/*
    * 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.ui;
  
  import java.io.IOException;
  import java.net.URL;
  import java.util.Collection;
  
  import javax.el.ELException;
  import javax.el.ValueExpression;
  import javax.el.VariableMapper;
  import javax.faces.FacesException;
  import javax.faces.application.ProjectStage;
  import javax.faces.application.StateManager;
  import javax.faces.component.UIComponent;
  import javax.faces.event.PhaseId;
  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.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.shared.util.ClassUtils;
  import org.apache.myfaces.view.facelets.AbstractFaceletContext;
  import org.apache.myfaces.view.facelets.FaceletCompositionContext;
  import org.apache.myfaces.view.facelets.el.VariableMapperWrapper;
  import org.apache.myfaces.view.facelets.impl.TemplateContextImpl;
  import org.apache.myfaces.view.facelets.tag.ComponentContainerHandler;
  import org.apache.myfaces.view.facelets.tag.TagHandlerUtils;
  import org.apache.myfaces.view.facelets.tag.jsf.ComponentSupport;
  
  /**
   * The include tag can point at any Facelet which might use the composition tag,
   * component tag, or simply be straight XHTML/XML. It should be noted that the 
   * src path does allow relative path names, but they will always be resolved 
   * against the original Facelet requested. 
   * 
   * The include tag can be used in conjunction with multiple <ui:param/> 
   * tags to pass EL expressions/values to the target page.
   * 
   * @author Jacob Hookom
   * @version $Id$
   */
  @JSFFaceletTag(name="ui:include", bodyContent="JSP")
  public final class IncludeHandler extends TagHandler implements ComponentContainerHandler
  {
  
      private static final String ERROR_PAGE_INCLUDE_PATH = "javax.faces.error.xhtml";
      private static final String ERROR_FACELET = "META-INF/rsc/myfaces-dev-error-include.xhtml";
      
      /**
       * A literal or EL expression that specifies the target Facelet that you 
       * would like to include into your document.
       */
      @JSFFaceletAttribute(
              className="javax.el.ValueExpression",
              deferredValueType="java.lang.String",
              required=true)
      private final TagAttribute src;
      
      private final ParamHandler[] _params;
  
      /**
       * @param config
       */
      public IncludeHandler(TagConfig config)
      {
          super(config);
          this.src = this.getRequiredAttribute("src");
          
          Collection<ParamHandler> params = TagHandlerUtils.findNextByType(nextHandler, ParamHandler.class);
          if (!params.isEmpty())
          {
              int i = 0;
              _params = new ParamHandler[params.size()];
              for (ParamHandler handler : params)
              {
                  _params[i++] = handler;
              }
          }
          else
         {
             _params = null;
         }
     }
 
     /*
      * (non-Javadoc)
      * 
      * @see javax.faces.view.facelets.FaceletHandler#apply(javax.faces.view.facelets.FaceletContext, javax.faces.component.UIComponent)
      */
     public void apply(FaceletContext ctx, UIComponent parent) throws IOException, FacesException, FaceletException,
             ELException
     {
         AbstractFaceletContext actx = (AbstractFaceletContext) ctx;
         FaceletCompositionContext fcc = FaceletCompositionContext.getCurrentInstance(ctx);
         String path;
         boolean markInitialState = false;
         String uniqueId = null;
         if (!src.isLiteral())
         {
             uniqueId = actx.generateUniqueFaceletTagId(
                 fcc.startComponentUniqueIdSection(), tagId);
         }
         else if (_params != null)
         {
             uniqueId = actx.generateUniqueFaceletTagId(
                 fcc.generateUniqueComponentId(), tagId);
         }
         if (!src.isLiteral())
         {
             //String uniqueId = fcc.startComponentUniqueIdSection();
             //path = getSrcValue(actx, fcc, parent, uniqueId);
             String restoredPath = (String) ComponentSupport.restoreInitialTagState(ctx, fcc, parent, uniqueId);
             if (restoredPath != null)
             {
                 // If is not restore view phase, the path value should be
                 // evaluated and if is not equals, trigger markInitialState stuff.
                 if (!PhaseId.RESTORE_VIEW.equals(ctx.getFacesContext().getCurrentPhaseId()))
                 {
                     path = this.src.getValue(ctx);
                     if (path == null || path.length() == 0)
                     {
                         return;
                     }
                     if (!path.equals(restoredPath))
                     {
                         markInitialState = true;
                     }
                 }
                 else
                 {
                     path = restoredPath;
                 }
             }
             else
             {
                 //No state restored, calculate path
                 path = this.src.getValue(ctx);
             }
             ComponentSupport.saveInitialTagState(ctx, fcc, parent, uniqueId, path);
         }
         else
         {
             path = this.src.getValue(ctx);
         }
         try
         {
             if (path == null || path.length() == 0)
             {
                 return;
             }
             VariableMapper orig = ctx.getVariableMapper();
             ctx.setVariableMapper(new VariableMapperWrapper(orig));
             try
             {
                 //Only ui:param could be inside ui:include.
                 //this.nextHandler.apply(ctx, null);
                 
