middleware.ts

import NextAuth from 'next-auth'
import authConfig from './auth.config'
import { NextRequest, NextResponse } from 'next/server'

// export const { auth: middleware } = NextAuth(authConfig)
let locales = ['en-US', 'es', 'en']

import { i18n } from './i18n-config'

import { match as matchLocale } from '@formatjs/intl-localematcher'
import Negotiator from 'negotiator'

function getLocale(request: NextRequest): string | undefined {
  // Negotiator expects plain object so we need to transform headers
  const negotiatorHeaders: Record<string, string> = {}
  request.headers.forEach((value, key) => (negotiatorHeaders[key] = value))

  // @ts-ignore locales are readonly
  const locales: string[] = i18n.locales

  // Use negotiator and intl-localematcher to get best locale
  let languages = new Negotiator({ headers: negotiatorHeaders }).languages(
    locales
  )

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

  return locale
}

export function middleware(request: NextRequest) {
  // Check if there is any supported locale in the pathname
  const { pathname } = request.nextUrl
  const pathnameHasLocale = locales.some(
    (locale) => pathname.startsWith(`/${locale}/`) || pathname === `/${locale}`
  )

  if (pathnameHasLocale) return

  // Redirect if there is no locale
  const locale = getLocale(request)
  request.nextUrl.pathname = `/${locale}${pathname}`
  // e.g. incoming request is /products
  // The new URL is now /en-US/products
  return NextResponse.redirect(request.nextUrl)
}

export const config = {
  matcher: ['/((?!api|_next|.*\\..*).*)'],
}