"use client";

import { useRouter } from "next/navigation";
import { useEffect } from "react";

import { parseInvalidationEvent } from "@/lib/events/invalidation";
import { createRefreshScheduler } from "@/lib/events/refresh";

export function LiveRefresh({ endpoint }: { endpoint: string }) {
  const router = useRouter();

  useEffect(() => {
    const scheduler = createRefreshScheduler(() => router.refresh());
    const source = new EventSource(endpoint);
    const connected = () => scheduler.connected();
    const notified = (message: Event) => {
      if (!(message instanceof MessageEvent) || typeof message.data !== "string") {
        return;
      }
      const event = parseInvalidationEvent(message.data);
      if (event) scheduler.notified(event);
    };
    source.addEventListener("open", connected);
    source.addEventListener("invalidation", notified);
    return () => {
      source.removeEventListener("open", connected);
      source.removeEventListener("invalidation", notified);
      source.close();
      scheduler.dispose();
    };
  }, [endpoint, router]);

  return null;
}