'use client';

import {
  createContext,
  useContext,
  useEffect,
  useState,
  useSyncExternalStore,
  type ReactNode,
} from 'react';
import { io, type Socket } from 'socket.io-client';

import { useSession } from '@/lib/auth/client';
import { usePortStore } from '@/stores/ui-store';

const SocketContext = createContext<Socket | null>(null);

/** Returns true once the component has mounted on the client. Avoids calling
 *  better-auth's `useSession()` (which dispatches React hooks via nanostores)
 *  during the SSR pass — that combo throws "Invalid hook call" intermittently
 *  in Next.js 15 dev mode. */
function useHasMounted(): boolean {
  return useSyncExternalStore(
    () => () => {},
    () => true,
    () => false,
  );
}

export function SocketProvider({ children }: { children: ReactNode }) {
  const hasMounted = useHasMounted();
  return hasMounted ? (
    <SocketProviderClient>{children}</SocketProviderClient>
  ) : (
    <SocketContext.Provider value={null}>{children}</SocketContext.Provider>
  );
}

function SocketProviderClient({ children }: { children: ReactNode }) {
  const { data: session } = useSession();
  const currentPortId = usePortStore((s) => s.currentPortId);
  const [socket, setSocket] = useState<Socket | null>(null);

  useEffect(() => {
    if (!session?.user || !currentPortId) return;

    const s = io(process.env.NEXT_PUBLIC_APP_URL!, {
      path: '/socket.io/',
      withCredentials: true,
      auth: { portId: currentPortId },
      transports: ['websocket', 'polling'],
    });

    s.on('connect', () => setSocket(s));
    s.on('disconnect', () => setSocket(null));

    return () => {
      s.disconnect();
      setSocket(null);
    };
  }, [session?.user, currentPortId]);

  return <SocketContext.Provider value={socket}>{children}</SocketContext.Provider>;
}

export function useSocket() {
  return useContext(SocketContext);
}
