Spec: Automated PDF Invoices & Packing Slips for Corporate B2B Clients

<?php
declare(strict_types=1);

use Dompdf\Dompdf;
use Dompdf\Options;

class AgenticLab_PDF_Generator {
    public static function generate_invoice_pdf(\WC_Order $order): string {
        $options = new Options();
        $options->set('isHtml5ParserEnabled', true);
        $options->set('isRemoteEnabled', true);
        $options->set('defaultFont', 'DejaVu Sans');

        $dompdf = new Dompdf($options);

        ob_start();
        include dirname(__DIR__) . '/templates/pdf/invoice-template.php';
        $html = ob_get_clean();

        $dompdf->loadHtml($html, 'UTF-8');
        $dompdf->setPaper('A4', 'portrait');
        $dompdf->render();

        $upload_dir = wp_upload_dir();
        $invoices_dir = $upload_dir['basedir'] . '/agenticlab-invoices';
        if (!file_exists($invoices_dir)) {
            wp_mkdir_p($invoices_dir);
            file_put_contents($invoices_dir . '/.htaccess', 'deny from all');
        }

        $file_path = $invoices_dir . '/invoice-' . $order->get_id() . '.pdf';
        file_put_contents($file_path, $dompdf->output());

        return $file_path;
    }
}