yjearth/src/main/java/com/yj/earth/common/util/GdalJsonConverter.java

package com.yj.earth.common.util;

import org.gdal.gdal.gdal;
import org.gdal.ogr.*;
import org.gdal.osr.CoordinateTransformation;
import org.gdal.osr.SpatialReference;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import static org.gdal.ogr.ogrConstants.*;

public class GdalJsonConverter {

    static {
        // 动态获取项目根目录下的lib文件夹路径
        String projectRoot = System.getProperty("user.dir");

        // 拼接lib目录路径（项目根目录/lib）
        String projLibPath = projectRoot + File.separator + "lib";

        // 设置PROJ库路径（指向包含proj.db的lib目录）
        gdal.SetConfigOption("PROJ_LIB", projLibPath);
        gdal.AllRegister();
    }

    /**
     * 将地理数据文件转换为指定结构的JSON
     */
    public static String convertToJson(String filePath) {
        return convertToJson(filePath, "");
    }

    /**
     * 将地理数据文件转换为指定结构的JSON
     */
    private static String convertToJson(String filePath, String targetCrs) {
        try {
            // 打开数据源
            DataSource dataSource = ogr.Open(filePath, 0);
            if (dataSource == null) {
                throw new RuntimeException("无法打开文件: " + filePath);
            }

            JSONObject result = new JSONObject();
            JSONArray listArray = new JSONArray();

            // 获取所有图层
            int layerCount = dataSource.GetLayerCount();
            for (int i = 0; i < layerCount; i++) {
                Layer layer = dataSource.GetLayer(i);
                String layerName = layer.GetName();

                JSONObject featureCollection = createFeatureCollection(layer, layerName, targetCrs);
                if (featureCollection != null) {
                    listArray.put(featureCollection);
                }
            }

            result.put("list", listArray);
            dataSource.delete();

            return result.toString(2);

        } catch (Exception e) {
            throw new RuntimeException("转换失败: " + e.getMessage(), e);
        }
    }

    /**
     * 创建 FeatureCollection 对象
     */
    private static JSONObject createFeatureCollection(Layer layer, String layerName, String targetCrs) throws JSONException {
        JSONObject featureCollection = new JSONObject();
        featureCollection.put("type", "FeatureCollection");
        featureCollection.put("name", layerName);

        // 获取源坐标系
        String crsSrc = getLayerCrs(layer);
        featureCollection.put("crs_src", crsSrc != null ? crsSrc : "");

        // 设置目标坐标系
        featureCollection.put("crs_dst", targetCrs != null ? targetCrs : "");

        JSONArray featuresArray = new JSONArray();
        Feature feature;

        // 重置图层读取位置
        layer.ResetReading();

        // 获取图层定义、用于字段信息
        FeatureDefn layerDefn = layer.GetLayerDefn();

        // 如果需要坐标转换、创建坐标转换对象
        SpatialReference sourceSrs = layer.GetSpatialRef();
        SpatialReference targetSrs = null;
        CoordinateTransformation coordTrans = null;

        if (targetCrs != null && !targetCrs.isEmpty() && sourceSrs != null) {
            try {
                targetSrs = new SpatialReference();
                if (targetCrs.startsWith("EPSG:")) {
                    int epsgCode = Integer.parseInt(targetCrs.substring(5));
                    targetSrs.ImportFromEPSG(epsgCode);
                } else {
                    targetSrs.ImportFromProj4(targetCrs);
                }
                coordTrans = new CoordinateTransformation(sourceSrs, targetSrs);
            } catch (Exception e) {
                System.err.println("坐标转换初始化失败: " + e.getMessage());
            }
        }

        while ((feature = layer.GetNextFeature()) != null) {
            JSONObject featureObj = createFeature(feature, layerDefn, coordTrans, targetSrs != null);
            if (featureObj != null) {
                featuresArray.put(featureObj);
            }
            feature.delete();
        }

        // 清理资源
        if (coordTrans != null) {
            coordTrans.delete();
        }
        if (targetSrs != null) {
            targetSrs.delete();
        }

        featureCollection.put("features", featuresArray);
        return featureCollection;
    }

    /**
     * 获取图层的坐标系信息
     */
    private static String getLayerCrs(Layer layer) {
        try {
            SpatialReference srs = layer.GetSpatialRef();
            if (srs != null) {
                // 优先尝试获取PROJ4字符串
                String proj4 = srs.ExportToProj4();
                if (proj4 != null && !proj4.trim().isEmpty()) {
                    return proj4.trim();
                }

                // 如果PROJ4为空、尝试获取WKT
                String wkt = srs.ExportToWkt();
                if (wkt != null && !wkt.trim().isEmpty()) {
                    return wkt.trim();
                }

