License API

function signRequest(array $payload, string $secretKey): array
{
    $payload['timestamp'] = time();
    $payload['nonce']     = bin2hex(random_bytes(16));

    $data = $payload;
    ksort($data); // sort alphabetically — required

    $message = $payload['timestamp'] . ':' . $payload['nonce'] . ':' . json_encode($data);
    $payload['signature'] = hash_hmac('sha256', $message, $secretKey);

    return $payload; // now contains timestamp, nonce, signature
}

function apiPost(string $url, array $payload): ?object
{
    $context = stream_context_create(['http' => [
        'method'        => 'POST',
        'header'        => "Content-Type: application/json\r\nAccept: application/json\r\n",
        'content'       => json_encode($payload),
        'timeout'       => 10,
        'ignore_errors' => true,
    ]]);
    $body = @file_get_contents($url, false, $context);
    return $body ? json_decode($body) : null;
}

<?php

class LicensePlatformSDK
{
    public function __construct(
        private string $licenseKey,
        private string $secretKey,
        private string $baseUrl = '{{ $baseUrl }}'
    ) {}

    // Call once on first install
    public function activate(array $extra = []): ?object
    {
        $response = $this->req('activate', array_merge([
            'domain'          => $_SERVER['HTTP_HOST'] ?? gethostname(),
            'installation_id' => hash('sha256', gethostname()),
        ], $extra));

        if ($response?->success) {
            $this->saveToken([
                'activation_token' => $response->activation_token,
                'activation_id'    => $response->activation_id,
                'expires_at'       => $response->expires_at,
            ]);
        }
        return $response;
    }

    // Call on every app boot — returns true if valid
    public function validate(): bool
    {
        $token = $this->loadToken();
        if (!$token) return false;
        $r = $this->req('validate', ['activation_token' => $token['activation_token']]);
        return (bool) ($r?->valid ?? false);
    }

    // Daily heartbeat — returns response with expires_at
    public function heartbeat(): ?object
    {
        $token = $this->loadToken();
        if (!$token) return null;
        return $this->req('heartbeat', ['activation_token' => $token['activation_token']]);
    }

    // Call from uninstall to free up an activation slot
    public function deactivate(): bool
    {
        $token = $this->loadToken();
        if (!$token) return false;
        $r = $this->req('deactivate', ['activation_token' => $token['activation_token']]);
        if ($r?->success) { @unlink($this->tokenPath()); return true; }
        return false;
    }

    // Check for new version — pass the currently installed version
    public function checkUpdate(string $currentVersion): ?object
    {
        return $this->req('check-update', ['current_version' => $currentVersion]);
    }

    // ── Private helpers ──────────────────────────────────────────
    private function req(string $endpoint, array $data): ?object
    {
        $data['license_key'] = $this->licenseKey;
        $payload = $this->sign($data);
        $ctx = stream_context_create(['http' => [
            'method'        => 'POST',
            'header'        => "Content-Type: application/json\r\nAccept: application/json\r\n",
            'content'       => json_encode($payload),
            'timeout'       => 10,
            'ignore_errors' => true,
        ]]);
        $body = @file_get_contents(rtrim($this->baseUrl,'/').'/api/license/'.$endpoint, false, $ctx);
        return $body ? json_decode($body) : null;
    }

    private function sign(array $p): array
    {
        $p['timestamp'] = time();
        $p['nonce']     = bin2hex(random_bytes(16));
        $d = $p; ksort($d);
        $p['signature'] = hash_hmac('sha256', $p['timestamp'].':'.$p['nonce'].':'.json_encode($d), $this->secretKey);
        return $p;
    }

    private function tokenPath(): string
    {
        return sys_get_temp_dir() . '/lp_' . md5($this->licenseKey) . '.json';
    }

    private function saveToken(array $data): void
    {
        file_put_contents($this->tokenPath(), json_encode($data));
    }

    private function loadToken(): ?array
    {
        $p = $this->tokenPath();
        return file_exists($p) ? json_decode(file_get_contents($p), true) : null;
    }
}

// ── Usage ─────────────────────────────────────────────────────────────────────
$sdk = new LicensePlatformSDK(
    licenseKey: 'ABCD1234-EFGH5678-IJKL9012-MNOP3456',
    secretKey:  'secret-key-from-license-credentials-page'
);

// First install
$r = $sdk->activate();
if (!$r?->success) die('Activation failed: ' . ($r?->message ?? 'no response'));

// Every boot
if (!$sdk->validate()) die('License invalid.');

// Hourly / daily cron
$sdk->heartbeat();

// Uninstall
$sdk->deactivate();