//
   //  ========================================================================
   //  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.annotations;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  import javax.servlet.Servlet;
  import javax.servlet.annotation.WebInitParam;
  import javax.servlet.annotation.WebServlet;
  import javax.servlet.http.HttpServlet;
  
  import org.eclipse.jetty.servlet.Holder;
  import org.eclipse.jetty.servlet.ServletHolder;
  import org.eclipse.jetty.servlet.ServletMapping;
  import org.eclipse.jetty.util.ArrayUtil;
  import org.eclipse.jetty.util.LazyList;
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  import org.eclipse.jetty.util.resource.Resource;
  import org.eclipse.jetty.webapp.DiscoveredAnnotation;
  import org.eclipse.jetty.webapp.MetaData;
  import org.eclipse.jetty.webapp.Origin;
  import org.eclipse.jetty.webapp.WebAppContext;
  
  /**
   * WebServletAnnotation
   *
   *
   */
  public class WebServletAnnotation extends DiscoveredAnnotation
  {
      private static final Logger LOG = Log.getLogger(WebServletAnnotation.class);
  
      public WebServletAnnotation (WebAppContext context, String className)
      {
          super(context, className);
      }
  
  
      public WebServletAnnotation (WebAppContext context, String className, Resource resource)
      {
          super(context, className, resource);
      }
  
      /**
       * @see DiscoveredAnnotation#apply()
       */
      public void apply()
      {
          //TODO check this algorithm with new rules for applying descriptors and annotations in order
          Class<? extends Servlet> clazz = (Class<? extends Servlet>)getTargetClass();
  
          if (clazz == null)
          {
              LOG.warn(_className+" cannot be loaded");
              return;
          }
  
          //Servlet Spec 8.1.1
          if (!HttpServlet.class.isAssignableFrom(clazz))
          {
              LOG.warn(clazz.getName()+" is not assignable from javax.servlet.http.HttpServlet");
              return;
          }
  
          WebServlet annotation = (WebServlet)clazz.getAnnotation(WebServlet.class);
  
          if (annotation.urlPatterns().length > 0 && annotation.value().length > 0)
          {
              LOG.warn(clazz.getName()+ " defines both @WebServlet.value and @WebServlet.urlPatterns");
              return;
          }
  
          String[] urlPatterns = annotation.value();
          if (urlPatterns.length == 0)
              urlPatterns = annotation.urlPatterns();
  
          if (urlPatterns.length == 0)
          {
              LOG.warn(clazz.getName()+ " defines neither @WebServlet.value nor @WebServlet.urlPatterns");
              return;
         }
 
         //canonicalize the patterns
         ArrayList<String> urlPatternList = new ArrayList<String>();
         for (String p : urlPatterns)
             urlPatternList.add(Util.normalizePattern(p));
 
         String servletName = (annotation.name().equals("")?clazz.getName():annotation.name());
 
         MetaData metaData = _context.getMetaData();
         ServletMapping mapping = null; //the new mapping
 
         //Find out if a <servlet> already exists with this name
         ServletHolder[] holders = _context.getServletHandler().getServlets();
 
         ServletHolder holder = null;
         if (holders != null)
         {
             for (ServletHolder h : holders)
             {
                 if (h.getName() != null && servletName.equals(h.getName()))
                 {
                     holder = h;
                     break;
                 }
             }
         }
 
         //handle creation/completion of a servlet
         if (holder == null)
         {
             //No servlet of this name has already been defined, either by a descriptor
             //or another annotation (which would be impossible).
             holder = _context.getServletHandler().newServletHolder(Holder.Source.ANNOTATION);
             holder.setHeldClass(clazz);
             metaData.setOrigin(servletName+".servlet.servlet-class",annotation,clazz);
 
             holder.setName(servletName);
             holder.setDisplayName(annotation.displayName());
             metaData.setOrigin(servletName+".servlet.display-name",annotation,clazz);
 
             holder.setInitOrder(annotation.loadOnStartup());
             metaData.setOrigin(servletName+".servlet.load-on-startup",annotation,clazz);
 
             holder.setAsyncSupported(annotation.asyncSupported());
             metaData.setOrigin(servletName+".servlet.async-supported",annotation,clazz);
 
             for (WebInitParam ip:annotation.initParams())
             {
                 holder.setInitParameter(ip.name(), ip.value());
                 metaData.setOrigin(servletName+".servlet.init-param."+ip.name(),ip,clazz);
             }
 
