<?php

namespace App\Utils;

class MemoryHelper
{
    /**
     * 获取系统内存使用情况
     *
     * @return array [
     *   'total' => 总内存（MB）
     *   'used'  => 已用内存（MB）
     *   'free'  => 剩余内存（MB）
     *   'usage' => 使用率（百分比）
     * ]
     */
    public static function getMemoryInfo(): array
    {
        $meminfo = self::readMeminfo();

        $total = $meminfo['MemTotal'] ?? 0;
        $free = ($meminfo['MemFree'] ?? 0)
            + ($meminfo['Buffers'] ?? 0)
            + ($meminfo['Cached'] ?? 0)
            + ($meminfo['SReclaimable'] ?? 0);

        $used = $total - $free;
        $usage = $total > 0 ? round($used / $total * 100, 2) : 0;

        return [
            'total' => round($total / 1024, 2), // 转 MB
            'used'  => round($used / 1024, 2),
            'free'  => round($free / 1024, 2),
            'usage' => $usage,
        ];
    }

    /**
     * 读取 /proc/meminfo 并返回数组
     */
    private static function readMeminfo(): array
    {
        $data = [];
        foreach (file('/proc/meminfo') as $line) {
            if (preg_match('/^(\S+):\s+(\d+)/', $line, $matches)) {
                $data[$matches[1]] = (int) $matches[2]; // 单位 kB
            }
        }
        return $data;
    }
}