/*
    * 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.List;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  import javax.faces.FacesException;
  import javax.faces.component.UIComponent;
  import javax.faces.component.search.UntargetableComponent;
  import javax.faces.component.search.SearchExpressionContext;
  import javax.faces.component.search.SearchKeywordContext;
  import javax.faces.component.search.SearchKeywordResolver;
  
  /**
   *
   */
  public class ChildSearchKeywordResolver extends SearchKeywordResolver
  {
  
      public static final String CHILD_KEYWORD = "child";
  
      private static final Pattern PATTERN = Pattern.compile("child\\((\\d+)\\)");
  
      @Override
      public void resolve(SearchKeywordContext expressionContext, UIComponent current, String keyword)
      {
          Matcher matcher = PATTERN.matcher(keyword);
  
          if (matcher.matches())
          {
              int childNumber = Integer.parseInt(matcher.group(1));
  
              if (childNumber + 1 > current.getChildCount())
              {
                  throw new FacesException("Component with clientId \""
                          + current.getClientId(expressionContext.getSearchExpressionContext().getFacesContext()) 
                          + "\" has fewer children as \"" + 
                            childNumber + "\". Expression: \"" + keyword + "\"");
              }
  
              List<UIComponent> list = current.getChildren();
              int count = 0;
              for (int i = 0; i < current.getChildCount(); i++)
              {
                  if (! (list.get(i) instanceof UntargetableComponent))
                  {
                      count++;
                  }
                  if (count == childNumber + 1)
                  {
                      expressionContext.invokeContextCallback(current.getChildren().get(childNumber));
                      break;
                  }
              }
              if (count < childNumber)
              {
                  throw new FacesException("Component with clientId \""
                          + current.getClientId(expressionContext.getSearchExpressionContext().getFacesContext()) 
                          + "\" has fewer children as \"" + 
                            childNumber + "\". Expression: \"" + keyword + "\"");
              }
          }
          else
          {
              throw new FacesException(
                      "Expression does not match following pattern @child(n). Expression: \"" + keyword + "\"");
          }
      }
  
      @Override
      public boolean isResolverForKeyword(SearchExpressionContext searchExpressionContext, String command)
      {
          if (command.length() > 6 && command.substring(0, CHILD_KEYWORD.length()).equalsIgnoreCase(CHILD_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;
     }
 
 }