/*
    * 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.el;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.regex.Pattern;
  
  import javax.faces.component.UIComponent;
  import javax.faces.context.FacesContext;
  import javax.faces.view.Location;
  
  /**
   * Utility class for composite components when used in EL Expressions --> #{cc}
   * 
   * @author Jakob Korherr (latest modification by $Author$)
   * @version $Revision$ $Date$
   */
  public final class CompositeComponentELUtils
  {
      
      /**
       * The key under which the component stack is stored in the FacesContext.
       * ATTENTION: this constant is duplicate in UIComponent.
       */
      //public static final String COMPONENT_STACK = "componentStack:" + UIComponent.class.getName();
      
      /**
       * The key under which the current composite component is stored in the attribute
       * map of the FacesContext.
       */
      public static final String CURRENT_COMPOSITE_COMPONENT_KEY = "org.apache.myfaces.compositecomponent.current";
      
      /**
       * The key under which the Location of the composite componente is stored
       * in the attributes map of the component by InterfaceHandler.
       */
      public static final String LOCATION_KEY = "org.apache.myfaces.compositecomponent.location";
  
      /**
       * Indicates the nesting level where the composite component was created, working as reference
       * point to all EL expressions created in that point from Facelets engine.
       */
      public static final String LEVEL_KEY = "oam.cc.ccLevel";
      
      /**
       * A regular expression used to determine if cc is used in an expression String.
       */
      public static final Pattern CC_EXPRESSION_REGEX = Pattern.compile(".*[^\\w\\.]cc[^\\w].*");
      
      /**
       * A regular expression used to determine if cc.attrs is used as a method expression
       * in an expression String. This means cc.attrs must occur, must stand before a '(',
       * because otherwise it would be a method parameter (EL 2.2), and there must be no '.' after
       * cc.attrs unless there is a left parenthesis before it (e.g. #{cc.attrs.method(bean.parameter)}).
       * 
       * Explanation of the parts:
       * - [^\\(]* - There can be any character except a '(' before cc.attrs
       * - [^\\w\\.\\(] - There must be no word character, dot, or left parenthesis directly before cc.attrs
       * - cc\\.attrs\\. - "cc.attrs." must occur
       * - [^\\.]* - There must be no dot after cc.attrs to indicate a method invocation on cc.attrs
       * - (\\(.*)? - If there is a left paranthesis after cc.attrs, a dot is allowed again
       */
      public static final Pattern CC_ATTRS_METHOD_EXPRESSION_REGEX
              = Pattern.compile("[^\\(]*[^\\w\\.\\(]cc\\.attrs\\.[^\\.]*(\\(.*)?");
      
      private static final String CC = "cc";
      
      private static final String CC_ATTRS = "cc.attrs";
      
      public static final String CC_FIND_COMPONENT_EXPRESSION = "oam.CC_FIND_COMPONENT_EXPRESSION";
      
      /**
       * private constructor
       */
      private CompositeComponentELUtils()
      {
          // no instantiation of this class
      }
      
      /**
       * Try to find a composite component on the composite component stack
       * and using UIComponent.getCurrentCompositeComponent() based on the 
      * location of the facelet page that generated the composite component.
      * @param facesContext
      * @param location
      * @return
      */
     public static UIComponent getCompositeComponentBasedOnLocation(final FacesContext facesContext, 
             final Location location)
     {
         //1 Use getCurrentComponent and getCurrentCompositeComponent to look on the component stack
         UIComponent currentCompositeComponent = UIComponent.getCurrentCompositeComponent(facesContext);
         
         //1.1 Use getCurrentCompositeComponent first!
         if (currentCompositeComponent != null)
         {
             Location componentLocation = (Location) currentCompositeComponent.getAttributes().get(LOCATION_KEY);
             if (componentLocation != null 
                     && componentLocation.getPath().equals(location.getPath()))
             {
                 return currentCompositeComponent;
             }
         }
 
