package com.onemap.file.utils;

import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.io.WKTWriter;
import org.geotools.data.FileDataStore;
import org.geotools.data.FileDataStoreFinder;
import org.geotools.data.simple.SimpleFeatureCollection;
import org.geotools.data.simple.SimpleFeatureSource;
import org.geotools.feature.FeatureIterator;
import org.geotools.referencing.CRS;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.referencing.crs.CoordinateReferenceSystem;

import java.io.File;

public class WktUtils {
    public static String getShpWkt(String shpPath) throws Exception {
        // 读取shp文件
        FileDataStore store = FileDataStoreFinder.getDataStore(new File(shpPath));
        SimpleFeatureSource featureSource = store.getFeatureSource();
        SimpleFeatureCollection featureCollection = featureSource.getFeatures();
        CoordinateReferenceSystem crs = featureSource.getSchema().getCoordinateReferenceSystem();

        // 合并几何图形
        Geometry combinedGeometry = null;
        try (FeatureIterator<SimpleFeature> features = featureCollection.features()) {
            while (features.hasNext()) {
                SimpleFeature feature = features.next();
                Geometry geometry = (Geometry) feature.getDefaultGeometry();
                if (combinedGeometry == null) {
                    combinedGeometry = geometry;
                } else {
                    combinedGeometry = combinedGeometry.union(geometry);
                }
            }
        }
        String ewkt = geometryToEWKT(combinedGeometry, crs);
        return ewkt;
    }


    public static String geometryToEWKT(Geometry geometry, CoordinateReferenceSystem crs) throws Exception {
        WKTWriter writer = new WKTWriter();
        String wkt = writer.write(geometry);
        Integer srid = CRS.lookupEpsgCode(crs, true);
        if (srid == null) {
            srid=4326;
        } else if (srid == -1) {
            srid=4326;
        }
        return "SRID=" + srid + ";" + wkt;
    }
}