import type { Event } from 'nostr-tools'
import { extractTagsFromEvent } from '../nostrTagSystem'
import { generateAuthorHashId } from '../hashIdGenerator'
import type { ExtractedAuthor } from './types'
import { getMetadataFromEvent } from './metadataJson'
import { firstString } from './utils'

export async function extractAuthorFromEvent(event: Event): Promise<ExtractedAuthor | null> {
  const tags = extractTagsFromEvent(event)
  if (tags.type !== 'author') {
    return null
  }

  const metadata = getMetadataFromEvent(event)
  if (metadata?.type !== 'author') {
    return null
  }

  const data = buildAuthorDataFromMetadata({ event, tags, metadata })
  const id = await generateAuthorHashId(data)
  return buildExtractedAuthor({ eventId: event.id, id, data, metadata })
}

function buildAuthorDataFromMetadata(params: {
  event: Event
  tags: ReturnType<typeof extractTagsFromEvent>
  metadata: Record<string, unknown>
}): {
  pubkey: string
  authorName: string
  presentation: string
  contentDescription: string
  mainnetAddress?: string
  pictureUrl?: string
  category: string
} {
  const pubkey = firstString(params.metadata.pubkey, params.event.pubkey) ?? params.event.pubkey
  const mainnetAddress = firstString(params.metadata.mainnetAddress)
  const pictureUrl = firstString(params.metadata.pictureUrl)
  return {
    pubkey,
    authorName: firstString(params.metadata.authorName) ?? '',
    presentation: firstString(params.metadata.presentation) ?? '',
    contentDescription: firstString(params.metadata.contentDescription) ?? '',
    ...(mainnetAddress ? { mainnetAddress } : {}),
    ...(pictureUrl ? { pictureUrl } : {}),
    category: firstString(params.metadata.category, params.tags.category, 'sciencefiction') ?? 'sciencefiction',
  }
}

function buildExtractedAuthor(params: {
  eventId: string
  id: string
  data: {
    pubkey: string
    authorName: string
    presentation: string
    contentDescription: string
    mainnetAddress?: string
    pictureUrl?: string
    category: string
  }
  metadata: Record<string, unknown>
}): ExtractedAuthor {
  const url = firstString(params.metadata.url)
  return {
    type: 'author',
    id: params.id,
    pubkey: params.data.pubkey,
    authorName: params.data.authorName,
    presentation: params.data.presentation,
    contentDescription: params.data.contentDescription,
    category: params.data.category,
    eventId: params.eventId,
    ...(params.data.mainnetAddress ? { mainnetAddress: params.data.mainnetAddress } : {}),
    ...(params.data.pictureUrl ? { pictureUrl: params.data.pictureUrl } : {}),
    ...(url ? { url } : {}),
  }
}