accounted/app/(auth)/auth/callback/route.ts

import { createServerClient } from '@supabase/ssr'
import { type NextRequest, NextResponse } from 'next/server'
import { hashInviteToken } from '@/lib/auth/invite-tokens'

export async function GET(request: NextRequest) {
  const { searchParams, origin } = new URL(request.url)
  const code = searchParams.get('code')
  const token_hash = searchParams.get('token_hash')
  const type = searchParams.get('type')
  const next = searchParams.get('next') ?? '/'

  // Collect cookies that Supabase sets during auth so we can
  // explicitly forward them on the redirect response.
  const pendingCookies: { name: string; value: string; options: Record<string, unknown> }[] = []

  const supabase = createServerClient(
    process.env.NEXT_PUBLIC_SUPABASE_URL!,
    process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!,
    {
      cookies: {
        getAll() {
          return request.cookies.getAll()
        },
        setAll(cookiesToSet) {
          pendingCookies.length = 0
          cookiesToSet.forEach((cookie) => {
            // Mirror the cookie into request.cookies so subsequent getAll()
            // calls within this request lifecycle return the updated values
            // (matches the pattern used in middleware.ts).
            request.cookies.set(cookie.name, cookie.value)
            pendingCookies.push(cookie)
          })
        },
      },
    }
  )

  let authenticated = false

  // Handle PKCE flow (code exchange)
  if (code) {
    const { error } = await supabase.auth.exchangeCodeForSession(code)
    authenticated = !error
  }
  // Handle token hash flow (email verification / magic link)
  else if (token_hash && type) {
    const { error } = await supabase.auth.verifyOtp({
      token_hash,
      type: type as 'signup' | 'invite' | 'magiclink' | 'recovery' | 'email_change' | 'email',
    })
    authenticated = !error
  }

  if (authenticated) {
    let redirectPath = next

    const { data: { user } } = await supabase.auth.getUser()
    if (user) {
      // Check MFA status — redirect to verify if factor is enrolled but session is AAL1
      const { data: aal } = await supabase.auth.mfa.getAuthenticatorAssuranceLevel()
      if (aal?.nextLevel === 'aal2' && aal?.currentLevel === 'aal1') {
        const response = NextResponse.redirect(new URL('/mfa/verify', origin))
        for (const { name, value, options } of pendingCookies) {
          response.cookies.set({ name, value, ...options })
        }
        return response
      }

      // Check for pending invite token (set by invite page before redirecting to register)
      const inviteToken = request.cookies.get('gnubok-invite-token')?.value
      if (inviteToken) {
        try {
          const tokenHash = hashInviteToken(inviteToken)

          // Use the service role client to bypass RLS for invite acceptance
          const serviceClient = createServerClient(
            process.env.NEXT_PUBLIC_SUPABASE_URL!,
            process.env.SUPABASE_SERVICE_ROLE_KEY!,
            { cookies: { getAll: () => [], setAll: () => {} } }
          )

          // Look up company invitation
          const { data: invite } = await serviceClient
            .from('company_invitations')
            .select('id, company_id, email, role, status, expires_at')
            .eq('token_hash', tokenHash)
            .single()

          if (
            invite &&
            invite.status === 'pending' &&
            new Date(invite.expires_at) > new Date() &&
            user.email?.toLowerCase() === invite.email.toLowerCase()
          ) {
            // Add user to company
            await serviceClient.from('company_members').insert({
              company_id: invite.company_id,
              user_id: user.id,
              role: invite.role,
              source: 'direct',
            })

            // Set active company
            await serviceClient.from('user_preferences').upsert({
              user_id: user.id,
              active_company_id: invite.company_id,
            }, { onConflict: 'user_id' })

            // Mark invite as accepted
            await serviceClient
              .from('company_invitations')
              .update({ status: 'accepted' })
              .eq('id', invite.id)

            // Invited user goes straight to dashboard — no onboarding needed
            redirectPath = '/'

            // Clear invite cookie and set company cookie on response
            const response = NextResponse.redirect(new URL(redirectPath, origin))
            for (const { name, value, options } of pendingCookies) {
              response.cookies.set({ name, value, ...options })
            }
            response.cookies.set('gnubok-company-id', invite.company_id, {
              path: '/',
              httpOnly: true,
              secure: process.env.NODE_ENV === 'production',
              sameSite: 'lax',
              maxAge: 60 * 60 * 24 * 365,
            })
            response.cookies.delete('gnubok-invite-token')
            return response
          }
        } catch (err) {
          console.error('[auth/callback] invite acceptance failed:', err)
          // Fall through to normal onboarding check
        }
      }

      // Check if user has completed onboarding (for any company they belong to)
      const { data: membership } = await supabase
        .from('company_members')
        .select('company_id')
        .eq('user_id', user.id)
        .limit(1)
        .single()

      if (membership?.company_id) {
        const { data: settings } = await supabase
          .from('company_settings')
          .select('onboarding_complete')
          .eq('company_id', membership.company_id)
          .single()

        if (!settings?.onboarding_complete) {
          redirectPath = '/onboarding'
        }
      } else {
        redirectPath = '/onboarding'
      }
    }

    // Create redirect and explicitly set auth cookies on the response
    const response = NextResponse.redirect(new URL(redirectPath, origin))
    for (const { name, value, options } of pendingCookies) {
      response.cookies.set({ name, value, ...options })
    }
    // Keep the invite cookie alive so the onboarding page fallback can
    // retry acceptance (only clear it when successfully processed above).
    return response
  }

  // Authentication failed — redirect to login with error
  return NextResponse.redirect(new URL('/login?error=auth_error', origin))
}