Bpistle/src/lib/event-metadata.ts

import { BIG_RELAY_URLS } from '@/constants'
import { TRelayList, TRelaySet } from '@/types'
import { Event, kinds } from 'nostr-tools'
import { getReplaceableEventIdentifier } from './event'
import { getAmountFromInvoice, getLightningAddressFromProfile } from './lightning'
import { formatPubkey, pubkeyToNpub } from './pubkey'
import { generateBech32IdFromETag, tagNameEquals } from './tag'
import { isWebsocketUrl, normalizeHttpUrl, normalizeUrl } from './url'
import { isTorBrowser } from './utils'

export function getRelayListFromEvent(event?: Event) {
  if (!event) {
    return { write: BIG_RELAY_URLS, read: BIG_RELAY_URLS, originalRelays: [] }
  }

  const torBrowserDetected = isTorBrowser()
  const relayList = { write: [], read: [], originalRelays: [] } as TRelayList
  event.tags.filter(tagNameEquals('r')).forEach(([, url, type]) => {
    if (!url || !isWebsocketUrl(url)) return

    const normalizedUrl = normalizeUrl(url)
    if (!normalizedUrl) return

    const scope = type === 'read' ? 'read' : type === 'write' ? 'write' : 'both'
    relayList.originalRelays.push({ url: normalizedUrl, scope })

    // Filter out .onion URLs if not using Tor browser
    if (normalizedUrl.endsWith('.onion/') && !torBrowserDetected) return

    if (type === 'write') {
      relayList.write.push(normalizedUrl)
    } else if (type === 'read') {
      relayList.read.push(normalizedUrl)
    } else {
      relayList.write.push(normalizedUrl)
      relayList.read.push(normalizedUrl)
    }
  })

  // If there are too many relays, use the default BIG_RELAY_URLS
  // Because they don't know anything about relays, their settings cannot be trusted
  return {
    write: relayList.write.length && relayList.write.length <= 8 ? relayList.write : BIG_RELAY_URLS,
    read: relayList.read.length && relayList.write.length <= 8 ? relayList.read : BIG_RELAY_URLS,
    originalRelays: relayList.originalRelays
  }
}

export function getProfileFromEvent(event: Event) {
  try {
    const profileObj = JSON.parse(event.content)
    const username =
      profileObj.display_name?.trim() ||
      profileObj.name?.trim() ||
      profileObj.nip05?.split('@')[0]?.trim()
    return {
      pubkey: event.pubkey,
      npub: pubkeyToNpub(event.pubkey) ?? '',
      banner: profileObj.banner,
      avatar: profileObj.picture,
      username: username || formatPubkey(event.pubkey),
      original_username: username,
      nip05: profileObj.nip05,
      about: profileObj.about,
      website: profileObj.website ? normalizeHttpUrl(profileObj.website) : undefined,
      lud06: profileObj.lud06,
      lud16: profileObj.lud16,
      lightningAddress: getLightningAddressFromProfile(profileObj),
      created_at: event.created_at
    }
  } catch (err) {
    console.error(err)
    return {
      pubkey: event.pubkey,
      npub: pubkeyToNpub(event.pubkey) ?? '',
      username: formatPubkey(event.pubkey)
    }
  }
}

export function getRelaySetFromEvent(event: Event): TRelaySet {
  const id = getReplaceableEventIdentifier(event)
  const relayUrls = event.tags
    .filter(tagNameEquals('relay'))
    .map((tag) => tag[1])
    .filter((url) => url && isWebsocketUrl(url))
    .map((url) => normalizeUrl(url))

  let name = event.tags.find(tagNameEquals('title'))?.[1]
  if (!name) {
    name = id
  }

  return { id, name, relayUrls }
}

export function getZapInfoFromEvent(receiptEvent: Event) {
  if (receiptEvent.kind !== kinds.Zap) return null

