"use client";

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

const INACTIVITY_TIMEOUT_MS = 2 * 60 * 60 * 1000;
const WARNING_BEFORE_LOGOUT_MS = 15 * 60 * 1000;

export function SessionTimeoutProvider({ children }: { children: React.ReactNode }) {
  const router = useRouter();
  const timeoutRef = useRef<NodeJS.Timeout | null>(null);
  const warningTimeoutRef = useRef<NodeJS.Timeout | null>(null);
  const warningShownRef = useRef<boolean>(false);

  function resetTimeout() {
    if (timeoutRef.current) clearTimeout(timeoutRef.current);
    if (warningTimeoutRef.current) clearTimeout(warningTimeoutRef.current);

    warningShownRef.current = false;

    warningTimeoutRef.current = setTimeout(() => {
      if (!warningShownRef.current) {
        warningShownRef.current = true;
        alert("⚠️ Ihre Session läuft in 15 Minuten ab. Bitte klicken Sie auf eine Taste oder bewegen Sie die Maus, um weiterzuarbeiten.");
      }
    }, INACTIVITY_TIMEOUT_MS - WARNING_BEFORE_LOGOUT_MS);

    timeoutRef.current = setTimeout(async () => {
      await fetch("/api/admin/login", { method: "DELETE" });
      router.push("/admin/login?session_expired=true");
    }, INACTIVITY_TIMEOUT_MS);
  }

  useEffect(() => {
    const events = ["mousedown", "keydown", "scroll", "touchstart"];
    const handleActivity = () => resetTimeout();
    events.forEach((e) => window.addEventListener(e, handleActivity));
    resetTimeout();
    return () => {
      events.forEach((e) => window.removeEventListener(e, handleActivity));
      if (timeoutRef.current) clearTimeout(timeoutRef.current);
      if (warningTimeoutRef.current) clearTimeout(warningTimeoutRef.current);
    };
  }, [router]);

  return <>{children}</>;
}