/*
    * The coLAB project
    * Copyright (C) 2021-2023 AlbaSim, MEI, HEIG-VD, HES-SO
    *
    * Licensed under the MIT License
    */
   package ch.colabproject.colab.api.persistence.jpa.user;
   
   import ch.colabproject.colab.api.exceptions.ColabMergeException;
  import ch.colabproject.colab.api.model.user.User;
  import java.util.List;
  import javax.ejb.LocalBean;
  import javax.ejb.Stateless;
  import javax.persistence.EntityManager;
  import javax.persistence.NoResultException;
  import javax.persistence.PersistenceContext;
  import javax.persistence.TypedQuery;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * User persistence
   * <p>
   * Note : Most of database operations are handled by managed entities and cascade.
   *
   * @author maxence
   */
  @Stateless
  @LocalBean
  public class UserDao {
  
      /** logger */
      private static final Logger logger = LoggerFactory.getLogger(UserDao.class);
  
      /**
       * Access to the persistence unit
       */
      @PersistenceContext(unitName = "COLAB_PU")
      private EntityManager em;
  
      /**
       * Find a user by id
       *
       * @param id the id of the user to fetch
       *
       * @return the user with the given id or null if such a user does not exist
       */
      public User findUser(Long id) {
          logger.trace("find user #{}", id);
  
          return em.find(User.class, id);
      }
  
      /**
       * Find all users
       *
       * @return list of all users
       */
      public List<User> findAllUsers() {
          logger.trace("find all users");
  
          TypedQuery<User> query = em.createNamedQuery("User.findAll", User.class);
  
          return query.getResultList();
      }
  
      /**
       * Retrieve the list of all admin user from database
       *
       * @return list of all administrator
       */
      public List<User> findAllAdmin() {
          logger.trace("find all admin users");
  
          TypedQuery<User> query = em.createNamedQuery("User.findAllAdmin", User.class);
  
          return query.getResultList();
      }
  
      /**
       * Find a user by username
       *
       * @param username needle
       *
       * @return the user which matching username or null if it not exist
       */
      public User findUserByUsername(String username) {
          logger.trace("find user with username {}", username);
          try {
              TypedQuery<User> query = em.createNamedQuery("User.findByUsername", User.class);
  
              query.setParameter("username", username);
  
              return query.getSingleResult();
          } catch (NoResultException ex) {
              return null;
          }
      }
  
     /**
      * Update user. Only fields which are editable by users will be impacted.
      *
      * @param user the user as supplied by clients (ie not managed by JPA)
      *
      * @return return updated managed user
      *
      * @throws ColabMergeException if the update failed
      */
     public User updateUser(User user) throws ColabMergeException {
         logger.trace("update user {}", user);
 
         User managedUser = this.findUser(user.getId());
 
         managedUser.mergeToUpdate(user);
 
         return managedUser;
     }
 
     /**
      * Persist a brand new user to database
      *
      * @param user the new user to persist
      *
      * @return the new persisted and managed user
      */
     public User persistUser(User user) {
         logger.trace("persist user {}", user);
 
         em.persist(user);
 
         return user;
     }
 
 }