/*
    * 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.webapp;
  
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFWebConfigParam;
  import org.apache.myfaces.config.FacesConfigValidator;
  import org.apache.myfaces.config.FacesConfigurator;
  import org.apache.myfaces.config.ManagedBeanBuilder;
  import org.apache.myfaces.config.RuntimeConfig;
  import org.apache.myfaces.config.element.ManagedBean;
  import org.apache.myfaces.context.ReleaseableExternalContext;
  import org.apache.myfaces.context.servlet.StartupFacesContextImpl;
  import org.apache.myfaces.context.servlet.StartupServletExternalContextImpl;
  import org.apache.myfaces.shared.context.ExceptionHandlerImpl;
  import org.apache.myfaces.shared.util.StateUtils;
  import org.apache.myfaces.shared.util.WebConfigParamUtils;
  import org.apache.myfaces.spi.WebConfigProvider;
  import org.apache.myfaces.spi.WebConfigProviderFactory;
  import org.apache.myfaces.view.facelets.tag.MetaRulesetImpl;
  
  import javax.el.ExpressionFactory;
  import javax.faces.application.Application;
  import javax.faces.application.ProjectStage;
  import javax.faces.component.UIViewRoot;
  import javax.faces.context.ExceptionHandler;
  import javax.faces.context.ExternalContext;
  import javax.faces.context.FacesContext;
  import javax.faces.event.PostConstructApplicationEvent;
  import javax.faces.event.PreDestroyApplicationEvent;
  import javax.faces.event.SystemEvent;
  import javax.servlet.ServletContext;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  import org.apache.myfaces.util.ExternalSpecifications;
  
  /**
   * Performs common initialization tasks.
   */
  public abstract class AbstractFacesInitializer implements FacesInitializer
  {
      /**
       * The logger instance for this class.
       */
      //private static final Log log = LogFactory.getLog(AbstractFacesInitializer.class);
      private static final Logger log = Logger.getLogger(AbstractFacesInitializer.class.getName());
      
      /**
       * If the servlet mapping for the FacesServlet is added dynamically, Boolean.TRUE 
       * is stored under this key in the ServletContext.
       * ATTENTION: this constant is duplicate in MyFacesContainerInitializer.
       */
      private static final String FACES_SERVLET_ADDED_ATTRIBUTE = "org.apache.myfaces.DYNAMICALLY_ADDED_FACES_SERVLET";
  
      /**
       * This parameter specifies the ExpressionFactory implementation to use.
       */
      @JSFWebConfigParam(since="1.2.7", group="EL")
      protected static final String EXPRESSION_FACTORY = "org.apache.myfaces.EXPRESSION_FACTORY";
      
      /**
       * If this param is set to true, the check for faces servlet mapping is not done 
       */
      @JSFWebConfigParam(since="2.0.3", defaultValue="false")
      protected static final String INITIALIZE_ALWAYS_STANDALONE = "org.apache.myfaces.INITIALIZE_ALWAYS_STANDALONE";
      
      /**
       * Indicate if log all web config params should be done before initialize the webapp. 
       * <p>
       * If is set in "auto" mode, web config params are only logged on "Development" and "Production" project stages.
       * </p> 
       */
      @JSFWebConfigParam(expectedValues="true, auto, false", defaultValue="auto")
      public static final String INIT_PARAM_LOG_WEB_CONTEXT_PARAMS = "org.apache.myfaces.LOG_WEB_CONTEXT_PARAMS";
      public static final String INIT_PARAM_LOG_WEB_CONTEXT_PARAMS_DEFAULT ="auto";
  
      /**
       * Performs all necessary initialization tasks like configuring this JSF
      * application.
      */
     public void initFaces(ServletContext servletContext)
     {
         try
         {
             if (log.isLoggable(Level.FINEST))
             {
                 log.finest("Initializing MyFaces");
             }
 
             // Some parts of the following configuration tasks have been implemented 
             // by using an ExternalContext. However, that's no problem as long as no 
             // one tries to call methods depending on either the ServletRequest or 
             // the ServletResponse.
             // JSF 2.0: FacesInitializer now has some new methods to
             // use proper startup FacesContext and ExternalContext instances.
             FacesContext facesContext = FacesContext.getCurrentInstance();
             ExternalContext externalContext = facesContext.getExternalContext();
 
