<?php
function checkIp(string $ip, string $apiKey): array
{
    if (!filter_var($ip, FILTER_VALIDATE_IP)) {
        throw new InvalidArgumentException('Supply a valid public IP address.');
    }
    if ($apiKey === '') {
        throw new InvalidArgumentException('Set PROXYRADAR_API_KEY on your server.');
    }
    $url = 'https://proxyradar.io/v1/check?' . http_build_query(
        ['ip' => $ip, 'format' => 'json'], '', '&', PHP_QUERY_RFC3986
    );
    $handle = curl_init($url);
    curl_setopt_array($handle, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_HTTPHEADER => ['Authorization: Bearer ' . $apiKey, 'Accept: application/json'],
        CURLOPT_CONNECTTIMEOUT => 5,
        CURLOPT_TIMEOUT => 15,
        CURLOPT_FOLLOWLOCATION => false,
    ]);
    $body = curl_exec($handle);
    $status = (int) curl_getinfo($handle, CURLINFO_RESPONSE_CODE);
    curl_close($handle);
    if ($body === false || $status !== 200 || strlen($body) > 65536) {
        throw new RuntimeException('Lookup unavailable; result is unknown.');
    }
    try {
        $data = json_decode($body, true, 32, JSON_THROW_ON_ERROR);
        if (!is_array($data) || ($data['status'] ?? null) !== 'success'
            || !in_array($data['proxy'] ?? null, [0, 1], true)) {
            throw new RuntimeException('Unexpected verdict');
        }
    } catch (Throwable $error) {
        throw new RuntimeException('Invalid lookup response; result is unknown.');
    }
    return ['ip' => $data['ip'], 'proxy' => $data['proxy'], 'flags' => $data['flags'] ?? null];
}

if (PHP_SAPI === 'cli' && realpath($_SERVER['SCRIPT_FILENAME'] ?? '') === __FILE__) {
    try {
        $result = checkIp($argv[1] ?? '', getenv('PROXYRADAR_API_KEY') ?: '');
        echo json_encode($result, JSON_PRETTY_PRINT | JSON_THROW_ON_ERROR) . PHP_EOL;
    } catch (Throwable $error) {
        fwrite(STDERR, $error->getMessage() . PHP_EOL);
        exit(1);
    }
}