klz-cables.com/app/[locale]/not-found.tsx

import { getTranslations } from 'next-intl/server';
import { Container, Button, Heading } from '@/components/ui';
import Scribble from '@/components/Scribble';
import { getPayload } from 'payload';
import configPromise from '@payload-config';
import { headers } from 'next/headers';
import ClientNotFoundTracker from '@/components/analytics/ClientNotFoundTracker';

export default async function NotFound() {
  const t = await getTranslations('Error.notFound');

  // Try to determine the requested path
  const headersList = await headers();
  const urlPath = headersList.get('x-invoke-path') || '';

  let suggestedUrl = null;
  let suggestedLang = null;

  // If we have a path, try to see if the last segment (slug) exists in ANY locale
  if (urlPath) {
    const slug = urlPath.split('/').filter(Boolean).pop();
    if (slug) {
      try {
        const payload = await getPayload({ config: configPromise });

        // Check posts
        const postRes = await payload.find({
          collection: 'posts',
          where: { slug: { equals: slug } },
          locale: 'all',
          limit: 1,
        });

        // Check products
        const productRes =
          postRes.docs.length === 0
            ? await payload.find({
                collection: 'products',
                where: { slug: { equals: slug } },
                locale: 'all',
                limit: 1,
              })
            : { docs: [] };

        // Check pages
        const pageRes =
          postRes.docs.length === 0 && productRes.docs.length === 0
            ? await payload.find({
                collection: 'pages',
                where: { slug: { equals: slug } },
                locale: 'all',
                limit: 1,
              })
            : { docs: [] };

        const anyDoc = postRes.docs[0] || productRes.docs[0] || pageRes.docs[0];

        if (anyDoc) {
          // If the doc exists, we can figure out its native locale or
          // offer the alternative locale (if we are in 'de', offer 'en')
          const currentLocale = urlPath.startsWith('/en') ? 'en' : 'de';
          const alternativeLocale = currentLocale === 'de' ? 'en' : 'de';

          suggestedLang = alternativeLocale === 'de' ? 'Deutsch' : 'English';

          // Reconstruct the URL for the alternative locale
          const pathParts = urlPath.split('/').filter(Boolean);
          if (pathParts.length > 0 && (pathParts[0] === 'en' || pathParts[0] === 'de')) {
            pathParts[0] = alternativeLocale;
          } else {
            pathParts.unshift(alternativeLocale);
          }
          suggestedUrl = '/' + pathParts.join('/');
        }
      } catch (e) {
        // Ignore Payload errors in 404
      }
    }
  }

  return (
    <>
      <ClientNotFoundTracker path={urlPath} />
      <Container className="relative py-24 flex flex-col items-center justify-center text-center min-h-[70vh] overflow-hidden">
        {/* Industrial Background Element */}
        <div className="absolute inset-0 -z-10 opacity-[0.03] pointer-events-none flex items-center justify-center">
          <span className="text-[20rem] font-bold select-none">404</span>
        </div>

        <div className="relative mb-8">
          <Heading level={1} className="text-6xl md:text-8xl font-bold mb-2">
            404
          </Heading>
          <Scribble
            variant="circle"
            className="w-[150%] h-[150%] -top-[25%] -left-[25%] text-accent/40"
          />
        </div>

        <Heading level={2} className="text-2xl md:text-3xl font-bold mb-4 text-primary">
          {t('title')}
        </Heading>

        <p className="text-text-secondary mb-10 max-w-md text-lg">{t('description')}</p>

        {suggestedUrl && (
          <div className="mb-12 p-6 bg-accent/10 border border-accent/20 rounded-2xl animate-fade-in shadow-lg relative overflow-hidden group">
            <div className="absolute inset-0 bg-accent/5 -skew-x-12 translate-x-full group-hover:translate-x-0 transition-transform duration-700" />
            <div className="relative z-10">
              <h3 className="text-primary font-bold mb-2 text-lg">
                Did you mean to visit the {suggestedLang} version?
              </h3>
              <p className="text-text-secondary text-sm mb-4">
                This page exists, but in another language.
              </p>
              <Button href={suggestedUrl} variant="accent" size="md" className="w-full sm:w-auto">
                Go to {suggestedLang} Version
              </Button>
            </div>
          </div>
        )}

        <div className="flex flex-col sm:flex-row gap-4">
          <Button href="/" variant={suggestedUrl ? 'outline' : 'accent'} size="lg">
            {t('cta')}
          </Button>
          <Button href="/contact" variant={suggestedUrl ? 'ghost' : 'outline'} size="lg">
            Contact Support
          </Button>
        </div>

        {/* Decorative Industrial Line */}
        <div className="absolute bottom-0 left-1/2 -translate-x-1/2 w-px h-24 bg-gradient-to-t from-accent/50 to-transparent" />
      </Container>
    </>
  );
}