import React, { createContext, useContext, useState, useEffect, useCallback } from "react";
import * as SecureStore from "expo-secure-store";
import { login as apiLogin, getMe } from "../api/client";

interface User { id: number; username: string; email: string; role: { name: string }; }
interface AuthCtx { user: User | null; loading: boolean; login(u: string, p: string): Promise<void>; logout(): void; isAdmin: boolean; }

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

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

  const loadUser = useCallback(async () => {
    const token = await SecureStore.getItemAsync("access_token");
    if (!token) { setLoading(false); return; }
    try {
      const { data } = await getMe();
      setUser(data);
    } catch {
      await SecureStore.deleteItemAsync("access_token");
      await SecureStore.deleteItemAsync("refresh_token");
    } finally { setLoading(false); }
  }, []);

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

  const login = async (username: string, password: string) => {
    const { data } = await apiLogin(username, password);
    await SecureStore.setItemAsync("access_token", data.access_token);
    await SecureStore.setItemAsync("refresh_token", data.refresh_token);
    await loadUser();
  };

  const logout = async () => {
    await SecureStore.deleteItemAsync("access_token");
    await SecureStore.deleteItemAsync("refresh_token");
    setUser(null);
  };

  const isAdmin = user?.role?.name === "admin";

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

export const useAuth = () => useContext(AuthContext)!;