import { jwtDecode } from 'jwt-decode';

export interface JWTPayload {
  client_id?: number;
  user_id?: number;
  username: string;
  role: string;
  session_id: string;
  iat: number;
  exp: number;
  iss: string;
}

export const decodeToken = (token: string): JWTPayload | null => {
  try {
    return jwtDecode<JWTPayload>(token);
  } catch {
    return null;
  }
};

export const extractUsernameFromToken = (token: string): string | null => {
  const payload = decodeToken(token);
  return payload?.username ?? null;
};

export const extractRoleFromToken = (token: string): string | null => {
  const payload = decodeToken(token);
  return payload?.role ?? null;
};

export const isTokenExpired = (token: string): boolean => {
  const payload = decodeToken(token);
  if (!payload) return true;
  return Date.now() >= payload.exp * 1000;
};