             // Parse and validate the web.xml configuration file
             
             if (!WebConfigParamUtils.getBooleanInitParameter(externalContext, INITIALIZE_ALWAYS_STANDALONE, false))
             {
                 WebConfigProvider webConfigProvider = WebConfigProviderFactory.getWebConfigProviderFactory(
                         facesContext.getExternalContext()).getWebConfigProvider(facesContext.getExternalContext());
 
                 if (webConfigProvider.getFacesServletMappings(facesContext.getExternalContext()).isEmpty())
                 {
                     // check if the FacesServlet has been added dynamically
                     // in a Servlet 3.0 environment by MyFacesContainerInitializer
                     Boolean mappingAdded = (Boolean) servletContext.getAttribute(FACES_SERVLET_ADDED_ATTRIBUTE);
                     if (mappingAdded == null || !mappingAdded)
                     {
                         if (log.isLoggable(Level.WARNING))
                         {
                             log.warning("No mappings of FacesServlet found. Abort initializing MyFaces.");
                         }
                         return;
                     }
                 }
             }
 
             initContainerIntegration(servletContext, externalContext);
 
             String useEncryption = servletContext.getInitParameter(StateUtils.USE_ENCRYPTION);
             if (!"false".equals(useEncryption)) // the default value is true
             {
                 StateUtils.initSecret(servletContext);
             }
 
             // initialize eager managed beans
             _createEagerBeans(facesContext);
 
             _dispatchApplicationEvent(servletContext, PostConstructApplicationEvent.class);
 
             if ( (facesContext.isProjectStage(ProjectStage.Development) || 
                   facesContext.isProjectStage(ProjectStage.Production)) &&
                  log.isLoggable(Level.INFO))
             {
                 log.info("ServletContext initialized.");
             }
 
             WebConfigParamsLogger.logWebContextParams(facesContext);
             
             //Force output EL message
             ExternalSpecifications.isUnifiedELAvailable();
             ExternalSpecifications.isBeanValidationAvailable();
 
             // print out a very prominent log message if the project stage is != Production
             if (!facesContext.isProjectStage(ProjectStage.Production) &&
                 !facesContext.isProjectStage(ProjectStage.UnitTest))
             {
                 ProjectStage projectStage = facesContext.getApplication().getProjectStage();
                 StringBuilder message = new StringBuilder("\n\n");
                 message.append("*******************************************************************\n");
                 message.append("*** WARNING: Apache MyFaces-2 is running in ");
                 message.append(projectStage.name().toUpperCase());        
                 message.append(" mode.");
                 int length = projectStage.name().length();
                 for (int i = 0; i < 11 - length; i++)
                 {
                     message.append(" ");
                 }
                 message.append("   ***\n");
                 message.append("***                                         ");
                 for (int i = 0; i < length; i++)
                 {
                     message.append("^");
                 }
                 for (int i = 0; i < 20 - length; i++)
                 {
                     message.append(" ");
                 }
                 message.append("***\n");
                 message.append("*** Do NOT deploy to your live server(s) without changing this. ***\n");
                 message.append("*** See Application#getProjectStage() for more information.     ***\n");
                 message.append("*******************************************************************\n");
                 log.log(Level.WARNING, message.toString());
             }
 
         }
         catch (Exception ex)
         {
             log.log(Level.SEVERE, "An error occured while initializing MyFaces: "
                       + ex.getMessage(), ex);
         }
     }
     
     /**
      * Checks for application scoped managed-beans with eager=true,
      * creates them and stores them in the application map.
      * @param facesContext
      */
     private void _createEagerBeans(FacesContext facesContext)
     {
         ExternalContext externalContext = facesContext.getExternalContext();
         RuntimeConfig runtimeConfig = RuntimeConfig.getCurrentInstance(externalContext);
         List<ManagedBean> eagerBeans = new ArrayList<ManagedBean>();
         
         // check all registered managed-beans
         for (ManagedBean bean : runtimeConfig.getManagedBeans().values())
         {
             String eager = bean.getEager();
             if (eager != null && "true".equals(eager))
             {
                 // eager beans are only allowed for application scope
                 if (ManagedBeanBuilder.APPLICATION.equals(bean.getManagedBeanScope()))
                 {
                     // add to eager beans
                     eagerBeans.add(bean);
                 }
                 else
                 {
                     // log warning and continue (the bean will be lazy loaded)
                     log.log(Level.WARNING, "The managed-bean with name "
                             + bean.getManagedBeanName()
                             + " must be application scoped to support eager=true.");
                 }
             }
         }
         
