Nested Form

<%# Markup for the nested / dynamic fields demo (invoice-style line items).
    The controller clones the <template> row (renumbering __INDEX__), removes rows by
    dropping unsaved ones / flagging _destroy on persisted ones, enforces min/max, and
    hands the row count to the shared stimeo--announcer your app seats once, in its
    layout (count changes are read out without moving focus away; the row list owns no
    live region of its own). Remove buttons are handled by delegation, so cloned rows
    need no per-row wiring. %>
<%
  item_label = t("components.nested_form.demo.item_label")
  remove_label = t("components.nested_form.demo.remove")
  count_message = t("components.nested_form.demo.count_message")
  persisted_value = t("components.nested_form.demo.persisted_value")
%>
<div class="nested-demo" data-controller="stimeo--nested-form"
     data-stimeo--nested-form-min-value="1"
     data-stimeo--nested-form-max-value="5"
     data-stimeo--nested-form-count-message-value="<%= count_message %>">
  <div class="nested-demo__list" data-stimeo--nested-form-target="list">
    <fieldset class="nested-demo__row">
      <label class="nested-demo__field">
        <span><%= item_label %></span>
        <input type="text" class="demo-input" name="order[items_attributes][0][name]">
      </label>
      <button type="button" class="demo-trigger"
              data-stimeo--nested-form-target="remove"><%= remove_label %></button>
    </fieldset>
    <%# A persisted row: its _destroy flag makes Remove hide it instead of deleting it. %>
    <fieldset class="nested-demo__row">
      <input type="hidden" name="order[items_attributes][1][_destroy]" value="0"
             data-stimeo--nested-form-target="destroyFlag">
      <label class="nested-demo__field">
        <span><%= item_label %></span>
        <input type="text" class="demo-input" value="<%= persisted_value %>"
               name="order[items_attributes][1][name]">
      </label>
      <button type="button" class="demo-trigger"
              data-stimeo--nested-form-target="remove"><%= remove_label %></button>
    </fieldset>
  </div>

  <template data-stimeo--nested-form-target="template">
    <fieldset class="nested-demo__row">
      <label class="nested-demo__field">
        <span><%= item_label %></span>
        <input type="text" class="demo-input" name="order[items_attributes][__INDEX__][name]">
      </label>
      <button type="button" class="demo-trigger"
              data-stimeo--nested-form-target="remove"><%= remove_label %></button>
    </fieldset>
  </template>

  <button type="button" class="demo-trigger" data-stimeo--nested-form-target="add"
          data-action="click->stimeo--nested-form#add">
    <%= t("components.nested_form.demo.add") %>
  </button>
</div>

/*
 * Presentation-only styles for the nested / dynamic fields demo.
 * The library clones rows, flags/hides destroyed ones, and reflects
 * data-nested-count / data-nested-at-min / data-nested-at-max; this CSS owns the
 * row layout and the disabled add-button affordance.
 */

.nested-demo {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  max-width: 32rem;
}

.nested-demo__list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.nested-demo__row {
  display: flex;
  align-items: flex-end;
  gap: 0.5rem;
  margin: 0;
  padding: 0.6rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
}

.nested-demo__field {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  flex: 1;
  font-size: 0.85rem;
}

/* The library disables the add button once data-nested-at-max is reached. */
.nested-demo .demo-trigger[disabled] {
  opacity: 0.5;
  cursor: not-allowed;
}

// Consumer-side JS for the nested-form demo (demo-only).
// The controller handles add/remove, focus, and the count announcement on its own;
// this only logs the add/remove events to show the event contract consumers can
// hook for analytics, totals, or enabling a submit button.
document.addEventListener("stimeo--nested-form:add", (event) => {
  console.log(`[nested-form] added row index=${event.detail.index}`);
});

document.addEventListener("stimeo--nested-form:remove", (event) => {
  console.log(`[nested-form] removed row persisted=${event.detail.persisted}`);
});