/*
    * 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.impl;
  
  import java.io.Externalizable;
  import java.io.IOException;
  import java.io.ObjectInput;
  import java.io.ObjectOutput;
  import java.net.URL;
  import java.text.DateFormat;
  import java.text.SimpleDateFormat;
  import java.util.Collections;
  import java.util.Collection;
  import java.util.Date;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.WeakHashMap;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import javax.el.ELException;
  import javax.el.ExpressionFactory;
  import javax.faces.FacesException;
  import javax.faces.application.Resource;
  import javax.faces.application.ViewResource;
  import javax.faces.component.UIComponent;
  import javax.faces.component.UIViewRoot;
  import javax.faces.component.UniqueIdVendor;
  import javax.faces.context.FacesContext;
  import javax.faces.view.facelets.FaceletContext;
  import javax.faces.view.facelets.FaceletException;
  import javax.faces.view.facelets.FaceletHandler;
  import org.apache.myfaces.shared.config.MyfacesConfig;
  
  import org.apache.myfaces.view.facelets.AbstractFacelet;
  import org.apache.myfaces.view.facelets.AbstractFaceletContext;
  import org.apache.myfaces.view.facelets.FaceletCompositionContext;
  import org.apache.myfaces.view.facelets.FaceletFactory;
  import org.apache.myfaces.view.facelets.compiler.EncodingHandler;
  import org.apache.myfaces.view.facelets.tag.jsf.ComponentSupport;
  
  
  /**
   * Default Facelet implementation.
   * 
   * @author Jacob Hookom
   * @version $Id$
   */
  final class DefaultFacelet extends AbstractFacelet
  {
      private static final Logger log = Logger.getLogger(DefaultFacelet.class.getName());
  
      private final static String APPLIED_KEY = "org.apache.myfaces.view.facelets.APPLIED";
  
      private final String _alias;
      
      private final String _faceletId;
  
      private final ExpressionFactory _elFactory;
  
      private final DefaultFaceletFactory _factory;
  
      private final long _createTime;
  
      private final long _refreshPeriod;
  
      private final Map<String, URL> _relativePaths;
  
      private final FaceletHandler _root;
  
      private final URL _src;
  
      private final boolean _isBuildingCompositeComponentMetadata; 
      
      private final boolean _encodingHandler;
  
      public DefaultFacelet(DefaultFaceletFactory factory, ExpressionFactory el, URL src, String alias,
                            String faceletId, FaceletHandler root)
      {
          _factory = factory;
          _elFactory = el;
          _src = src;
         _root = root;
         _alias = alias;
         _faceletId = faceletId;
         _createTime = System.currentTimeMillis();
         _refreshPeriod = _factory.getRefreshPeriod();
         _relativePaths = Collections.synchronizedMap(new WeakHashMap());
         _isBuildingCompositeComponentMetadata = false;
         _encodingHandler = (root instanceof EncodingHandler);
     }
 
     public DefaultFacelet(DefaultFaceletFactory factory, ExpressionFactory el, URL src, String alias,
             String faceletId, FaceletHandler root, boolean isBuildingCompositeComponentMetadata)
     {
         _factory = factory;
         _elFactory = el;
         _src = src;
         _root = root;
         _alias = alias;
         _faceletId = faceletId;
         _createTime = System.currentTimeMillis();
         _refreshPeriod = _factory.getRefreshPeriod();
         _relativePaths = Collections.synchronizedMap(new WeakHashMap());
         _isBuildingCompositeComponentMetadata = isBuildingCompositeComponentMetadata;
         _encodingHandler = (root instanceof EncodingHandler);
     }    
 
