data.DataStoreFactorySpi;
import org.geotools.data.DefaultTransaction;
import org.geotools.data.FeatureWriter;
import org.geotools.data.Transaction;
import org.geotools.data.shapefile.ShapefileDataStore;
import org.geotools.data.shapefile.ShapefileDataStoreFactory;
import org.geotools.data.simple.SimpleFeatureIterator;
import org.geotools.feature.FeatureIterator;
import org.geotools.feature.FeatureCollection;
import org.geotools.feature.simple.SimpleFeatureTypeBuilder;
import org.geotools.geojson.feature.FeatureJSON;
import org.geotools.geometry.jts.JTS;
import org.geotools.referencing.CRS;

import de.intevation.flys.model.RiverAxis;


public class GeometryUtils {

    private static final Logger logger = Logger.getLogger(GeometryUtils.class);

    public static final String DEFAULT_EPSG = "EPSG:31467";


    private GeometryUtils() {
    }


    public static Envelope getRiverBoundary(String rivername) {
        List<RiverAxis> axes = RiverAxis.getRiverAxis(rivername);
        if (axes != null && axes.size() > 0) {
            Envelope max = null;

            for (RiverAxis axis: axes) {
                // TODO Take the correct EPSG into account. Maybe, we need to
                // reproject the geometry.
                Envelope env = axis.getGeom().getEnvelopeInternal();

                if (max == null) {
                    max = env;
                }
                else {
                    max.expandToInclude(env);
                }
            }

            return max;
        }

        return null;
    }


    public static String getRiverBounds(String rivername) {
        Envelope env = getRiverBoundary(rivername);

        if (env == null) {
            return jtsBoundsToOLBounds(env);
        }

        return null;
    }


    /**
     * Returns the boundary of Envelope <i>env</i> in OpenLayers
     * representation.
     *
     * @param env The envelope of a geometry.
     *
     * @return the OpenLayers boundary of <i>env</i>.
     */
    public static String jtsBoundsToOLBounds(Envelope env) {
        return "" +
            env.getMinX() + " " +
            env.getMinY() + " " +
            env.getMaxX() + " " +
            env.getMaxY();
    }


    public static String createOLBounds(Geometry a, Geometry b) {
        Coordinate[] ca = a.getCoordinates();
        Coordinate[] cb = b.getCoordinates();

        double lowerX = Double.MAX_VALUE;
        double lowerY = Double.MAX_VALUE;
        double upperX = -Double.MAX_VALUE;
        double upperY = -Double.MAX_VALUE;

        for (Coordinate c: ca) {
            lowerX = lowerX < c.x ? lowerX : c.x;
            lowerY = lowerY < c.y ? lowerY : c.y;

            upperX = upperX > c.x ? upperX : c.x;
            upperY = upperY > c.y ? upperY : c.y;
        }

        for (Coordinate c: cb) {
            lowerX = lowerX < c.x ? lowerX : c.x;
            lowerY = lowerY < c.y ? lowerY : c.y;

            upperX = upperX > c.x ? upperX : c.x;
            upperY = upperY > c.y ? upperY : c.y;
        }

        return "" + lowerX + " " + lowerY + " " + upperX + " " + upperY;
    }


    public static SimpleFeatureType buildFeatureType(
        String name, String srs, Class geometryType)
    {
        return buildFeatureType(name, srs, geometryType, null);
    }


    /**
     * Creates a new SimpleFeatureType using a SimpleFeatureTypeBuilder.
     *
     * @param name The name of the FeatureType.
     * @param srs The SRS (e.g. "EPSG:31466").
     * @param geometryType The geometry type's class (e.g. Polygon.class).
     * @param attrs Optional. An object with attribute-name/attribute-class
     * pairs where index 0 specifies the name as string and index 1 the type
     * as class.
     *
     * @return a new SimpleFeatureType.
     */
    public static SimpleFeatureType buildFeatureType(
        String name, String srs, Class geometryType, Object[][] attrs)
    {
        try {
            SimpleFeatureTypeBuilder builder = new SimpleFeatureTypeBuilder();
            CoordinateReferenceSystem crs    = CRS.decode(srs);