         UIComponent currentComponent = UIComponent.getCurrentComponent(facesContext);
         
         if (currentComponent == null)
         {
             // Cannot found any component, because we don't have any reference!
             return null;
         }
 
         //2. Look on the stack using a recursive algorithm.
         UIComponent matchingCompositeComponent
                 = lookForCompositeComponentOnStack(facesContext, location, currentComponent);
         
         if (matchingCompositeComponent != null)
         {
             return matchingCompositeComponent;
         }
         
         //2. Try to find it using UIComponent.getCurrentCompositeComponent(). 
         // This one will look the direct parent hierarchy of the component,
         // to see if the composite component can be found.
         if (currentCompositeComponent != null)
         {
             currentComponent = currentCompositeComponent;
         }
         else
         {
             //Try to find the composite component looking directly the parent
             //ancestor of the current component
             //currentComponent = UIComponent.getCurrentComponent(facesContext);
             boolean found = false;
             while (currentComponent != null && !found)
             {
                 String findComponentExpr = (String) currentComponent.getAttributes().get(CC_FIND_COMPONENT_EXPRESSION);
                 if (findComponentExpr != null)
                 {
                     UIComponent foundComponent = facesContext.getViewRoot().findComponent(findComponentExpr);
                     if (foundComponent != null)
                     {
                         Location foundComponentLocation = (Location) currentComponent.getAttributes().get(LOCATION_KEY);
                         if (foundComponentLocation != null 
                                 && foundComponentLocation.getPath().equals(location.getPath()))
                         {
                             return foundComponent;
                         }
                         else
                         {
                             while (foundComponent != null)
                             {
                                 Location componentLocation
                                         = (Location) foundComponent.getAttributes().get(LOCATION_KEY);
                                 if (componentLocation != null 
                                         && componentLocation.getPath().equals(location.getPath()))
                                 {
                                     return foundComponent;
                                 }
                                 // get the composite component's parent
                                 foundComponent = UIComponent.getCompositeComponentParent(foundComponent);
                             }
                         }
                     }
                 }
 
                 if (UIComponent.isCompositeComponent(currentComponent))
                 {
                     found = true;
                 }
                 else
                 {
                     currentComponent = currentComponent.getParent();
                 }
             }
         }
         
         //if currentComponent != null means we have a composite component that we can check
         //Use UIComponent.getCompositeComponentParent() to traverse here.
         while (currentComponent != null)
         {
             Location componentLocation = (Location) currentComponent.getAttributes().get(LOCATION_KEY);
             if (componentLocation != null 
                     && componentLocation.getPath().equals(location.getPath()))
             {
                 return currentComponent;
             }
             // get the composite component's parent
             currentComponent = UIComponent.getCompositeComponentParent(currentComponent);
         }
         
         // not found
         return null;
     }
     
     private static UIComponent lookForCompositeComponentOnStack(final FacesContext facesContext,
                                                                 final Location location,
                                                                 UIComponent currentComponent)
     {
         if (UIComponent.isCompositeComponent(currentComponent))
         {
             Location componentLocation = (Location) currentComponent.getAttributes().get(LOCATION_KEY);
             if (componentLocation != null 
                     && componentLocation.getPath().equals(location.getPath()))
             {
                 return currentComponent;
             }
         }
         currentComponent.popComponentFromEL(facesContext);
         try
         {
             UIComponent c = UIComponent.getCurrentComponent(facesContext);
             if (c != null)
             {
                 return lookForCompositeComponentOnStack( facesContext, location, c);
             }
             else
             {
                 return null;
             }
         }
         finally
         {
             currentComponent.pushComponentToEL(facesContext, currentComponent);
         }
     }
 
     private static int getCCLevel(UIComponent component)
     {
         Integer ccLevel = (Integer) component.getAttributes().get(LEVEL_KEY);
         if (ccLevel == null)
         {
             return 0;
         }
         return ccLevel.intValue();
     }
     
     public static UIComponent getCompositeComponentBasedOnLocation(final FacesContext facesContext, 
             UIComponent baseComponent, final Location location)
     {
         UIComponent currentComponent = baseComponent;
         while (currentComponent != null)
         {
             Location componentLocation = (Location) currentComponent.getAttributes().get(
                 LOCATION_KEY);
             if (componentLocation != null 
                     && componentLocation.getPath().equals(location.getPath()))
             {
                 return currentComponent;
             }
             // get the composite component's parent
             currentComponent = UIComponent.getCompositeComponentParent(currentComponent);
         }
         return null;
     }
 
