story-research-zapwall/lib/nostrEventParsing.ts

import type { Event } from 'nostr-tools'
import type { Article, KindType, MediaRef, Review, Series } from '@/types/nostr'

/**
 * Parse article metadata from Nostr event
 */
export function parseArticleFromEvent(event: Event): Article | null {
  try {
    const tags = extractTags(event)
    if (tags.kindType && tags.kindType !== 'article') {
      return null
    }
    const { previewContent } = getPreviewContent(event.content, tags.preview)
    return buildArticle(event, tags, previewContent)
  } catch (e) {
    console.error('Error parsing article:', e)
    return null
  }
}

export function parseSeriesFromEvent(event: Event): Series | null {
  try {
    const tags = extractTags(event)
    if (tags.kindType && tags.kindType !== 'series') {
      return null
    }
    if (!tags.title || !tags.description) {
      return null
    }
    const series: Series = {
      id: event.id,
      pubkey: event.pubkey,
      title: tags.title,
      description: tags.description,
      preview: tags.preview ?? event.content.substring(0, 200),
      ...(tags.category ? { category: tags.category } : { category: 'science-fiction' }),
      ...(tags.coverUrl ? { coverUrl: tags.coverUrl } : {}),
    }
    if (tags.kindType) {
      series.kindType = tags.kindType
    }
    return series
  } catch (e) {
    console.error('Error parsing series:', e)
    return null
  }
}

export function parseReviewFromEvent(event: Event): Review | null {
  try {
    const tags = extractTags(event)
    if (tags.kindType && tags.kindType !== 'review') {
      return null
    }
    const articleId = tags.articleId
    const reviewer = tags.reviewerPubkey
    if (!articleId || !reviewer) {
      return null
    }
    const rewardedTag = event.tags.find((tag) => tag[0] === 'rewarded' && tag[1] === 'true')
    const rewardAmountTag = event.tags.find((tag) => tag[0] === 'reward_amount')

    const review: Review = {
      id: event.id,
      articleId,
      authorPubkey: tags.author ?? event.pubkey,
      reviewerPubkey: reviewer,
      content: event.content,
      createdAt: event.created_at,
      ...(tags.title ? { title: tags.title } : {}),
      ...(rewardedTag ? { rewarded: true } : {}),
      ...(rewardAmountTag ? { rewardAmount: parseInt(rewardAmountTag[1] ?? '0', 10) } : {}),
    }
    if (tags.kindType) {
      review.kindType = tags.kindType
    }
    return review
  } catch (e) {
    console.error('Error parsing review:', e)
    return null
  }
}

function extractTags(event: Event) {
  const findTag = (key: string) => event.tags.find((tag) => tag[0] === key)?.[1]
  const mediaTags = event.tags.filter((tag) => tag[0] === 'media')
  const media: MediaRef[] =
    mediaTags
      .map((tag) => {
        const url = tag[1]
        const type = tag[2] === 'video' ? 'video' : 'image'
        if (!url) {
          return null
        }
        return { url, type }
      })
      .filter(Boolean) as MediaRef[]

  return {
    title: findTag('title') ?? 'Untitled',
    preview: findTag('preview'),
    description: findTag('description'),
    zapAmount: parseInt(findTag('zap') ?? '800', 10),
    invoice: findTag('invoice'),
    paymentHash: findTag('payment_hash'),
    category: findTag('category') as import('@/types/nostr').ArticleCategory | undefined,
    isPresentation: findTag('presentation') === 'true',
    mainnetAddress: findTag('mainnet_address'),
    totalSponsoring: parseInt(findTag('total_sponsoring') ?? '0', 10),
    authorPresentationId: findTag('author_presentation_id'),
    seriesId: findTag('series'),
    bannerUrl: findTag('banner'),
    coverUrl: findTag('cover'),
    media,
    kindType: findTag('kind_type') as KindType | undefined,
    articleId: findTag('article'),
    reviewerPubkey: findTag('reviewer'),
    author: findTag('author'),
  }
}

function getPreviewContent(content: string, previewTag?: string) {
  const lines = content.split('\n')
  const previewContent = previewTag ?? lines[0] ?? content.substring(0, 200)
  return { previewContent }
}

function buildArticle(event: Event, tags: ReturnType<typeof extractTags>, preview: string): Article {
  return {
    id: event.id,
    pubkey: event.pubkey,
    title: tags.title,
    preview,
    content: '',
    createdAt: event.created_at,
    zapAmount: tags.zapAmount,
    paid: false,
    ...(tags.invoice ? { invoice: tags.invoice } : {}),
    ...(tags.paymentHash ? { paymentHash: tags.paymentHash } : {}),
    ...(tags.category ? { category: tags.category } : {}),
    ...(tags.isPresentation ? { isPresentation: tags.isPresentation } : {}),
    ...(tags.mainnetAddress ? { mainnetAddress: tags.mainnetAddress } : {}),
    ...(tags.totalSponsoring ? { totalSponsoring: tags.totalSponsoring } : {}),
    ...(tags.authorPresentationId ? { authorPresentationId: tags.authorPresentationId } : {}),
    ...(tags.seriesId ? { seriesId: tags.seriesId } : {}),
    ...(tags.bannerUrl ? { bannerUrl: tags.bannerUrl } : {}),
    ...(tags.media.length ? { media: tags.media } : {}),
    ...(tags.kindType ? { kindType: tags.kindType } : {}),
  }
}