export type RealtimeRefreshFilter =
  | { kind: "form"; formId?: string }
  | { kind: "uploads" }
  | { kind: "profile" }
  | { kind: "xp" }
  | { kind: "vc"; channelId?: string };

export type RealtimeRefreshEvent =
  | { kind: "open" }
  | { kind: "form"; formId: string }
  | { kind: "upload" }
  | { kind: "xp" }
  | { kind: "vc"; channelId: string };

export type RealtimeRefreshSubscription = { clean: () => void };

export function matchesRealtimeRefresh(
  filter: RealtimeRefreshFilter,
  event: Exclude<RealtimeRefreshEvent, { kind: "open" }>,
) {
  if (filter.kind === "form") {
    return event.kind === "form" && (!filter.formId || event.formId === filter.formId);
  }
  if (filter.kind === "uploads") return event.kind === "upload";
  if (filter.kind === "xp") return event.kind === "xp";
  if (filter.kind === "profile") return event.kind === "xp" || event.kind === "vc";
  return event.kind === "vc" && (!filter.channelId || event.channelId === filter.channelId);
}

export function startRealtimeRefresh({
  filter,
  debounceMs,
  refresh,
  subscribe,
}: {
  filter: RealtimeRefreshFilter;
  debounceMs: number;
  refresh: () => void;
  subscribe: (emit: (event: RealtimeRefreshEvent) => void) => RealtimeRefreshSubscription;
}) {
  let connectedOnce = false;
  let refreshTimer: ReturnType<typeof setTimeout> | undefined;

  const scheduleRefresh = () => {
    if (refreshTimer) clearTimeout(refreshTimer);
    refreshTimer = setTimeout(refresh, debounceMs);
  };

  const subscription = subscribe((event) => {
    if (event.kind === "open") {
      if (connectedOnce) scheduleRefresh();
      connectedOnce = true;
      return;
    }

    if (matchesRealtimeRefresh(filter, event)) scheduleRefresh();
  });

  return () => {
    if (refreshTimer) clearTimeout(refreshTimer);
    subscription.clean();
  };
}