Form Validation

<%# Markup for the form-validation demo.
    stimeo--form-validation orchestrates WHEN native constraint validation runs
    (submit / blur / change / input) and routes each control's validationMessage
    into its stimeo--form-field error region — the ARIA wiring stays in form-field.
    Rules are plain markup attributes (required, type="email"); message text comes
    from the browser. The plan listbox joins through a validatable mirror:
    <input type="text" hidden required> — the hidden ATTRIBUTE, not type="hidden",
    which is barred from constraint validation. The authored novalidate keeps the
    no-JS fallback graceful (the controller preserves it). Valid submissions are
    kept on the page by demo.js so the catalog can show a success status. %>
<form class="form-validation-demo" action="#" method="get" novalidate
      data-controller="stimeo--form-validation"
      data-stimeo--form-validation-stimeo--form-field-outlet=".form-validation-demo__field">

  <div class="form-validation-demo__field" data-controller="stimeo--form-field">
    <label class="form-validation-demo__label" for="fv-email">
      <%= t("components.form_validation.demo.email_label") %>
    </label>
    <input class="form-validation-demo__control" id="fv-email" name="email" type="email"
           required placeholder="<%= t('components.form_validation.demo.email_placeholder') %>"
           data-stimeo--form-field-target="control" />
    <p class="form-validation-demo__error" role="alert" hidden
       data-stimeo--form-field-target="error"></p>
  </div>

  <%# The listbox keeps its committed value in the mirror below. The form-field
      control is the visible trigger, so aria-invalid and invalid focus land there. %>
  <div class="form-validation-demo__field listbox"
       data-controller="stimeo--form-field stimeo--listbox">
    <span id="fv-plan-label" class="form-validation-demo__label">
      <%= t("components.form_validation.demo.plan_label") %>
    </span>
    <button
      type="button"
      class="listbox__trigger"
      role="combobox"
      aria-haspopup="listbox"
      aria-expanded="false"
      aria-controls="fv-plan-options"
      aria-labelledby="fv-plan-label fv-plan-value"
      data-stimeo--listbox-target="trigger"
      data-stimeo--form-field-target="control"
      data-action="click->stimeo--listbox#toggle keydown->stimeo--listbox#onTriggerKeydown">
      <span id="fv-plan-value" data-stimeo--listbox-target="value">
        <%= t("components.form_validation.demo.plan_placeholder") %>
      </span>
      <span class="listbox__chevron" aria-hidden="true">▾</span>
    </button>
    <ul id="fv-plan-options" class="listbox__list" role="listbox"
        aria-labelledby="fv-plan-label" hidden data-stimeo--listbox-target="list">
      <% %w[free pro team].each_with_index do |plan, index| %>
        <li id="fv-plan-opt-<%= index %>" class="listbox__option" role="option"
            aria-selected="false" data-value="<%= plan %>"
            data-stimeo--listbox-target="option"
            data-action="click->stimeo--listbox#select">
          <%= t("components.form_validation.demo.plans.#{plan}") %>
        </li>
      <% end %>
    </ul>
    <%# Validatable mirror: the hidden attribute participates in constraint
        validation and submits with the form — type="hidden" would do neither. %>
    <input type="text" hidden required name="plan" data-stimeo--listbox-target="field" />
    <p class="form-validation-demo__error" role="alert" hidden
       data-stimeo--form-field-target="error"></p>
  </div>

  <p class="form-validation-demo__note"><%= t("components.form_validation.demo.note") %></p>

  <button type="submit" class="demo-trigger">
    <%= t("components.form_validation.demo.submit") %>
  </button>

  <%# Status line updated by demo.js; templates ride data-* so the copy stays bilingual. %>
  <p class="form-validation-demo__status" id="fv-status" aria-live="polite"
     data-valid-text="<%= t('components.form_validation.demo.valid_status') %>"
     data-invalid-template="<%= t('components.form_validation.demo.invalid_template') %>"></p>
</form>

/*
 * Presentation-only styles for the form-validation demo.
 * The invalid state is expressed by the library through aria-invalid on each
 * field's control (the email input / the listbox trigger) and the form-field
 * error region; this CSS only reacts to those hooks.
 */

.form-validation-demo {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  max-width: 22rem;
}

.form-validation-demo__field {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

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

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

/* The library's invalid hook — covers the email input and the listbox trigger. */
.form-validation-demo [aria-invalid="true"] {
  border-color: var(--danger-500);
}

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

/* Note conveying the demo's intent. Shown in a muted tone. */
.form-validation-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-validation-demo .demo-trigger {
  align-self: flex-start;
}

/* Outcome status line; data-state is set by demo.js from the dispatched events. */
.form-validation-demo__status {
  margin: 0;
  min-height: 1.25rem;
  font-size: 0.85rem;
}

.form-validation-demo__status[data-state="valid"] {
  color: var(--leaf-500);
}

.form-validation-demo__status[data-state="invalid"] {
  color: var(--danger-500);
}

/* Listbox presentation (mirrors the listbox demo, scoped to this page). */
.listbox {
  position: relative;
}

.listbox__trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--border-strong);
  border-radius: 0.375rem;
  background: var(--surface, var(--surface-card));
  color: var(--fg, var(--color-text));
  font: inherit;
  cursor: pointer;
}

.listbox__trigger[aria-expanded="true"] {
  border-color: var(--accent, var(--color-primary));
}

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

.listbox__chevron {
  color: var(--color-text-muted);
}

.listbox__list {
  position: absolute;
  top: calc(100% + 0.25rem);
  left: 0;
  right: 0;
  z-index: 10;
  margin: 0;
  padding: 0.25rem;
  list-style: none;
  background: var(--surface, var(--surface-card));
  border: 1px solid var(--border-strong);
  border-radius: 0.375rem;
  box-shadow: 0 8px 24px rgb(15 23 42 / 0.12);
}

.listbox__option {
  padding: 0.45rem 0.6rem;
  border-radius: 0.25rem;
  cursor: pointer;
}

.listbox__option[data-active] {
  background: var(--color-primary-soft);
}

.listbox__option[aria-selected="true"] {
  font-weight: 600;
  color: var(--accent, var(--color-primary));
}

// Form-validation demo (consumer-side JS).
//
// The controller owns the validation behavior; this script only (1) keeps the
// catalog page in place by cancelling the real — i.e. valid — submission
// (invalid submissions never reach this listener: the controller cancels them
// in the capture phase) and (2) renders a status line for the outcome. Status
// text rides data-* attributes so the catalog stays bilingual; JS injects
// values only (the {count} token).
const form = document.querySelector(".form-validation-demo");
const status = document.getElementById("fv-status");

if (form) {
  form.addEventListener("submit", (event) => {
    // Target-phase listener: runs before Turbo's document-level handler.
    event.preventDefault();
    if (!status) return;
    status.dataset.state = "valid";
    status.textContent = status.dataset.validText || "";
  });

  form.addEventListener("stimeo--form-validation:invalid", (event) => {
    if (!status) return;
    const template = status.dataset.invalidTemplate || "{count}";
    status.dataset.state = "invalid";
    status.textContent = template.replace("{count}", String(event.detail.invalid.length));
  });
}