import createMiddleware from 'next-intl/middleware'
import type { NextRequest } from 'next/server'
import { NextResponse } from 'next/server'
import { defaultLocale, locales } from './i18n/config'
import { getSiteUrl } from './lib/seo'

const intlMiddleware = createMiddleware({
  locales: [...locales],
  defaultLocale,
  localePrefix: 'always',
  localeDetection: false,
})

function shouldUseSimplifiedChinese(request: NextRequest) {
  const acceptLanguage = request.headers.get('accept-language') || ''
  const firstLanguage = acceptLanguage
    .split(',')
    .map((part) => part.trim().split(';')[0]?.toLowerCase())
    .find(Boolean)

  return Boolean(
    firstLanguage &&
      (firstLanguage === 'zh-cn' ||
        firstLanguage === 'zh-hans' ||
        firstLanguage === 'zh-sg' ||
        firstLanguage.startsWith('zh-hans-')),
  )
}

export default function middleware(request: NextRequest) {
  const { pathname, search } = request.nextUrl

  if (pathname === '/admin/forgot' || pathname.startsWith('/admin/forgot/')) {
    return new NextResponse(null, { status: 404 })
  }

  const hasLocalePrefix = locales.some(
    (locale) => pathname === `/${locale}` || pathname.startsWith(`/${locale}/`),
  )

  if (!hasLocalePrefix) {
    const locale = shouldUseSimplifiedChinese(request) ? 'zh' : 'en'
    const url = new URL(request.nextUrl.pathname, getSiteUrl())
    url.pathname = `/${locale}${pathname === '/' ? '' : pathname}`
    url.search = search
    return NextResponse.redirect(url)
  }

  return intlMiddleware(request)
}

export const config = {
  matcher: [
    '/admin/forgot/:path*',
    // Skip all internal paths (_next, _vercel, api, admin, payload assets, static files)
    '/((?!api|admin|_next|_vercel|favicon\\.ico|robots\\.txt|sitemap.*|Products|Product|.*\\..*).*)',
  ],
}