     /**
      * @see org.apache.myfaces.view.facelets.Facelet#apply(javax.faces.context.FacesContext,
      *      javax.faces.component.UIComponent)
      */
     public void apply(FacesContext facesContext, UIComponent parent) throws IOException, FacesException,
             FaceletException, ELException
     {
         FaceletCompositionContext myFaceletContext = null;
         boolean faceletCompositionContextInitialized = false;
         boolean recordUniqueIds = false;
         myFaceletContext = FaceletCompositionContext.getCurrentInstance(facesContext);
         if (myFaceletContext == null)
         {
             myFaceletContext = new FaceletCompositionContextImpl(_factory, facesContext);
             myFaceletContext.init(facesContext);
             faceletCompositionContextInitialized = true;
             if (_encodingHandler && !myFaceletContext.isBuildingViewMetadata()
                     && MyfacesConfig.getCurrentInstance(
                     facesContext.getExternalContext()).isViewUniqueIdsCacheEnabled() && 
                     _refreshPeriod <= 0)
             {
                 List<String> uniqueIdList = ((EncodingHandler)_root).getUniqueIdList();
                 if (uniqueIdList == null)
                 {
                     myFaceletContext.initUniqueIdRecording();
                     recordUniqueIds = true;
                 }
                 else
                 {
                     myFaceletContext.setUniqueIdsIterator(uniqueIdList.iterator());
                 }
             }
             if (parent instanceof UIViewRoot)
             {
                 myFaceletContext.setViewRoot((UIViewRoot)parent);
                 ComponentSupport.setCachedFacesContext((UIViewRoot)parent, facesContext);
             }
         }
         DefaultFaceletContext ctx = new DefaultFaceletContext(facesContext, this, myFaceletContext);
         
         //Set FACELET_CONTEXT_KEY on FacesContext attribute map, to 
         //reflect the current facelet context instance
         FaceletContext oldCtx = (FaceletContext) 
                 facesContext.getAttributes().put(FaceletContext.FACELET_CONTEXT_KEY, ctx);
         
         ctx.pushPageContext(new PageContextImpl());
         
         try
         {
             // push the parent as a UniqueIdVendor to the stack here,
             // if there is no UniqueIdVendor on the stack yet
             boolean pushedUniqueIdVendor = false;
             if (parent instanceof UniqueIdVendor
                 && ctx.getFaceletCompositionContext().getUniqueIdVendorFromStack() == null)
             {
                 ctx.getFaceletCompositionContext().pushUniqueIdVendorToStack((UniqueIdVendor) parent);
                 pushedUniqueIdVendor = true;
             }
             
             this.refresh(parent);
             myFaceletContext.markForDeletion(parent);
             _root.apply(ctx, parent);
             if (faceletCompositionContextInitialized &&
                 parent instanceof UIViewRoot)
             {
                 UIComponent metadataFacet = parent.getFacet(UIViewRoot.METADATA_FACET_NAME);
                 if (metadataFacet != null)
                 {
                     // Ensure metadata facet is removed from deletion, so if by some reason
                     // is not refreshed, its content will not be removed from the component tree.
                     // This behavior is preferred, even if the spec suggest to include it using
                     // a trick with the template client.
                     myFaceletContext.removeComponentForDeletion(metadataFacet);
                 }
                 if (myFaceletContext.isRefreshingTransientBuild())
                 {
                     myFaceletContext.finalizeRelocatableResourcesForDeletion((UIViewRoot) parent);
                 }
             }
             myFaceletContext.finalizeForDeletion(parent);
             this.markApplied(parent);
             
             // remove the UniqueIdVendor from the stack again
             if (pushedUniqueIdVendor)
             {
                 ctx.getFaceletCompositionContext().popUniqueIdVendorToStack();
             }
         }
         finally
         {
             ctx.popPageContext();
             
             if (faceletCompositionContextInitialized)
             {
                 if (parent instanceof UIViewRoot)
                 {
                     ComponentSupport.setCachedFacesContext((UIViewRoot)parent, null);
                 }
                 myFaceletContext.release(facesContext);
                 List<String> uniqueIdList = ((EncodingHandler)_root).getUniqueIdList();
                 if (recordUniqueIds &&  uniqueIdList == null)
                 {
                     uniqueIdList = Collections.unmodifiableList(
                             myFaceletContext.getUniqueIdList());
                     ((EncodingHandler)_root).setUniqueIdList(uniqueIdList);
                 }
             }
             
             if (oldCtx != null)
             {
                 facesContext.getAttributes().put(FaceletContext.FACELET_CONTEXT_KEY, oldCtx);
             }
         }
     }
     
     public void applyDynamicComponentHandler(FacesContext facesContext, 
             UIComponent parent, String baseKey)
          throws IOException, FacesException, FaceletException, ELException
     {
         FaceletCompositionContext fcctx = null;
         boolean faceletCompositionContextInitialized = false;
         fcctx = FaceletCompositionContext.getCurrentInstance(facesContext);
         boolean pushDynCompSection = false;
         if (fcctx == null)
         {
             fcctx = new FaceletCompositionContextImpl(_factory, facesContext, 
                 baseKey);
             fcctx.init(facesContext);
             faceletCompositionContextInitialized = true;
         }
         else
         {
             pushDynCompSection = true;
             fcctx.pushDynamicComponentSection(baseKey);
         }
         // Disable dynamic component top level if the parent is a
         // dynamic wrapper, to allow the content to be reorganized properly under
         // a refresh.
         if (parent.getAttributes().containsKey("oam.vf.DYN_WRAPPER"))
         {
             fcctx.setDynamicComponentTopLevel(false);
         }
         
