middle-ware.ts

import { NextResponse, type NextRequest } from "next/server"
import { i18n } from "@/i18n.config"
import { match as matchLocale } from "@formatjs/intl-localematcher"
import Negotiator from "negotiator"

function getLocale(request: NextRequest): string | undefined {
  const negotiatorHeaders: Record<string, string> = {}
  request.headers.forEach((value, key) => (negotiatorHeaders[key] = value))

  const cookieLocale: any = request.cookies.get("locale")
  // @ts-ignore locales are readonly
  const locales: string[] = i18n.locales
  const languages = new Negotiator({ headers: negotiatorHeaders }).languages()

  const locale = matchLocale(languages, locales, i18n.defaultLocale)

  if (
    matchLocale(cookieLocale?.value, locales, i18n.defaultLocale) ===
    cookieLocale?.value
  ) {
    return cookieLocale?.value
  } else {
    request.cookies.set("locale", locale)
  }
  return locale
}

export function middleware(request: NextRequest) {
  const pathname = request.nextUrl.pathname
  const pathnameIsMissingLocale = i18n.locales.every(
    (locale) => !pathname.startsWith(`/${locale}/`) && pathname !== `/${locale}`
  )

  // Redirect if there is no locale
  if (pathnameIsMissingLocale) {
    const locale = getLocale(request)
    return NextResponse.redirect(
      new URL(
        `/${locale}${pathname.startsWith("/") ? "" : "/"}${pathname}`,
        request.url
      )
    )
  }
}

export const config = {
  // Matcher ignoring `/_next/` and `/api/`
  matcher: ["/((?!api|_next/static|_next/image|favicon.ico).*)"],
}