middleware.ts

import { createServerClient } from '@supabase/ssr'
import { NextResponse, type NextRequest } from 'next/server'

export async function middleware(request: NextRequest) {
  // Handle WWW to non-WWW redirect (canonicalization)
  const hostname = request.headers.get('host') || ''
  if (hostname.startsWith('www.')) {
    const url = request.nextUrl.clone()
    url.host = hostname.replace('www.', '')
    return NextResponse.redirect(url, 301)
  }

  let supabaseResponse = NextResponse.next({
    request,
  })

  const supabase = createServerClient(
    process.env.NEXT_PUBLIC_SUPABASE_URL!,
    process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!,
    {
      cookies: {
        getAll() {
          return request.cookies.getAll()
        },
        setAll(cookiesToSet) {
          cookiesToSet.forEach(({ name, value }) => {
            request.cookies.set(name, value)
          })
          supabaseResponse = NextResponse.next({
            request,
          })
          cookiesToSet.forEach(({ name, value, options }) => {
            supabaseResponse.cookies.set(name, value, options)
          })
        },
      },
    }
  )

  // Refresh session if expired - required for Server Components
  const { data: { user } } = await supabase.auth.getUser()

  // Protect dashboard routes
  if (request.nextUrl.pathname.startsWith('/dashboard') && !user) {
    const url = request.nextUrl.clone()
    url.pathname = '/auth/login'
    return NextResponse.redirect(url)
  }

  // Redirect authenticated users away from auth pages
  if (
    (request.nextUrl.pathname.startsWith('/auth/login') ||
     request.nextUrl.pathname.startsWith('/auth/signup')) &&
    user
  ) {
    const url = request.nextUrl.clone()
    url.pathname = '/dashboard'
    return NextResponse.redirect(url)
  }

  return supabaseResponse
}

export const config = {
  matcher: [
    '/((?!_next/static|_next/image|favicon.ico|.*\\.(?:svg|png|jpg|jpeg|gif|webp)$).*)',
  ]
}