         FaceletContext oldCtx = (FaceletContext) facesContext.getAttributes().get(
             FaceletContext.FACELET_CONTEXT_KEY);
         DefaultFaceletContext ctx = new DefaultFaceletContext(facesContext, this, fcctx);
         
         //Set FACELET_CONTEXT_KEY on FacesContext attribute map, to 
         //reflect the current facelet context instance
         facesContext.getAttributes().put(FaceletContext.FACELET_CONTEXT_KEY, ctx);
         
         ctx.pushPageContext(new PageContextImpl());
         
         try
         {
             // push the parent as a UniqueIdVendor to the stack here,
             // if there is no UniqueIdVendor on the stack yet
             boolean pushedUniqueIdVendor = false;
             if (parent instanceof UniqueIdVendor
                 && ctx.getFaceletCompositionContext().getUniqueIdVendorFromStack() == null)
             {
                 ctx.getFaceletCompositionContext().pushUniqueIdVendorToStack((UniqueIdVendor) parent);
                 pushedUniqueIdVendor = true;
             }
             
             //this.refresh(parent);
             //myFaceletContext.markForDeletion(parent);
             _root.apply(ctx, parent);
             //myFaceletContext.finalizeForDeletion(parent);
             //this.markApplied(parent);
             
             // remove the UniqueIdVendor from the stack again
             if (pushedUniqueIdVendor)
             {
                 ctx.getFaceletCompositionContext().popUniqueIdVendorToStack();
             }
         }
         finally
         {
             ctx.popPageContext();
             facesContext.getAttributes().put(FaceletContext.FACELET_CONTEXT_KEY, oldCtx);
             
             if (pushDynCompSection)
             {
                 fcctx.popDynamicComponentSection();
             }
             if (faceletCompositionContextInitialized)
             {
                 fcctx.release(facesContext);
             }
         }
     }    
 
     private void refresh(UIComponent c)
     {
         if (_refreshPeriod > 0)
         {
 
             // finally remove any children marked as deleted
             int sz = c.getChildCount();
             if (sz > 0)
             {
                 UIComponent cc = null;
                 List<UIComponent> cl = c.getChildren();
                 ApplyToken token;
                 while (--sz >= 0)
                 {
                     cc = cl.get(sz);
                     if (!cc.isTransient())
                     {
                         token = (ApplyToken) cc.getAttributes().get(APPLIED_KEY);
                         if (token != null && token._time < _createTime && token._alias.equals(_alias))
                         {
                             if (log.isLoggable(Level.INFO))
                             {
                                 DateFormat df = SimpleDateFormat.getTimeInstance();
                                 log.info("Facelet[" + _alias + "] was modified @ "
                                         + df.format(new Date(_createTime)) + ", flushing component applied @ "
                                         + df.format(new Date(token._time)));
                             }
                             cl.remove(sz);
                         }
                     }
                 }
             }
 
             // remove any facets marked as deleted
             if (c.getFacetCount() > 0)
             {
                 Collection<UIComponent> col = c.getFacets().values();
                 UIComponent fc;
                 ApplyToken token;
                 for (Iterator<UIComponent> itr = col.iterator(); itr.hasNext();)
                 {
                     fc = itr.next();
                     if (!fc.isTransient())
                     {
                         token = (ApplyToken) fc.getAttributes().get(APPLIED_KEY);
                         if (token != null && token._time < _createTime && token._alias.equals(_alias))
                         {
                             if (log.isLoggable(Level.INFO))
                             {
                                 DateFormat df = SimpleDateFormat.getTimeInstance();
                                 log.info("Facelet[" + _alias + "] was modified @ "
                                         + df.format(new Date(_createTime)) + ", flushing component applied @ "
                                         + df.format(new Date(token._time)));
                             }
                             itr.remove();
                         }
                     }
                 }
             }
         }
     }
 
