/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache 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.apache.org/licenses/LICENSE-2.0
   *
   * 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 javax.faces.component.behavior;
  
  import java.io.Serializable;
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.faces.component.PartialStateHolder;
  import javax.faces.component.StateHolder;
  import javax.faces.context.FacesContext;
  import javax.faces.event.BehaviorEvent;
  import javax.faces.event.BehaviorListener;
  
  /**
   * @since 2.0
   */
  public class BehaviorBase implements Behavior, PartialStateHolder
  {
      private _DeltaList<BehaviorListener> _behaviorListeners;
      
      private boolean _initialState;
      
      private transient boolean _transient;
  
      /**
       * 
       */
      public BehaviorBase()
      {
      }
      
      //public abstract String getRendererType();
      /**
       * {@inheritDoc}
       */
      public void broadcast(BehaviorEvent event)
      {
          if (event == null)
          {
              throw new NullPointerException("event");
          }
          
          if (_behaviorListeners != null)
          {
              // This code prevent listeners from unregistering themselves while processing the event.
              // I believe it should always be alright in this case. However, the need rise, then it 
              // should be possible to remove that limitation by using a clone for the looping
              for (int i = 0; i < _behaviorListeners.size() ; i++)
              {
                  BehaviorListener listener = _behaviorListeners.get(i);
                  if (event.isAppropriateListener(listener))
                  {
                      event.processListener(listener);
                  }
              }
          }
      }
  
      public void clearInitialState()
      {
          _initialState = false;
          if (_behaviorListeners != null)
          {
              _behaviorListeners.clearInitialState();
          }
      }
  
      public boolean initialStateMarked()
      {
          return _initialState;
      }
  
      public boolean isTransient()
      {
          return _transient;
      }
  
      public void markInitialState()
      {
          _initialState = true;
          if (_behaviorListeners != null)
          {
             _behaviorListeners.markInitialState();
         }
     }
 
     public void restoreState(FacesContext context, Object state)
     {
         if (state == null)
         {
             return;
         }
         else if (state instanceof _AttachedDeltaWrapper)
         {
             //Delta: check for null is not necessary since _behaviorListener field
             //is only set once and never reset
             //if (_behaviorListeners != null)
             //{
                 ((StateHolder)_behaviorListeners).restoreState(context,
                         ((_AttachedDeltaWrapper) state).getWrappedStateObject());
             //}
         }
         else
         {
             //Full
             _behaviorListeners = (_DeltaList<BehaviorListener>)
                 restoreAttachedState(context, state);
         }
     }
 
     public Object saveState(FacesContext context)
     {
         return saveBehaviorListenersList(context);
     }
     
     private Object saveBehaviorListenersList(FacesContext facesContext)
     {
         PartialStateHolder holder = (PartialStateHolder) _behaviorListeners;
         if (initialStateMarked() && _behaviorListeners != null && holder.initialStateMarked())
         {                
             Object attachedState = holder.saveState(facesContext);
             if (attachedState != null)
             {
                 return new _AttachedDeltaWrapper(_behaviorListeners.getClass(),
                         attachedState);
             }
             //_behaviorListeners instances once is created never changes, we can return null
             return null;
         }
         else
         {
             return saveAttachedState(facesContext,_behaviorListeners);
         }
     }
 
     private static Object saveAttachedState(FacesContext context, Object attachedObject)
     {
         if (context == null)
         {
             throw new NullPointerException ("context");
         }
         
         if (attachedObject == null)
         {
             return null;
         }
         // StateHolder interface should take precedence over
         // List children
         if (attachedObject instanceof StateHolder)
         {
             StateHolder holder = (StateHolder) attachedObject;
             if (holder.isTransient())
             {
                 return null;
             }
 
             return new _AttachedStateWrapper(attachedObject.getClass(), holder.saveState(context));
         }        
         else if (attachedObject instanceof List)
         {
             List<Object> lst = new ArrayList<Object>(((List<?>) attachedObject).size());
             for (Object item : (List<?>) attachedObject)
             {
                 if (item != null)
                 {
                     lst.add(saveAttachedState(context, item));
                 }
             }
 
             return new _AttachedListStateWrapper(lst);
         }
         else if (attachedObject instanceof Serializable)
         {
             return attachedObject;
         }
         else
         {
             return new _AttachedStateWrapper(attachedObject.getClass(), null);
         }
     }
 
     private static Object restoreAttachedState(FacesContext context, Object stateObj) throws IllegalStateException
     {
         if (context == null)
         {
             throw new NullPointerException("context");
         }
         if (stateObj == null)
         {
             return null;
         }
         if (stateObj instanceof _AttachedListStateWrapper)
         {
             List<Object> lst = ((_AttachedListStateWrapper) stateObj).getWrappedStateList();
             List<Object> restoredList = new ArrayList<Object>(lst.size());
             for (Object item : lst)
             {
                 restoredList.add(restoreAttachedState(context, item));
             }
             return restoredList;
         }
         else if (stateObj instanceof _AttachedStateWrapper)
         {
             Class<?> clazz = ((_AttachedStateWrapper) stateObj).getClazz();
             Object restoredObject;
             try
             {
                 restoredObject = clazz.newInstance();
             }
             catch (InstantiationException e)
             {
                 throw new RuntimeException("Could not restore StateHolder of type " + clazz.getName()
                         + " (missing no-args constructor?)", e);
             }
             catch (IllegalAccessException e)
             {
                 throw new RuntimeException(e);
             }
             if (restoredObject instanceof StateHolder)
             {
                 _AttachedStateWrapper wrapper = (_AttachedStateWrapper) stateObj;
                 Object wrappedState = wrapper.getWrappedStateObject();
 
                 StateHolder holder = (StateHolder) restoredObject;
                 holder.restoreState(context, wrappedState);
             }
             return restoredObject;
         }
         else
         {
             return stateObj;
         }
     }
 
     public void setTransient(boolean newTransientValue)
     {
         _transient = newTransientValue;
     }
     
     protected void addBehaviorListener(BehaviorListener listener)
     {
         if (listener == null)
         {
             throw new NullPointerException("listener");
         }
         
         if (_behaviorListeners == null)
         {
             // Lazy instanciation with size 1:
             // the only posibility how to add listener is <f:ajax listener="" /> - there is no <f:ajaxListener/> tag 
             _behaviorListeners = new _DeltaList<BehaviorListener>(new ArrayList<BehaviorListener>(1));
         }
         
         _behaviorListeners.add(listener);
     }
     
     protected void removeBehaviorListener(BehaviorListener listener)
     {
         if (listener == null)
         {
             throw new NullPointerException("listener");
         }
 
         if (_behaviorListeners != null)
         {
             _behaviorListeners.remove(listener);
         }
     }
 }