                // 最后尝试获取EPSG代码
                String authorityCode = srs.GetAuthorityCode(null);
                String authorityName = srs.GetAuthorityName(null);
                if (authorityName != null && authorityCode != null) {
                    return authorityName + ":" + authorityCode;
                }
            }
        } catch (Exception e) {
            System.err.println("获取坐标系信息失败: " + e.getMessage());
        }
        return null;
    }

    /**
     * 创建单个Feature对象
     */
    private static JSONObject createFeature(Feature feature, FeatureDefn layerDefn, CoordinateTransformation coordTrans, boolean transformCoords) throws JSONException {
        JSONObject featureObj = new JSONObject();
        featureObj.put("type", "Feature");

        // 处理属性字段
        JSONObject properties = new JSONObject();
        int fieldCount = layerDefn.GetFieldCount();

        for (int i = 0; i < fieldCount; i++) {
            FieldDefn fieldDefn = layerDefn.GetFieldDefn(i);
            String fieldName = fieldDefn.GetName();
            Object fieldValue = getFieldValue(feature, fieldDefn, i);

            if (fieldValue != null) {
                properties.put(fieldName, fieldValue);
            }
        }

        featureObj.put("properties", properties);

        // 处理几何图形
        Geometry geometry = feature.GetGeometryRef();
        if (geometry != null && !geometry.IsEmpty()) {
            Geometry geomToUse = geometry;

            // 如果需要坐标转换
            if (transformCoords && coordTrans != null) {
                try {
                    Geometry transformedGeom = geometry.Clone();
                    transformedGeom.Transform(coordTrans);
                    geomToUse = transformedGeom;
                } catch (Exception e) {
                    System.err.println("坐标转换失败: " + e.getMessage());
                    // 如果转换失败、使用原始几何
                    geomToUse = geometry;
                }
            }

            JSONObject geometryObj = convertGeometryToJson(geomToUse);
            featureObj.put("geometry", geometryObj);

            // 清理临时几何对象
            if (geomToUse != geometry) {
                geomToUse.delete();
            }
        } else {
            // 如果没有几何信息、创建空的MultiPolygon
            featureObj.put("geometry", createEmptyMultiPolygon());
        }

        return featureObj;
    }

    /**
     * 获取字段值
     */
    private static Object getFieldValue(Feature feature, FieldDefn fieldDefn, int fieldIndex) {
        int fieldType = fieldDefn.GetFieldType();

        if (feature.IsFieldSet(fieldIndex)) {
            switch (fieldType) {
                case ogr.OFTInteger:
                    return feature.GetFieldAsInteger(fieldIndex);
                case ogr.OFTInteger64:
                    return feature.GetFieldAsInteger64(fieldIndex);
                case ogr.OFTReal:
                    return feature.GetFieldAsDouble(fieldIndex);
                case ogr.OFTString:
                    return feature.GetFieldAsString(fieldIndex);
                case ogr.OFTDate:
                case ogr.OFTTime:
                case ogr.OFTDateTime:
                    return feature.GetFieldAsString(fieldIndex);
                default:
                    return feature.GetFieldAsString(fieldIndex);
            }
        }
        return null;
    }

    /**
     * 将几何图形转换为JSON
     */
    private static JSONObject convertGeometryToJson(Geometry geometry) throws JSONException {
        JSONObject geometryObj = new JSONObject();
        String geometryType = geometry.GetGeometryName();

        // 根据几何类型处理
        switch (geometry.GetGeometryType()) {
            case wkbPoint:
            case wkbPoint25D:
                geometryObj.put("type", "Point");
                geometryObj.put("coordinates", getPointCoordinates(geometry));
                break;
            case wkbLineString:
            case wkbLineString25D:
                geometryObj.put("type", "LineString");
                geometryObj.put("coordinates", getLineStringCoordinates(geometry));
                break;
            case wkbPolygon:
            case wkbPolygon25D:
                geometryObj.put("type", "Polygon");
                geometryObj.put("coordinates", getPolygonCoordinates(geometry));
                break;
            case wkbMultiPoint:
            case wkbMultiPoint25D:
                geometryObj.put("type", "MultiPoint");
                geometryObj.put("coordinates", getMultiPointCoordinates(geometry));
                break;
            case wkbMultiLineString:
            case wkbMultiLineString25D:
                geometryObj.put("type", "MultiLineString");
                geometryObj.put("coordinates", getMultiLineStringCoordinates(geometry));
                break;
            case wkbMultiPolygon:
            case wkbMultiPolygon25D:
                geometryObj.put("type", "MultiPolygon");
                geometryObj.put("coordinates", getMultiPolygonCoordinates(geometry));
                break;
            case wkbGeometryCollection:
            case wkbGeometryCollection25D:
                geometryObj.put("type", "GeometryCollection");
                geometryObj.put("geometries", getGeometryCollection(geometry));
                break;
            default:
                // 默认使用WKT格式
                geometryObj.put("type", geometryType);
                geometryObj.put("wkt", geometry.ExportToWkt());
                break;
        }

        return geometryObj;
    }

    /**
     * 获取点坐标
     */
    private static JSONArray getPointCoordinates(Geometry geometry) throws JSONException {
        JSONArray coords = new JSONArray();
        coords.put(geometry.GetX());
        coords.put(geometry.GetY());
        if (geometry.GetGeometryType() == wkbPoint25D) {
            coords.put(geometry.GetZ());
        }
        return coords;
    }

