/*
    * Copyright 2011 The Kuali Foundation Licensed under the Educational Community
    * License, Version 1.0 (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/ecl1.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.krad.uif.util;
  
  import org.kuali.rice.krad.uif.core.ReferenceCopy;
  
  import java.lang.reflect.Field;
  import java.lang.reflect.Modifier;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.concurrent.atomic.AtomicInteger;
  import java.util.concurrent.atomic.AtomicLong;
  
  /**
   * Utility class for copying objects using reflection. Modified from the jCommon
   * library: http://www.matthicks.com/2008/05/fastest-deep-cloning.html
   * 
   * @author Matt Hicks
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class CloneUtils {
      private static final org.apache.log4j.Logger LOG = org.apache.log4j.Logger.getLogger(CloneUtils.class);
  
      private static final Map<String, Field[]> fieldCache = new HashMap<String, Field[]>();
      private static final Map<String, Field> internalFields = new HashMap<String, Field>();
  
      public static final <O> O deepClone(O original) throws Exception {
          return deepCloneReflection(original);
      }
  
      @SuppressWarnings("unchecked")
      public static final <O> O deepCloneReflection(O original) throws Exception {
          return (O) deepCloneReflectionInternal(original, new HashMap<Object, Object>(), false);
      }
  
      protected static final Object deepCloneReflectionInternal(Object original, Map<Object, Object> cache,
              boolean referenceCollectionCopy) throws Exception {
          if (original == null) { // No need to clone nulls
              return original;
          }
          else if (cache.containsKey(original)) {
              return cache.get(original);
          }
  
          // Deep clone
          Object clone = null;
          if (List.class.isAssignableFrom(original.getClass())) {
              clone = deepCloneList(original, cache, referenceCollectionCopy);
          }
          else if (Map.class.isAssignableFrom(original.getClass())) {
              clone = deepCloneMap(original, cache, referenceCollectionCopy);
          }
          else {
              clone = deepCloneObject(original, cache);
          }
  
          return clone;
      }
  
      protected static Object deepCloneObject(Object original, Map<Object, Object> cache) throws Exception {
          if (original instanceof Number) { // Numbers are immutable
              if (original instanceof AtomicInteger) {
                  // AtomicIntegers are mutable
              }
              else if (original instanceof AtomicLong) {
                  // AtomLongs are mutable
              }
              else {
                  return original;
              }
          }
          else if (original instanceof String) { // Strings are immutable
              return original;
          }
          else if (original instanceof Character) { // Characters are immutable
              return original;
          }
          else if (original instanceof Class) { // Classes are immutable
              return original;
          }
          else if (original instanceof Boolean) {
              return new Boolean(((Boolean) original).booleanValue());
          }
  
          // To our understanding, this is a mutable object, so clone it
          Class<?> c = original.getClass();
         Field[] fields = getFields(c, false);
         try {
             Object copy = instantiate(original);
 
             // Put into cache
             cache.put(original, copy);
 
             // iterate through and copy fields
             for (Field f : fields) {
                 Object object = f.get(original);
 
                 boolean referenceCopy = false;
                 boolean referenceCollectionCopy = false;
                 ReferenceCopy copyAnnotation = f.getAnnotation(ReferenceCopy.class);
                 if (copyAnnotation != null) {
                     referenceCopy = true;
                     referenceCollectionCopy = copyAnnotation.newCollectionInstance();
                 }
 
                 if (!referenceCopy || referenceCollectionCopy) {
                     object = CloneUtils.deepCloneReflectionInternal(object, cache, referenceCollectionCopy);
                 }
                 f.set(copy, object);
             }
 
             return copy;
         }
         catch (Throwable t) {
             LOG.warn("Exception during clone (returning original): " + t.getMessage());
             return original;
         }
     }
 
     @SuppressWarnings("unchecked")
     protected static Object deepCloneMap(Object original, Map<Object, Object> cache, boolean referenceCollectionCopy)
             throws Exception {
         // Instantiate a new instance
         Map<Object, Object> clone = (Map<Object, Object>) instantiate(original);
 
