utilities/backend/src/auth.js

import { jwtVerify } from 'jose'
import { isOnsite } from './ip-check.js'

const APP_SLUG = process.env.APP_SLUG || 'utilities'
const secret = new TextEncoder().encode(process.env.CENTRAL_AUTH_SECRET || '')

export async function requireAuth(request, reply) {
  const token = request.cookies?.hnf_session
  if (!token) return reply.status(401).send({ error: 'Not authenticated' })

  let payload
  try {
    const { payload: p } = await jwtVerify(token, secret)
    payload = p
  } catch {
    return reply.status(401).send({ error: 'Invalid session' })
  }

  if (!payload.apps?.includes(APP_SLUG)) {
    return reply.status(403).send({ error: 'No permission for this app' })
  }

  if (!payload.offsite_allowed) {
    const clientIP = request.headers['x-real-ip'] || request.ip
    if (!(await isOnsite(clientIP))) {
      return reply.status(403).send({ error: 'Access restricted to site network' })
    }
  }

  const prefix = `${APP_SLUG}:`
  let caps
  if (Array.isArray(payload.caps)) {
    caps = payload.caps.filter(c => c.startsWith(prefix)).map(c => c.slice(prefix.length))
  } else {
    // Legacy token — grant all non-settings caps until re-login
    caps = ['readings', 'meters', 'tariffs', 'reports', 'estimates']
  }

  request.user = {
    email: payload.sub,
    name: payload.name,
    is_admin: payload.is_admin ?? false,
    caps,
  }
}

export function hasCap(request, cap) {
  return request.user?.is_admin === true || request.user?.caps?.includes(cap) === true
}

export function requireCap(cap) {
  return async (request, reply) => {
    if (!hasCap(request, cap)) {
      return reply.status(403).send({ error: `Missing capability: ${cap}` })
    }
  }
}