/*

  * 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.config;

 import java.net.MalformedURLException;

 import java.net.URL;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.List;

 import java.util.Map;

 import javax.faces.context.ExternalContext;

 import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFWebConfigParam;

 import org.apache.myfaces.config.element.ManagedBean;

 import org.apache.myfaces.config.element.NavigationCase;

 import org.apache.myfaces.config.element.NavigationRule;

 import org.apache.myfaces.shared.util.ClassUtils;

 public class FacesConfigValidator

 {

     /**

      * Validate if the managed beans and navigations rules are correct.

      * 

      * <p>For example, it checks if the managed bean classes really exists, or if the 

      * navigation rules points to existing view files.</p>

      */

     @JSFWebConfigParam(since="2.0", defaultValue="false", expectedValues="true, false")

     public static final String VALIDATE_CONTEXT_PARAM = "org.apache.myfaces.VALIDATE";

     private FacesConfigValidator()

     {

         // hidden 

     }

     public static List<String> validate(ExternalContext ctx)

     {

         RuntimeConfig runtimeConfig = RuntimeConfig.getCurrentInstance(ctx);

         Map<String, ManagedBean> managedBeansMap = runtimeConfig.getManagedBeans();

         Collection<? extends ManagedBean> managedBeans = null;

         if (managedBeansMap != null)

         {

             managedBeans = managedBeansMap.values();

         }

         Collection<? extends NavigationRule> navRules = runtimeConfig.getNavigationRules();

         return validate(managedBeans, navRules, ctx);

     }

     public static List<String> validate(Collection<? extends ManagedBean> managedBeans, 

                                         Collection<? extends NavigationRule> navRules, ExternalContext ctx)

     {

         List<String> list = new ArrayList<String>();

         if (managedBeans != null)

         {

             validateManagedBeans(managedBeans, list);

         }

         if (navRules != null)

         {

             validateNavRules(navRules, list, ctx);

         }

         return list;

     }

     private static void validateNavRules(Collection<? extends NavigationRule> navRules, List<String> list,

                                          ExternalContext ctx)

     {

         for (NavigationRule navRule : navRules)

         {

             validateNavRule(navRule, list, ctx);

         }

     }

     private static void validateNavRule(NavigationRule navRule, List<String> list, ExternalContext ctx)

     {

         String fromId = navRule.getFromViewId();

         URL filePath;

         try

         {

             filePath = ctx.getResource(fromId);

             if(fromId != null && ! "*".equals(fromId) && filePath == null)

             {

                 list.add("File for navigation 'from id' does not exist " + filePath);

             }            

         }

         catch (MalformedURLException e)

         {

             list.add("File for navigation 'from id' does not exist " + fromId);

         }

         for (NavigationCase caze : navRule.getNavigationCases())

         {

             try

             {

                 URL toViewPath = ctx.getResource(caze.getToViewId());

                 if(toViewPath == null)

                 {

                     list.add("File for navigation 'to id' does not exist " + toViewPath);

                 }

             }

             catch (MalformedURLException e)

             {

                 list.add("File for navigation 'from id' does not exist " + caze.getToViewId());

             }

         }

     }

     private static void validateManagedBeans(Collection<? extends ManagedBean> managedBeans, List<String> list)

     {

         for (ManagedBean managedBean : managedBeans)

         {

             validateManagedBean(managedBean, list);

         }

     }

     private static void validateManagedBean(ManagedBean managedBean, List<String> list)

     {

         String className = managedBean.getManagedBeanClassName();

         try

         {

             ClassUtils.classForName(className);

         }

         catch (ClassNotFoundException e)

         { 

             String msg = "Could not locate class " 

                 + className + " for managed bean '" + managedBean.getManagedBeanName() + "'";

             list.add(msg);

         }

     }

 }