  let senderPubkey: string | undefined
  let recipientPubkey: string | undefined
  let originalEventId: string | undefined
  let eventId: string | undefined
  let invoice: string | undefined
  let amount: number | undefined
  let comment: string | undefined
  let description: string | undefined
  let preimage: string | undefined
  try {
    receiptEvent.tags.forEach((tag) => {
      const [tagName, tagValue] = tag
      switch (tagName) {
        case 'P':
          senderPubkey = tagValue
          break
        case 'p':
          recipientPubkey = tagValue
          break
        case 'e':
          originalEventId = tag[1]
          eventId = generateBech32IdFromETag(tag)
          break
        case 'bolt11':
          invoice = tagValue
          break
        case 'description':
          description = tagValue
          break
        case 'preimage':
          preimage = tagValue
          break
      }
    })
    if (!recipientPubkey || !invoice) return null
    amount = invoice ? getAmountFromInvoice(invoice) : 0
    if (description) {
      try {
        const zapRequest = JSON.parse(description)
        comment = zapRequest.content
        if (!senderPubkey) {
          senderPubkey = zapRequest.pubkey
        }
      } catch {
        // ignore
      }
    }

    return {
      senderPubkey,
      recipientPubkey,
      eventId,
      originalEventId,
      invoice,
      amount,
      comment,
      preimage
    }
  } catch {
    return null
  }
}

export function getLongFormArticleMetadataFromEvent(event: Event) {
  let title: string | undefined
  let summary: string | undefined
  let image: string | undefined
  const tags = new Set<string>()

  event.tags.forEach(([tagName, tagValue]) => {
    if (tagName === 'title') {
      title = tagValue
    } else if (tagName === 'summary') {
      summary = tagValue
    } else if (tagName === 'image') {
      image = tagValue
    } else if (tagName === 't' && tagValue && tags.size < 6) {
      tags.add(tagValue.toLocaleLowerCase())
    }
  })

  if (!title) {
    title = event.tags.find(tagNameEquals('d'))?.[1] ?? 'no title'
  }

  return { title, summary, image, tags: Array.from(tags) }
}

export function getLiveEventMetadataFromEvent(event: Event) {
  let title: string | undefined
  let summary: string | undefined
  let image: string | undefined
  let status: string | undefined
  const tags = new Set<string>()

  event.tags.forEach(([tagName, tagValue]) => {
    if (tagName === 'title') {
      title = tagValue
    } else if (tagName === 'summary') {
      summary = tagValue
    } else if (tagName === 'image') {
      image = tagValue
    } else if (tagName === 'status') {
      status = tagValue
    } else if (tagName === 't' && tagValue && tags.size < 6) {
      tags.add(tagValue.toLocaleLowerCase())
    }
  })

  if (!title) {
    title = event.tags.find(tagNameEquals('d'))?.[1] ?? 'no title'
  }

  return { title, summary, image, status, tags: Array.from(tags) }
}

export function getGroupMetadataFromEvent(event: Event) {
  let d: string | undefined
  let name: string | undefined
  let about: string | undefined
  let picture: string | undefined
  const tags = new Set<string>()

  event.tags.forEach(([tagName, tagValue]) => {
    if (tagName === 'name') {
      name = tagValue
    } else if (tagName === 'about') {
      about = tagValue
    } else if (tagName === 'picture') {
      picture = tagValue
    } else if (tagName === 't' && tagValue) {
      tags.add(tagValue.toLocaleLowerCase())
    } else if (tagName === 'd') {
      d = tagValue
    }
  })

  if (!name) {
    name = d ?? 'no name'
  }

  return { d, name, about, picture, tags: Array.from(tags) }
}

export function getCommunityDefinitionFromEvent(event: Event) {
  let name: string | undefined
  let description: string | undefined
  let image: string | undefined

  event.tags.forEach(([tagName, tagValue]) => {
    if (tagName === 'name') {
      name = tagValue
    } else if (tagName === 'description') {
      description = tagValue
    } else if (tagName === 'image') {
      image = tagValue
    }
  })

  if (!name) {
    name = event.tags.find(tagNameEquals('d'))?.[1] ?? 'no name'
  }

  return { name, description, image }
}