/*
    * Copyright 2007 Tim Peierls
    *
    * Licensed 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.directwebremoting.guice;
  
  import com.google.inject.Key;
  import com.google.inject.Provider;
  import com.google.inject.Scope;
  import com.google.inject.util.ToStringBuilder;
  
  import java.util.ArrayList;
  import java.util.Enumeration;
  import java.util.Iterator;
  import java.util.List;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpSession;
  import javax.servlet.ServletContext;
  
  import org.directwebremoting.ScriptSession;
  import org.directwebremoting.WebContext;
  import org.directwebremoting.WebContextFactory;
  import org.directwebremoting.util.Logger;
  
  import static org.directwebremoting.guice.DwrGuiceUtil.getServletContext;
  
  /**
   * Scopes available to DWR applications.
   * @author Tim Peierls [tim at peierls dot net]
   */
  public class DwrScopes 
  {
      /**
       * HTTP request scope.
       */
      public static final ContextScope<HttpServletRequest> REQUEST = 
          new AbstractSimpleContextScope<HttpServletRequest>(
              HttpServletRequest.class, "DwrScopes.REQUEST")
          {
              public HttpServletRequest get()
              {
                  return WebContextFactory.get().getHttpServletRequest();
              }
              
              public Object get(HttpServletRequest request, String name)
              {
                  return request.getAttribute(name);
              }
              
              public void put(HttpServletRequest request, String name, Object value)
              {
                  request.setAttribute(name, value);
              }
          };
  
      /**
       * DWR script session scope.
       */
      public static final ContextScope<ScriptSession> SCRIPT = 
          new AbstractSimpleContextScope<ScriptSession>(ScriptSession.class, "DwrScopes.SCRIPT")
          {
              public ScriptSession get()
              {
                  return WebContextFactory.get().getScriptSession();
              }
              
              public Object get(ScriptSession scriptSession, String name)
              {
                  return scriptSession.getAttribute(name);
              }
              
              public void put(ScriptSession scriptSession, String name, Object value)
              {
                  scriptSession.setAttribute(name, value);
              }
          };
  
      /**
       * HTTP session scope. The implementation uses session identity to
       * to track which sessions are open. Since the servlet spec doesn't
       * guarantee identity of sessions between requests, don't rely on
       * {@code getOpenContexts()} or {@code close(session, handlers)} to
       * work correctly for this scope.
       */
      public static final ContextScope<HttpSession> SESSION = 
          new AbstractSimpleContextScope<HttpSession>(HttpSession.class, "DwrScopes.SESSION")
          {
             public HttpSession get()
             {
                 return WebContextFactory.get().getSession();
             }
             
             public Object get(HttpSession session, String name)
             {
                 return session.getAttribute(name);
             }
             
             public void put(HttpSession session, String name, Object value)
             {
                 session.setAttribute(name, value);
             }
         };
 
     /**
      * Application scope: objects in this scope <em>are</em> eagerly initialized 
      * during DWR servlet initialization, and Closeable objects in this scope are 
      * closed during DWR servlet destruction.
      */
     public static final ContextScope<ServletContext> APPLICATION = 
         new ApplicationScope("DwrScopes.APPLICATION");
 
     /**
      * Global application scope: like {@link #APPLICATION}, but objects in 
      * this scope are <em>not</em> eagerly initialized and Closeable objects
      * in this scope are closed during servlet context destruction (not
      * during DWR servlet destruction).
      */
     public static final ContextScope<ServletContext> GLOBAL = 
         new ApplicationScope("DwrScopes.GLOBAL");
     
     
     static class ApplicationScope extends AbstractSimpleContextScope<ServletContext>
     {
         ApplicationScope(String scopeName)
         {
             super(ServletContext.class, scopeName);
         }
 
         public ServletContext get()
         {
             return getServletContext();
         }
         
         public Object get(ServletContext servletContext, String name)
         {
             if (log.isDebugEnabled())
             {
                 log.debug(String.format("servletContext.getAttribute(%s)", name));
             }
             return servletContext.getAttribute(name);
         }
         
         public void put(ServletContext servletContext, String name, Object value)
         {
             if (log.isDebugEnabled())
             {
                 log.debug(String.format("servletContext.setAttribute(%s, %s)", name, value));
             }
             servletContext.setAttribute(name, value);
         }
     };
 
     private DwrScopes() { /* uninstantiable */ }
 
     /**
      * The log stream
      */
     private static final Logger log = Logger.getLogger(DwrScopes.class);
 }