         // check if there are any eager beans
         if (!eagerBeans.isEmpty())
         {
             ManagedBeanBuilder managedBeanBuilder = new ManagedBeanBuilder();
             Map<String, Object> applicationMap = externalContext.getApplicationMap();
             
             for (ManagedBean bean : eagerBeans)
             {
                 // check application scope for bean instance
                 if (applicationMap.containsKey(bean.getManagedBeanName()))
                 {
                     // do not build bean, because it already exists
                     // (e.g. @ManagedProperty from previous managed bean already created it)
                     continue;
                 }
 
                 // create instance
                 Object beanInstance = managedBeanBuilder.buildManagedBean(facesContext, bean);
                 
                 // put in application scope
                 applicationMap.put(bean.getManagedBeanName(), beanInstance);
             }
         }
     }
 
     /**
      * Eventually we can use our plugin infrastructure for this as well
      * it would be a cleaner interception point than the base class
      * but for now this position is valid as well
      * <p/>
      * Note we add it for now here because the application factory object
      * leaves no possibility to have a destroy interceptor
      * and applications are per web application singletons
      * Note if this does not work out
      * move the event handler into the application factory
      *
      * @param servletContext the servlet context to be passed down
      * @param eventClass     the class to be passed down into the dispatching
      *                       code
      */
     private void _dispatchApplicationEvent(ServletContext servletContext, Class<? extends SystemEvent> eventClass)
     {
         FacesContext facesContext = FacesContext.getCurrentInstance();
         Application application = facesContext.getApplication();
         application.publishEvent(facesContext, eventClass, Application.class, application);
     }
     
     /**
      * Cleans up all remaining resources (well, theoretically).
      */
     public void destroyFaces(ServletContext servletContext)
     {
 
         FacesContext facesContext = FacesContext.getCurrentInstance();
 
         if (!WebConfigParamUtils.getBooleanInitParameter(facesContext.getExternalContext(),
                                                          INITIALIZE_ALWAYS_STANDALONE, false))
         {
             //We need to check if the current application was initialized by myfaces
             WebConfigProvider webConfigProvider = WebConfigProviderFactory.getWebConfigProviderFactory(
                     facesContext.getExternalContext()).getWebConfigProvider(facesContext.getExternalContext());
 
             if (webConfigProvider.getFacesServletMappings(facesContext.getExternalContext()).isEmpty())
             {
                 // check if the FacesServlet has been added dynamically
                 // in a Servlet 3.0 environment by MyFacesContainerInitializer
                 Boolean mappingAdded = (Boolean) servletContext.getAttribute(FACES_SERVLET_ADDED_ATTRIBUTE);
                 if (mappingAdded == null || !mappingAdded)
                 {
                     if (log.isLoggable(Level.WARNING))
                     {
                         log.warning("No mappings of FacesServlet found. Abort destroy MyFaces.");
                     }
                     return;
                 }
             }
         }
 
         _dispatchApplicationEvent(servletContext, PreDestroyApplicationEvent.class);
 
         // clear the cache of MetaRulesetImpl in order to prevent a memory leak
         MetaRulesetImpl.clearMetadataTargetCache();
         
         // clear UIViewParameter default renderer map
         try
         {
             Class<?> c = Class.forName("javax.faces.component.UIViewParameter");
             Method m = c.getDeclaredMethod("releaseRenderer");
             m.setAccessible(true);
             m.invoke(null);
         }
         catch(ClassNotFoundException e)
         {
             log.log(Level.SEVERE, e.getMessage(), e);
         }
         catch(NoSuchMethodException e)
         {
             log.log(Level.SEVERE, e.getMessage(), e);
         }
         catch(IllegalAccessException e)
         {
             log.log(Level.SEVERE, e.getMessage(), e);
         }
         catch(InvocationTargetException e)
         {
             log.log(Level.SEVERE, e.getMessage(), e);
         }
 
         // TODO is it possible to make a real cleanup?
     }
 
     /**
      * Configures this JSF application. It's required that every
      * FacesInitializer (i.e. every subclass) calls this method during
      * initialization.
      *
      * @param servletContext    the current ServletContext
      * @param externalContext   the current ExternalContext
      * @param expressionFactory the ExpressionFactory to use
      * @return the current runtime configuration
      */
     protected RuntimeConfig buildConfiguration(ServletContext servletContext,
                                                ExternalContext externalContext, ExpressionFactory expressionFactory)
     {
         RuntimeConfig runtimeConfig = RuntimeConfig.getCurrentInstance(externalContext);
         runtimeConfig.setExpressionFactory(expressionFactory);
 
