correos_api/src/auth/auth.service.ts

import { Injectable } from '@nestjs/common';
import { JwtService } from '@nestjs/jwt';

@Injectable()
export class AuthService {
  constructor(private jwtService: JwtService) {}

  generarToken(payload: any) {
    return this.jwtService.sign(payload, {
      secret: process.env.JWT_SECRET, 
      expiresIn: '1d',
    });
  }

  verificarToken(token: string) {
    try {
      return this.jwtService.verify(token, {
        secret: process.env.JWT_SECRET, 
      });
    } catch {
      return null;
    }
  }
}