package com.xiaopeng.pushMessage.utils;

import com.alibaba.fastjson2.JSON;
import com.alibaba.fastjson2.JSONArray;
import com.alibaba.fastjson2.JSONObject;
import com.xiaopeng.api.dto.operation.LonLatDto;
import lombok.extern.slf4j.Slf4j;
import org.gavaghan.geodesy.Ellipsoid;
import org.gavaghan.geodesy.GeodeticCalculator;
import org.gavaghan.geodesy.GeodeticCurve;
import org.gavaghan.geodesy.GlobalCoordinates;
import org.springframework.data.geo.Point;

import java.util.*;
import java.util.concurrent.*;


@Slf4j
public class MapMatchingUtil {




    /**
     * 获取剩余导航数据
     * @param polyline
     * @param longitude
     * @param latitude
     * @return
     */
    public static Map<String, List<LonLatDto>> getRemainingNavigation(List<LonLatDto> polyline, Double longitude, Double latitude){
        //导航数据只有一个点的情况
        Map<String, List<LonLatDto>> map = new HashMap<>();
        if(polyline.size() == 1){
            LonLatDto lonLatDto = polyline.get(0);
            GlobalCoordinates source1 = new GlobalCoordinates(lonLatDto.getLatitude(), lonLatDto.getLongitude());
            GlobalCoordinates target1 = new GlobalCoordinates(latitude, longitude);
            GeodeticCurve geoCurve1 = new GeodeticCalculator().calculateGeodeticCurve(Ellipsoid.WGS84, source1, target1);
            double distance =geoCurve1.getEllipsoidalDistance();
            //判断距离小于5米，则可以返回空数据
            if(5 >= distance){
                map.put("unserved", new ArrayList<>());
                map.put("served", new ArrayList<>());
                return map;
            }
            //大于5米的情况，将车子当前位置添加进结果中
            map.put("unserved", polyline);
            map.put("served", new ArrayList<>());
            return map;
        }
        //多个点位的情况，需要找出当前点位处于那两个点位之间，然后截取掉超出的部分轨迹
        return getRecentlyPoint(polyline, longitude, latitude);
    }


    /**
     * 判断点位在轨迹线路中的点位之间
     * 返回截取后的剩余轨迹
     * @param polyline
     * @param longitude
     * @param latitude
     * @return
     */
    public static Map<String, List<LonLatDto>> getRecentlyPoint(List<LonLatDto> polyline, Double longitude, Double latitude){
        Map<String, List<LonLatDto>> map = new HashMap<>();
        for (int i = 0; i < polyline.size(); i++) {
            if(i == polyline.size() - 1){
                break;
            }
            LonLatDto lonLatDto1 = polyline.get(i);

            //车辆到第一个点位的距离
            GlobalCoordinates source1 = new GlobalCoordinates(lonLatDto1.getLatitude(), lonLatDto1.getLongitude());
            GlobalCoordinates target1 = new GlobalCoordinates(latitude, longitude);
            GeodeticCurve geoCurve1 = new GeodeticCalculator().calculateGeodeticCurve(Ellipsoid.WGS84, source1, target1);
            double distance1 =geoCurve1.getEllipsoidalDistance();

            //车辆到第二个点位的距离
            LonLatDto lonLatDto2 = polyline.get(i + 1);
            GlobalCoordinates source2 = new GlobalCoordinates(lonLatDto2.getLatitude(), lonLatDto2.getLongitude());
            GlobalCoordinates target2 = new GlobalCoordinates(latitude, longitude);
            GeodeticCurve geoCurve2 = new GeodeticCalculator().calculateGeodeticCurve(Ellipsoid.WGS84, source2, target2);
            double distance2 =geoCurve2.getEllipsoidalDistance();

            //第一个点位到第二个点位的距离
            GlobalCoordinates source3 = new GlobalCoordinates(lonLatDto1.getLatitude(), lonLatDto1.getLongitude());
            GlobalCoordinates target3 = new GlobalCoordinates(lonLatDto2.getLatitude(), lonLatDto2.getLongitude());
            GeodeticCurve geoCurve3 = new GeodeticCalculator().calculateGeodeticCurve(Ellipsoid.WGS84, source3, target3);
            double distance3 =geoCurve3.getEllipsoidalDistance();

