"use client";

import { createContext, useContext, useEffect, useState, useCallback } from "react";
import type { User } from "./types";

// The logged-in user's own data can safely carry a couple of fields that
// the shared public User type deliberately excludes (isAdmin isn't safe to
// embed in every post/comment author object, but is fine here since this
// only ever describes "you, to yourself").
export type SessionUser = User & { isAdmin?: boolean };

type AuthState = {
  user: SessionUser | null;
  loading: boolean;
  refresh: () => Promise<void>;
  logout: () => Promise<void>;
};

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

export function AuthProvider({ children }: { children: React.ReactNode }) {
  const [user, setUser] = useState<SessionUser | null>(null);
  const [loading, setLoading] = useState(true);

  const refresh = useCallback(async () => {
    const res = await fetch("/api/auth/me");
    const data = await res.json();
    setUser(data.user);
    setLoading(false);
  }, []);

  const logout = useCallback(async () => {
    await fetch("/api/auth/logout", { method: "POST" });
    setUser(null);
  }, []);

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

  return (
    <AuthContext.Provider value={{ user, loading, refresh, logout }}>
      {children}
    </AuthContext.Provider>
  );
}

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