import { EventKind, RequestBuilder, type TaggedNostrEvent, type UsersRelays, parseRelaysFromKind } from ".."
import { unixNowMs } from "@snort/shared"
import { RelayListCacheExpire } from "../const"
import { BackgroundLoader } from "../background-loader"

export class RelayMetadataLoader extends BackgroundLoader<UsersRelays> {
  override name(): string {
    return "RelayMetadataLoader"
  }

  override onEvent(e: Readonly<TaggedNostrEvent>): UsersRelays | undefined {
    try {
      const relays = parseRelaysFromKind(e)
      if (!relays) return
      return {
        relays: relays,
        pubkey: e.pubkey,
        created: e.created_at,
        loaded: unixNowMs(),
      }
    } catch (e) {
      // ignored
    }
  }

  override getExpireCutoff(): number {
    return unixNowMs() - RelayListCacheExpire
  }

  protected override buildSub(missing: string[]): RequestBuilder {
    const rb = new RequestBuilder("relay-loader")
    rb.withOptions({
      outboxPickN: 4,
    })
    rb.withFilter().authors(missing).kinds([EventKind.Relays, EventKind.ContactList])
    return rb
  }
}