     private void markApplied(UIComponent parent)
     {
         if (this._refreshPeriod > 0)
         {
             int facetCount = parent.getFacetCount();
             int childCount = parent.getChildCount();
             if (childCount > 0 || facetCount > 0)
             {
                 ApplyToken token = new ApplyToken(_alias, System.currentTimeMillis() + _refreshPeriod);
 
                 if (facetCount > 0)
                 {
                     for (UIComponent facet : parent.getFacets().values())
                     {
                         markApplied(token, facet);
                     }
                 }
                 for (int i = 0; i < childCount; i++)
                 {
                     UIComponent child = parent.getChildren().get(i);
                     markApplied(token, child);
                 }
             }
         }
     }
 
     private void markApplied(ApplyToken token, UIComponent c)
     {
         if (!c.isTransient())
         {
             Map<String, Object> attr = c.getAttributes();
             if (!attr.containsKey(APPLIED_KEY))
             {
                 attr.put(APPLIED_KEY, token);
             }
         }
     }
 
     /**
      * Return the alias name for error messages and logging
      * 
      * @return alias name
      */
     public String getAlias()
     {
         return _alias;
     }
     
     public String getFaceletId()
     {
         return _faceletId;
     }
 
     /**
      * Return this Facelet's ExpressionFactory instance
      * 
      * @return internal ExpressionFactory instance
      */
     public ExpressionFactory getExpressionFactory()
     {
         return _elFactory;
     }
 
     /**
      * The time when this Facelet was created, NOT the URL source code
      * 
      * @return final timestamp of when this Facelet was created
      */
     public long getCreateTime()
     {
         return _createTime;
     }
 
     /**
      * Delegates resolution to DefaultFaceletFactory reference. Also, caches URLs for relative paths.
      * 
      * @param path
      *            a relative url path
      * @return URL pointing to destination
      * @throws IOException
      *             if there is a problem creating the URL for the path specified
      */
     private URL getRelativePath(FacesContext facesContext, String path) throws IOException
     {
         URL url = (URL) _relativePaths.get(path);
         if (url == null)
         {
             url = _factory.resolveURL(facesContext, _src, path);
             if (url != null)
             {
                 ViewResource viewResource = (ViewResource) facesContext.getAttributes().get(
                     FaceletFactory.LAST_RESOURCE_RESOLVED);
                 if (viewResource != null)
                 {
                     // If a view resource has been used to resolve a resource, the cache is in
                     // the ResourceHandler implementation. No need to cache in _relativeLocations.
                 }
                 else
                 {
                     _relativePaths.put(path, url);
                 }
             }
         }
         return url;
     }
 
     /**
      * The URL this Facelet was created from.
      * 
      * @return the URL this Facelet was created from
      */
     public URL getSource()
     {
         return _src;
     }
 
     /**
      * Given the passed FaceletContext, apply our child FaceletHandlers to the passed parent
      * 
      * @see FaceletHandler#apply(FaceletContext, UIComponent)
      * @param ctx
      *            the FaceletContext to use for applying our FaceletHandlers
      * @param parent
      *            the parent component to apply changes to
      * @throws IOException
      * @throws FacesException
      * @throws FaceletException
      * @throws ELException
      */
     private void include(AbstractFaceletContext ctx, UIComponent parent) throws IOException, FacesException,
             FaceletException, ELException
     {
         ctx.pushPageContext(new PageContextImpl());
         try
         {
             this.refresh(parent);
             DefaultFaceletContext ctxWrapper = new DefaultFaceletContext((DefaultFaceletContext)ctx, this, false);
             ctx.getFacesContext().getAttributes().put(FaceletContext.FACELET_CONTEXT_KEY, ctxWrapper);
             _root.apply(ctxWrapper, parent);
             ctx.getFacesContext().getAttributes().put(FaceletContext.FACELET_CONTEXT_KEY, ctx);
             this.markApplied(parent);
         }
         finally
         {
             ctx.popPageContext();
         }
     }
 
