Reservair/includes/Services/Forms/RsvFormHtmlRenderer.php

<?php

use Reservair\Templating\RsvTemplateEngine;

class RsvFormHtmlRenderer {
    public function draw(RsvFormDefinition $form): bool {
        if (!$form->hasElements()) {
            return false;
        }

        $form_id = esc_attr($form->getId());
        ?>
        <div>
        <form class="reservair-form confirmation"
            id="<?= $form_id ?>"
            onsubmit="RsvFormSender.send_form(event)"
            method="POST">

        <?php foreach ($form->getElements() as $element): ?>
            <?php $this->draw_element($element); ?>
        <?php endforeach; ?>

        </form>
        <?php $this->draw_success_template($form); ?>
        </div>
        <?php

        return true;
    }

    /**
     * Emits the admin-configured success message as an inert <template> that the
     * client clones once the form is submitted. A <reservation-summary> element
     * expands to a placeholder div that RsvFormSender fills with the visitor's
     * selected slots.
     */
    private function draw_success_template(RsvFormDefinition $form): void {
        $message = trim($form->getSuccessMessage());
        if ($message === '') {
            return;
        }

        global $rsv_template_registry;
        $engine = new RsvTemplateEngine(registry: $rsv_template_registry);

        // Sanitize admin HTML before rendering, allowing the registered template
        // custom elements through so the engine can expand them.
        $allowed = $rsv_template_registry->kses_allowed(wp_kses_allowed_html('post'));
        $html    = $engine->render(wp_kses($message, $allowed));
        ?>
        <template class="rsv-form-success"><?= $html ?></template>
        <?php
    }

    public function draw_element(RsvFormElementDefinition $data): void {
        global $rsv_form_registry;

        $handler = $rsv_form_registry->get($data->getType());
        if ($handler === null) {
            return;
        }
        $handler->draw($data);
    }
}