[docs] Add analytics and close banner btn (#4005)

## Description

Adds a dedicated GTM container for banner tracking and introduces a
close option in docs with localStorage persistence. These changes will
be replaced by the upcoming banner system in the future.

Author: p-malecki

packages/docs-gesture-handler/src/components/TopPromoRotator/index.tsx

@@ -1,9 +1,15 @@
 import clsx from 'clsx';
-import React, { type ReactNode, useEffect, useMemo, useState } from 'react';
+import { type ReactNode, useEffect, useMemo, useState } from 'react';
 
 import HandIcon from '../HandIcon';
 import styles from './styles.module.css';
 
+declare global {
+  interface Window {
+    dataLayer?: unknown[];
+  }
+}
+
 type Promo = {
   key: string;
   href: string;
@@ -45,11 +51,44 @@ const PROMOS: readonly Promo[] = [
   },
 ];
 
-export default function TopPromoRotator() {
+// bump when adding promos so users who dismissed banner see the new one
+export const PROMO_VERSION = 1;
+
+type Props = {
+  onClose?: () => void;
+};
+
+export default function TopPromoRotator({ onClose }: Props) {
   const promos = useMemo(() => PROMOS, []);
 
   const [index, setIndex] = useState(0);
 
+  useEffect(() => {
+    if (typeof window === 'undefined' || typeof document === 'undefined') {
+      return;
+    }
+
+    const existingScript = document.querySelector<HTMLScriptElement>(
+      'script[src*="www.googletagmanager.com/gtm.js?id=GTM-WV2G3SQL"]'
+    );
+
+    if (existingScript) return;
+
+    (function (w: Window, d: Document, s: string, l: string, i: string) {
+      w.dataLayer = w.dataLayer || [];
+      w.dataLayer.push({
+        'gtm.start': new Date().getTime(),
+        event: 'gtm.js',
+      });
+      const f = d.getElementsByTagName(s)[0] as HTMLScriptElement;
+      const j = d.createElement(s) as HTMLScriptElement;
+      const dl = l !== 'dataLayer' ? `&l=${l}` : '';
+      j.async = true;
+      j.src = `https://www.googletagmanager.com/gtm.js?id=${i}${dl}`;
+      f.parentNode?.insertBefore(j, f);
+    })(window, document, 'script', 'dataLayer', 'GTM-WV2G3SQL');
+  }, []);
+
   useEffect(() => {
     const id = window.setInterval(() => {
       setIndex(i => (i + 1) % promos.length);
@@ -89,6 +128,15 @@ export default function TopPromoRotator() {
           </a>
         ))}
       </div>
+      {onClose && (
+        <button
+          type="button"
+          className={styles.closeButton}
+          aria-label="Close promotion banner"
+          onClick={onClose}>
+          ×
+        </button>
+      )}
       <span className="sr-only">
         {typeof active.label === 'string' ? active.label : ''}
       </span>

packages/docs-gesture-handler/src/components/TopPromoRotator/styles.module.css

@@ -75,3 +75,17 @@
   text-decoration: underline;
   text-underline-offset: 2px;
 }
+
+.closeButton {
+  position: absolute;
+  right: 8px;
+  top: 50%;
+  transform: translateY(-50%);
+  border: none;
+  background: transparent;
+  color: #001a72;
+  cursor: pointer;
+  padding: 4px;
+  line-height: 1;
+  font-size: 16px;
+}

packages/docs-gesture-handler/src/theme/Navbar/index.js

@@ -1,9 +1,48 @@
 import React from 'react';
 import useBaseUrl from '@docusaurus/useBaseUrl';
+import { useLocation } from '@docusaurus/router';
 import { Navbar } from '@swmansion/t-rex-ui';
-import TopPromoRotator from '@site/src/components/TopPromoRotator';
+import TopPromoRotator, {
+  PROMO_VERSION,
+} from '@site/src/components/TopPromoRotator';
 
 export default function NavbarWrapper(props) {
+  const location = useLocation();
+  const baseUrl = useBaseUrl('/');
+  const isLanding = location.pathname === baseUrl;
+
+  const [showPromo, setShowPromo] = React.useState(true);
+
+  React.useEffect(() => {
+    if (isLanding || typeof globalThis === 'undefined') {
+      return;
+    }
+
+    try {
+      const raw = globalThis.localStorage?.getItem('topPromoState');
+      const state = raw ? JSON.parse(raw) : null;
+      if (state?.v === PROMO_VERSION && state?.hidden) {
+        setShowPromo(false);
+      }
+    } catch (_) {
+      // ignore
+    }
+  }, [isLanding]);
+
+  const handleClosePromo = React.useCallback(() => {
+    setShowPromo(false);
+    if (typeof globalThis !== 'undefined') {
+      try {
+        globalThis.localStorage?.setItem(
+          'topPromoState',
+          JSON.stringify({ v: PROMO_VERSION, hidden: true })
+        );
+      } catch {
+        // ignore
+      }
+    }
+  }, []);
+
   const titleImages = {
     light: useBaseUrl('/img/title.svg'),
     dark: useBaseUrl('/img/title-dark.svg'),
@@ -12,9 +51,14 @@ export default function NavbarWrapper(props) {
   const heroImages = {
     logo: useBaseUrl('/img/logo-hero.svg'),
   };
+
   return (
     <div style={{ display: 'flex', flexDirection: 'column', flexShrink: 0 }}>
-      <TopPromoRotator />
+      {isLanding ? (
+        <TopPromoRotator />
+      ) : (
+        showPromo && <TopPromoRotator onClose={handleClosePromo} />
+      )}
       <Navbar heroImages={heroImages} titleImages={titleImages} {...props} />
     </div>
   );