/**
 * AuthService
 * Manages authentication tokens securely using localStorage.
 * 
 * Methods:
 *   addToken(token)   — store JWT token
 *   getToken()        — retrieve JWT token
 *   deleteToken()     — remove JWT token
 *
 * Usage:
 *   import AuthService from '@/app/services/AuthService';
 *   AuthService.addToken(token);
 *   const token = AuthService.getToken();
 *   AuthService.deleteToken();
 */
const TOKEN_KEY = 'auth_token';

const AuthService = Object.freeze({
  /**
   * Store token in localStorage
   * @param {string} token — JWT string
   */
  addToken(token) {
    if (!token || typeof token !== 'string') {
      console.error('[AuthService] addToken: invalid token', token);
      return;
    }
    localStorage.setItem(TOKEN_KEY, token);
    console.log('[AuthService] Token stored');
  },

  /**
   * Retrieve token from localStorage
   * @returns {string|null}
   */
  getToken() {
    const token = localStorage.getItem(TOKEN_KEY);
    console.log('[AuthService] getToken:', token ? '***exists***' : null);
    return token;
  },

  /**
   * Remove token from localStorage
   */
  deleteToken() {
    localStorage.removeItem(TOKEN_KEY);
    console.log('[AuthService] Token deleted');
  },
});

export default AuthService;