<?php
/**
 * Click tracking capture endpoint.
 * Logs request details to data/tracks.jsonl and redirects to the main page.
 * Usage: track.php (no parameters required)
 */

$dataDir = __DIR__ . '/data';
$logFile = $dataDir . '/tracks.jsonl';

$mainPageUrl = (isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] === 'on' ? 'https' : 'http')
    . '://' . ($_SERVER['HTTP_HOST'] ?? 'localhost')
    . rtrim(dirname($_SERVER['SCRIPT_NAME'] ?? '/'), '/') . '/index.php';

$ip = isset($_SERVER['REMOTE_ADDR']) ? $_SERVER['REMOTE_ADDR'] : '';
$forwarded = isset($_SERVER['HTTP_X_FORWARDED_FOR']) ? $_SERVER['HTTP_X_FORWARDED_FOR'] : '';
$realIp = isset($_SERVER['HTTP_X_REAL_IP']) ? $_SERVER['HTTP_X_REAL_IP'] : '';

function lookupCountryCode($ip)
{
    if (!filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE)) {
        return null;
    }
    $context = stream_context_create(['http' => ['timeout' => 2]]);
    $response = @file_get_contents(
        'http://ip-api.com/json/' . urlencode($ip) . '?fields=status,countryCode',
        false,
        $context
    );
    if ($response === false) {
        return null;
    }
    $data = json_decode($response, true);
    if (!is_array($data) || ($data['status'] ?? '') !== 'success') {
        return null;
    }
    return $data['countryCode'] ?? null;
}

$countryCode = lookupCountryCode($ip);

$key = isset($_GET['key']) && $_GET['key'] !== '' ? trim($_GET['key']) : null;

if ($key === 'KEY') {
    header('Location: ' . $mainPageUrl);
    exit;
}

$payload = [
    'timestamp' => date('c'),
    'key' => $key,
    'target_url' => null,
    'ip' => $ip,
    'ip_forwarded' => $forwarded !== '' ? $forwarded : null,
    'ip_real' => $realIp !== '' ? $realIp : null,
    'country_code' => $countryCode,
    'user_agent' => isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : null,
    'referrer' => isset($_SERVER['HTTP_REFERER']) && $_SERVER['HTTP_REFERER'] !== '' ? $_SERVER['HTTP_REFERER'] : null,
    'request_uri' => isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : null,
    'request_method' => isset($_SERVER['REQUEST_METHOD']) ? $_SERVER['REQUEST_METHOD'] : null,
    'query_string' => isset($_SERVER['QUERY_STRING']) ? $_SERVER['QUERY_STRING'] : null,
    'accept_language' => isset($_SERVER['HTTP_ACCEPT_LANGUAGE']) ? $_SERVER['HTTP_ACCEPT_LANGUAGE'] : null,
    'accept' => isset($_SERVER['HTTP_ACCEPT']) ? $_SERVER['HTTP_ACCEPT'] : null,
];

if (!is_dir($dataDir)) {
    mkdir($dataDir, 0755, true);
}

$line = json_encode($payload, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) . "\n";
file_put_contents($logFile, $line, FILE_APPEND | LOCK_EX);

header('Location: ' . $mainPageUrl);
exit;