/**
 * @file FilesPage.tsx
 * @description `/files` — the file manager (`FileBrowser`) as a page of its
 * own, reached from the sidebar's **Files** entry. The location is kept in the
 * URL (`?home=<me|user>&path=` or `?lane=<id>&path=`), so Back and a shared
 * link land in the same folder. With neither it opens the workspace last
 * shown (`agenthub.workspace.selected`) — reached from a workspace, Files is
 * about THAT workspace — else the user's own HOME (their Linux home under S3),
 * else the first workspace.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

import { useEffect, useState } from "react";
import { useSearchParams } from "react-router-dom";
import { useTranslation } from "react-i18next";
import { api, isHomePlace, type FsPlace } from "../lib/api";
import { FileBrowser } from "../components/lanes/FileExplorer";

function lastWorkspace(): number | null {
  try {
    const v = Number(localStorage.getItem("agenthub.workspace.selected"));
    return Number.isInteger(v) && v > 0 ? v : null;
  } catch {
    return null;
  }
}

type Start = { lane: number } | { home: string };

export function FilesPage() {
  const { t } = useTranslation(["lanes"]);
  const [params, setParams] = useSearchParams();
  const askedLane = Number(params.get("lane"));
  const askedHome = params.get("home");
  // The URL wins on every render: a place picked in the browser (another
  // user's home) lands in the URL, and a frozen start would send the next
  // folder opened there back to the first place.
  const asked: Start | null = askedHome
    ? { home: askedHome }
    : Number.isInteger(askedLane) && askedLane > 0
      ? { lane: askedLane }
      : null;
  const [fallback, setStart] = useState<Start | null>(null);
  const start = asked ?? fallback;
  const [none, setNone] = useState(false);

  useEffect(() => {
    if (start) return;
    void (async () => {
      // The workspace last shown first: Files reached from a workspace opens
      // THAT workspace (from PhuNT → AC_SHOP it opened your own home, empty
      // but for hidden files); the home is the fallback.
      const { lanes } = await api.lanes.list().catch(() => ({ lanes: [] }));
      const last = lastWorkspace();
      const shown = lanes.find((l) => l.id === last);
      if (shown) return setStart({ lane: shown.id });
      const homes = await api.files.homes().catch(() => ({ homes: [] }));
      if (homes.homes.some((h) => h.id === "me")) return setStart({ home: "me" });
      if (lanes[0]) setStart({ lane: lanes[0].id });
      else setNone(true);
    })();
  }, [start]);

  if (none) return <p className="p-8 text-sm text-fg-muted">{t("fx.noWorkspace")}</p>;
  if (!start) return null;
  return (
    // Cancels Layout's page padding, like the Workspace session view.
    <div className="-m-5 flex h-[calc(100vh-1.5rem)] max-md:h-[calc(100vh-4.25rem)] lg:-m-6">
      <FileBrowser
        laneId={"lane" in start ? start.lane : null}
        initialHome={"home" in start ? start.home : null}
        initialPath={params.get("path") ?? ""}
        onNavigate={(place: FsPlace, path) => {
          const next = new URLSearchParams(
            isHomePlace(place)
              ? { home: place.home }
              : { lane: String(typeof place === "number" ? place : place.lane) }
          );
          if (path) next.set("path", path);
          setParams(next, { replace: false });
        }}
      />
    </div>
  );
}