            //车辆位置在第二个点位的前面
            //这种情况需要从第二个点位开始截取，最终剩余的轨迹从第三个点位开始
            if(distance1 > distance2 && distance1 > distance3){
                //继续向前找，找车辆处于那一段点位中间
                continue;
            }
            //车辆位置在两点之间的情况
            //车辆位置到上一个点的距离+车辆位置到下一个点的距离 = 上一个点到下一个点的距离
            //车辆位置到上一个点的距离+车辆位置到下一个点的距离 <= 上一个点到下一个点的距离 + 5米的漂移量
            if ((distance1 + distance2) == distance3 || (distance1 + distance2) <= distance3 + 5) {
                //剩余未服务的点位
                List<LonLatDto> unserved = new ArrayList<>(polyline.subList(i + 1, polyline.size()));
                List<LonLatDto> served = new ArrayList<>(polyline.subList(0, i + 1));
                map.put("unserved", unserved);
                map.put("served", served);

                System.err.println("车辆在两点之间，从第二个开始截取 : " + i);
                return map;
            }
        }
        //所有数据遍历完后任然没有合适的数据则返回原始数据
        map.put("unserved", polyline);
        map.put("served", new ArrayList<>());
        return map;
    }



    public static Map<String, List<LonLatDto>> getRemainingNavigationByAngle(List<LonLatDto> polyline, Double longitude, Double latitude){
        //导航数据只有一个点的情况
        Map<String, List<LonLatDto>> map = new HashMap<>();
        if(polyline.size() < 3){
            map.put("unserved", new ArrayList<>());
            map.put("served", polyline);
            return map;
        }

        for (int i = 0; i < polyline.size(); i++) {
            if(i+1 == polyline.size()){
                break;
            }
            LonLatDto centerPoint = polyline.get(i);
            LonLatDto nextPoint = polyline.get(i+1);


            // 定义三个点
            // Point A
            double[] pointA = {nextPoint.getLongitude(), nextPoint.getLatitude()};
            // Point B: 中间点
            double[] pointB = {centerPoint.getLongitude(), centerPoint.getLatitude()};
            // Point C
            double[] pointC = {longitude, latitude};
            //正向夹角
            double angle = calculateAngle(pointA, pointB, pointC);
            // 定义三个点
            // Point A
            double[] pointA1 = {centerPoint.getLongitude(), centerPoint.getLatitude()};
            // Point B: 中间点
            double[] pointB1 = {nextPoint.getLongitude(), nextPoint.getLatitude()};
            // Point C
            double[] pointC1 = {longitude, latitude};
            //反向夹角
            double angle1 = calculateAngle(pointA1, pointB1, pointC1);
            //正向夹角和反向夹角都小于90度，则认为车辆在两点之间
            if(90 >= angle && 90 >= angle1){
                double lon = centerPoint.getLongitude();
                double lat = centerPoint.getLatitude();
                if(angle < angle1){
                    lon = nextPoint.getLongitude();
                    lat = nextPoint.getLatitude();
                }
                //计算距离，定位偏移10米内
                GlobalCoordinates source3 = new GlobalCoordinates(lat, lon);
                GlobalCoordinates target3 = new GlobalCoordinates(latitude, longitude);
                GeodeticCurve geoCurve3 = new GeodeticCalculator().calculateGeodeticCurve(Ellipsoid.WGS84, source3, target3);
                double distance3 =geoCurve3.getEllipsoidalDistance();
                if(distance3 > 10){
                    continue;
                }
                map.put("unserved", polyline.subList(i, polyline.size()));
                map.put("served", polyline.subList(0, i));
                System.err.println("车辆在两点之间，点位夹角 : " + angle + "  " + i);
                return map;
            }
        }
        map.put("unserved", polyline);
        map.put("served", new ArrayList<>());
        return map;
        
