<?php

namespace App\Helpers;

class Location
{

    public static function juli($user_lat = 0, $user_lng = 0, $lat = 0, $lng = 0)
    {
        if ($user_lat == 0 || $user_lng == 0 || $lat == 0 || $lng == 0) {
            return ''; //用户定位失败
        }

        $juli = ROUND(6378.138 * 2 * ASIN(SQRT(POW(SIN(($user_lat * PI() / 180 - $lat * PI() / 180) / 2), 2) + COS($user_lat * PI() / 180) * COS($lat * PI() / 180) * POW(SIN(($user_lng * PI() / 180 - $lng * PI() / 180) / 2), 2))) * 1000);
        if ($juli > 1000) {
            return round($juli / 1000, 1) . 'Km';
        } else {
            return $juli . 'M';
        }
    }
}