         // Populate data
         for (Entry<Object, Object> entry : ((Map<Object, Object>) original).entrySet()) {
             if (referenceCollectionCopy) {
                 clone.put(entry.getKey(), entry.getValue());
             }
             else {
                 clone.put(deepCloneReflectionInternal(entry.getKey(), cache, false),
                         deepCloneReflectionInternal(entry.getValue(), cache, false));
             }
         }
 
         return clone;
     }
 
     @SuppressWarnings("unchecked")
     protected static Object deepCloneList(Object original, Map<Object, Object> cache, boolean referenceCollectionCopy)
             throws Exception {
         // Instantiate a new instance
         List<Object> clone = (List<Object>) instantiate(original);
 
         // Populate data
         for (Iterator<Object> iterator = ((List<Object>) original).iterator(); iterator.hasNext();) {
             Object object = iterator.next();
             if (referenceCollectionCopy) {
                 clone.add(object);
             }
             else {
                 clone.add(deepCloneReflectionInternal(object, cache, false));
             }
         }
 
         return clone;
     }
 
     protected static final Object instantiate(Object original) throws InstantiationException, IllegalAccessException {
         return original.getClass().newInstance();
     }
 
     public static Field[] getFields(Object object, boolean includeStatic) {
         return getFields(object, includeStatic, true);
     }
 
     public static Field[] getFields(Object object, boolean includeStatic, boolean includeTransient) {
         Class<?> c = object.getClass();
         return getFields(c, includeStatic, includeTransient);
     }
 
     public static Field[] getFields(Class<?> c, boolean includeStatic) {
         return getFields(c, includeStatic, true);
     }
 
     public static Field[] getFields(Class<?> c, boolean includeStatic, boolean includeTransient) {
         String cacheKey = c.getCanonicalName() + ":" + includeStatic;
         Field[] array = fieldCache.get(cacheKey);
 
         if (array == null) {
             ArrayList<Field> fields = new ArrayList<Field>();
 
             List<Class<?>> classes = getClassHierarchy(c, false);
 
             // Reverse order so we make sure we maintain consistent order
             Collections.reverse(classes);
 
             for (Class<?> clazz : classes) {
                 Field[] allFields = clazz.getDeclaredFields();
                 for (Field f : allFields) {
                     if ((!includeTransient) && ((f.getModifiers() & Modifier.TRANSIENT) == Modifier.TRANSIENT)) {
                         continue;
                     }
                     else if (f.isSynthetic()) {
                         // Synthetic fields are bad!!!
                         continue;
                     }
                     boolean isStatic = (f.getModifiers() & Modifier.STATIC) == Modifier.STATIC;
                     if ((isStatic) && (!includeStatic)) {
                         continue;
                     }
                     if (f.getName().equalsIgnoreCase("serialVersionUID")) {
                         continue;
                     }
                     f.setAccessible(true);
                     fields.add(f);
                 }
             }
 
             array = fields.toArray(new Field[fields.size()]);
             fieldCache.put(cacheKey, array);
         }
         return array;
     }
 
     protected static final Field internalField(Object object, String fieldName) {
         if (object == null) {
             System.out.println("Internal Field: " + object + ", " + fieldName);
             return null;
         }
 
         String key = object.getClass().getCanonicalName() + "." + fieldName;
         Field field = internalFields.get(key);
         if (field == null) {
             Field[] fields = getFields(object.getClass(), false);
 
             for (Field f : fields) {
                 String name = f.getName();
                 if (name.equals(fieldName)) {
                     field = f;
                     internalFields.put(key, field);
                     break;
                 }
             }
         }
 
         return field;
     }
 
     protected static List<Class<?>> getClassHierarchy(Class<?> c, boolean includeInterfaces) {
         List<Class<?>> classes = new ArrayList<Class<?>>();
         while (c != Object.class) {
             classes.add(c);
             if (includeInterfaces) {
                 Class<?>[] interfaces = c.getInterfaces();
                 for (Class<?> i : interfaces) {
                     classes.add(i);
                 }
             }
             c = c.getSuperclass();
             if (c == null) {
                 break;
             }
         }
 
         return classes;
     }
 
 }