/*
    * 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.tobago.facelets;
  
  import javax.el.ELException;
  import javax.el.ValueExpression;
  import javax.faces.FacesException;
  import javax.faces.component.UIComponent;
  import javax.faces.component.ValueHolder;
  import javax.faces.context.FacesContext;
  import javax.faces.convert.Converter;
  import javax.faces.view.facelets.ComponentHandler;
  import javax.faces.view.facelets.FaceletContext;
  import javax.faces.view.facelets.TagAttribute;
  import javax.faces.view.facelets.TagAttributeException;
  import javax.faces.view.facelets.TagConfig;
  import javax.faces.view.facelets.TagException;
  import javax.faces.view.facelets.TagHandler;
  import java.io.IOException;
  
  /*
     TBD: Why we don't use a converter directly via the tobago.taglib.xml?
   */
  public class ConverterHandler extends TagHandler {
  
    private final TagAttribute converterId;
  
    private final TagAttribute binding;
  
    public ConverterHandler(TagConfig config) {
      super(config);
      binding = getAttribute("binding");
      converterId = getAttribute("type");
    }
  
    public void apply(FaceletContext faceletContext, UIComponent parent)
        throws IOException, FacesException, ELException {
      if (parent instanceof ValueHolder) {
        if (ComponentHandler.isNew(parent)) {
          ValueHolder valueHolder = (ValueHolder) parent;
          Converter converter = null;
          ValueExpression valueExpression = null;
          if (binding != null) {
            valueExpression = binding.getValueExpression(faceletContext, Converter.class);
            converter = (Converter) valueExpression.getValue(faceletContext);
          }
          if (converter == null) {
            try {
              converter = FacesContext.getCurrentInstance().getApplication().createConverter(
                  (String) converterId.getValueExpression(faceletContext, String.class).getValue(faceletContext));
            } catch (Exception e) {
              throw new TagAttributeException(tag, converterId, e.getCause());
            }
            if (valueExpression != null) {
              valueExpression.setValue(faceletContext, converter);
            }
          }
          if (converter != null) {
            valueHolder.setConverter(converter);
          }
          // TODO else LOG.warn?
        }
      } else {
        throw new TagException(tag, "Parent is not of type ValueHolder, type is: " + parent);
      }
    }
  }