    }


    /**
     * 计算两个点位之间的夹角
     * @param a 起始点
     * @param m 中点
     * @param b 终点
     * @return
     */
    public static double calculateAngle(double a_x, double a_y, double m_x, double m_y, double b_x, double b_y) {
        // 获取从A到M和从B到M的向量
        double[] vectorAM = new double[]{a_x - m_x, a_y - m_y};
        double[] vectorBM = new double[]{b_x - m_x, b_y - m_y};

        // 计算两个向量的点积
        double dotProduct = vectorAM[0] * vectorBM[0] + vectorAM[1] * vectorBM[1];

        // 计算两个向量的模（长度）
        double magnitudeAM = Math.sqrt(vectorAM[0] * vectorAM[0] + vectorAM[1] * vectorAM[1]);
        double magnitudeBM = Math.sqrt(vectorBM[0] * vectorBM[0] + vectorBM[1] * vectorBM[1]);

        // 计算夹角的余弦值
        double cosTheta = dotProduct / (magnitudeAM * magnitudeBM);

        // 计算夹角（弧度）并转换为度
        double angleInRadians = Math.acos(cosTheta);
        double angleInDegrees = Math.toDegrees(angleInRadians);

        return angleInDegrees;
    }

//    public static void main(String[] args) {
//        // 计算坐标差
//        double x1 = 113.3843844686235;
//
//        double y1 = 23.155130575839845;
//
//        double x2 = 113.3836848841087;
//
//        double y2 = 23.155180919552134;
//
//        double x3 = 113.38368194444445;
//
//        double y3 = 23.15508361111111;
//
//        //计算三条边
//
//        double a = Math.sqrt((x2 - x3) * (x2 - x3) + (y2 - y3) * (y2- y3));
//
//        double b = Math.sqrt((x1 - x3) * (x1 - x3) + (y1 - y3) * (y1 - y3));
//
//        double c = Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
//
//        //计算三个角
//
//        double A = Math.toDegrees(Math.acos((a * a - b * b - c * c) / (-2 * b * c)));
//
//        double B = Math.toDegrees(Math.acos((b * b - a * a - c * c) / (-2 * a * c)));
//
//        double C = Math.toDegrees(Math.acos((c * c - a * a - b * b) / (-2 * a * b)));
//
//        //显示结果，保留小数点后两位
//
//        System.out.println("The three angles are " +
//
//                Math.round(A * 100) / 100.0 + " " +
//
//                Math.round(B * 100) / 100.0 + " " +
//
//                Math.round(C * 100) / 100.0);
//    }

