fixed language switching in the frontend

resources/js/lib/__tests__/localizedPath.test.ts

@@ -0,0 +1,29 @@
+import { describe, expect, it } from 'vitest';
+import { buildLocalizedPath, defaultLocaleRewrites } from '../localizedPath';
+
+describe('buildLocalizedPath', () => {
+  const supported = ['de', 'en'];
+
+  it('prefixes path with locale', () => {
+    expect(buildLocalizedPath('/packages', 'en', supported)).toBe('/en/packages');
+    expect(buildLocalizedPath('/packages', 'de', supported)).toBe('/de/packages');
+  });
+
+  it('applies rewrite rules between locales', () => {
+    expect(buildLocalizedPath('/kontakt', 'en', supported, 'de', defaultLocaleRewrites)).toBe('/en/contact');
+    expect(buildLocalizedPath('/contact', 'de', supported, 'de', defaultLocaleRewrites)).toBe('/de/kontakt');
+  });
+
+  it('preserves query strings', () => {
+    expect(buildLocalizedPath('/contact?ref=ad', 'de', supported)).toBe('/de/kontakt?ref=ad');
+  });
+
+  it('falls back to default locale when target not supported', () => {
+    expect(buildLocalizedPath('/demo', 'fr', supported)).toBe('/de/demo');
+  });
+
+  it('handles empty or invalid paths gracefully', () => {
+    expect(buildLocalizedPath('', 'en', supported)).toBe('/de');
+    expect(buildLocalizedPath(undefined, 'en', supported)).toBe('/de');
+  });
+});

resources/js/lib/localizedPath.ts

@@ -0,0 +1,57 @@
+export type LocaleRewriteMap = Record<string, Record<string, string>>;
+
+export const defaultLocaleRewrites: LocaleRewriteMap = {
+  '/': {},
+  '/kontakt': { en: '/contact' },
+  '/contact': { de: '/kontakt' },
+  '/so-funktionierts': { en: '/how-it-works' },
+  '/how-it-works': { de: '/so-funktionierts' },
+  '/anlaesse': { en: '/occasions' },
+  '/anlaesse/hochzeit': { en: '/occasions/wedding' },
+  '/anlaesse/geburtstag': { en: '/occasions/birthday' },
+  '/anlaesse/firmenevent': { en: '/occasions/corporate-event' },
+  '/anlaesse/konfirmation': { en: '/occasions/confirmation' },
+  '/occasions/wedding': { de: '/anlaesse/hochzeit' },
+  '/occasions/birthday': { de: '/anlaesse/geburtstag' },
+  '/occasions/corporate-event': { de: '/anlaesse/firmenevent' },
+  '/occasions/confirmation': { de: '/anlaesse/konfirmation' },
+};
+
+const sanitizePath = (input: string): string => {
+  if (!input || input.trim().length === 0) {
+    return '/';
+  }
+
+  const withLeading = input.startsWith('/') ? input : `/${input}`;
+  const withoutTrailing = withLeading.replace(/\/{2,}/g, '/');
+
+  return withoutTrailing;
+};
+
+export const buildLocalizedPath = (
+  path: string | null | undefined,
+  targetLocale: string | undefined,
+  supportedLocales: string[],
+  defaultLocale = 'de',
+  rewrites: LocaleRewriteMap = defaultLocaleRewrites,
+): string => {
+  const fallbackLocale = supportedLocales.length > 0 ? supportedLocales[0] : defaultLocale;
+  const nextLocale = targetLocale && supportedLocales.includes(targetLocale)
+    ? targetLocale
+    : fallbackLocale;
+
+  if (typeof path !== 'string' || path.trim().length === 0) {
+    return `/${fallbackLocale}`;
+  }
+
+  const trimmed = path.trim();
+  const [rawPath, rawQuery] = trimmed.split('?');
+  const normalizedPath = sanitizePath(rawPath);
+  const rewritesForPath = rewrites[normalizedPath] ?? {};
+  const rewrittenPath = rewritesForPath[nextLocale] ?? normalizedPath;
+  const base = rewrittenPath === '/' ? `/${nextLocale}` : `/${nextLocale}${rewrittenPath}`;
+  const sanitisedBase = base.replace(/\/{2,}/g, '/');
+  const query = rawQuery ? `?${rawQuery}` : '';
+
+  return `${sanitisedBase}${query}`;
+};