package ejava.examples.asyncmarket.jpa;
   
   import java.util.ArrayList;
   import java.util.List;
   import java.util.Map;
   
   import javax.persistence.EntityManager;
   import javax.persistence.Query;
   
  import ejava.examples.asyncmarket.bo.AuctionItem;
  import ejava.examples.asyncmarket.bo.Bid;
  import ejava.examples.asyncmarket.dao.AuctionItemDAO;
  
  public class JPAAuctionItemDAO implements AuctionItemDAO {
      private EntityManager em;
      
      public void setEntityManager(EntityManager em) {
          this.em = em;
      }
  
      public AuctionItem getItem(long itemId) {
          return em.find(AuctionItem.class, itemId);
      }
  
      public AuctionItem createItem(AuctionItem item) {
          em.persist(item);
          return item;
      }
      
      public AuctionItem updateItem(AuctionItem item) {
          return em.merge(item);
      }
  
      public Bid addBid(long itemId, Bid bid) {
          AuctionItem item = em.find(AuctionItem.class, itemId);
          bid.setItem(item);
          item.getBids().add(bid);
          em.persist(bid);
          return bid;
      }
      
      @SuppressWarnings("unchecked")
      public List<AuctionItem> getItems(int index, int count) {
          Query query = em.createNamedQuery("AsyncMarket_getAuctionItems")
                          .setFirstResult(index)
                          .setMaxResults(count);
          return query.getResultList();
      }
      
      @SuppressWarnings("unchecked")
      public List<AuctionItem> getAvailableItems(int index, int count) {
          Query query = em.createNamedQuery("AsyncMarket_getAvailableAuctionItems")
                          .setFirstResult(index)
                          .setMaxResults(count);
          return query.getResultList();
      }
      
      @SuppressWarnings("unchecked")
      public List<AuctionItem> getItems(
              String queryString, Map<String, Object> params, 
              int index, int count) {
          Query query = em.createNamedQuery(queryString)
                          .setFirstResult(index)
                          .setMaxResults(count);
          if (params != null && params.size() != 0) {
              for (String name: params.keySet()) {
                  query.setParameter(name, params.get(name));
              }
          }
          return query.getResultList();
      }
  
      public void removeItem(long id) {
          AuctionItem item = getItem(id);
          //create a copy to prevent iterating over changing collection
          List<Bid> bids = new ArrayList<Bid>(item.getBids());
          for (Bid bid : bids) {
              bid.getBidder().getBids().remove(bid);
              item.getBids().remove(bid);
              em.remove(bid);
          }
          item.getOwner().getItems().remove(item);
          em.createQuery("delete from Order o " +
                  "where o.item.id = :itemId")
            .setParameter("itemId", id)
            .executeUpdate();
          em.remove(item);
      }
  
      public Bid getBid(long bidId) {
          return em.find(Bid.class, bidId);
      }
  
      public void removeBid(Bid bid) {
          bid.getBidder().getBids().remove(bid);
          bid.getItem().getBids().remove(bid);
          em.remove(bid);
      }
  }