/*
    * 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.component.search;
  
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  import javax.faces.FacesException;
  import javax.faces.component.ContextCallback;
  import javax.faces.component.UIComponent;
  import javax.faces.component.search.SearchExpressionContext;
  import javax.faces.component.search.SearchExpressionHint;
  import javax.faces.component.search.SearchKeywordContext;
  import javax.faces.component.search.SearchKeywordResolver;
  import javax.faces.component.visit.VisitCallback;
  import javax.faces.component.visit.VisitContext;
  import javax.faces.component.visit.VisitResult;
  import javax.faces.context.FacesContext;
  
  /**
   *
   */
  public class IdSearchKeywordResolver extends SearchKeywordResolver
  {
  
      public static final String ID_KEYWORD = "id";
  
      private static final Pattern PATTERN = Pattern.compile("id\\((\\w+)\\)");
  
      @Override
      public void resolve(SearchKeywordContext expressionContext, UIComponent current, String keyword)
      {
          FacesContext facesContext = expressionContext.getSearchExpressionContext().getFacesContext();
          
          final String targetId = extractId(keyword);
          if (expressionContext.getSearchExpressionContext().getExpressionHints() != null
                  && expressionContext.getSearchExpressionContext().getExpressionHints().contains(
                          SearchExpressionHint.SKIP_VIRTUAL_COMPONENTS))
          {
              // Avoid visit tree because in this case we need real component instances.
              // This means components inside UIData will not be scanned. 
              withId(facesContext, targetId, current, expressionContext.getCallback());
              expressionContext.setKeywordResolved(true);
          }
          else
          {
              current.visitTree(
                      VisitContext.createVisitContext(facesContext, null,
                              expressionContext.getSearchExpressionContext().getVisitHints()),
                      new VisitCallback()
                      {
                          @Override
                          public VisitResult visit(VisitContext context, UIComponent target)
                          {
                              if (targetId.equals(target.getId()))
                              {
                                  expressionContext.invokeContextCallback(target);
                                  
                                  if (expressionContext.getSearchExpressionContext().getExpressionHints() != null
                                          && expressionContext.getSearchExpressionContext().getExpressionHints().contains(
                                                  SearchExpressionHint.RESOLVE_SINGLE_COMPONENT))
                                  {
                                      return VisitResult.COMPLETE;
                                  }
                                  
                                  return VisitResult.ACCEPT;
                              }
                              else
                              {
                                  return VisitResult.ACCEPT;
                              }
                          }
                      });
          }
      }
  
      protected String extractId(String expression)
      {
          Matcher matcher = PATTERN.matcher(expression);
          if (matcher.matches())
          {
              return matcher.group(1);
          }
          else
         {
             throw new FacesException("Expression does not match following pattern @id(id). Expression: \""
                     + expression + "\"");
         }
     }
 
     private static void withId(FacesContext context, String id, UIComponent base, ContextCallback callback)
     {
         if (id.equals(base.getId()))
         {
             callback.invokeContextCallback(context, base);
         }
 
         if (base.getFacetCount() > 0)
         {
             for (UIComponent facet : base.getFacets().values())
             {
                 withId(context, id, facet, callback);
             }
         }
 
         if (base.getChildCount() > 0)
         {
             for (int i = 0, childCount = base.getChildCount(); i < childCount; i++)
             {
                 UIComponent child = base.getChildren().get(i);
                 withId(context, id, child, callback);
             }
         }
     }
     
     @Override
     public boolean isResolverForKeyword(SearchExpressionContext searchExpressionContext, String command)
     {
         if (command.length() > 6 && command.substring(0, ID_KEYWORD.length()).equalsIgnoreCase(ID_KEYWORD))
         {
             Matcher matcher = PATTERN.matcher(command);
 
             if (matcher.matches())
             {
                 return true;
             }
             else
             {
                 return false;
             }
         }
         return false;
     }
 
     @Override
     public boolean isPassthrough(SearchExpressionContext searchExpressionContext, String keyword)
     {
         return false;
     }
 
     @Override
     public boolean isLeaf(SearchExpressionContext searchExpressionContext, String keyword)
     {
         return false;
     }
 
 }