    public static void main(String[] args) {
        String json = "[{\n" +
                "\t\"latitude\": 23.155130575839845,\n" +
                "\t\"longitude\": 113.3843844686235\n" +
                "}, {\n" +
                "\t\"latitude\": 23.155210151679693,\n" +
                "\t\"longitude\": 113.38426593724698\n" +
                "}, {\n" +
                "\t\"latitude\": 23.155289727519538,\n" +
                "\t\"longitude\": 113.38414740587048\n" +
                "}, {\n" +
                "\t\"latitude\": 23.15529,\n" +
                "\t\"longitude\": 113.384147\n" +
                "}, {\n" +
                "\t\"latitude\": 23.155362958389055,\n" +
                "\t\"longitude\": 113.38402358903004\n" +
                "}, {\n" +
                "\t\"latitude\": 23.155435916778114,\n" +
                "\t\"longitude\": 113.38390017806007\n" +
                "}, {\n" +
                "\t\"latitude\": 23.15550887516717,\n" +
                "\t\"longitude\": 113.3837767670901\n" +
                "}, {\n" +
                "\t\"latitude\": 23.155581833556226,\n" +
                "\t\"longitude\": 113.38365335612013\n" +
                "}, {\n" +
                "\t\"latitude\": 23.155585,\n" +
                "\t\"longitude\": 113.383648\n" +
                "}, {\n" +
                "\t\"latitude\": 23.155542,\n" +
                "\t\"longitude\": 113.383621\n" +
                "}, {\n" +
                "\t\"latitude\": 23.155312,\n" +
                "\t\"longitude\": 113.383648\n" +
                "}, {\n" +
                "\t\"latitude\": 23.155180919552134,\n" +
                "\t\"longitude\": 113.3836848841087\n" +
                "}, {\n" +
                "\t\"latitude\": 23.155081,\n" +
                "\t\"longitude\": 113.383713\n" +
                "}, {\n" +
                "\t\"latitude\": 23.15495796304221,\n" +
                "\t\"longitude\": 113.38377424506344\n" +
                "}, {\n" +
                "\t\"latitude\": 23.154856,\n" +
                "\t\"longitude\": 113.383825\n" +
                "}, {\n" +
                "\t\"latitude\": 23.154741004509642,\n" +
                "\t\"longitude\": 113.38390239240225\n" +
                "}, {\n" +
                "\t\"latitude\": 23.154626009019285,\n" +
                "\t\"longitude\": 113.38397978480451\n" +
                "}, {\n" +
                "\t\"latitude\": 23.154593,\n" +
                "\t\"longitude\": 113.384002\n" +
                "}, {\n" +
                "\t\"latitude\": 23.154488868635756,\n" +
                "\t\"longitude\": 113.3840956684042\n" +
                "}, {\n" +
                "\t\"latitude\": 23.15438473727151,\n" +
                "\t\"longitude\": 113.3841893368084\n" +
                "}, {\n" +
                "\t\"latitude\": 23.153869,\n" +
                "\t\"longitude\": 113.384732\n" +
                "}, {\n" +
                "\t\"latitude\": 23.153783434325412,\n" +
                "\t\"longitude\": 113.38484554532484\n" +
                "}, {\n" +
                "\t\"latitude\": 23.153697868650823,\n" +
                "\t\"longitude\": 113.38495909064967\n" +
                "}, {\n" +
                "\t\"latitude\": 23.153612302976235,\n" +
                "\t\"longitude\": 113.3850726359745\n" +
                "}, {\n" +
                "\t\"latitude\": 23.153606,\n" +
                "\t\"longitude\": 113.385081\n" +
                "}, {\n" +
                "\t\"latitude\": 23.15352802191651,\n" +
                "\t\"longitude\": 113.38520076538181\n" +
                "}, {\n" +
                "\t\"latitude\": 23.153450043833022,\n" +
                "\t\"longitude\": 113.38532053076364\n" +
                "}, {\n" +
                "\t\"latitude\": 23.153397,\n" +
                "\t\"longitude\": 113.385402\n" +
                "}, {\n" +
                "\t\"latitude\": 23.15332878835048,\n" +
                "\t\"longitude\": 113.38552854437049\n" +
                "}, {\n" +
                "\t\"latitude\": 23.15326057670096,\n" +
                "\t\"longitude\": 113.38565508874098\n" +
                "}, {\n" +
                "\t\"latitude\": 23.153252,\n" +
                "\t\"longitude\": 113.385671\n" +
                "}, {\n" +
                "\t\"latitude\": 23.153190501345524,\n" +
                "\t\"longitude\": 113.3858015058656\n" +
                "}, {\n" +
                "\t\"latitude\": 23.15312900269105,\n" +
                "\t\"longitude\": 113.38593201173121\n" +
                "}, {\n" +
                "\t\"latitude\": 23.15308,\n" +
                "\t\"longitude\": 113.386036\n" +
                "}, {\n" +
                "\t\"latitude\": 23.15306,\n" +
                "\t\"longitude\": 113.386128\n" +
                "}]";
        List<LonLatDto> polyline = JSON.parseArray(json, LonLatDto.class);
        String xcgj = "[{\"longitude\":113.38358194444445,\"latitude\":23.15508361111111}]";
        List<LonLatDto> lonLatDtos = JSON.parseArray(xcgj, LonLatDto.class);
        for (LonLatDto lonLatDto : lonLatDtos) {
            Map<String, List<LonLatDto>> remainingNavigation = getRemainingNavigation(polyline, lonLatDto.getLongitude(), lonLatDto.getLatitude());
            List<LonLatDto> unserved = remainingNavigation.get("unserved");
            List<LonLatDto> served = remainingNavigation.get("served");
            System.err.println(JSON.toJSONString(served));
            polyline = unserved;

