<?php
/**
 * AIBuildZone License Client SDK (drop this into any PHP script you sell)
 * Compatible with PHP 7.4 to 8.x
 *
 * Usage:
 *   require_once 'LicenseClient.php';
 *   $client = new AIBuildZoneLicense('https://aibuildzone.top', 'YOUR_SECRET_OPTIONAL');
 *   $result = $client->activate('ABZ-XXXX-XXXX-XXXX-XXXX');
 *   if (!$result['valid']) {
 *       die('License invalid: ' . $result['message']);
 *   }
 */
class AIBuildZoneLicense
{
    private string $serverUrl;
    private ?string $apiSecret;
    private int $timeout;

    public function __construct(string $serverUrl, ?string $apiSecret = null, int $timeout = 10)
    {
        $this->serverUrl = rtrim($serverUrl, '/');
        $this->apiSecret = $apiSecret;
        $this->timeout = $timeout;
    }

    public function activate(string $licenseKey, ?string $domain = null, ?string $product = null): array
    {
        return $this->request('activate', $licenseKey, $domain, $product);
    }

    public function verify(string $licenseKey, ?string $domain = null, ?string $product = null): array
    {
        return $this->request('verify', $licenseKey, $domain, $product);
    }

    public function deactivate(string $licenseKey, ?string $domain = null): array
    {
        return $this->request('deactivate', $licenseKey, $domain, null);
    }

    public function currentDomain(): string
    {
        $host = $_SERVER['HTTP_HOST'] ?? ($_SERVER['SERVER_NAME'] ?? 'localhost');
        $host = preg_replace('/:\d+$/', '', $host);
        return strtolower(trim($host));
    }

    private function request(string $action, string $key, ?string $domain, ?string $product): array
    {
        $domain = $domain ?: $this->currentDomain();
        $url = $this->serverUrl . '/api/license.php';
        $payload = [
            'action'      => $action,
            'key'         => trim($key),
            'domain'      => $domain,
            'product'     => $product,
            'php_version' => PHP_VERSION,
        ];

        $postData = http_build_query(array_filter($payload, function ($v) { return $v !== null && $v !== ''; }));

        if (function_exists('curl_init')) {
            $ch = curl_init($url);
            curl_setopt_array($ch, [
                CURLOPT_POST           => true,
                CURLOPT_POSTFIELDS     => $postData,
                CURLOPT_RETURNTRANSFER => true,
                CURLOPT_TIMEOUT        => $this->timeout,
                CURLOPT_SSL_VERIFYPEER => true,
                CURLOPT_USERAGENT      => 'AIBuildZone-Client/1.0',
            ]);
            $raw = curl_exec($ch);
            $err = curl_error($ch);
            curl_close($ch);
            if ($raw === false) {
                return ['valid' => false, 'status' => 'network_error', 'message' => 'Connection failed: ' . $err];
            }
        } else {
            $ctx = stream_context_create([
                'http' => [
                    'method'  => 'POST',
                    'header'  => "Content-Type: application/x-www-form-urlencoded\r\nUser-Agent: AIBuildZone-Client/1.0\r\n",
                    'content' => $postData,
                    'timeout' => $this->timeout,
                ],
            ]);
            $raw = @file_get_contents($url, false, $ctx);
            if ($raw === false) {
                return ['valid' => false, 'status' => 'network_error', 'message' => 'Unable to connect to license server.'];
            }
        }

        $data = json_decode($raw, true);
        if (!is_array($data)) {
            return ['valid' => false, 'status' => 'parse_error', 'message' => 'Invalid server response.'];
        }

        // Optional signature verification
        if ($this->apiSecret && !empty($data['signature'])) {
            $str = ($data['license_key'] ?? '') . '|' . ($data['domain'] ?? '') . '|' . ($data['status'] ?? '') . '|' . ($data['timestamp'] ?? '');
            $expected = hash_hmac('sha256', $str, $this->apiSecret);
            if (!hash_equals($expected, $data['signature'])) {
                return ['valid' => false, 'status' => 'tampered', 'message' => 'Response signature verification failed.'];
            }
        }

        return $data;
    }
}

// If accessed directly from browser, trigger a download of this file
if (PHP_SAPI !== 'cli' && basename($_SERVER['SCRIPT_NAME'] ?? '') === 'sample-client.php') {
    header('Content-Type: text/plain; charset=utf-8');
    header('Content-Disposition: attachment; filename="LicenseClient.php"');
    readfile(__FILE__);
    exit;
}