Form Field

<%# Markup for the form-field demo.
    Associates label / description / error with the control via aria-describedby /
    aria-invalid / aria-errormessage. Showing/clearing the error uses the action
    parameter (message) and #clearError. The error text is spoken assertively by the
    shared stimeo--announcer your app seats once, in its layout — a region that stands
    in the accessibility tree ahead of the first error, which is what makes the message
    observable. The look switches on data-stimeo--form-field-invalid and aria-invalid. %>
<div class="form-field-demo" data-controller="stimeo--form-field"
     data-stimeo--form-field-focus-on-error-value="true">
  <label class="form-field-demo__label" for="ff-email">
    <%= t("components.form_field.demo.label") %>
  </label>

  <input class="form-field-demo__control" id="ff-email" type="email" aria-invalid="false"
         placeholder="<%= t('components.form_field.demo.placeholder') %>"
         data-stimeo--form-field-target="control" />

  <%# Helper description. It is assigned an id and linked into the control's
      aria-describedby. %>
  <p class="form-field-demo__description" data-stimeo--form-field-target="description">
    <%= t("components.form_field.demo.hint") %>
  </p>

  <%# Note clarifying the demo's intent (this part only wires up the error state;
      it doesn't validate or clear the value). %>
  <p class="form-field-demo__note"><%= t("components.form_field.demo.note") %></p>

  <%# Visual error region. Starts hidden; speech is delegated to the shared announcer. %>
  <p class="form-field-demo__error" hidden
     data-stimeo--form-field-target="error"></p>

  <div class="form-field-demo__actions">
    <%# setError reads the message from the action parameter (no consumer JS needed). %>
    <button type="button" class="demo-trigger"
            data-stimeo--form-field-message-param="<%= t('components.form_field.demo.error') %>"
            data-action="click->stimeo--form-field#setError">
      <%= t("components.form_field.demo.validate") %>
    </button>
    <button type="button" class="demo-trigger"
            data-action="click->stimeo--form-field#clearError">
      <%= t("components.form_field.demo.clear") %>
    </button>
  </div>

  <%# Helper region that subscribes to the validate event and shows the valid
      state only (updated by demo.js). %>
  <p class="form-field-demo__status" id="ff-status" aria-live="polite"
     data-valid-text="<%= t('components.form_field.demo.valid') %>"></p>
</div>

/*
 * Presentation-only styles for the form-field demo.
 * The invalid state is expressed via data-stimeo--form-field-invalid (root) and
 * aria-invalid (control).
 */

.form-field-demo {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  max-width: 22rem;
}

.form-field-demo__label {
  font-weight: 600;
}

.form-field-demo__control {
  padding: 0.5rem 0.75rem;
  font-size: 1rem;
  color: var(--fg);
  background: var(--bg);
  border: 1px solid var(--border-interactive);
  border-radius: 0.375rem;
  transition: border-color 0.15s ease;
}

.form-field-demo__control:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* Show the invalid state (aria-invalid) with an error-colored border. */
.form-field-demo__control[aria-invalid="true"] {
  border-color: var(--danger-500);
}

.form-field-demo__description {
  margin: 0;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* Note conveying the demo's intent. Shown in a more muted tone than the description. */
.form-field-demo__note {
  margin: 0;
  font-size: 0.8rem;
  line-height: 1.5;
  color: var(--color-text-muted);
  border-left: 2px solid var(--border-strong);
  padding-left: 0.6rem;
}

.form-field-demo__error {
  margin: 0;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--danger-500);
}

.form-field-demo__actions {
  display: flex;
  gap: 0.5rem;
  margin-top: 0.25rem;
}

.form-field-demo__status {
  margin: 0;
  min-height: 1.25rem;
  font-size: 0.85rem;
  color: var(--leaf-500);
}

// Demo script that subscribes to the form-field validate event and updates the status text.
// The error message is read by the shared announcer, so this region shows the valid state
// only and never duplicates that wording.
// Listen on the demo root (the controller element the event is dispatched on / bubbles
// through), not document: a document listener survives Turbo body swaps and stacks up on
// every navigate-away→back, whereas a root-scoped listener is torn down with the body.
const root = document.querySelector('.form-field-demo');
root?.addEventListener('stimeo--form-field:validate', function (event) {
  const status = document.getElementById('ff-status');
  if (!status) return;
  if (event.detail.valid) {
    status.textContent = status.dataset.validText || '';
    status.style.color = '#16a34a';
  } else {
    status.textContent = '';
  }
});