        }
        System.err.println("------------------------------------");

        polyline = JSON.parseArray(json, LonLatDto.class);
        for (LonLatDto lonLatDto : lonLatDtos) {
            Map<String, List<LonLatDto>> remainingNavigation = getRemainingNavigationByAngle(polyline, lonLatDto.getLongitude(), lonLatDto.getLatitude());
            List<LonLatDto> unserved = remainingNavigation.get("unserved");
            List<LonLatDto> served = remainingNavigation.get("served");
            System.err.println(JSON.toJSONString(served));
            polyline = unserved;

        }




//        JSONArray objects = JSON.parseArray("[{\n" +
//                "\t\"latitude\": 23.155130575839845,\n" +
//                "\t\"longitude\": 113.3843844686235\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.155210151679693,\n" +
//                "\t\"longitude\": 113.38426593724698\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.155289727519538,\n" +
//                "\t\"longitude\": 113.38414740587048\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.15529,\n" +
//                "\t\"longitude\": 113.384147\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.155362958389055,\n" +
//                "\t\"longitude\": 113.38402358903004\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.155435916778114,\n" +
//                "\t\"longitude\": 113.38390017806007\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.15550887516717,\n" +
//                "\t\"longitude\": 113.3837767670901\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.155581833556226,\n" +
//                "\t\"longitude\": 113.38365335612013\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.155585,\n" +
//                "\t\"longitude\": 113.383648\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.155542,\n" +
//                "\t\"longitude\": 113.383621\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.155312,\n" +
//                "\t\"longitude\": 113.383648\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.155180919552134,\n" +
//                "\t\"longitude\": 113.3836848841087\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.155081,\n" +
//                "\t\"longitude\": 113.383713\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.15495796304221,\n" +
//                "\t\"longitude\": 113.38377424506344\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.154856,\n" +
//                "\t\"longitude\": 113.383825\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.154741004509642,\n" +
//                "\t\"longitude\": 113.38390239240225\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.154626009019285,\n" +
//                "\t\"longitude\": 113.38397978480451\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.154593,\n" +
//                "\t\"longitude\": 113.384002\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.154488868635756,\n" +
//                "\t\"longitude\": 113.3840956684042\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.15438473727151,\n" +
//                "\t\"longitude\": 113.3841893368084\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.153869,\n" +
//                "\t\"longitude\": 113.384732\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.153783434325412,\n" +
//                "\t\"longitude\": 113.38484554532484\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.153697868650823,\n" +
//                "\t\"longitude\": 113.38495909064967\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.153612302976235,\n" +
//                "\t\"longitude\": 113.3850726359745\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.153606,\n" +
//                "\t\"longitude\": 113.385081\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.15352802191651,\n" +
//                "\t\"longitude\": 113.38520076538181\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.153450043833022,\n" +
//                "\t\"longitude\": 113.38532053076364\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.153397,\n" +
//                "\t\"longitude\": 113.385402\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.15332878835048,\n" +
//                "\t\"longitude\": 113.38552854437049\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.15326057670096,\n" +
//                "\t\"longitude\": 113.38565508874098\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.153252,\n" +
//                "\t\"longitude\": 113.385671\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.153190501345524,\n" +
//                "\t\"longitude\": 113.3858015058656\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.15312900269105,\n" +
//                "\t\"longitude\": 113.38593201173121\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.15308,\n" +
//                "\t\"longitude\": 113.386036\n" +
//                "}, {\n" +
//                "\t\"latitude\": 23.15306,\n" +
//                "\t\"longitude\": 113.386128\n" +
//                "}]");
//        String str = "[";
//        for (int i = 0; i < objects.size(); i++) {
//            JSONObject jsonObject = objects.getJSONObject(i);
//            str += "[" + jsonObject.getDouble("longitude") + "," + jsonObject.getDouble("latitude") + "],";
//        }
//        System.err.println(str + "]");
    }



    private static final double EARTH_RADIUS_KM = 6371.0; // 地球平均半径 (公里)

