import { useEffect, useRef } from 'react';
import { useMatrixClient } from './useMatrixClient';
import { useSetting } from '../state/hooks/settings';
import { settingsAtom } from '../state/settings';

const IDLE_TIMEOUT_MS = 10 * 60 * 1000;
const ACTIVITY_THROTTLE_MS = 1000;

export function usePresenceUpdater() {
  const mx = useMatrixClient();
  const [hidePresence] = useSetting(settingsAtom, 'hidePresence');
  const [presenceStatus] = useSetting(settingsAtom, 'presenceStatus');

  const idleTimerRef = useRef<ReturnType<typeof setTimeout> | undefined>(undefined);
  const isIdleRef = useRef(false);
  const lastActivityRef = useRef(0);

  useEffect(() => {
    const userId = mx.getUserId();

    // Read status from localStorage at call time so manual updates from the
    // Profile settings are never overwritten by a stale closure value.
    const readStatus = () =>
      userId ? (localStorage.getItem(`lotus-status-msg-${userId}`) ?? '') : '';

    const setOnline = () => {
      const status = readStatus();
      return mx
        .setPresence({
          presence: 'online',
          ...(status ? { status_msg: status } : {}),
        })
        .catch(() => undefined);
    };
    const setUnavailable = (statusMsg?: string) => {
      const status = readStatus();
      return mx
        .setPresence({
          presence: 'unavailable',
          ...(statusMsg ? { status_msg: statusMsg } : status ? { status_msg: status } : {}),
        })
        .catch(() => undefined);
    };
    const setOffline = () =>
      mx.setPresence({ presence: 'offline', status_msg: '' }).catch(() => undefined);

    // Manual presence overrides — no activity tracking needed.
    if (hidePresence || presenceStatus === 'invisible') {
      setOffline();
      return undefined;
    }
    if (presenceStatus === 'online') {
      setOnline();
      return undefined;
    }
    if (presenceStatus === 'idle') {
      setUnavailable();
      return undefined;
    }
    if (presenceStatus === 'dnd') {
      setUnavailable('dnd');
      return undefined;
    }

    // presenceStatus === 'auto' — original activity-tracking behavior.
    const startIdleTimer = () => {
      clearTimeout(idleTimerRef.current);
      idleTimerRef.current = setTimeout(() => {
        isIdleRef.current = true;
        setUnavailable();
      }, IDLE_TIMEOUT_MS);
    };

    const handleActivity = () => {
      const now = Date.now();
      if (now - lastActivityRef.current < ACTIVITY_THROTTLE_MS) return;
      lastActivityRef.current = now;

      if (isIdleRef.current && !document.hidden) {
        isIdleRef.current = false;
        setOnline();
      }
      startIdleTimer();
    };

    const handleVisibilityChange = () => {
      if (document.hidden) {
        clearTimeout(idleTimerRef.current);
        setUnavailable();
      } else {
        isIdleRef.current = false;
        lastActivityRef.current = Date.now();
        setOnline();
        startIdleTimer();
      }
    };

    const handlePageHide = () => {
      const token = mx.getAccessToken();
      const baseUrl = mx.getHomeserverUrl();
      if (!userId || !token || !baseUrl) return;

      fetch(`${baseUrl}/_matrix/client/v3/presence/${encodeURIComponent(userId)}/status`, {
        method: 'PUT',
        headers: {
          Authorization: `Bearer ${token}`,
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({ presence: 'offline' }),
        keepalive: true,
      }).catch(() => undefined);
    };

    setOnline();
    startIdleTimer();

    const activityEvents = ['mousemove', 'keydown', 'touchstart', 'click', 'scroll'] as const;
    activityEvents.forEach((e) => window.addEventListener(e, handleActivity, { passive: true }));
    document.addEventListener('visibilitychange', handleVisibilityChange);
    window.addEventListener('pagehide', handlePageHide);

    return () => {
      clearTimeout(idleTimerRef.current);
      activityEvents.forEach((e) => window.removeEventListener(e, handleActivity));
      document.removeEventListener('visibilitychange', handleVisibilityChange);
      window.removeEventListener('pagehide', handlePageHide);
    };
  }, [mx, hidePresence, presenceStatus]);
}