/*

  * Copyright 2006-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  * http://www.opensource.org/licenses/ecl2.php

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.kuali.rice.core.framework.persistence.jpa;

 import org.kuali.rice.core.api.config.property.Config;

 import org.kuali.rice.core.api.config.property.ConfigContext;

 import org.kuali.rice.core.api.resourceloader.GlobalResourceLoader;

 import org.kuali.rice.core.api.util.RiceConstants;

 import org.kuali.rice.core.framework.persistence.jpa.annotations.Sequence;

 import org.kuali.rice.core.framework.persistence.platform.DatabasePlatform;

 import javax.persistence.Entity;

 import javax.persistence.EntityManager;

 import javax.persistence.MappedSuperclass;

 import java.lang.reflect.Field;

 import java.lang.reflect.Modifier;

 import java.util.HashMap;

 import java.util.HashSet;

 import java.util.Map;

 import java.util.Set;

 /**

  * A utility for common ORM related functions.

  * 

  * @author Kuali Rice Team (rice.collab@kuali.org)

  */

 public final class OrmUtils {

         private static final org.apache.log4j.Logger LOG = org.apache.log4j.Logger.getLogger(OrmUtils.class);

         private static Map<String, Boolean> cache = new HashMap<String, Boolean>();

         private OrmUtils() {

                 throw new UnsupportedOperationException("do not call");

         }

         public static void populateAutoIncValue(Object entity, Long value) {

             try {                            

                     if (entity.getClass().isAnnotationPresent(Sequence.class)) {

                             Sequence sequence = entity.getClass().getAnnotation(Sequence.class);

                             Field field = getPrivateField(entity.getClass(), sequence.property());

                             field.setAccessible(true);

                             if (java.lang.String.class.equals(field.getType())) {                                    

                                 field.set(entity, value.toString());

                             } else {

                                     field.set(entity, value);

                             }

                     } 

             } catch (Exception e) {

                     LOG.error(e.getMessage(), e);

             }

         }

         public static void populateAutoIncValue(Object entity, EntityManager manager) {

                 if (entity.getClass().isAnnotationPresent(Sequence.class)) {

                         Sequence sequence = entity.getClass().getAnnotation(Sequence.class); 

                         populateAutoIncValue(entity, getNextAutoIncValue(sequence, manager));

                 } 

         }

         public static Long getNextAutoIncValue(Class entityClass, EntityManager manager) {

             return getNextAutoIncValue((Sequence)entityClass.getAnnotation(Sequence.class), manager);

         }

         private static Long getNextAutoIncValue(Sequence sequence, EntityManager manager) {

                 Long value = -1L;

                 try {

                         DatabasePlatform platform = (DatabasePlatform) GlobalResourceLoader.getService(RiceConstants.DB_PLATFORM);

                         value = platform.getNextValSQL(sequence.name(), manager);

                 } catch (Exception e) {

                         LOG.error(e.getMessage(), e);

                 }

                 return value;

         }

         public static void reattach(Object detached, Object attached) {

             if ( LOG.isDebugEnabled() ) {

                     LOG.debug("Reattaching entity: " + attached.getClass().getName());

             }

             // Don't want to get parent fields if overridden in children since we are walking the tree from child to parent

             Set<String> cachedFields = new HashSet<String>(); 

             Class attachedClass = detached.getClass();

             do {

                     for (Field attachedField : attachedClass.getDeclaredFields()) {

                             try {

                                     attachedField.setAccessible(true);

                                     int mods = attachedField.getModifiers();

                                     if (!cachedFields.contains(attachedField.getName()) && !Modifier.isFinal(mods) && !Modifier.isStatic(mods)) {

                                             //detached.getClass().getDeclaredField(attachedField.getName()).get(attached)

                                             attachedField.set(attached, attachedField.get(detached));

                                             cachedFields.add(attachedField.getName());

                                     }

                             } catch (Exception e) {

                                     LOG.error(e.getMessage(), e);

                             }

                     }

                     attachedClass = attachedClass.getSuperclass();

             } while (attachedClass != null && !(attachedClass.equals(Object.class)));

     }

     public static void merge(EntityManager manager, Object entity) {

         if(manager.contains(entity)) {

             manager.merge(entity);

         }

         else {

             OrmUtils.reattach(entity, manager.merge(entity));                

         }

     }

     public static boolean isJpaAnnotated(Class<?> clazz) {

             if (clazz == null) {

                     return false;

             }

             if (!cache.containsKey(clazz.getName())) {

                     if (clazz.getName().contains("EnhancerByCGLIB")) {

                             try {

                                     // Strip a proxy if found

                                     clazz = Class.forName(clazz.getName().substring(0, clazz.getName().indexOf("$$EnhancerByCGLIB")));

                             } catch (Exception e) {

                                     LOG.error(e.getMessage(), e);

                             }

                     }

                     synchronized (cache) {

                         cache.put(clazz.getName(), new Boolean(clazz.isAnnotationPresent(Entity.class) || clazz.isAnnotationPresent(MappedSuperclass.class)));

                         }

             }

             return cache.get(clazz.getName()).booleanValue();

     }

     public static boolean isJpaEnabled() {

             return Boolean.valueOf( ConfigContext.getCurrentContextConfig().getProperty(RiceConstants.RICE_JPA_ENABLED) );

     }

     public static boolean isJpaEnabled(String prefix) {

         Config config = ConfigContext.getCurrentContextConfig();

         return Boolean.valueOf( config.getProperty(RiceConstants.RICE_JPA_ENABLED) ) || Boolean.valueOf( config.getProperty(prefix + RiceConstants.JPA_ENABLED_SUFFIX) );

     }

     private static Field getPrivateField(Class clazz, String fieldName) throws NoSuchFieldException {

         if(clazz == null) {

             throw new NoSuchFieldException();

         }

         try {

             return clazz.getDeclaredField(fieldName);

         }

         catch(NoSuchFieldException exception) {

             return getPrivateField(clazz.getSuperclass(), fieldName);

         }

     }

 }