         // And configure everything
         new FacesConfigurator(externalContext).configure();
 
         validateFacesConfig(servletContext, externalContext);
 
         return runtimeConfig;
     }
 
     protected void validateFacesConfig(ServletContext servletContext, ExternalContext externalContext)
     {
         String validate = servletContext.getInitParameter(FacesConfigValidator.VALIDATE_CONTEXT_PARAM);
         if ("true".equals(validate) && log.isLoggable(Level.WARNING))
         { // the default value is false
             List<String> warnings = FacesConfigValidator.validate(
                     externalContext);
 
             for (String warning : warnings)
             {
                 log.warning(warning);
             }
         }
     }
 
     /**
      * Try to load user-definied ExpressionFactory. Returns <code>null</code>,
      * if no custom ExpressionFactory was specified.
      *
      * @param externalContext the current ExternalContext
      * @return User-specified ExpressionFactory, or
      *         <code>null</code>, if no no custom implementation was specified
      */
     protected static ExpressionFactory getUserDefinedExpressionFactory(ExternalContext externalContext)
     {
         String expressionFactoryClassName
                 = WebConfigParamUtils.getStringInitParameter(externalContext, EXPRESSION_FACTORY);
         if (expressionFactoryClassName != null
                 && expressionFactoryClassName.trim().length() > 0)
         {
             if (log.isLoggable(Level.FINE))
             {
                 log.fine("Attempting to load the ExpressionFactory implementation "
                         + "you've specified: '" + expressionFactoryClassName + "'.");
             }
 
             return loadExpressionFactory(expressionFactoryClassName);
         }
 
         return null;
     }
 
     /**
      * Loads and instantiates the given ExpressionFactory implementation.
      *
      * @param expressionFactoryClassName the class name of the ExpressionFactory implementation
      * @return the newly created ExpressionFactory implementation, or
      *         <code>null</code>, if an error occurred
      */
     protected static ExpressionFactory loadExpressionFactory(String expressionFactoryClassName)
     {
         try
         {
             Class<?> expressionFactoryClass = Class.forName(expressionFactoryClassName);
             return (ExpressionFactory) expressionFactoryClass.newInstance();
         }
         catch (Exception ex)
         {
             if (log.isLoggable(Level.FINE))
             {
                 log.log(Level.FINE, "An error occured while instantiating a new ExpressionFactory. "
                         + "Attempted to load class '" + expressionFactoryClassName + "'.", ex);
             }
         }
 
         return null;
     }
 
     public FacesContext initStartupFacesContext(ServletContext servletContext)
     {
         // We cannot use FacesContextFactory, because it is necessary to initialize 
         // before Application and RenderKit factories, so we should use different object. 
         return _createFacesContext(servletContext, true);
     }
         
     public void destroyStartupFacesContext(FacesContext facesContext)
     {
         _releaseFacesContext(facesContext);
     }
     
     public FacesContext initShutdownFacesContext(ServletContext servletContext)
     {
         return _createFacesContext(servletContext, false);
     }
         
     public void destroyShutdownFacesContext(FacesContext facesContext)
     {
         _releaseFacesContext(facesContext);
     }
     
     private FacesContext _createFacesContext(ServletContext servletContext, boolean startup)
     {
         ExternalContext externalContext = new StartupServletExternalContextImpl(servletContext, startup);
         ExceptionHandler exceptionHandler = new ExceptionHandlerImpl();
         FacesContext facesContext = new StartupFacesContextImpl(externalContext, 
                 (ReleaseableExternalContext) externalContext, exceptionHandler, startup);
         
         // If getViewRoot() is called during application startup or shutdown, 
         // it should return a new UIViewRoot with its locale set to Locale.getDefault().
         UIViewRoot startupViewRoot = new UIViewRoot();
         startupViewRoot.setLocale(Locale.getDefault());
         facesContext.setViewRoot(startupViewRoot);
         
         return facesContext;
     }
     
     private void _releaseFacesContext(FacesContext facesContext)
     {        
         // make sure that the facesContext gets released.
         // This is important in an OSGi environment 
         if (facesContext != null)
         {
             facesContext.release();
         }        
     }
     
     /**
      * Performs initialization tasks depending on the current environment.
      *
      * @param servletContext  the current ServletContext
      * @param externalContext the current ExternalContext
      */
     protected abstract void initContainerIntegration(
             ServletContext servletContext, ExternalContext externalContext);
 
 }