Function useAwaySummary

src/hooks/useAwaySummary.ts:32–125

(
  messages: readonly Message[],
  setMessages: SetMessages,
  isLoading: boolean,
)

 * Focus state 'unknown' (terminal doesn't support DECSET 1004) is a no-op.
 */
export function useAwaySummary(
  messages: readonly Message[],
  setMessages: SetMessages,
  isLoading: boolean,
): void {
  const timerRef = useRef<ReturnType<typeof setTimeout> | null>(null)
  const abortRef = useRef<AbortController | null>(null)
  const messagesRef = useRef(messages)
  const isLoadingRef = useRef(isLoading)
  const pendingRef = useRef(false)
  const generateRef = useRef<(() => Promise<void>) | null>(null)

  messagesRef.current = messages
  isLoadingRef.current = isLoading

  // 3P default: false
  const gbEnabled = getFeatureValue_CACHED_MAY_BE_STALE(
    'tengu_sedge_lantern',
    false,
  )

  useEffect(() => {
    if (!feature('AWAY_SUMMARY')) return
    if (!gbEnabled) return

    function clearTimer(): void {
      if (timerRef.current !== null) {
        clearTimeout(timerRef.current)
        timerRef.current = null
      }
    }

    function abortInFlight(): void {
      abortRef.current?.abort()
      abortRef.current = null
    }

    async function generate(): Promise<void> {
      pendingRef.current = false
      if (hasSummarySinceLastUserTurn(messagesRef.current)) return
      abortInFlight()
      const controller = new AbortController()
      abortRef.current = controller
      const text = await generateAwaySummary(
        messagesRef.current,
        controller.signal,
      )
      if (controller.signal.aborted || text === null) return
      setMessages(prev => [...prev, createAwaySummaryMessage(text)])
    }

    function onBlurTimerFire(): void {
      timerRef.current = null
      if (isLoadingRef.current) {
        pendingRef.current = true
        return
      }
      void generate()