story-research-zapwall/lib/contentDeliveryVerification.ts

import { nostrService } from './nostr'
import type { SimplePoolWithSub } from '@/types/nostr-tools-extended'

const RELAY_URL = process.env.NEXT_PUBLIC_NOSTR_RELAY_URL ?? 'wss://relay.damus.io'

export interface ContentDeliveryStatus {
  messageEventId: string | null
  published: boolean
  verifiedOnRelay: boolean
  retrievable: boolean
  error?: string
}

/**
 * Verify that private content was successfully delivered to recipient
 * Checks multiple aspects to ensure delivery certainty
 */
export async function verifyContentDelivery(
  articleId: string,
  authorPubkey: string,
  recipientPubkey: string,
  messageEventId: string
): Promise<ContentDeliveryStatus> {
  const status: ContentDeliveryStatus = {
    messageEventId,
    published: false,
    verifiedOnRelay: false,
    retrievable: false,
  }

  try {
    const pool = nostrService.getPool()
    if (!pool) {
      status.error = 'Pool not initialized'
      return status
    }

    const poolWithSub = pool as SimplePoolWithSub

    const filters: Array<{
      kinds: number[]
      ids?: string[]
      authors: string[]
      '#p': string[]
      '#e': string[]
      limit: number
    }> = [
      {
        kinds: [4],
        authors: [authorPubkey],
        '#p': [recipientPubkey],
        '#e': [articleId],
        limit: 1,
      },
    ]

    if (messageEventId && filters[0]) {
      filters[0].ids = [messageEventId]
    }

    return new Promise((resolve) => {
      let resolved = false
      const sub = poolWithSub.sub([RELAY_URL], filters)

      const finalize = (result: ContentDeliveryStatus) => {
        if (resolved) {
          return
        }
        resolved = true
        sub.unsub()
        resolve(result)
      }

      sub.on('event', (event) => {
        status.published = true
        status.verifiedOnRelay = true
        status.messageEventId = event.id
        status.retrievable = true
        finalize(status)
      })

      sub.on('eose', () => {
        if (!status.published) {
          status.error = 'Message not found on relay'
        }
        finalize(status)
      })

      setTimeout(() => {
        if (!resolved) {
          if (!status.published) {
            status.error = 'Timeout waiting for message verification'
          }
          finalize(status)
        }
      }, 5000)
    })
  } catch (error) {
    status.error = error instanceof Error ? error.message : 'Unknown error'
    return status
  }
}

/**
 * Check if recipient can retrieve the private message
 * This verifies that the message is accessible with the recipient's key
 */
export async function verifyRecipientCanRetrieve(
  articleId: string,
  authorPubkey: string,
  recipientPubkey: string,
  messageEventId: string
): Promise<boolean> {
  try {
    const status = await verifyContentDelivery(articleId, authorPubkey, recipientPubkey, messageEventId)
    return status.retrievable && status.verifiedOnRelay
  } catch (error) {
    console.error('Error verifying recipient can retrieve', {
      articleId,
      recipientPubkey,
      messageEventId,
      error: error instanceof Error ? error.message : 'Unknown error',
    })
    return false
  }
}