     
     /**
      * Same as getCompositeComponentBasedOnLocation(final FacesContext facesContext, final Location location),
      * but takes into account the ccLevel to resolve the composite component. 
      * 
      * @param facesContext
      * @param location
      * @param ccLevel
      * @return 
      */
     public static UIComponent getCompositeComponentBasedOnLocation(final FacesContext facesContext, 
             final Location location, int ccLevel)
     {
         //1 Use getCurrentComponent and getCurrentCompositeComponent to look on the component stack
         UIComponent currentCompositeComponent = UIComponent.getCurrentCompositeComponent(facesContext);
         
         //1.1 Use getCurrentCompositeComponent first!
         if (currentCompositeComponent != null)
         {
             Location componentLocation = (Location) currentCompositeComponent.getAttributes().get(LOCATION_KEY);
             if (componentLocation != null 
                     && componentLocation.getPath().equals(location.getPath()) && 
                     (ccLevel == getCCLevel(currentCompositeComponent)) )
             {
                 return currentCompositeComponent;
             }
         }
 
         UIComponent currentComponent = UIComponent.getCurrentComponent(facesContext);
         
         if (currentComponent == null)
         {
             // Cannot found any component, because we don't have any reference!
             return null;
         }
         
         //2. Look on the stack using a recursive algorithm.
         UIComponent matchingCompositeComponent
                 = lookForCompositeComponentOnStack(facesContext, location, ccLevel, currentComponent);
         
         if (matchingCompositeComponent != null)
         {
             return matchingCompositeComponent;
         }
         
         //2. Try to find it using UIComponent.getCurrentCompositeComponent(). 
         // This one will look the direct parent hierarchy of the component,
         // to see if the composite component can be found.
         if (currentCompositeComponent != null)
         {
             currentComponent = currentCompositeComponent;
         }
         else
         {
             //Try to find the composite component looking directly the parent
             //ancestor of the current component
             //currentComponent = UIComponent.getCurrentComponent(facesContext);
             boolean found = false;
             while (currentComponent != null && !found)
             {
                 String findComponentExpr = (String) currentComponent.getAttributes().get(CC_FIND_COMPONENT_EXPRESSION);
                 if (findComponentExpr != null)
                 {
                     UIComponent foundComponent = facesContext.getViewRoot().findComponent(findComponentExpr);
                     if (foundComponent != null)
                     {
                         Location foundComponentLocation = (Location) currentComponent.getAttributes().get(LOCATION_KEY);
                         if (foundComponentLocation != null 
                                 && foundComponentLocation.getPath().equals(location.getPath()) &&
                                 ccLevel == getCCLevel(foundComponent))
                         {
                             return foundComponent;
                         }
                         else
                         {
                             while (foundComponent != null)
                             {
                                 Location componentLocation
                                         = (Location) foundComponent.getAttributes().get(LOCATION_KEY);
                                 if (componentLocation != null 
                                         && componentLocation.getPath().equals(location.getPath()) &&
                                         ccLevel == getCCLevel(foundComponent))
                                 {
                                     return foundComponent;
                                 }
                                 // get the composite component's parent
                                 foundComponent = UIComponent.getCompositeComponentParent(foundComponent);
                             }
                         }
                     }
                 }
 
                 if (UIComponent.isCompositeComponent(currentComponent))
                 {
                     found = true;
                 }
                 else
                 {
                     currentComponent = currentComponent.getParent();
                 }
             }
         }
         
