/*
    * 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;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.el.ValueExpression;
  import javax.faces.FacesWrapper;
  import javax.faces.component.EditableValueHolder;
  import javax.faces.component.UIComponent;
  import javax.faces.context.FacesContext;
  import javax.faces.validator.Validator;
  import javax.faces.view.EditableValueHolderAttachedObjectHandler;
  import javax.faces.view.facelets.ComponentHandler;
  import javax.faces.view.facelets.FaceletContext;
  import javax.faces.view.facelets.MetaRuleset;
  import javax.faces.view.facelets.TagAttribute;
  import javax.faces.view.facelets.TagException;
  import javax.faces.view.facelets.TagHandlerDelegate;
  import javax.faces.view.facelets.ValidatorHandler;
  import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFWebConfigParam;
  
  import org.apache.myfaces.shared.renderkit.JSFAttr;
  import org.apache.myfaces.shared.util.WebConfigParamUtils;
  import org.apache.myfaces.view.facelets.FaceletCompositionContext;
  import org.apache.myfaces.view.facelets.compiler.FaceletsCompilerUtils;
  import org.apache.myfaces.view.facelets.tag.MetaRulesetImpl;
  
  /**
   * Handles setting a Validator instance on a EditableValueHolder. Will wire all attributes set to the Validator instance
   * created/fetched. Uses the "binding" attribute for grabbing instances to apply attributes to. <p> Will only
   * set/create Validator is the passed UIComponent's parent is null, signifying that it wasn't restored from an existing
   * tree.</p>
   * 
   * @author Leonardo Uribe (latest modification by $Author$)
   * @version $Revision$ $Date$
   *
   * @since 2.0
   */
  public class ValidatorTagHandlerDelegate extends TagHandlerDelegate 
      implements EditableValueHolderAttachedObjectHandler, FacesWrapper<ValidatorHandler>
  {
      
      /**
       * if &lt;f:validateBean&gt; has no children and its disabled attribute is true,
       * its validatorId will be added to the exclusion list stored under
       * this key on the parent UIComponent.
       */
      public final static String VALIDATOR_ID_EXCLUSION_LIST_KEY
              = "org.apache.myfaces.validator.VALIDATOR_ID_EXCLUSION_LIST";
      
      /**
       * Enforce f:validateBean to be called first before any JSF validator.
       */
      @JSFWebConfigParam(defaultValue="false", expectedValues="true, false", since = "2.2.10", group="validation")
      private final static String BEAN_BEFORE_JSF_VALIDATION
              = "org.apache.myfaces.validator.BEAN_BEFORE_JSF_VALIDATION";
      
      private final static String BEAN_BEFORE_JSF_PROPERTY = "oam.beanBeforeJsf";
      
      private ValidatorHandler _delegate;
      
      /**
       * true - this tag has children
       * false - this tag is a leave
       */
      private final boolean _wrapMode;
      
      private Boolean _beanBeforeJsfValidation;
      
      public ValidatorTagHandlerDelegate(ValidatorHandler delegate)
      {
          _delegate = delegate;
  
          // According to jsf 2.0 spec section 10.4.1.4
          // this tag can be used as a leave within an EditableValueHolder
          // or as a container to provide validator information for all 
          // EditableValueHolder-children (and grandchildren and ...)
          // (this behavior is analog to <f:ajax>)
          // --> Determine if we have children:
          _wrapMode = FaceletsCompilerUtils.hasChildren(_delegate.getValidatorConfig());
         _beanBeforeJsfValidation = null;
     }
 
     @Override
     public void apply(FaceletContext ctx, UIComponent parent) throws IOException
     {
         // we need methods from AbstractFaceletContext
         FaceletCompositionContext mctx = FaceletCompositionContext.getCurrentInstance(ctx);
 
         if (_wrapMode)
         {
             // the tag has children --> provide validator information for all children
             
             // FIXME the spec says we should save the validation groups in an attribute
             // on the parent UIComponent, but this will be a problem in the following scenario:
             // <h:form>
             //     <f:validateBean>
             //         <h:inputText />
             //     </f:validateBean>
             //     <h:inputText />
             // </h:form>
             // because the validator would also be applied to the second h:inputText,
             // which it should not, on my opinion. In addition, mojarra also does not
             // attach the validator to the second h:inputText in this scenario (blackbox test).
             // So I use the same way as f:ajax for this problem. -=Jakob Korherr=-
             
             String validatorId = _delegate.getValidatorConfig().getValidatorId();
             /*
             boolean disabled = _delegate.isDisabled(ctx);
             if (disabled)
             {
                 // the validator is disabled --> add its id to the exclusion stack
                 boolean validatorIdAvailable = validatorId != null && !"".equals(validatorId);
                 try
                 {
                     if (validatorIdAvailable)
                     {
                         mctx.pushExcludedValidatorIdToStack(validatorId);
                     }
                     _delegate.getValidatorConfig().getNextHandler().apply(ctx, parent);
                 }
                 finally
                 {
                     if (validatorIdAvailable)
                     {
                         mctx.popExcludedValidatorIdToStack();
                     }
                 }
             }
             else
             {*/
                 // the validator is enabled 
                 // --> add the validation groups and the validatorId to the stack
                 //String groups = getValidationGroups(ctx);
                 // spec: don't save the validation groups string if it is null or empty string
                 //boolean groupsAvailable = groups != null 
                         //&& !groups.matches(BeanValidator.EMPTY_VALIDATION_GROUPS_PATTERN);
                 //try
                 //{
                     //if (groupsAvailable)
                     //{
                     //    mctx.pushValidationGroupsToStack(groups);
                     //}
                     try
                     {
                         mctx.pushEnclosingValidatorIdToStack(validatorId, this);
                         _delegate.applyNextHandler(ctx, parent);
                     }
                     finally
                     {
                         mctx.popEnclosingValidatorIdToStack();
                     }
                 //}
                 //finally
                 //{
                     //if (groupsAvailable)
                     //{
                         //mctx.popValidationGroupsToStack();
                     //}
                 //}
             /*}*/
         }
         else
         {
             // Apply only if we are creating a new component
             if (!ComponentHandler.isNew(parent))
             {
                 return;
             }
 