    /**
     * 计算由三个经纬度点构成的夹角
     *
     * @param pointA 经纬度点 A (格式: {经度, 纬度})
     * @param pointB 经纬度点 B (格式: {经度, 纬度}) - 此点为夹角的顶点
     * @param pointC 经纬度点 C (格式: {经度, 纬度})
     * @return 夹角 ABC 的大小，单位为度
     */
    public static double calculateAngle(double[] pointA, double[] pointB, double[] pointC) {
        // 1. 将经纬度（度）转换为弧度
        double lat1 = Math.toRadians(pointA[1]);
        double lon1 = Math.toRadians(pointA[0]);
        double lat2 = Math.toRadians(pointB[1]);
        double lon2 = Math.toRadians(pointB[0]);
        double lat3 = Math.toRadians(pointC[1]);
        double lon3 = Math.toRadians(pointC[0]);

        // 2. 计算各点对之间的中心角 (angular distance)
        double angularDist_AB = haversineDistanceInRadians(lat1, lon1, lat2, lon2);
        double angularDist_BC = haversineDistanceInRadians(lat2, lon2, lat3, lon3);
        double angularDist_AC = haversineDistanceInRadians(lat1, lon1, lat3, lon3);

        // 3. 使用球面余弦定律计算夹角 B (angle at point B)
        // cos(B) = (cos(b) - cos(c) * cos(a)) / (sin(c) * sin(a))
        // 其中 a 是 BC 的中心角, b 是 AC 的中心角, c 是 AB 的中心角
        double cos_angle_B = (
                Math.cos(angularDist_AC) -
                        Math.cos(angularDist_AB) * Math.cos(angularDist_BC)
        ) / (
                Math.sin(angularDist_AB) * Math.sin(angularDist_BC)
        );

        // 4. 防止由于浮点数精度问题导致的无效输入 (例如 cos_angle_B > 1 或 < -1)
        cos_angle_B = Math.max(-1.0, Math.min(1.0, cos_angle_B));

        // 5. 计算夹角 B 并转换为度
        double angle_B_rad = Math.acos(cos_angle_B);
        double angle_B_deg = Math.toDegrees(angle_B_rad);

        return angle_B_deg;
    }

    /**
     * 使用 Haversine 公式计算两个经纬度点之间的中心角 (弧度)
     * 此函数计算的是球心角，不是地面距离
     */
    private static double haversineDistanceInRadians(double lat1, double lon1, double lat2, double lon2) {
        double delta_lat = lat2 - lat1;
        double delta_lon = lon2 - lon1;

        double a = Math.sin(delta_lat / 2) * Math.sin(delta_lat / 2) +
                Math.cos(lat1) * Math.cos(lat2) *
                        Math.sin(delta_lon / 2) * Math.sin(delta_lon / 2);

        double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));

        return c; // 返回中心角 (弧度)
    }

    // --- 示例 ---
//    public static void main(String[] args) {
//        // 定义三个点
//        // Point A: 北京天安门广场附近
//        double[] pointA = {113.3836848841087,23.155180919552134};
//        // Point B: 北京某个中间点
//        double[] pointB = {113.383713,23.155081};
//        // Point C: 北京另一个方向的点
//        double[] pointC = {113.38368194444445,23.15508361111111};
//
//        double angle = calculateAngle(pointA, pointB, pointC);
//
//        System.out.printf("由点 A(%f, %f), B(%f, %f), C(%f, %f) 构成的夹角 ABC 为: %.2f 度%n",
//                pointA[0], pointA[1], pointB[0], pointB[1], pointC[0], pointC[1], angle);
//    }
}