         //if currentComponent != null means we have a composite component that we can check
         //Use UIComponent.getCompositeComponentParent() to traverse here.
         while (currentComponent != null)
         {
             Location componentLocation = (Location) currentComponent.getAttributes().get(LOCATION_KEY);
             if (componentLocation != null 
                     && componentLocation.getPath().equals(location.getPath()) &&
                     ccLevel == getCCLevel(currentComponent))
             {
                 return currentComponent;
             }
             // get the composite component's parent
             currentComponent = UIComponent.getCompositeComponentParent(currentComponent);
         }
         
         // not found
         return null;
     }
 
     private static UIComponent lookForCompositeComponentOnStack(final FacesContext facesContext,
                                                                 final Location location, int ccLevel,
                                                                 UIComponent currentComponent)
     {
         if (UIComponent.isCompositeComponent(currentComponent))
         {
             Location componentLocation = (Location) currentComponent.getAttributes().get(LOCATION_KEY);
             if (componentLocation != null 
                     && componentLocation.getPath().equals(location.getPath()) &&
                     (ccLevel == getCCLevel(currentComponent)) )
             {
                 return currentComponent;
             }
         }
         currentComponent.popComponentFromEL(facesContext);
         try
         {
             UIComponent c = UIComponent.getCurrentComponent(facesContext);
             if (c != null)
             {
                 return lookForCompositeComponentOnStack( facesContext, location, ccLevel, c);
             }
             else
             {
                 return null;
             }
         }
         finally
         {
             currentComponent.pushComponentToEL(facesContext, currentComponent);
         }
     }
     
     /**
      * Trys to get the composite component using getCompositeComponentBasedOnLocation()
      * and saves it in an attribute on the FacesContext, which is then used by 
      * CompositeComponentImplicitObject.
      * @param facesContext
      * @param location
      */
     public static void saveCompositeComponentForResolver(FacesContext facesContext, Location location, int ccLevel)
     {
         UIComponent cc = ccLevel > 0 ? getCompositeComponentBasedOnLocation(facesContext, location, ccLevel)
                 : getCompositeComponentBasedOnLocation(facesContext, location);
         List<UIComponent> list = (List<UIComponent>) facesContext.getAttributes().get(CURRENT_COMPOSITE_COMPONENT_KEY);
         if (list == null)
         {
             list = new ArrayList<UIComponent>();
             facesContext.getAttributes().put(CURRENT_COMPOSITE_COMPONENT_KEY, list);
         }
         list.add(cc);
     }
     
     /**
      * Removes the composite component from the attribute map of the FacesContext.
      * @param facesContext
      */
     public static void removeCompositeComponentForResolver(FacesContext facesContext)
     {
         List<UIComponent> list = (List<UIComponent>) facesContext.getAttributes().get(CURRENT_COMPOSITE_COMPONENT_KEY);
         if (list != null)
         {
             list.remove(list.size()-1);
         }
     }
     
     /**
      * Tests if the expression refers to the current composite component: #{cc}
      * @return
      */
     public static boolean isCompositeComponentExpression(String expression)
     {
         if (expression.contains(CC))
         {
             return CC_EXPRESSION_REGEX.matcher(expression).matches();
         }
         else
         {
             return false;
         }
     }
     
     /**
      * Tests if cc.attrs is used as a method expression in an expression String. This means 
      * cc.attrs must occur, must stand before a '(', because otherwise it would be a method parameter 
      * (EL 2.2), and there must be no '.' after cc.attrs unless there is a left parenthesis
      * before it (e.g. #{cc.attrs.method(bean.parameter)}).
      * @param expression
      * @return
      */
     public static boolean isCompositeComponentAttrsMethodExpression(String expression)
     {
         if (expression.contains(CC_ATTRS))
         {
             return CC_ATTRS_METHOD_EXPRESSION_REGEX.matcher(expression).matches();
         }
         else
         {
             return false;
         }
     }
     
 }