* move setLang() to a root layout

* fix: findLang only returns acceptable languages
* fix: fallback to use header x-lang if we haven't setLang yet
* fix: languageSchema, allow uppercase

Approved-by: Linus Flood

utils/languages.ts

@@ -1,7 +1,21 @@
+import { z } from "zod"
+
 import { Lang } from "@/constants/languages"
 
 export function findLang(pathname: string) {
-  return Object.values(Lang).find(
+  const langFromPath = Object.values(Lang).find(
     (l) => pathname.startsWith(`/${l}/`) || pathname === `/${l}`
   )
+
+  const parsedLang = languageSchema.safeParse(langFromPath)
+  if (!parsedLang.success) {
+    return undefined
+  }
+
+  return parsedLang.data
 }
+
+export const languageSchema = z.preprocess(
+  (arg) => (typeof arg === "string" ? arg.toLowerCase() : arg),
+  z.nativeEnum(Lang)
+)