             // the tag is a leave --> attach validator to parent
             if (parent instanceof EditableValueHolder)
             {
                 applyAttachedObject(ctx.getFacesContext(), parent);
             }
             else if (UIComponent.isCompositeComponent(parent))
             {
                 if (getFor() == null)
                 {
                     throw new TagException(_delegate.getTag(), "is nested inside a composite component"
                             + " but does not have a for attribute.");
                 }
                 mctx.addAttachedObjectHandler(parent, _delegate);
             }
             else
             {
                 throw new TagException(_delegate.getTag(),
                         "Parent not composite component or an instance of EditableValueHolder: " + parent);
             }
         }
     }
 
     /**
      * Template method for creating a Validator instance
      * 
      * @param ctx FaceletContext to use
      * @return a new Validator instance
      */
     protected Validator createValidator(FaceletContext ctx)
     {
         if (_delegate.getValidatorId(ctx) == null)
         {
             throw new TagException(_delegate.getTag(), "Default behavior invoked of requiring " +
                     "a validator-id passed in the constructor, must override ValidateHandler(ValidatorConfig)");
         }
         return ctx.getFacesContext().getApplication().createValidator(_delegate.getValidatorId(ctx));
     }
 
     @Override
     public MetaRuleset createMetaRuleset(Class type)
     {
         MetaRuleset metaRuleset = new MetaRulesetImpl(_delegate.getTag(), type);
         
         // ignore binding and disabled, because they are handled by DelegatingMetaTagHandler
         metaRuleset.ignore(JSFAttr.BINDING_ATTR).ignore(JSFAttr.DISABLED_ATTR);
         // ignore for, because it is handled by FaceletsAttachedObjectHandler
         metaRuleset.ignore(JSFAttr.FOR_ATTR);
         
         return metaRuleset;
     }
 
     @SuppressWarnings("unchecked")
     public void applyAttachedObject(FacesContext context, UIComponent parent)
     {
         // Retrieve the current FaceletContext from FacesContext object
         FaceletContext faceletContext = (FaceletContext) context.getAttributes().get(
                 FaceletContext.FACELET_CONTEXT_KEY);
         
         // spec: if the disabled attribute is true, the validator should not be added.
         // in addition, the validatorId, if present, should be added to an exclusion
         // list on the parent component to prevent a default validator with the same
         // id from beeing registered on the component.
         if (_delegate.isDisabled(faceletContext))
         {
             // tag is disabled --> add its validatorId to the parent's exclusion list
             String validatorId = _delegate.getValidatorConfig().getValidatorId();
             if (validatorId != null && !"".equals(validatorId))
             {
                 List<String> exclusionList = (List<String>) parent.getAttributes()
                         .get(VALIDATOR_ID_EXCLUSION_LIST_KEY);
                 if (exclusionList == null)
                 {
                     exclusionList = new ArrayList<String>();
                     parent.getAttributes().put(VALIDATOR_ID_EXCLUSION_LIST_KEY, exclusionList);
                 }
                 exclusionList.add(validatorId);
             }
         }
         else
         {
             // tag is enabled --> create the validator and attach it
             
             // cast to a ValueHolder
             EditableValueHolder evh = (EditableValueHolder) parent;
             ValueExpression ve = null;
             Validator v = null;
             if (_delegate.getBinding() != null)
             {
                 ve = _delegate.getBinding().getValueExpression(faceletContext, Validator.class);
                 v = (Validator) ve.getValue(faceletContext);
             }
             if (v == null)
             {
                 v = this.createValidator(faceletContext);
                 if (ve != null)
                 {
                     ve.setValue(faceletContext, v);
                 }
             }
             if (v == null)
             {
                 throw new TagException(_delegate.getTag(), "No Validator was created");
             }
             _delegate.setAttributes(faceletContext, v);
             if (shouldBeanBeforeJsfValidationEnabled(context))
             {
                 parent.getAttributes().put(BEAN_BEFORE_JSF_PROPERTY, Boolean.TRUE);
             }
             evh.addValidator(v); 
         }
     }
     
     private boolean shouldBeanBeforeJsfValidationEnabled(FacesContext context)
     {
         if (_beanBeforeJsfValidation == null)
         {
             _beanBeforeJsfValidation = WebConfigParamUtils.getBooleanInitParameter(context.getExternalContext(),
                     BEAN_BEFORE_JSF_VALIDATION, false);
         }
         return _beanBeforeJsfValidation;
     }
             
 
     public String getFor()
     {
         TagAttribute forAttribute = _delegate.getTagAttribute("for");
         
         if (forAttribute == null)
         {
             return null;
         }
         else
         {
             return forAttribute.getValue();
         }
     }
     
     public String getValidationGroups(FaceletContext ctx)
     {
         TagAttribute attribute = _delegate.getTagAttribute("validationGroups");
         
         if (attribute == null)
         {
             return null;
         }
         else
         {
             return attribute.getValue(ctx);
         }
     }
 
     public ValidatorHandler getWrapped()
     {
         return _delegate;
     }
 
 }