$parts_total = $totals['parts'] ?? 0;

$stmt = $pdo->prepare("
    INSERT INTO workorders
        (customer_id, unit_id, km, tech_notes,
         labor_rate, labor_subtotal, parts_total, shop_supplies,
         enviro_fee, tire_levy, discount,
         gst, total, status, internal_notes,
         payment_status, created_at)
    VALUES
        (?, ?, 0, '',
         0, ?, ?, ?,
         ?, 0, 0,
         ?, ?, ?, '',
         'Unpaid', NOW())
");

$stmt->execute([
    $customerId,
    $unitId,
    $labor_subtotal,
    $parts_total,
    $shop_supplies,
    $enviro_fee,
    $gst,
    $total,
    $status
]);