package com.zy.asrs.utils;

/**
 * 距离优先级工具:
 * 1) 距离 <= 阈值: 优先级 [0,1], 越近越高
 * 2) 距离 > 阈值: 优先级 [0,-1], 越远越低
 */
public final class DistancePriorityUtil {

    private DistancePriorityUtil() {
    }

    public static double calculate(long distance, long threshold, long perimeter) {
        if (threshold <= 0L || perimeter <= 0L) {
            return 0D;
        }
        long d = Math.max(0L, distance);
        if (d <= threshold) {
            double score = 1D - ((double) d / (double) threshold);
            return clamp(score, 0D, 1D);
        }
        long outside = d - threshold;
        long outsideMax = Math.max(1L, perimeter - threshold);
        double score = -((double) outside / (double) outsideMax);
        return clamp(score, -1D, 0D);
    }

    public static boolean isInRange(long distance, long threshold) {
        return threshold > 0L && distance <= threshold;
    }

    private static double clamp(double value, double min, double max) {
        if (value < min) {
            return min;
        }
        if (value > max) {
            return max;
        }
        return value;
    }
}