     /**
      * Used for delegation by the DefaultFaceletContext. First pulls the URL from {@link #getRelativePath(String)
      * getRelativePath(String)}, then calls
      * {@link #include(org.apache.myfaces.view.facelets.AbstractFaceletContext,
      * javax.faces.component.UIComponent, java.net.URL)}.
      * 
      * @see FaceletContext#includeFacelet(UIComponent, String)
      * @param ctx
      *            FaceletContext to pass to the included Facelet
      * @param parent
      *            UIComponent to apply changes to
      * @param path
      *            relative path to the desired Facelet from the FaceletContext
      * @throws IOException
      * @throws FacesException
      * @throws FaceletException
      * @throws ELException
      */
     public void include(AbstractFaceletContext ctx, UIComponent parent, String path)
             throws IOException, FacesException, FaceletException, ELException
     {
         URL url = this.getRelativePath(ctx.getFacesContext(), path);
         this.include(ctx, parent, url);
     }
 
     /**
      * Grabs a DefaultFacelet from referenced DefaultFaceletFacotry
      * 
      * @see DefaultFaceletFactory#getFacelet(URL)
      * @param ctx
      *            FaceletContext to pass to the included Facelet
      * @param parent
      *            UIComponent to apply changes to
      * @param url
      *            URL source to include Facelet from
      * @throws IOException
      * @throws FacesException
      * @throws FaceletException
      * @throws ELException
      */
     public void include(AbstractFaceletContext ctx, UIComponent parent, URL url) throws IOException, FacesException,
             FaceletException, ELException
     {
         DefaultFacelet f = (DefaultFacelet) _factory.getFacelet(ctx, url);
         f.include(ctx, parent);
     }
     
     public void applyCompositeComponent(AbstractFaceletContext ctx, UIComponent parent, Resource resource)
             throws IOException, FacesException, FaceletException, ELException
     {
         // Here we are creating a facelet using the url provided by the resource.
         // It works, but the Resource API provides getInputStream() for that. But the default
         // implementation wraps everything that could contain ValueExpression and decode so
         // we can't use it here.
         //DefaultFacelet f = (DefaultFacelet) _factory.getFacelet(resource.getURL());
         //f.apply(ctx.getFacesContext(), parent);
         DefaultFacelet f = (DefaultFacelet) _factory.getFacelet(resource.getURL());
         
         ctx.pushPageContext(new PageContextImpl());
         try
         {
             // push the parent as a UniqueIdVendor to the stack here,
             // if there is no UniqueIdVendor on the stack yet
             boolean pushedUniqueIdVendor = false;
             FaceletCompositionContext mctx = ctx.getFaceletCompositionContext();
             if (parent instanceof UniqueIdVendor
                 && ctx.getFaceletCompositionContext().getUniqueIdVendorFromStack() == null)
             {
                 mctx.pushUniqueIdVendorToStack((UniqueIdVendor) parent);
                 pushedUniqueIdVendor = true;
             }
             
             f.refresh(parent);
             mctx.markForDeletion(parent);
             DefaultFaceletContext ctxWrapper = new DefaultFaceletContext( (DefaultFaceletContext)ctx, f, true);
             //Update FACELET_CONTEXT_KEY on FacesContext attribute map, to 
             //reflect the current facelet context instance
             ctx.getFacesContext().getAttributes().put(FaceletContext.FACELET_CONTEXT_KEY, ctxWrapper);
             f._root.apply(ctxWrapper, parent);
             ctx.getFacesContext().getAttributes().put(FaceletContext.FACELET_CONTEXT_KEY, ctx);
             mctx.finalizeForDeletion(parent);
             f.markApplied(parent);
             
             // remove the UniqueIdVendor from the stack again
             if (pushedUniqueIdVendor)
             {
                 ctx.getFaceletCompositionContext().popUniqueIdVendorToStack();
             }
         }
         finally
         {
             ctx.popPageContext();
         }
     }
 
     private static class ApplyToken implements Externalizable
     {
         public String _alias;
 
         public long _time;
 
         public ApplyToken()
         {
         }
 
         public ApplyToken(String alias, long time)
         {
             _alias = alias;
             _time = time;
         }
 
         public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
         {
             _alias = in.readUTF();
             _time = in.readLong();
         }
 
         public void writeExternal(ObjectOutput out) throws IOException
         {
             out.writeUTF(_alias);
             out.writeLong(_time);
         }
     }
 
     public String toString()
     {
         return _alias;
     }
 
     @Override
     public boolean isBuildingCompositeComponentMetadata()
     {
         return _isBuildingCompositeComponentMetadata;
     }
 }