feat: add full-guide language toggle

Document the client-side, dual-rendered locale contract and dispatch a narrow language-change event for guide selector panels.\n\nDo not assemble the full-guide page or change its content collections; task 15d owns that integration.
2026-09-05 17:44:20 +00:00
parent aa2653340a
commit 59bbff0ad9
2 changed files with 108 additions and 0 deletions
@@ -0,0 +1,68 @@
+---
+// LanguageToggle — idle-hydrated, full-guide-only locale control.
+//
+// The guide server-renders both locales. This leaf owns the persisted locale
+// and announces changes so selector islands can rebuild their active panels
+// from collection data without knowing about this control's markup.
+---
+
+<div class="lang-switch" aria-label="Language" data-language-toggle>
+  <button class="active" data-lang="en" aria-pressed="true">EN</button>
+  <span>/</span>
+  <button data-lang="pt" aria-pressed="false">PT</button>
+</div>
+
+<script>
+  type Language = 'en' | 'pt';
+
+  function setup(root: HTMLElement) {
+    const buttons = root.querySelectorAll<HTMLButtonElement>('[data-lang]');
+
+    function renderLanguage(next: Language) {
+      document.documentElement.lang = next === 'pt' ? 'pt-BR' : 'en';
+      buttons.forEach((button) => {
+        const isActive = button.dataset.lang === next;
+        button.classList.toggle('active', isActive);
+        button.setAttribute('aria-pressed', String(isActive));
+      });
+      document.querySelectorAll<HTMLElement>('[data-language-content]').forEach((node) => {
+        node.hidden = node.dataset.languageContent !== next;
+      });
+      window.dispatchEvent(
+        new CustomEvent('ai-for-dummies:languagechange', { detail: { language: next } }),
+      );
+    }
+
+    function selectLanguage(value: string | undefined): Language {
+      return value === 'pt' ? 'pt' : 'en';
+    }
+
+    buttons.forEach((button) => {
+      button.addEventListener('click', () => {
+        const language = selectLanguage(button.dataset.lang);
+        renderLanguage(language);
+        try {
+          localStorage.setItem('ai-for-dummies-language', language);
+        } catch {
+          // Preview environments can disable storage.
+        }
+      });
+    });
+
+    let savedLanguage = 'en';
+    try {
+      savedLanguage = localStorage.getItem('ai-for-dummies-language') || 'en';
+    } catch {
+      // Preview environments can disable storage.
+    }
+    renderLanguage(selectLanguage(savedLanguage));
+  }
+
+  document.querySelectorAll<HTMLElement>('[data-language-toggle]').forEach((root) => {
+    if ('requestIdleCallback' in window) {
+      window.requestIdleCallback(() => setup(root));
+    } else {
+      setTimeout(() => setup(root), 0);
+    }
+  });
+</script>