             _context.getServletHandler().addServlet(holder);
 
 
             mapping = new ServletMapping();
             mapping.setServletName(holder.getName());
             mapping.setPathSpecs( LazyList.toStringArray(urlPatternList));
         }
         else
         {
             //set the class according to the servlet that is annotated, if it wasn't already
             //NOTE: this may be considered as "completing" an incomplete servlet registration, and it is
             //not clear from servlet 3.0 spec whether this is intended, or if only a ServletContext.addServlet() call
             //can complete it, see http://java.net/jira/browse/SERVLET_SPEC-42
             if (holder.getClassName() == null)
                 holder.setClassName(clazz.getName());
             if (holder.getHeldClass() == null)
                 holder.setHeldClass(clazz);
 
             //check if the existing servlet has each init-param from the annotation
             //if not, add it
             for (WebInitParam ip:annotation.initParams())
             {
                 if (metaData.getOrigin(servletName+".servlet.init-param."+ip.name())==Origin.NotSet)
                 {
                     holder.setInitParameter(ip.name(), ip.value());
                     metaData.setOrigin(servletName+".servlet.init-param."+ip.name(),ip,clazz);
                 }
             }
 
 
             //check the url-patterns
             //ServletSpec 3.0 p81 If a servlet already has url mappings from a
             //webxml or fragment descriptor the annotation is ignored.
             //However, we want to be able to replace mappings that were given in webdefault.xml
             List<ServletMapping> existingMappings = getServletMappingsForServlet(servletName);
 
             //if any mappings for this servlet already set by a descriptor that is not webdefault.xml forget
             //about processing these url mappings
             if (existingMappings.isEmpty() || !containsNonDefaultMappings(existingMappings))
             {
                 mapping = new ServletMapping();
                 mapping.setServletName(servletName);
                 mapping.setPathSpecs(LazyList.toStringArray(urlPatternList));
             }
         }
 
 
         //We also want to be able to replace mappings that were defined in webdefault.xml
         //that were for a different servlet eg a mapping in webdefault.xml for / to the jetty
         //default servlet should be able to be replaced by an annotation for / to a different
         //servlet
         if (mapping != null)
         {
             //url mapping was permitted by annotation processing rules
 
             //take a copy of the existing servlet mappings that we can iterate over and remove from. This is
             //because the ServletHandler interface does not support removal of individual mappings.
             List<ServletMapping> allMappings = ArrayUtil.asMutableList(_context.getServletHandler().getServletMappings());
 
             //for each of the urls in the annotation, check if a mapping to same/different servlet exists
             //  if mapping exists and is from a default descriptor, it can be replaced. NOTE: we do not
             //  guard against duplicate path mapping here: that is the job of the ServletHandler
             for (String p:urlPatternList)
             {
                 ServletMapping existingMapping = _context.getServletHandler().getServletMapping(p);
                 if (existingMapping != null && existingMapping.isDefault())
                 {
                     String[] updatedPaths = ArrayUtil.removeFromArray(existingMapping.getPathSpecs(), p);
                     //if we removed the last path from a servletmapping, delete the servletmapping
                     if (updatedPaths == null || updatedPaths.length == 0)
                     {
                         boolean success = allMappings.remove(existingMapping);
                         if (LOG.isDebugEnabled()) LOG.debug("Removed empty mapping {} from defaults descriptor success:{}",existingMapping, success);
                     }
                     else
                     {
                         existingMapping.setPathSpecs(updatedPaths);
                         if (LOG.isDebugEnabled()) LOG.debug("Removed path {} from mapping {} from defaults descriptor ", p,existingMapping);
                     }
                 }
                 _context.getMetaData().setOrigin(servletName+".servlet.mapping."+p, annotation, clazz);
             }
             allMappings.add(mapping);
             _context.getServletHandler().setServletMappings(allMappings.toArray(new ServletMapping[allMappings.size()]));
         }
     }
 
 
 
 
     /**
      * @param name
      * @return
      */
     private List<ServletMapping>  getServletMappingsForServlet (String name)
     {
         ServletMapping[] allMappings = _context.getServletHandler().getServletMappings();
         if (allMappings == null)
             return Collections.emptyList();
 
         List<ServletMapping> mappings = new ArrayList<ServletMapping>();
         for (ServletMapping m:allMappings)
         {
             if (m.getServletName() != null && name.equals(m.getServletName()))
             {
                 mappings.add(m);
             }
         }
         return mappings;
     }
 
 
     /**
      * @param mappings
      * @return
      */
     private boolean containsNonDefaultMappings (List<ServletMapping> mappings)
     {
         if (mappings == null)
             return false;
         for (ServletMapping m:mappings)
         {
             if (!m.isDefault())
                 return true;
         }
         return false;
     }
 }