                 URL url = null;
                 boolean oldMarkInitialState = false;
                 Boolean isBuildingInitialState = null;
                 // if we are in ProjectStage Development and the path equals "javax.faces.error.xhtml"
                 // we should include the default error page
                 if (ctx.getFacesContext().isProjectStage(ProjectStage.Development) 
                         && ERROR_PAGE_INCLUDE_PATH.equals(path))
                 {
                     url =ClassUtils.getResource(ERROR_FACELET);
                 }
                 if (markInitialState)
                 {
                     //set markInitialState flag
                     oldMarkInitialState = fcc.isMarkInitialState();
                     fcc.setMarkInitialState(true);
                     isBuildingInitialState = (Boolean) ctx.getFacesContext().getAttributes().put(
                             StateManager.IS_BUILDING_INITIAL_STATE, Boolean.TRUE);
                 }
                 try
                 {
                     if (_params != null)
                     {
                         // ui:include defines a new TemplateContext, but ui:param EL expressions
                         // defined inside should be built before the new context is setup, to
                         // apply then after. The final effect is EL expressions will be resolved
                         // correctly when nested ui:params with the same name or based on other
                         // ui:params are used.
                         
                         String[] names = new String[_params.length];
                         ValueExpression[] values = new ValueExpression[_params.length];
                         
                         for (int i = 0; i < _params.length; i++)
                         {
                             names[i] = _params[i].getName(ctx);
                             values[i] = _params[i].getValue(ctx);
                         }
                         
                         actx.pushTemplateContext(new TemplateContextImpl());
                         
                         for (int i = 0; i < _params.length; i++)
                         {
                             _params[i].apply(ctx, parent, names[i], values[i], uniqueId);
                         }
                     }
                     else
                     {
                         actx.pushTemplateContext(new TemplateContextImpl());
                     }
                     if (url == null)
                     {
                         ctx.includeFacelet(parent, path);
                     }
                     else
                     {
                         ctx.includeFacelet(parent, url);
                     }
                 }
                 finally
                 {
                     if (markInitialState)
                     {
                         //unset markInitialState flag
                         if (isBuildingInitialState == null)
                         {
                             ctx.getFacesContext().getAttributes().remove(
                                     StateManager.IS_BUILDING_INITIAL_STATE);
                         }
                         else
                         {
                             ctx.getFacesContext().getAttributes().put(
                                     StateManager.IS_BUILDING_INITIAL_STATE, isBuildingInitialState);
                         }
                         fcc.setMarkInitialState(oldMarkInitialState);
                     }
                     actx.popTemplateContext();
                 }
             }
             finally
             {
                 ctx.setVariableMapper(orig);
             }
         }
         finally
         {
             if (!src.isLiteral())
             {
                 fcc.endComponentUniqueIdSection();
                 
                 if (fcc.isUsingPSSOnThisView() && fcc.isRefreshTransientBuildOnPSS() &&
                     !fcc.isRefreshingTransientBuild())
                 {
                     //Mark the parent component to be saved and restored fully.
                     ComponentSupport.markComponentToRestoreFully(ctx.getFacesContext(), parent);
                 }
                 if (fcc.isDynamicComponentSection())
                 {
                     ComponentSupport.markComponentToRefreshDynamically(ctx.getFacesContext(), parent);
                 }
             }
         }
     }
 }