"use client";
import { useEffect, useRef, useState } from "react";
import { useRouter } from "next/navigation";
import { authDestination, getAuthSessionVersion, isAuthSessionCurrent, renewAuthSession, type SafeAuthSession } from "./auth-client";

export function SessionMonitor({ session }: { session: SafeAuthSession }) {
  const router = useRouter();
  const [error, setError] = useState("");
  const [busy, setBusy] = useState(false);
  const retry = useRef<() => void>(() => {});
  useEffect(() => {
    let active = true;
    let working = false;
    const version = getAuthSessionVersion();
    let deadline = session.expiresAtMs;
    let timer: ReturnType<typeof setTimeout>;
    function schedule(delay: number) {
      clearTimeout(timer);
      timer = setTimeout(() => { void attempt(); }, Math.max(1000, delay));
    }
    async function attempt() {
      if (!active || working || !isAuthSessionCurrent(version)) return;
      working = true;
      setBusy(true);
      const result = await renewAuthSession(version);
      working = false;
      if (!active) return;
      setBusy(false);
      if (!isAuthSessionCurrent(version) || (!result.ok && result.cancelled)) return;
      if (result.ok && result.session) {
        setError("");
        deadline = result.session.expiresAtMs;
        schedule(deadline - Date.now() - 60_000);
        if (result.session.passwordSetupRequired) router.replace("/set-password");
        router.refresh();
      } else if (!result.ok && (result.status === 401 || result.status === 403)) {
        router.replace("/signin");
        router.refresh();
      } else {
        setError(result.ok ? "Your session could not be renewed. Please sign in again." : result.error);
        schedule(30_000);
      }
    }
    function resume() {
      if (document.visibilityState === "visible" && Date.now() >= deadline - 60_000) void attempt();
    }
    retry.current = () => { void attempt(); };
    schedule(deadline - Date.now() - 60_000);
    window.addEventListener("focus", resume);
    document.addEventListener("visibilitychange", resume);
    return () => {
      active = false;
      clearTimeout(timer);
      window.removeEventListener("focus", resume);
      document.removeEventListener("visibilitychange", resume);
    };
  }, [session.expiresAtMs, router]);
  if (!error) return null;
  return <div role="status" className="mb-4 rounded-lg border border-destructive/30 bg-card p-3 text-sm">
    {error} <button type="button" disabled={busy} onClick={() => retry.current()} className="ml-2 underline disabled:opacity-50">{busy ? "Retrying…" : "Retry"}</button>
  </div>;
}

export function SessionRecovery({ enabled, children }: { enabled: boolean; children: React.ReactNode }) {
  const router = useRouter();
  const [message, setMessage] = useState(enabled ? "Restoring your session…" : "");
  useEffect(() => {
    if (!enabled) return;
    let active = true;
    const version = getAuthSessionVersion();
    void renewAuthSession(version).then((result) => {
      if (!active || !isAuthSessionCurrent(version) || (!result.ok && result.cancelled)) return;
      if (result.ok && result.session) {
        router.replace(authDestination(result.session));
        router.refresh();
      } else {
        setMessage(result.ok ? "Please sign in again." : result.error);
      }
    });
    return () => { active = false; };
  }, [enabled, router]);
  return <div className="w-full max-w-md">{message && <p role="status" className="mb-3 text-sm text-muted-foreground">{message}</p>}{children}</div>;
}