package com.atlassian.plugins.rest.module.servlet;
   
   import static com.google.common.collect.Ordering.natural;
   
   import com.atlassian.plugin.event.PluginEventManager;
   import com.atlassian.plugin.servlet.DefaultServletModuleManager;
   import com.atlassian.plugin.servlet.ServletModuleManager;
   import com.atlassian.plugin.servlet.descriptors.ServletFilterModuleDescriptor;
   import com.atlassian.plugin.servlet.descriptors.ServletModuleDescriptor;
  import com.atlassian.plugin.servlet.filter.FilterDispatcherCondition;
  import com.atlassian.plugin.servlet.filter.FilterLocation;
  import com.atlassian.plugin.servlet.util.DefaultPathMapper;
  import com.atlassian.plugin.servlet.util.PathMapper;
  import com.atlassian.plugins.rest.module.RestApiContext;
  import com.atlassian.plugins.rest.module.RestServletFilterModuleDescriptor;
  import com.google.common.collect.Multimaps;
  import com.google.common.collect.SortedSetMultimap;
  import com.google.common.collect.TreeMultimap;
  
  import org.apache.commons.lang.StringUtils;
  
  import javax.servlet.Filter;
  import javax.servlet.FilterConfig;
  import javax.servlet.ServletConfig;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServlet;
  import java.util.Comparator;
  import java.util.SortedSet;
  
  /**
   * <p>Servlet module manager to handle REST servlets.</p>
   */
  public class DefaultRestServletModuleManager implements RestServletModuleManager
  {
      private static final RestServletFilterModuleDescriptorComparator VALUE_COMPARATOR = new RestServletFilterModuleDescriptorComparator();
  
      /**
       * Multimap of filter module descriptors, the key is the "api path" of the REST module descriptor.
       */
      private final SortedSetMultimap<String, RestServletFilterModuleDescriptor> filterModuleDescriptors =
              Multimaps.synchronizedSortedSetMultimap(TreeMultimap.<String, RestServletFilterModuleDescriptor>create(natural(), VALUE_COMPARATOR));
  
      private final ServletModuleManager delegateModuleManager;
      private final PathMapper filterPathMapper;
      private final String path;
  
      public DefaultRestServletModuleManager(PluginEventManager pluginEventManager, String path)
      {
          this.filterPathMapper = new DefaultPathMapper();
          this.delegateModuleManager = new DefaultServletModuleManager(pluginEventManager, new DefaultPathMapper(), filterPathMapper);
          this.path = StringUtils.isNotBlank(path) ? path : "";
      }
  
      DefaultRestServletModuleManager(ServletModuleManager delegate, PathMapper filterPathMapper, String path)
      {
          this.filterPathMapper = filterPathMapper;
          this.delegateModuleManager = delegate;
          this.path = StringUtils.isNotBlank(path) ? path : "";
      }
  
      public void addServletModule(ServletModuleDescriptor descriptor)
      {
          delegateModuleManager.addServletModule(descriptor);
      }
  
      public HttpServlet getServlet(String path, ServletConfig servletConfig) throws ServletException
      {
          return delegateModuleManager.getServlet(path, servletConfig);
      }
  
      public void removeServletModule(ServletModuleDescriptor descriptor)
      {
          delegateModuleManager.removeServletModule(descriptor);
      }
  
      public void addFilterModule(ServletFilterModuleDescriptor descriptor)
      {
          if (descriptor instanceof RestServletFilterModuleDescriptor)
          {
              final RestServletFilterModuleDescriptor restServletFilterModuleDescriptor = (RestServletFilterModuleDescriptor) descriptor;
              final RestServletFilterModuleDescriptor latest = getRestServletFilterModuleDescriptorForLatest(restServletFilterModuleDescriptor.getBasePath());
              if (VALUE_COMPARATOR.compare(latest, restServletFilterModuleDescriptor) < 0)
              {
                  if (latest != null)
                  {
                      filterPathMapper.put(latest.getCompleteKey(), null);
                      for (String path : latest.getPaths())
                      {
                          filterPathMapper.put(latest.getCompleteKey(), path);
                      }
                  }
                  filterPathMapper.put(descriptor.getCompleteKey(), getPathPattern(restServletFilterModuleDescriptor.getBasePath()));
              }
              filterModuleDescriptors.put(restServletFilterModuleDescriptor.getBasePath(), restServletFilterModuleDescriptor);
          }
          delegateModuleManager.addFilterModule(descriptor);
      }
  
      private RestServletFilterModuleDescriptor getRestServletFilterModuleDescriptorForLatest(String path)
     {
         if (path == null)
         {
             return null;
         }
 
         final SortedSet<RestServletFilterModuleDescriptor> moduleDescriptors = filterModuleDescriptors.get(path);
         return moduleDescriptors.isEmpty() ? null : moduleDescriptors.last();
     }
 
     public Iterable<Filter> getFilters(FilterLocation location, String pathInfo, FilterConfig filterConfig) throws ServletException
     {
         return delegateModuleManager.getFilters(location, pathInfo, filterConfig);
     }
 
     public Iterable<Filter> getFilters(FilterLocation location, String pathInfo, FilterConfig filterConfig, FilterDispatcherCondition filterDispatcherCondition) throws ServletException
     {
         return delegateModuleManager.getFilters(location, StringUtils.removeStart(pathInfo, path), filterConfig, filterDispatcherCondition);
     }
 
     public void removeFilterModule(ServletFilterModuleDescriptor descriptor)
     {
         if (descriptor instanceof RestServletFilterModuleDescriptor)
         {
             final RestServletFilterModuleDescriptor restServletFilterModuleDescriptor = (RestServletFilterModuleDescriptor) descriptor;
 
             // check if it was the latest, before removing from the MultiMap
             RestServletFilterModuleDescriptor latest = getRestServletFilterModuleDescriptorForLatest(restServletFilterModuleDescriptor.getBasePath());
             filterModuleDescriptors.remove(restServletFilterModuleDescriptor.getBasePath(), restServletFilterModuleDescriptor);
 
             if (latest != null && latest.getCompleteKey().equals(descriptor.getCompleteKey()))
             {
                 // latest has changed as we have removed an item from the multimap
                 latest = getRestServletFilterModuleDescriptorForLatest(restServletFilterModuleDescriptor.getBasePath());
                 if (latest != null)
                 {
                     filterPathMapper.put(latest.getCompleteKey(), getPathPattern(latest.getBasePath()));
                 }
             }
         }
 
         // remaing mapping of the descriptor will be removed by this call.
         delegateModuleManager.removeFilterModule(descriptor);
     }
 
     String getPathPattern(String basePath)
     {
         return basePath + RestApiContext.LATEST + RestApiContext.ANY_PATH_PATTERN;
     }
 
     private static final class RestServletFilterModuleDescriptorComparator implements Comparator<RestServletFilterModuleDescriptor>
     {
         public int compare(RestServletFilterModuleDescriptor descriptor1, RestServletFilterModuleDescriptor descriptor2)
         {
             if (descriptor1 == null)
             {
                 return -1;
             }
             if (descriptor2 == null)
             {
                 return +1;
             }
             return descriptor1.getVersion().compareTo(descriptor2.getVersion());
         }
     }
 }