template = db.get(EmailTemplate, cr.generated_template_id) if cr.generated_template_id else None
        subject = subject_row.subject if subject_row else campaign.name
        if template is None:
            cr.status = "perm_failed"
            cr.last_error = "No template assigned"
            campaign.failed_count += 1
            db.commit()
            return {"ok": False, "status": "perm_failed", "reason": "no template"}

        var_cfg = dict(campaign.variable_config or {})
        engine = VariableEngine(var_cfg)
        _today = date.today()
        g = GeneratedValues(
            invoice_number=cr.generated_invoice_number,
            amount=cr.generated_amount,
            shipping=cr.generated_shipping,
            random_name=engine.generate_random_name(),
            invoice_date=var_cfg.get("invoice_date") or _today.isoformat(),
            due_date=var_cfg.get("due_date")
                      or (_today + timedelta(days=int(var_cfg.get("due_days", 14)))).isoformat(),
            phone=cr.generated_phone or var_cfg.get("company_phone", ""),
        )
        unsub_url = _unsubscribe_url(recipient, campaign)
        rec = _recipient_dict(recipient)
        cf = (recipient.custom_fields if recipient else None) or {}
        result_html = engine.substitute(template.body_html, rec, g, custom_fields=cf,
                                        extra={"unsubscribe_link": unsub_url}).text
        result_text = engine.substitute(template.body_text or _plain_fallback(result_html),
                                        rec, g, custom_fields=cf,
                                        extra={"unsubscribe_link": unsub_url}).text

        attachments, att_names = [], []
        if campaign.attach_mode == "pdf" and campaign.attach_pdf:
            att_html = ""
            if campaign.attach_pdf_template_id:
                att_tpl = db.get(EmailTemplate, campaign.attach_pdf_template_id)
                if att_tpl:
                    att_html = engine.substitute(att_tpl.body_html, rec, g, custom_fields=cf,
                                                 extra={"unsubscribe_link": unsub_url}).text
            elif campaign.attachment_id:
                att = db.get(Attachment, campaign.attachment_id)