package info.ejava.examples.jaxrs.todos.ejb;
   
   import java.util.List;
   
   import javax.ejb.Stateless;
   import javax.ejb.TransactionAttribute;
   import javax.ejb.TransactionAttributeType;
   import javax.inject.Inject;
   import javax.persistence.EntityManager;
  import javax.persistence.TypedQuery;
  
  import info.ejava.examples.jaxrs.todos.bo.TodoItem;
  import info.ejava.examples.jaxrs.todos.bo.TodoList;
  import info.ejava.examples.jaxrs.todos.dto.TodoItemDTO;
  import info.ejava.examples.jaxrs.todos.dto.TodoListDTO;
  import info.ejava.examples.jaxrs.todos.dto.TodoListListDTO;
  
  @Stateless
  public class TodosMgmtEJB implements TodosMgmtRemote {
      @Inject
      DtoMapper dtoMapper;
      
      @Inject
      EntityManager em;
  
      @Override
      @TransactionAttribute(TransactionAttributeType.SUPPORTS)
      public TodoListListDTO getTodoLists(int offset, int limit) {        
          List<TodoList> result = getTodoListsLocal(offset, limit);
          return dtoMapper.map(result);
      }
      
      @TransactionAttribute(TransactionAttributeType.SUPPORTS)
      public List<TodoList> getTodoListsLocal(int offset, int limit) {
          TypedQuery<TodoList> query=em.createNamedQuery("TodoList.getTodoLists", TodoList.class);
          if (offset>0) {
              query.setFirstResult(offset);
          }
          if (limit>0) {
              query.setMaxResults(limit);
          }
          return query.getResultList();
      }
  
  
      @Override
      @TransactionAttribute(TransactionAttributeType.REQUIRED)
      public TodoListDTO createTodoList(TodoListDTO todoList) {
          try {
              TodoList result = createTodoList(dtoMapper.map(todoList));
              return dtoMapper.map(result);
          } catch (RuntimeException ex) {
              throw new InternalErrorException("Error creating todoList: %s", ex.toString());            
          }
      }
      
      @TransactionAttribute(TransactionAttributeType.REQUIRED)
      public TodoList createTodoList(TodoList todoList) {
          em.persist(todoList);
          return todoList;
      }
  
      @Override
      @TransactionAttribute(TransactionAttributeType.SUPPORTS)
      public TodoListDTO getTodoList(String listName) throws ResourceNotFoundException {
          try {
              TodoList result = getTodoListLocal(listName);
              if (result==null) {
                  throw new ResourceNotFoundException("listName[%s] not found", listName);
              }
              return dtoMapper.map(result);
          } catch (RuntimeException ex) {            
              throw new InternalErrorException("Error getting todoList: %s", ex.toString());
          }
      }
      
      @TransactionAttribute(TransactionAttributeType.SUPPORTS)
      public TodoList getTodoListLocal(String listName) {
          List<TodoList> results = em.createNamedQuery("TodoList.getListByName", 
                  TodoList.class)
                   .setParameter("name", listName)
                  .getResultList();        
          return results.isEmpty() ? null : results.get(0);
      }
      
      @Override
      @TransactionAttribute(TransactionAttributeType.REQUIRED)
      public TodoListDTO renameTodoList(String oldName, String newName) throws ResourceNotFoundException {
          try {
              TodoList todoList = getTodoListLocal(oldName);
              if (todoList==null) {
                  throw new ResourceNotFoundException("todoList[%s] not found", oldName);
              }
              todoList.setName(newName);
              return dtoMapper.map(todoList);
          } catch (RuntimeException ex) {
              throw new InternalErrorException("Error renaming todoList: %s", ex.toString());            
          }
      }
 
     @Override
     @TransactionAttribute(TransactionAttributeType.REQUIRED)
     public void deleteTodoList(String listName) throws ResourceNotFoundException {
         try {
             if (deleteTodoListLocal(listName)==0) {
                 throw new ResourceNotFoundException("todoList[%s] not found", listName);
             }
         } catch (RuntimeException ex) {
             throw new InternalErrorException("Error deleting todoList: %s", ex.toString());            
         }
     }
     
