web/apps/scandic-web/middlewares/redirect.ts

import { type NextMiddleware, NextResponse } from "next/server"

import { getCacheClient } from "@scandic-hotels/common/dataCache"
import { logger } from "@scandic-hotels/common/logger"
import { createCounter } from "@scandic-hotels/common/telemetry"
import { findLang } from "@scandic-hotels/common/utils/languages"

import { notFound } from "@/server/errors/next"
import { getPublicNextURL } from "@/server/utils"

import { getDefaultRequestHeaders } from "./utils"

import type { Lang } from "@scandic-hotels/common/constants/language"

import type { MiddlewareMatcher } from "@/types/middleware"

async function fetchAndCacheRedirect(lang: Lang, pathname: string) {
  const cacheKey = `${lang}:redirect:${pathname}`
  const cache = await getCacheClient()

  return await cache.cacheOrGet(
    cacheKey,
    async () => {
      const matchedRedirect = await fetch(
        "https://redirect-scandic-hotels.netlify.app",
        {
          method: "POST",
          body: JSON.stringify({ lang, pathname }),
          headers: {
            "Content-Type": "application/json",
          },
          signal: AbortSignal.timeout(15_000),
        }
      )

      if (matchedRedirect.ok) {
        const result = await matchedRedirect.text()

        if (result) {
          return result
        }
      }
      return null
    },
    // longer once tested
    "1d"
  )
}

const redirectCounter = createCounter("middleware.redirect")
export const middleware: NextMiddleware = async (request) => {
  const lang = findLang(request.nextUrl.pathname)!
  const headers = getDefaultRequestHeaders(request)
  try {
    const matchedRedirect = await fetchAndCacheRedirect(
      lang,
      request.nextUrl.pathname
    )

    if (matchedRedirect) {
      redirectCounter
        .init({
          lang,
          pathname: request.nextUrl.pathname,
          newPathname: matchedRedirect,
        })
        .success()

      const newUrl = new URL(matchedRedirect, getPublicNextURL(request))
      headers.set("Cache-control", "public, max-age=14400") // 4 hours
      return NextResponse.redirect(newUrl, {
        headers,
        status: 308,
      })
    }
    headers.set("x-continue", "1")
    return NextResponse.next({ headers })
  } catch (e) {
    logger.error("Redirect error: ", e)
    throw notFound()
  }
}

export const matcher: MiddlewareMatcher = (_) => {
  return true
}