<?php

function testLatency($host) {
    $start_time = microtime(true);
    
    $output = shell_exec("ping -c 10 $host");

    $end_time = microtime(true);
    $latency = $end_time - $start_time;

    if ($output !== null) {
        if (preg_match('/avg\/min\/max = (\d+\.\d+)\/(\d+\.\d+)\/(\d+\.\d+)/', $output, $matches)) {
            $avg_ping = $matches[1];
        } else {
            $avg_ping = 'Unknown';
        }

        $latency_rounded = round($latency, 2);

        $latency_rounded = number_format($latency_rounded, 2, '.', '');

        $response = [
            'host' => $host,
            'latency_ms' => $latency_rounded,
        ];
        
        return json_encode($response, JSON_PRETTY_PRINT);
    } else {
        return json_encode([
            'error' => 'Ping failed',
        ], JSON_PRETTY_PRINT);
    }
}

$client_ip = $_SERVER['REMOTE_ADDR'];

echo testLatency($client_ip);
?>