Function createTimelineModel

packages/app/src/pages/session/timeline/model.ts:10–95

(input: {
  sessionID: Accessor<string | undefined>
  revertMessageID: Accessor<string | undefined>
})

const sessionFreshness = 15_000

export function createTimelineModel(input: {
  sessionID: Accessor<string | undefined>
  revertMessageID: Accessor<string | undefined>
}) {
  const serverSync = useServerSync()
  const sync = useSync()
  let refreshFrame: number | undefined
  let refreshTimer: number | undefined

  const [resource] = createResource(
    () => input.sessionID(),
    (id) => {
      clearRefresh()
      if (!id) return

      const cached = untrack(() => sync().data.message[id] !== undefined)
      const stale = cached && !serverSync().session.fresh(id, sessionFreshness)

      refreshFrame = requestAnimationFrame(() => {
        refreshFrame = undefined
        refreshTimer = window.setTimeout(() => {
          refreshTimer = undefined
          if (input.sessionID() !== id) return
          untrack(() => {
            if (stale) void sync().session.sync(id, { force: true })
          })
        }, 0)
      })

      return sync().session.sync(id)
    },
  )
  const messages = createMemo(() => {
    const id = input.sessionID()
    return id ? (sync().data.message[id] ?? []) : []
  })
  const ready = createMemo(() => {
    const id = input.sessionID()
    return !id || sync().data.message[id] !== undefined
  })
  const userMessages = createMemo(() => selectUserMessages(messages()), emptyUserMessages, { equals: same })
  const visibleUserMessages = createMemo(
    () => {
      return selectVisibleUserMessages(userMessages(), input.revertMessageID())
    },
    emptyUserMessages,
    { equals: same },
  )
  const more = createMemo(() => {
    const id = input.sessionID()
    return id ? sync().session.history.more(id) : false
  })
  const loading = createMemo(() => {
    const id = input.sessionID()
    return id ? sync().session.history.loading(id) : false
  })
  const loadOlder = async (options?: { before?: () => void; after?: (done: boolean) => void }) => {
    return loadOlderTimeline({