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()

  // Protected routes
  const protectedPaths = ['/dashboard', '/compose', '/history']
  const isProtectedPath = protectedPaths.some((path) =>
    req.nextUrl.pathname.startsWith(path)
  )

  if (isProtectedPath && !session) {
    return NextResponse.redirect(new URL('/login', req.url))
  }

  // Redirect authenticated users away from auth pages
  const authPaths = ['/login']
  const isAuthPath = authPaths.some((path) =>
    req.nextUrl.pathname.startsWith(path)
  )

  if (isAuthPath && session) {
    return NextResponse.redirect(new URL('/dashboard', req.url))
  }

  return res
}

export const config = {
  matcher: [
    /*
     * Match all request paths except for the ones starting with:
     * - _next/static (static files)
     * - _next/image (image optimization files)
     * - favicon.ico (favicon file)
     * - api routes (handled separately)
     */
    '/((?!_next/static|_next/image|favicon.ico|api).*)',
  ],
}