     @TransactionAttribute(TransactionAttributeType.REQUIRED)
     public int deleteTodoListLocal(String listName) {
         TodoList todoList = getTodoListLocal(listName);
         if (todoList==null) {
             return 0;
         } else {
             em.remove(todoList); //use casecades
             return 1;
         }            
     }
 
     @Override
     @TransactionAttribute(TransactionAttributeType.REQUIRED)
     public void addTodoListItem(String listName, TodoItemDTO item) 
             throws ResourceNotFoundException, InvalidRequestException {
         try {
             TodoList todoList = getTodoListLocal(listName);
             if (todoList==null) {
                 throw new ResourceNotFoundException("todoList[%s] not found", listName);
             }
             TodoItem itemBO = dtoMapper.map(item);
             if (itemBO==null) {
                 throw new InvalidRequestException("required item not supplied");
             }
             
             addTodoListItem(todoList, itemBO);
         } catch (RuntimeException ex) {
             throw new InternalErrorException("Error adding listItem to todoList[%s]: %s", listName, ex.toString());            
         }
     }
     
     @TransactionAttribute(TransactionAttributeType.REQUIRED)
     public void addTodoListItem(TodoList todoList, TodoItem item) {
         item.setTodoList(todoList);
         todoList.getTodoItems().add(item);
         em.persist(item);
         em.flush();
     }
 
     @TransactionAttribute(TransactionAttributeType.SUPPORTS)
     public TodoItem getTodoListItem(String listName, String itemName) {
         List<TodoItem> results = em.createNamedQuery("TodoItem.getTodoItem", TodoItem.class)
                 .setParameter("listName", listName)
                 .setParameter("itemName", itemName)
                 .getResultList();
         return results.isEmpty() ? null : results.get(0);
     }
     
     @Override
     @TransactionAttribute(TransactionAttributeType.REQUIRED)
     public TodoItemDTO updateTodoListItem(String listName, String itemName, TodoItemDTO item) 
             throws ResourceNotFoundException {
         try {
             TodoItem dbCopy = getTodoListItem(listName, itemName);
             if (dbCopy==null) {
                 throw new ResourceNotFoundException("todoList[%s], todoItem[%s] not found", listName, itemName);
             }
                 //assign the PK from the DB copy retrieved by distinct list+item name
             TodoItem toUpdate = dtoMapper.map(item);
             toUpdate.setId(dbCopy.getId());
             
             return dtoMapper.map(updateTodoListItem(toUpdate));
         } catch (RuntimeException ex) {
             throw new InternalErrorException("Error updating todoList: %s", ex.toString());            
         }
     }
     
     @TransactionAttribute(TransactionAttributeType.REQUIRED)
     public TodoItem updateTodoListItem(TodoItem item) {
         return em.merge(item);
     }
 
 
     @Override
     @TransactionAttribute(TransactionAttributeType.REQUIRED)
     public void deleteTodoListItem(String listName, String itemName) throws ResourceNotFoundException {
         try {
             TodoItem item = getTodoListItem(listName, itemName);
             if (item==null) {
                 throw new ResourceNotFoundException("todoList[%s], todoItem[%s] not found", listName, itemName);
             }
             deleteTodoListItem(item);
         } catch (RuntimeException ex) {
             throw new InternalErrorException("Error deleting todoList: %s", ex.toString());            
         }
     }
     
     @TransactionAttribute(TransactionAttributeType.REQUIRED)
     public void deleteTodoListItem(TodoItem item) {
         em.createNamedQuery("TodoItem.deleteTodoItem")
             .setParameter("id", item.getId())
             .executeUpdate();
     }
 
     
     @Override
     public void deleteAll() {
         for (String entityName : new String[] {"TodoItem","TodoList"}) {
             em.createQuery(String.format("delete from %s o", entityName)).executeUpdate();
         }
     }
 }