package com.zhgd.xmgl.util;

import java.util.ArrayList;
import java.util.Optional;

public class PolygonUtil {

    /**
     * 五边形面积
     *
     * @param r 从五边形中心到顶点的距离，计算五边形的面积
     * @return
     */
    public static double pentagonArea(double r) {
        double s = 2 * r * Math.sin(Math.PI / 5);
        return (5 * Math.pow(s, 2)) / (4 * Math.tan(Math.PI / 5));
    }

    /**
     * 八边形面积
     *
     * @param r
     * @return
     */
    public static double octagonArea(double r) {
        double s = 2 * r * Math.sin(Math.PI / 8);
        return (8 * Math.pow(s, 2)) / (4 * Math.tan(Math.PI / 8));
    }

    /**
     * 多边形面积
     *
     * @param r
     * @return
     */
    public static double polygonArea(double r, int edgeNum) {
        double s = 2 * r * Math.sin(Math.PI / edgeNum);
        return (edgeNum * Math.pow(s, 2)) / (4 * Math.tan(Math.PI / edgeNum));
    }

    /**
     * 计算雷达图面积
     *
     * @param r       从多边形中心到顶点的距离
     * @param edgeNum 边数
     * @param data    三角形的边长
     * @return
     */
    public static double calRadioArea(double r, int edgeNum, Double... data) {
        double sinVal = Math.sin(Math.toRadians(360.0 / edgeNum));
        ArrayList<Double> dataList = new ArrayList<>();
        for (Double d : data) {
            dataList.add(Optional.ofNullable(d).orElse(0.0));
        }
        ArrayList<Double> doubles = new ArrayList<>();
        for (int i = 0; i < edgeNum; i++) {
            double r1;
            if (i == edgeNum - 1) {
                r1 = dataList.get(i) * dataList.get(0) * sinVal / 2;
            } else {
                r1 = dataList.get(i) * dataList.get(i + 1) * sinVal / 2;
            }
            doubles.add(r1);
        }
        double sum = doubles.stream().mapToDouble(value -> value).sum();
        return sum / pentagonArea(1);
    }

    public static void main(String[] args) {
        System.out.println(calRadioArea(1, 5, 1.0, 1.0, 1.0, 1.0, 1.0));
    }

}