flotilla/src/app/featured.ts

import {derived} from "svelte/store"
import {APP_DATA, relay, sortEventsDesc, tagSpec, tagValues} from "@welshman/util"
import {AppData} from "@welshman/domain"
import {Relays, publish} from "@welshman/app"
import {command, fromApp, relays, writer} from "@app/core"
import {deriveEventsForUrl} from "@app/repository"

// NIP-78 app data published by the space's owner, the pubkey its NIP-11 document names. Each
// featured entry is a ["content", <value>] tag (freeform text, intended to be a url or nevent).
export const FEATURED_CONTENT_D = "flotilla/featured-content"

export const deriveFeaturedContent = (url: string) =>
  derived(
    [
      fromApp($app => $app.use(Relays).one(url)),
      deriveEventsForUrl(url, [{kinds: [APP_DATA], "#d": [FEATURED_CONTENT_D]}]),
    ],
    ([$relay, $events]) => {
      const [event] = sortEventsDesc($events.filter(e => e.pubkey === $relay?.pubkey))

      return tagValues(tagSpec("content"), event?.tags ?? [])
    },
  )

export const setFeaturedContent = async (url: string, content: string[]) => {
  const tags = content
    .map(value => value.trim())
    .filter(Boolean)
    .map(value => ["content", value])

  const eventWriter = writer(AppData)
    .setIdentifier(FEATURED_CONTENT_D)
    .setProtected(await relays.get().hasNip(url, 70))
    .forceRoutes(relay(url))
    .addTags(...tags)

  return command(eventWriter).then(publish)
}