/*
    * 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 org.apache.myfaces.commons.converter;
  
  import java.io.Serializable;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  
  import javax.el.ValueExpression;
  import javax.faces.application.FacesMessage;
  import javax.faces.component.PartialStateHolder;
  import javax.faces.component.StateHelper;
  import javax.faces.component.StateHolder;
  import javax.faces.context.FacesContext;
  import javax.faces.convert.Converter;
  
  import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFConverter;
  import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFProperty;
  import org.apache.myfaces.commons.util.MessageUtils;
  
  /**
   * Base converter implementation for Apache MyFaces Commons Converters.
   *
   */
  @JSFConverter(
     configExcluded = true,
     evaluateELOnExecution = true,
     tagClass = "org.apache.myfaces.commons.converter.ConverterBaseTag",
     tagHandler = "org.apache.myfaces.commons.converter.ConverterBaseTagHandler")
  public abstract class ConverterBase implements PartialStateHolder, Converter {
  
      private boolean _transient = false;
      
      private transient FacesContext _facesContext;
      private StateHelper _stateHelper = null;
      private boolean _initialStateMarked = false;
  
      /**
       * alternate conversion error summary message format string
       * 
       * @return  The summary message to be displayed
       */
      @JSFProperty
      public String getSummaryMessage()
      {
          return (String) getStateHelper().eval(PropertyKeys.summaryMessage);
      }
  
      /**
       *
       * @param message   The summary message to be displayed.
       */
      public void setSummaryMessage(String message) {
          getStateHelper().put(PropertyKeys.summaryMessage, message);
      }
  
      /**
       * alternate conversion error detail message format string 
       * (use 'message' and 'detailMessage' alternatively)
       *
       * @return  The detail message.
       */
      @JSFProperty
      public String getDetailMessage() {
          return (String) getStateHelper().eval(PropertyKeys.detailMessage);
      }
  
      /**
       *
       * @param message  The detail message to be displayed.
       */
      public void setDetailMessage(String message) {
          getStateHelper().put(PropertyKeys.detailMessage, message);
      }
  
  
      /**
       * @param context
       */
      public Object saveState(FacesContext context)
      {
         if (context == null)
         {
             throw new NullPointerException ("context");
         }
         
         StateHelper stateHelper = getStateHelper(false);
         if (stateHelper != null)
         {
             return stateHelper.saveState(context);
         }
         else
         {
             return null;
         }
     }
 
     public void restoreState(FacesContext context, Object state)
     {
         getStateHelper().restoreState(context, state);
     }
 
     public boolean isTransient() {
         return _transient;
     }
 
     public void setTransient(boolean newTransientValue) {
         _transient = newTransientValue;
     }
 
     // Utility methods
 
     /**
      * @param defaultMessage The default message we would expect.
      * @param args Arguments for parsing this message.
      * @return FacesMessage
      */
     protected FacesMessage getFacesMessage(String defaultMessage, Object[] args) {
         FacesMessage msg;
 
         if (getSummaryMessage() == null && getDetailMessage() == null)
         {
             msg = MessageUtils.getMessage(FacesMessage.SEVERITY_ERROR, defaultMessage, args);
         } else {
             Locale locale = MessageUtils.getCurrentLocale();
             String summaryText = MessageUtils.substituteParams(locale, getSummaryMessage(), args);
             String detailText = MessageUtils.substituteParams(locale, getDetailMessage(), args);
             msg = new FacesMessage(FacesMessage.SEVERITY_ERROR, summaryText, detailText);
         }
         return msg;
     }
 
     // --------------------- borrowed from UIComponentBase ------------
 
     @SuppressWarnings("unchecked")
     public ValueExpression getValueExpression(String name)
     {
         if (name == null) throw new NullPointerException("name");
         StateHelper helper = getStateHelper(false);
         if (helper == null)
         {
             return null;
         }
         Map<String,Object> bindings = (Map<String,Object>) helper.get(PropertyKeys.bindings); 
         if (bindings == null)
         {
             return null;
         }
         else
         {
             return (ValueExpression) bindings.get(name);
         }
     }
     
     public void setValueExpression(String name, ValueExpression expression)
     {
         if (name == null) throw new NullPointerException("name");
         if (expression == null) {
             getStateHelper().remove(PropertyKeys.bindings, name);
         } else {
             getStateHelper().put(PropertyKeys.bindings, name, expression);
         }
     }
 
     /**
      * Serializes objects which are "attached" to this component but which are
      * not UIComponent children of it. Examples are converter and listener
      * objects. To be precise, it returns an object which implements
      * java.io.Serializable, and which when serialized will persist the
      * state of the provided object.
      * <p>
      * If the attachedObject is a List then every object in the list is saved
      * via a call to this method, and the returned wrapper object contains
      * a List object.
      * <p>
      * If the object implements StateHolder then the object's saveState is
      * called immediately, and a wrapper is returned which contains both
      * this saved state and the original class name. However in the case
      * where the StateHolder.isTransient method returns true, null is
      * returned instead.
      * <p>
      * If the object implements java.io.Serializable then the object is simply
      * returned immediately; standard java serialization will later be used
      * to store this object.
      * <p>
      * In all other cases, a wrapper is returned which simply stores the type
      * of the provided object. When deserialized, a default instance of that
      * type will be recreated.
      */
     public 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);
         }
     }
 
     @SuppressWarnings("unchecked")
     public 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;
         }
     }
 
     protected FacesContext getFacesContext()
     {
         if (_facesContext == null)
         {
             return FacesContext.getCurrentInstance();
         }
         else
         {
             return _facesContext;
         }
     }
     
     boolean isCachedFacesContext()
     {
         return _facesContext != null;
     }
     
     void setCachedFacesContext(FacesContext facesContext)
     {
         _facesContext = facesContext;
     }
     
     protected StateHelper getStateHelper() {
         return getStateHelper(true);
     }
 
     /**
      * returns a delta state saving enabled state helper
      * for the current component
      * @param create if true a state helper is created if not already existing
      * @return an implementation of the StateHelper interface or null if none exists and create is set to false
      */
     protected StateHelper getStateHelper(boolean create) {
         if(_stateHelper != null) {
             return _stateHelper;
         }
         if(create) {
             _stateHelper = new _DeltaStateHelper(this);
         }
         return _stateHelper;
     }
     
     public void clearInitialState()
     {
         _initialStateMarked = false;
     }
 
     public boolean initialStateMarked()
     {
         return _initialStateMarked;
     }
 
     public void markInitialState()
     {
         _initialStateMarked = true;
     }
 
     protected String getStringValue(FacesContext context, ValueExpression vb)
     {
         Object value = vb.getValue(context.getELContext());
         if (value != null)
         {
             return value.toString();
         }
         return null;
     }
     
     enum PropertyKeys
     {
         bindings,
         summaryMessage,
         detailMessage
     }
 }