import type { IngestResult } from './reference-hook.js'

export interface AttentionDelivery {
  domainId: string
  source: string
  instanceId: string
  records: unknown[]
}

type AttentionHandler = (delivery: AttentionDelivery) => IngestResult | Promise<IngestResult>
let handler: AttentionHandler | undefined

/** Product modules opt into the ATTENTIONS lane; core owns only transport routing. */
export function registerAttentionHandler(next: AttentionHandler): void {
  handler = next
}

export async function deliverAttention(delivery: AttentionDelivery): Promise<IngestResult> {
  if (!handler) throw new Error('ATTENTIONS lane has no registered product handler')
  return await handler(delivery)
}