mintel.me/apps/web/app/[locale]/layout.tsx

import type { Metadata, Viewport } from "next";
import type { StaticImageData } from "next/image";
import { Inter, JetBrains_Mono, Newsreader } from "next/font/google";
import { BitBurst } from "@/src/components/bits/BitBurst";
import { BitGlow } from "@/src/components/bits/BitGlow";
import { Footer } from "@/src/components/Footer";
import { Header } from "@/src/components/Header";
import { InteractiveElements } from "@/src/components/InteractiveElements";
import { ContentProvider } from "@/src/components/ContentProvider";
import { BitCurtain } from "@/src/components/bits/BitCurtain";
import shareImageDe from "@/src/assets/share/share-de.png";
import shareImageEn from "@/src/assets/share/share-en.png";
import { contentFor } from "@/src/content";
import { INDEXING, SITE_NAME, SITE_URL } from "@/src/content/site";
import { robotsMeta } from "@/src/domain/indexing";
import {
  DEFAULT_LOCALE,
  LOCALES,
  parseLocale,
  type Locale,
} from "@/src/domain/locale";
import { pathFor } from "@/src/domain/routes";
import "../globals.css";

const inter = Inter({ subsets: ["latin"], variable: "--font-inter" });
// A real monospaced fallback has almost the same letter width. The default
// fallback (a resized Arial) wraps the mono labels differently, so the hero
// jumped when the font arrived.
const jetbrainsMono = JetBrains_Mono({
  subsets: ["latin"],
  variable: "--font-jetbrains-mono",
  display: "swap",
  adjustFontFallback: false,
  fallback: ["ui-monospace", "Menlo", "Consolas", "monospace"],
});
const newsreader = Newsreader({
  subsets: ["latin"],
  variable: "--font-newsreader",
  style: "italic",
  display: "swap",
});

type Props = {
  readonly children: React.ReactNode;
  readonly params: Promise<{ readonly locale: string }>;
};

/** The share image is a screenshot of the hero in that language (see scripts/render-share-image.mjs). */
const SHARE_IMAGE: Readonly<Record<Locale, StaticImageData>> = {
  en: shareImageEn,
  de: shareImageDe,
};

export function generateStaticParams() {
  return LOCALES.map((locale) => ({ locale }));
}

export async function generateMetadata({ params }: Props): Promise<Metadata> {
  const locale = parseLocale((await params).locale) ?? DEFAULT_LOCALE;
  const { site } = contentFor(locale);
  const image = SHARE_IMAGE[locale];
  const images = [
    {
      url: image.src,
      width: image.width,
      height: image.height,
      alt: site.shareImageAlt,
    },
  ];

  return {
    metadataBase: new URL(SITE_URL),
    title: {
      default: site.title,
      template: `%s | ${SITE_NAME}`,
    },
    description: site.description,
    applicationName: SITE_NAME,
    authors: [{ name: SITE_NAME, url: SITE_URL }],
    creator: SITE_NAME,
    robots: robotsMeta(INDEXING),
    icons: {
      icon: "/favicon.svg",
      apple: "/apple-touch-icon.png",
    },
    openGraph: {
      type: "website",
      url: pathFor("home", locale),
      siteName: SITE_NAME,
      locale: site.ogLocale,
      alternateLocale: LOCALES.filter((other) => other !== locale).map(
        (other) => contentFor(other).site.ogLocale,
      ),
      title: site.title,
      description: site.description,
      images,
    },
    twitter: {
      card: "summary_large_image",
      title: site.title,
      description: site.description,
      images,
    },
  };
}

export const viewport: Viewport = {
  themeColor: "#ffffff",
  colorScheme: "light",
  viewportFit: "cover",
};

export default async function RootLayout({ children, params }: Props) {
  // The proxy only lets the two languages through; anything else is a file-like
  // address that ends in the error page of the main language.
  const locale = parseLocale((await params).locale) ?? DEFAULT_LOCALE;

  return (
    <html
      lang={locale}
      className={`${inter.variable} ${newsreader.variable} ${jetbrainsMono.variable}`}
    >
      <body className="min-h-screen bg-white">
        <ContentProvider locale={locale} content={contentFor(locale)}>
          <Header />
          <main>{children}</main>
          <Footer />
          <InteractiveElements />
          <BitCurtain />
        </ContentProvider>
        <BitBurst />
        <BitGlow />
      </body>
    </html>
  );
}