            builder.setName("flys");
            builder.setNamespaceURI("http://www.intevation.de/");
            builder.setCRS(crs);
            builder.setSRS(srs);

            builder.add("geometry", geometryType, crs);

            if (attrs != null) {
                for (Object[] attr: attrs) {
                    builder.add((String) attr[0], (Class) attr[1]);
                }
            }

            return builder.buildFeatureType();
        }
        catch (NoSuchAuthorityCodeException nsae) {
        }
        catch (FactoryException fe) {
        }

        return null;
    }


    public static List<SimpleFeature> parseGeoJSON(
        String geojson, SimpleFeatureType ft
    ) {
        List<SimpleFeature> collection = new ArrayList<SimpleFeature>();

        try {
            FeatureJSON fjson = new FeatureJSON();
            fjson.setFeatureType(ft);

            FeatureIterator<SimpleFeature> iterator =
                fjson.streamFeatureCollection(geojson);

            while (iterator.hasNext()) {
                collection.add(iterator.next());
            }
        }
        catch (IOException ioe) {
            // TODO handle exception
        }

        return collection;
    }


    public static boolean writeShapefile(
        File              shape,
        SimpleFeatureType featureType,
        FeatureCollection collection
    ) {
        return writeShapefile(
            shape, featureType, collection, featureType.getCoordinateReferenceSystem());
    }


    public static boolean writeShapefile(
        File                      shape,
        SimpleFeatureType         featureType,
        FeatureCollection         collection,
        CoordinateReferenceSystem crs
    ) {
        if (collection.isEmpty()) {
            logger.warn("Shapefile is not written - no features given!");
            return false;
        }

        Transaction   transaction = null;

        try {
            MathTransform transform = CRS.findMathTransform(
                CRS.decode(DEFAULT_EPSG), crs);

            Map<String, Serializable> params =
                new HashMap<String, Serializable>();

            params.put("url", shape.toURI().toURL());
            params.put("create spatial index", Boolean.TRUE);

            DataStoreFactorySpi dataStoreFactory =
                new ShapefileDataStoreFactory();

            ShapefileDataStore newDataStore =
                (ShapefileDataStore)dataStoreFactory.createNewDataStore(params);
            newDataStore.createSchema(featureType);

            transaction = new DefaultTransaction("create");

            String typeName = newDataStore.getTypeNames()[0];

            FeatureWriter<SimpleFeatureType, SimpleFeature> writer =
                newDataStore.getFeatureWriter(typeName, transaction);

            SimpleFeatureIterator iterator = (SimpleFeatureIterator) collection.features();

            while (iterator.hasNext()){
                SimpleFeature feature = iterator.next();
                SimpleFeature copy    = writer.next();

                copy.setAttributes(feature.getAttributes());

                Geometry orig        = (Geometry) feature.getDefaultGeometry();
                Geometry reprojected = JTS.transform(orig, transform);

                copy.setDefaultGeometry(reprojected);
                writer.write();
            }

            transaction.commit();

            return true;
        }
        catch (MalformedURLException mue) {
            logger.error("Unable to prepare shapefile: " + mue.getMessage());
        }
        catch (IOException ioe) {
            logger.error("Unable to write shapefile: " + ioe.getMessage());
        }
        catch (NoSuchAuthorityCodeException nsae) {
            logger.error("Cannot get CoordinateReferenceSystem for '"
                + DEFAULT_EPSG + "'");
        }
        catch (FactoryException fe) {
            logger.error("Cannot get CoordinateReferenceSystem for '"
                + DEFAULT_EPSG + "'");
        }
        catch (TransformException te) {
            logger.error("Was not able to transform geometry!", te);
        }
        finally {
            if (transaction != null) {
                try {
                    transaction.close();
                }
                catch (IOException ioe) { /* do nothing */ }
            }
        }

        return false;
    }
}
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