// Mode Gate Overlay
// Purpose: Defines the Mode Gate Overlay module and the local helpers/components used in this file.
// Scope: Keeps behavior unchanged while isolating this concern into a clear, single-responsibility unit.
import { useMemo } from 'react';
import AuthPanel from '../AuthPanel/index.jsx';
import { useSessionSelector } from '../../context/SessionContext.jsx';
import { useSharedClock } from '../../hooks/useSharedClock.js';
import SocialButton from '../SocialButton/index.jsx';
import ChatPanel from '../ChatPanel/index.jsx';
import InterInstancePanel from '../InterInstancePanel/index.jsx';
import { isFeatureEnabled } from '../../lib/features.js';

const PRIVILEGED_ROLES = new Set(['admin', 'lockdown']);
const LOCKDOWN_ROLES = new Set(['lockdown']);
const RESTRICTED_MODES = new Set(['admin', 'lockdown']);

function getModeDetails(mode = 'admin') {
  if (mode === 'lockdown') {
    return {
      title: 'Lockdown mode active',
      description:
        'Only the server owners can access the interface at this time.',
    };
  }
  return {
    title: 'Admin mode active',
    // description:
    //   'The server is currently in admin mode. Only admins can access the interface.',
  };
}

export default function ModeGateOverlay() {
  const mode = useSessionSelector((state) => state.session?.mode || null);
  const role = useSessionSelector((state) => state.session?.role || null);
  const reason = useSessionSelector((state) => state.session?.adminReason?.text || '');
  const timezone = useSessionSelector((state) => state.session?.timezone || 'UTC');
  const interInstanceEnabled = useSessionSelector((state) => isFeatureEnabled(state, 'interInstance'));
  const restricted = RESTRICTED_MODES.has(mode);
  const privileged = mode === 'lockdown' ? LOCKDOWN_ROLES.has(role) : PRIVILEGED_ROLES.has(role);
  /*
    The overlay is mounted for the whole app, but the server-time display is
    only visible while access is actually blocked. Gating the shared clock here
    prevents the hidden overlay from registering a permanent interval.
  */
  const nowMs = useSharedClock(1000, restricted && !privileged);

  const serverTime = useMemo(() => {
    const now = new Date(nowMs);
    try {
      return new Intl.DateTimeFormat('en-US', {
        timeZone: timezone,
        hour: 'numeric',
        minute: '2-digit',
        second: '2-digit',
      }).format(now);
    } catch {
      return now.toLocaleTimeString();
    }
  }, [nowMs, timezone]);

  if (!restricted || privileged) {
    return null;
  }

  const details = getModeDetails(mode);

  return (
    <div className="pointer-events-auto fixed inset-0 z-50 overflow-y-auto bg-black px-0.5 py-0.5">
      <div className="mx-auto flex min-h-full w-full max-w-6xl flex-col items-center justify-center gap-0.5">
        <div className="surface w-full max-w-md space-y-0.5 text-slate-100 shadow-2xl">
          <div className="space-y-0.5">
            <p className="text-lg font-semibold">{details.title}</p>
            <p className="text-sm text-slate-300">{details.description}</p>
          </div>
          <div className="surface-muted space-y-0.5">
            <p className="text-[0.7rem] tracking-wide text-slate-400">Reason for locking:</p>
            <p className="text-lg font-semibold text-slate-100">
              {reason ? reason : 'No reason set.'}
            </p>
            <p className="text-center text-sm text-slate-300">Server time: {serverTime}</p>
          </div>
          <div className="surface-muted">
            <AuthPanel />
          </div>
          <SocialButton id="discord" label="Join our Discord server for updates!" />
          You can still use the chat while the server is locked:
          {/* set max height of this box */}
          <div className='max-h-80 overflow-y-auto'>
            <ChatPanel nicknameLayout="stacked" />
          </div>
          
          {/* <p className="text-xs text-slate-500">
            Your controls are paused until access is granted. You will automatically regain the interface once the mode
            changes or after a successful login.
          </p> */}
        </div>
        {interInstanceEnabled ? (
          <div className="w-full">
            <InterInstancePanel centered />
          </div>
        ) : null}
      </div>
    </div>
  );
}