middleware.ts

import { Ratelimit } from '@upstash/ratelimit'
import { Redis } from '@upstash/redis'
import { NextFetchEvent, NextRequest, NextResponse } from 'next/server'

const ratelimit = new Ratelimit({
  redis: Redis.fromEnv(),
  limiter: Ratelimit.cachedFixedWindow(10, '10s'),
  ephemeralCache: new Map(),
  analytics: true
})

export default async function middleware(
  request: NextRequest,
  event: NextFetchEvent
): Promise<Response | undefined> {
  const ip = request.ip ?? '127.0.0.1'

  const { success, pending, limit, reset, remaining } = await ratelimit.limit(
    `ratelimit_middleware_${ip}`
  )
  event.waitUntil(pending)

  const res = success
    ? NextResponse.next()
    : NextResponse.redirect(new URL('/api/blocked', request.url))

  res.headers.set('X-RateLimit-Limit', limit.toString())
  res.headers.set('X-RateLimit-Remaining', remaining.toString())
  res.headers.set('X-RateLimit-Reset', reset.toString())
  return res
}

export const config = {
  matcher: '/api/generate'
}