fix(locale): align DE/EN component structures, fix dynamic language switcher slug mapping, and localize referenzen map

components/layout/LanguageSwitcher.test.tsx

@@ -0,0 +1,70 @@
+import * as React from 'react';
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import { LanguageSwitcher } from './LanguageSwitcher';
+import { usePathname } from 'next/navigation';
+
+// Mock next/navigation
+vi.mock('next/navigation', () => ({
+  usePathname: vi.fn(),
+}));
+
+// Mock TransitionLink to render standard anchor tag and forward all props
+vi.mock('@/components/ui/TransitionLink', () => ({
+  TransitionLink: ({ children, href, onClick, ...props }: any) => (
+    <a href={href} onClick={onClick} {...props}>
+      {children}
+    </a>
+  ),
+}));
+
+// Mock HoverShineOverlay
+vi.mock('@/components/ui/HoverShineOverlay', () => ({
+  HoverShineOverlay: () => <div data-testid="hover-shine" />,
+}));
+
+describe('LanguageSwitcher TDD', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it('translates /en/events to /de/messen when switching to German', () => {
+    vi.mocked(usePathname).mockReturnValue('/en/events');
+    render(<LanguageSwitcher />);
+
+    const deLink = screen.getByLabelText('Switch to Deutsch');
+    expect(deLink.getAttribute('href')).toBe('/de/messen');
+  });
+
+  it('translates /de/messen to /en/events when switching to English', () => {
+    vi.mocked(usePathname).mockReturnValue('/de/messen');
+    render(<LanguageSwitcher />);
+
+    const enLink = screen.getByLabelText('Switch to English');
+    expect(enLink.getAttribute('href')).toBe('/en/events');
+  });
+
+  it('translates /en/about-us to /de/ueber-uns when switching to German', () => {
+    vi.mocked(usePathname).mockReturnValue('/en/about-us');
+    render(<LanguageSwitcher />);
+
+    const deLink = screen.getByLabelText('Switch to Deutsch');
+    expect(deLink.getAttribute('href')).toBe('/de/ueber-uns');
+  });
+
+  it('translates /de/ueber-uns to /en/about-us when switching to English', () => {
+    vi.mocked(usePathname).mockReturnValue('/de/ueber-uns');
+    render(<LanguageSwitcher />);
+
+    const enLink = screen.getByLabelText('Switch to English');
+    expect(enLink.getAttribute('href')).toBe('/en/about-us');
+  });
+
+  it('preserves nested paths like blog posts', () => {
+    vi.mocked(usePathname).mockReturnValue('/de/blog/some-post');
+    render(<LanguageSwitcher />);
+
+    const enLink = screen.getByLabelText('Switch to English');
+    expect(enLink.getAttribute('href')).toBe('/en/blog/some-post');
+  });
+});

components/layout/LanguageSwitcher.tsx

@@ -3,6 +3,41 @@
 import { TransitionLink } from '@/components/ui/TransitionLink';
 import { usePathname } from 'next/navigation';
 import { HoverShineOverlay } from '@/components/ui/HoverShineOverlay';
+import enMessages from '@/messages/en.json';
+import deMessages from '@/messages/de.json';
+
+const getMessages = (locale: string) => {
+  return locale === 'de' ? deMessages : enMessages;
+};
+
+// Synchronous version of mapSlugToFileSlug
+function syncMapSlugToFileSlug(translatedSlug: string, locale: string): string {
+  const messages = getMessages(locale);
+  const slugs = messages.Slugs;
+
+  if (slugs.pages && translatedSlug in slugs.pages) {
+    return slugs.pages[translatedSlug as keyof typeof slugs.pages];
+  }
+  return translatedSlug;
+}
+
+// Synchronous version of mapFileSlugToTranslated
+function syncMapFileSlugToTranslated(fileSlug: string, locale: string): string {
+  const messages = getMessages(locale);
+  const slugs = messages.Slugs;
+
+  const sections = [slugs.pages];
+  for (const sectionData of sections) {
+    if (sectionData && typeof sectionData === 'object') {
+      for (const [translatedSlug, mappedSlug] of Object.entries(sectionData)) {
+        if (mappedSlug === fileSlug) {
+          return translatedSlug;
+        }
+      }
+    }
+  }
+  return fileSlug;
+}
 
 interface LanguageSwitcherProps {
   mobile?: boolean;
@@ -14,8 +49,23 @@ export function LanguageSwitcher({ mobile = false, isSolidMode = false }: Langua
   const currentLocale = pathname.startsWith('/en') ? 'en' : 'de';
 
   const getSwitchedUrl = (newLocale: string) => {
-    const pathWithoutLocale = pathname.replace(/^\/(en|de)/, '');
-    return `/${newLocale}${pathWithoutLocale === '' ? '' : pathWithoutLocale}`;
+    const segments = pathname.split('/').filter(Boolean);
+    if (segments.length === 0) {
+      return `/${newLocale}`;
+    }
+
+    const currentLoc = segments[0] === 'en' || segments[0] === 'de' ? segments[0] : 'de';
+    const hasLocale = segments[0] === 'en' || segments[0] === 'de';
+    const pathSegments = hasLocale ? segments.slice(1) : segments;
+
+    if (pathSegments.length === 1) {
+      const slug = pathSegments[0];
+      const fileSlug = syncMapSlugToFileSlug(slug, currentLoc);
+      const translatedSlug = syncMapFileSlugToTranslated(fileSlug, newLocale);
+      return `/${newLocale}/${translatedSlug}`;
+    }
+
+    return `/${newLocale}/${pathSegments.join('/')}`;
   };
 
   const locales = [