package example.ejb.impl;

import example.ejb.interfaces.UserCredentialManager;
import example.entity.UserCredential;

import javax.ejb.*;
import javax.persistence.*;

@Stateless
@Remote
public class UserCredentialManagerBean implements UserCredentialManager {

    @PersistenceContext
    private EntityManager em;

    public void createUser(UserCredential uc) {

        // em.persist makes the new object as persistent and managed.
        em.persist(uc);
    }

    public void authenticate(String name, String password) {
        UserCredential uc = em.find(UserCredential.class, name);

        // em.find returns null if not found, hence null check.
        if (uc == null || !uc.isMatchingPassword(password)) {
            throw new EJBException("Incorrect user name or password");
        }
    }

    public void removeUser(String name) {
        UserCredential uc = em.find(UserCredential.class, name);

        // em.find returns null if not found, hence null check.
        if (uc != null) {
            em.remove(uc);
        } else {
            throw new EJBException("No such user");
        }
    }

}