Function ChannelRouteScreen

desktop/src/app/routes/ChannelRouteScreen.tsx:96–212

({
  channelId,
  selectedPostId,
  targetMessageId,
  targetReplyId,
  targetThreadRootId,
}: ChannelRouteScreenProps)

}

export function ChannelRouteScreen({
  channelId,
  selectedPostId,
  targetMessageId,
  targetReplyId,
  targetThreadRootId,
}: ChannelRouteScreenProps) {
  const { closeForumPost, goForumPost } = useAppNavigation();
  const channelsQuery = useChannelsQuery();
  const identityQuery = useIdentityQuery();
  const profileQuery = useProfileQuery();
  const channels = channelsQuery.data ?? [];
  const activeChannel =
    channels.find((channel) => channel.id === channelId) ?? null;
  const [targetMessageEvents, setTargetMessageEvents] = React.useState<
    RelayEvent[]
  >(() => {
    const cachedTarget = getCachedSearchHitEvent(targetMessageId);
    return cachedTarget ? [cachedTarget] : [];
  });

  // Reset spliced target events when the channel context changes (channel
  // switch or entering/leaving a forum post). Tied to channel identity rather
  // than the route target so clearing the `messageId` param mid-channel keeps
  // the deep-linked row in view. Seeded with the mount key so the initial
  // cache-seeded events survive first commit; only a genuine channel change
  // clears them. Declared before the fetch effect so a channel switch clears
  // stale events before the new target is fetched.
  const previousResetKeyRef = React.useRef<string>(
    `${channelId}::${selectedPostId ?? ""}`,
  );
  React.useEffect(() => {
    const resetKey = `${channelId}::${selectedPostId ?? ""}`;
    if (previousResetKeyRef.current === resetKey) return;
    previousResetKeyRef.current = resetKey;
    setTargetMessageEvents([]);
  }, [channelId, selectedPostId]);

  React.useEffect(() => {
    let isCancelled = false;

    // Don't wipe already-spliced target events just because the route target
    // cleared (e.g. `onTargetReached` clears the `messageId` URL param once the
    // row is centered). In a channel whose feed doesn't already contain the
    // deep-linked message, the spliced event is the only copy — dropping it on
    // param-clear blanks the timeline. Resetting on channel / forum-post change
    // is handled by the effect below; here we only fetch when there's a target.
    if ((!targetMessageId && !targetThreadRootId) || selectedPostId) {
      return () => {
        isCancelled = true;
      };
    }

    const cachedTarget = getCachedSearchHitEvent(targetMessageId);
    if (cachedTarget) {
      setTargetMessageEvents((currentEvents) =>
        currentEvents.some((event) => event.id === cachedTarget.id)
          ? currentEvents