    /**
     * 获取线坐标
     */
    private static JSONArray getLineStringCoordinates(Geometry geometry) throws JSONException {
        JSONArray coords = new JSONArray();
        int pointCount = geometry.GetPointCount();
        for (int i = 0; i < pointCount; i++) {
            JSONArray point = new JSONArray();
            point.put(geometry.GetX(i));
            point.put(geometry.GetY(i));
            if (geometry.GetGeometryType() == wkbLineString25D) {
                point.put(geometry.GetZ(i));
            }
            coords.put(point);
        }
        return coords;
    }

    /**
     * 获取多边形坐标
     */
    private static JSONArray getPolygonCoordinates(Geometry geometry) throws JSONException {
        JSONArray rings = new JSONArray();

        // 外环
        Geometry exteriorRing = geometry.GetGeometryRef(0);
        rings.put(getLineStringCoordinates(exteriorRing));

        // 内环（如果有）
        int ringCount = geometry.GetGeometryCount();
        for (int i = 1; i < ringCount; i++) {
            Geometry interiorRing = geometry.GetGeometryRef(i);
            rings.put(getLineStringCoordinates(interiorRing));
        }

        return rings;
    }

    /**
     * 获取多点坐标
     */
    private static JSONArray getMultiPointCoordinates(Geometry geometry) throws JSONException {
        JSONArray points = new JSONArray();
        int geometryCount = geometry.GetGeometryCount();
        for (int i = 0; i < geometryCount; i++) {
            Geometry point = geometry.GetGeometryRef(i);
            points.put(getPointCoordinates(point));
        }
        return points;
    }

    /**
     * 获取多线坐标
     */
    private static JSONArray getMultiLineStringCoordinates(Geometry geometry) throws JSONException {
        JSONArray lines = new JSONArray();
        int geometryCount = geometry.GetGeometryCount();
        for (int i = 0; i < geometryCount; i++) {
            Geometry line = geometry.GetGeometryRef(i);
            lines.put(getLineStringCoordinates(line));
        }
        return lines;
    }

    /**
     * 获取多多边形坐标
     */
    private static JSONArray getMultiPolygonCoordinates(Geometry geometry) throws JSONException {
        JSONArray polygons = new JSONArray();
        int geometryCount = geometry.GetGeometryCount();
        for (int i = 0; i < geometryCount; i++) {
            Geometry polygon = geometry.GetGeometryRef(i);
            polygons.put(getPolygonCoordinates(polygon));
        }
        return polygons;
    }

    /**
     * 获取几何集合
     */
    private static JSONArray getGeometryCollection(Geometry geometry) throws JSONException {
        JSONArray geometries = new JSONArray();
        int geometryCount = geometry.GetGeometryCount();
        for (int i = 0; i < geometryCount; i++) {
            Geometry geom = geometry.GetGeometryRef(i);
            geometries.put(convertGeometryToJson(geom));
        }
        return geometries;
    }

    /**
     * 创建空的 MultiPolygon 几何
     */
    private static JSONObject createEmptyMultiPolygon() throws JSONException {
        JSONObject geometry = new JSONObject();
        geometry.put("type", "MultiPolygon");
        geometry.put("coordinates", new JSONArray());
        return geometry;
    }

    /**
     * 获取文件信息（辅助方法）
     */
    public static Map<String, Object> getFileInfo(String filePath) {
        Map<String, Object> info = new HashMap<>();
        try {
            DataSource dataSource = ogr.Open(filePath, 0);
            if (dataSource != null) {
                info.put("driver", dataSource.GetDriver().GetName());
                info.put("layerCount", dataSource.GetLayerCount());

                List<Map<String, Object>> layers = new ArrayList<>();
                for (int i = 0; i < dataSource.GetLayerCount(); i++) {
                    Layer layer = dataSource.GetLayer(i);
                    Map<String, Object> layerInfo = new HashMap<>();
                    layerInfo.put("name", layer.GetName());
                    layerInfo.put("featureCount", layer.GetFeatureCount());
                    layerInfo.put("geometryType", ogr.GeometryTypeToName(layer.GetGeomType()));
                    // 添加坐标系信息
                    String crs = getLayerCrs(layer);
                    layerInfo.put("crs", crs != null ? crs : "未知");
                    layers.add(layerInfo);
                }
                info.put("layers", layers);
                dataSource.delete();
            }
        } catch (Exception e) {
            info.put("error", e.getMessage());
        }
        return info;
    }
}