/*
    * 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.view.facelets.tag.jsf.core;
  
  import java.io.IOException;
  import java.io.Serializable;
  
  import javax.el.ELContext;
  import javax.el.ELException;
  import javax.el.ExpressionFactory;
  import javax.el.ValueExpression;
  import javax.faces.FacesException;
  import javax.faces.component.ActionSource;
  import javax.faces.component.UIComponent;
  import javax.faces.context.FacesContext;
  import javax.faces.event.AbortProcessingException;
  import javax.faces.event.ActionEvent;
  import javax.faces.event.ActionListener;
  import javax.faces.view.ActionSource2AttachedObjectHandler;
  import javax.faces.view.facelets.ComponentHandler;
  import javax.faces.view.facelets.FaceletContext;
  import javax.faces.view.facelets.FaceletException;
  import javax.faces.view.facelets.TagAttribute;
  import javax.faces.view.facelets.TagConfig;
  import javax.faces.view.facelets.TagException;
  import javax.faces.view.facelets.TagHandler;
  
  import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFFaceletAttribute;
  import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFFaceletTag;
  import org.apache.myfaces.view.facelets.FaceletCompositionContext;
  
  @JSFFaceletTag(
          name = "f:setPropertyActionListener",
          bodyContent = "empty", 
          tagClass="org.apache.myfaces.taglib.core.SetPropertyActionListenerTag")
  public class SetPropertyActionListenerHandler extends TagHandler
      implements ActionSource2AttachedObjectHandler 
  {
      private final TagAttribute _target;
      private final TagAttribute _value;
  
      public SetPropertyActionListenerHandler(TagConfig config)
      {
          super(config);
          this._value = this.getRequiredAttribute("value");
          this._target = this.getRequiredAttribute("target");
      }
  
      public void apply(FaceletContext ctx, UIComponent parent) throws IOException, FacesException, FaceletException,
              ELException
      {
          //Apply only if we are creating a new component
          if (!ComponentHandler.isNew(parent))
          {
              return;
          }
          if (parent instanceof ActionSource)
          {
              applyAttachedObject(ctx.getFacesContext(), parent);
          }
          else if (UIComponent.isCompositeComponent(parent))
          {
              FaceletCompositionContext mctx = FaceletCompositionContext.getCurrentInstance(ctx);
              mctx.addAttachedObjectHandler(parent, this);
          }
          else
          {
              throw new TagException(this.tag, "Parent is not composite component or of type ActionSource, type is: " + parent);
          }
      }
  
      private static class SetPropertyListener implements ActionListener, Serializable
      {
          private ValueExpression _target;
          private ValueExpression _value;
  
          public SetPropertyListener()
          {
          };
  
          public SetPropertyListener(ValueExpression value, ValueExpression target)
          {
              _value = value;
             _target = target;
         }
 
         public void processAction(ActionEvent evt) throws AbortProcessingException
         {
             FacesContext facesContext = FacesContext.getCurrentInstance();
             
             ELContext elContext = facesContext.getELContext();
             
             // Spec f:setPropertyActionListener: 
             
             // Call getValue() on the "value" ValueExpression.
             Object value = _value.getValue(elContext);
             
             // If value of the "value" expression is null, call setValue() on the "target" ValueExpression with the null
             
             // If the value of the "value" expression is not null, call getType()on the "value" and "target"
             // ValueExpressions to determine their property types.
             if (value != null)
             {
                 Class<?> targetType = _target.getType(elContext);
                 // Spec says: "all getType() on the "value" to determine  property type" but it is not necessary
                 // beacuse type we have objValue already
 
                 //   Coerce the value of the "value" expression to the "target" expression value type following the Expression
                 // Language coercion rules. 
                 ExpressionFactory expressionFactory = facesContext.getApplication().getExpressionFactory();
                 value = expressionFactory.coerceToType(value, targetType);
             }
 
             // Call setValue()on the "target" ValueExpression with the resulting value.
             _target.setValue(elContext, value);
         }
     }
 
     public void applyAttachedObject(FacesContext context, UIComponent parent)
     {
         // Retrieve the current FaceletContext from FacesContext object
         FaceletContext faceletContext = (FaceletContext) context.getAttributes().get(
                 FaceletContext.FACELET_CONTEXT_KEY);
 
         ActionSource src = (ActionSource) parent;
         ValueExpression valueExpr = _value.getValueExpression(faceletContext, Object.class);
         ValueExpression targetExpr = _target.getValueExpression(faceletContext, Object.class);
 
         src.addActionListener(new SetPropertyListener(valueExpr, targetExpr));
     }
 
     /**
      * TODO: Document me!
      */
     @JSFFaceletAttribute
     public String getFor()
     {
         TagAttribute forAttribute = getAttribute("for");
         
         if (forAttribute == null)
         {
             return null;
         }
         else
         {
             return forAttribute.getValue();
         }
     }
 }