'use client';

import React, {
  createContext,
  useContext,
  useState,
  useEffect,
  useCallback,
  ReactNode,
} from 'react';
import { useRouter } from 'next/navigation';
import { authApi, setToken, removeToken, getToken } from './api';
import { User } from '@/types';

// -----------------------------------------------------------------------
interface AuthContextType {
  user: User | null;
  isLoading: boolean;
  isAuthenticated: boolean;
  login: (username: string, password: string) => Promise<any>;
  logout: () => Promise<void>;
  refreshUser: () => Promise<void>;
}

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

// -----------------------------------------------------------------------
export function AuthProvider({ children }: { children: ReactNode }) {
  const router = useRouter();
  const [user, setUser] = useState<User | null>(null);
  const [isLoading, setIsLoading] = useState(true);

  const refreshUser = useCallback(async () => {
    const token = getToken();
    if (!token) {
      setUser(null);
      setIsLoading(false);
      return;
    }
    try {
      const res = await authApi.me();
      setUser(res.data);
    } catch {
      removeToken();
      setUser(null);
    } finally {
      setIsLoading(false);
    }
  }, []);

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

  const login = useCallback(
    async (username: string, password: string) => {
      const res = await authApi.login(username, password);
      return res.data;
    },
    []
  );

  const logout = useCallback(async () => {
    try {
      await authApi.logout();
    } catch {
      // ignore
    }
    removeToken();
    setUser(null);
    router.push('/auth/login');
  }, [router]);

  const value: AuthContextType = {
    user,
    isLoading,
    isAuthenticated: !!user,
    login,
    logout,
    refreshUser,
  };

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

// -----------------------------------------------------------------------
export function useAuth(): AuthContextType {
  const ctx = useContext(AuthContext);
  if (!ctx) throw new Error('useAuth must be used within AuthProvider');
  return ctx;
}

// Permission helpers
export function usePermissions() {
  const { user } = useAuth();

  return {
    isMasterAdmin: user?.role === 'master-admin',
    isAdmin: user?.role === 'admin' || user?.role === 'master-admin',
    isOperator: user?.role === 'operator',
    canManageUsers: user?.role === 'master-admin' || user?.role === 'admin',
    canDeleteUsers: user?.role === 'master-admin',
    canChangeRoles: user?.role === 'master-admin',
    canSetOperatorStatus: user?.role === 'master-admin' || user?.role === 'admin',
  };
}