"use client";

import { useEffect } from "react";
import { usePathname } from "next/navigation";
import { LAST_PAGE_KEY, isRecordable } from "@/lib/last-page";

// The recorder rides in the root layout and writes down where you are. What
// reads it back is components/dashboard/ResumeChip.tsx, which offers the URL as
// a link on the dashboard -- / stopped being a doorway when it became a page.
//
// Neither uses useSearchParams(). That hook demands a Suspense boundary, and
// this app has none anywhere on purpose -- putting the first one in the root
// layout to satisfy a nav recorder would be the tail wagging the dog, with a
// real risk of pushing every route out of static rendering. window.location
// read inside an effect is the house pattern (Deck.tsx, MixBench.tsx,
// Waveform.tsx) and gives the query string for free.

/** pathname + query, exactly as the address bar has it. */
function here(): string {
  return window.location.pathname + window.location.search;
}

function remember() {
  // Private mode, a full quota, storage disabled by policy: none of these are
  // worth breaking a page over. Forgetting where you were is the cost.
  try {
    const url = here();
    if (isRecordable(url)) localStorage.setItem(LAST_PAGE_KEY, url);
  } catch {
    /* not remembering is not an error */
  }
}

/**
 * Mounted once, in the root layout. Renders nothing.
 *
 * usePathname() fires on every navigation, which covers moving between pages.
 * It does NOT move when only the query changes -- /browse/find rewriting ?q= as
 * you search stays one pathname -- so `pagehide` records too, which doubles as
 * the honest capture of the URL you were on when you closed the tab.
 */
export function LastPageRecorder() {
  const pathname = usePathname();
  useEffect(() => {
    remember();
    window.addEventListener("pagehide", remember);
    return () => window.removeEventListener("pagehide", remember);
  }, [pathname]);
  return null;
}