package com.ard.data.region.utils;

import com.ard.data.region.domain.Coordinate;
import org.springframework.util.CollectionUtils;

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

/**
 * 区域坐标工具类
 *
 * @author ruoyi
 */
public class RegionCoordinateUtils {
    /**
     * 根据坐标数量自动判断区域类型
     *
     * @param coordinates 坐标集合
     * @return POINT/LINE/POLYGON
     */
    public static String getRegionTypeByCoordinates(List<Coordinate> coordinates) {
        if (CollectionUtils.isEmpty(coordinates)) {
            throw new RuntimeException("坐标集合不能为空");
        }

        int size = coordinates.size();
        if (size == 1) {
            return "POINT";
        } else if (size == 2) {
            return "LINE";
        } else {
            return "POLYGON";
        }
    }

    /**
     * 将坐标集合转换为 WKT 格式（自动判断类型）
     */
    public static String toWkt(List<Coordinate> coordinates) {
        if (CollectionUtils.isEmpty(coordinates)) {
            throw new RuntimeException("坐标集合不能为空");
        }

        int size = coordinates.size();

        if (size == 1) {
            // 点
            Coordinate coord = coordinates.get(0);
            return String.format("POINT(%s)", coord.toLatLngString());
        } else if (size == 2) {
            // 线
            List<String> points = coordinates.stream()
                    .map(Coordinate::toLatLngString)
                    .collect(Collectors.toList());
            return String.format("LINESTRING(%s, %s)", points.get(0), points.get(1));
        } else {
            // 面（多边形）
            List<String> points = coordinates.stream()
                    .map(Coordinate::toLatLngString)
                    .collect(Collectors.toList());
            String allPoints = String.join(", ", points);
            String firstPoint = points.get(0);
            return String.format("POLYGON((%s, %s))", allPoints, firstPoint);
        }
    }

    /**
     * 将 WKT 字符串转换为坐标集合
     *
     * @param wkt 如：POLYGON((45.718839 126.670721, 45.708756 126.670151, ...))
     * @return 坐标集合
     */
    public static List<Coordinate> toCoordinates(String wkt) {
        List<Coordinate> coordinates = new ArrayList<>();
        if (wkt == null || wkt.isEmpty()) {
            return coordinates;
        }
        // 提取括号内的坐标字符串
        String coordStr = wkt;
        if (wkt.startsWith("POLYGON")) {
            coordStr = wkt.substring(wkt.indexOf("((") + 2, wkt.lastIndexOf("))"));
        } else if (wkt.startsWith("LINESTRING")) {
            coordStr = wkt.substring(wkt.indexOf("(") + 1, wkt.lastIndexOf(")"));
        } else if (wkt.startsWith("POINT")) {
            coordStr = wkt.substring(wkt.indexOf("(") + 1, wkt.lastIndexOf(")"));
        }

        // 分割坐标点
        String[] points = coordStr.split(",");
        for (String point : points) {
            String[] lngLat = point.trim().split(" ");
            if (lngLat.length >= 2) {
                Double lat = Double.parseDouble(lngLat[0]);
                Double lng = Double.parseDouble(lngLat[1]);
                coordinates.add(new Coordinate(lng, lat));
            }
        }
        return coordinates;
    }

    /**
     * 计算中心点
     */
    public static Coordinate calculateCenter(List<Coordinate> coordinates) {
        if (CollectionUtils.isEmpty(coordinates)) {
            return null;
        }
        double sumLng = 0;
        double sumLat = 0;
        for (Coordinate coord : coordinates) {
            sumLng += coord.getLng();
            sumLat += coord.getLat();
        }
        return new Coordinate(sumLng / coordinates.size(), sumLat / coordinates.size());
    }

    /**
     * 计算面积（仅面类型有效）
     */
    public static double calculateArea(List<Coordinate> coordinates) {
        if (coordinates == null || coordinates.size() < 3) {
            return 0;
        }

        double area = 0;
        int n = coordinates.size();
        for (int i = 0; i < n; i++) {
            Coordinate current = coordinates.get(i);
            Coordinate next = coordinates.get((i + 1) % n);
            area += current.getLng() * next.getLat() - next.getLng() * current.getLat();
        }
        area = Math.abs(area) / 2;

        double lat = coordinates.get(0).getLat();
        double meterPerDegree = 111000 * Math.cos(Math.toRadians(lat));
        return area * meterPerDegree * 111000;
    }

    /**
     * 验证坐标集合
     */
    public static void validateCoordinates(List<Coordinate> coordinates) {
        if (CollectionUtils.isEmpty(coordinates)) {
            throw new RuntimeException("坐标集合不能为空");
        }

        for (Coordinate coord : coordinates) {
            if (!coord.isValid()) {
                throw new RuntimeException("无效坐标");
            }
        }
    }
}