package example.ejb.impl;

import example.ejb.interfaces.UserCredentialManager;
import example.ejb.interfaces.NoSuchUserException;
import example.ejb.interfaces.IncorrectPasswordException;
import example.entity.UserCredential;
import example.entity.LoginAttempt;

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

@Stateless
@Local
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);
    }

    /**
     * This method runs in a new transaction because it logs an unsuccessful
     * login attempt.
     */
    @TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)
    public void authenticate(String name, String password) 
            throws NoSuchUserException, IncorrectPasswordException {
        UserCredential uc = em.find(UserCredential.class, name);

        // em.find returns null if not found, hence null check.
        if (uc == null) {
            throw new NoSuchUserException("There is no user by name ["
                    + name + "].");
        }
        final boolean matchingPassword = uc.isMatchingPassword(password);
        LoginAttempt attempt = new LoginAttempt(uc, matchingPassword);
        uc.addLoginAttempt(attempt);
        em.persist(attempt);
        if (!matchingPassword) {
            throw new IncorrectPasswordException("Password is incorrect. " +
                    "Your login attempt may be reported to sys-admin.");
        }
    }

    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");
        }
    }

    public UserCredential lookupUser(String name) {
        System.out.println("Inside EJB: em = " + em);
        System.out.println("Inside EJB: delegate = " + em.getDelegate());
        return em.find(UserCredential.class, name);
    }

}