"use client";

import { useRouter } from "next/navigation";
import { createContext, useContext, useEffect, useMemo, useState } from "react";

type AuthContextValue = {
  token: string | null;
  setToken: (value: string | null) => void;
  logout: () => void;
};

const AuthContext = createContext<AuthContextValue | null>(null);

export function AuthProvider({ children }: { children: React.ReactNode }) {
  const router = useRouter();
  const [token, setTokenState] = useState<string | null>(null);

  useEffect(() => {
    setTokenState(window.localStorage.getItem("atlas_token"));
  }, []);

  const value = useMemo<AuthContextValue>(() => {
    const setToken = (next: string | null) => {
      setTokenState(next);
      if (next) {
        window.localStorage.setItem("atlas_token", next);
      } else {
        window.localStorage.removeItem("atlas_token");
      }
    };
    return {
      token,
      setToken,
      logout: () => {
        setToken(null);
        router.push("/login");
      }
    };
  }, [router, token]);

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

export function useAuth() {
  const value = useContext(AuthContext);
  if (!value) {
    throw new Error("useAuth must be used inside AuthProvider");
  }
  return value;
}