middleware.ts

import { createMiddlewareClient } from '@supabase/auth-helpers-nextjs'
import { NextResponse } from 'next/server'
import type { NextRequest } from 'next/server'

export async function middleware(req: NextRequest) {
  const res = NextResponse.next()
  const supabase = createMiddlewareClient({ req, res })

  const {
    data: { session },
  } = await supabase.auth.getSession()

  // Protect routes that require authentication
  const protectedPaths = ['/settings']
  if (!session && protectedPaths.some(path => req.nextUrl.pathname.startsWith(path))) {
    const redirectUrl = req.nextUrl.clone()
    redirectUrl.pathname = '/auth'
    return NextResponse.redirect(redirectUrl)
  }

  // Redirect to settings if already logged in and trying to access auth page
  if (session && req.nextUrl.pathname === '/auth') {
    const redirectUrl = req.nextUrl.clone()
    redirectUrl.pathname = '/settings'
    return NextResponse.redirect(redirectUrl)
  }

  return res
}

export const config = {
  matcher: ['/settings', '/auth'],
}