import type { Event } from 'nostr-tools'
import type { Article } from '@/types/nostr'

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

function extractTags(event: Event) {
  const findTag = (key: string) => event.tags.find((tag) => tag[0] === key)?.[1]
  return {
    title: findTag('title') ?? 'Untitled',
    preview: findTag('preview'),
    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'),
  }
}

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,
    invoice: tags.invoice,
    paymentHash: tags.paymentHash,
    category: tags.category,
    isPresentation: tags.isPresentation,
    mainnetAddress: tags.mainnetAddress,
    totalSponsoring: tags.totalSponsoring,
    authorPresentationId: tags.authorPresentationId,
  }
}