/**
 * Session context — polls `/api/auth/get-session` on mount and exposes
 * `useSession()` and a `refresh()` to forms.
 */
import React, {
  createContext,
  useCallback,
  useContext,
  useEffect,
  useMemo,
  useState,
} from "react";
import { fetchSession, type Session } from "./auth-client.js";

export interface SessionContextValue {
  readonly session: Session | null;
  readonly loading: boolean;
  readonly refresh: () => Promise<void>;
}

const SessionContext = createContext<SessionContextValue | null>(null);

export function useSession(): SessionContextValue {
  const ctx = useContext(SessionContext);
  if (ctx === null) throw new Error("useSession must be inside <SessionProvider>");
  return ctx;
}

export function SessionProvider({ children }: { children: React.ReactNode }): React.JSX.Element {
  const [session, setSession] = useState<Session | null>(null);
  const [loading, setLoading] = useState(true);

  const refresh = useCallback(async () => {
    setLoading(true);
    try {
      const next = await fetchSession();
      setSession(next);
    } finally {
      setLoading(false);
    }
  }, []);

  useEffect(() => {
    void refresh();
  }, [refresh]);

  const value = useMemo<SessionContextValue>(
    () => ({ session, loading, refresh }),
    [session, loading, refresh]
  );

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