//
   //  ========================================================================
   //  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.server.session;
  
  import java.io.DataOutputStream;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.ObjectOutputStream;
  import java.io.OutputStream;
  import java.util.Enumeration;
  
  import javax.servlet.http.HttpServletRequest;
  
  import org.eclipse.jetty.util.IO;
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  
  public class HashedSession extends MemSession
  {
      private static final Logger LOG = Log.getLogger(HashedSession.class);
  
      private final HashSessionManager _hashSessionManager;
  
      /** Whether the session has been saved because it has been deemed idle;
       * in which case its attribute map will have been saved and cleared. */
      private transient boolean _idled = false;
  
      /** Whether there has already been an attempt to save this session
       * which has failed.  If there has, there will be no more save attempts
       * for this session.  This is to stop the logs being flooded with errors
       * due to serialization failures that are most likely caused by user
       * data stored in the session that is not serializable. */
      private transient boolean _saveFailed = false;
      
      /**
       * True if an attempt has been made to de-idle a session and it failed. Once
       * true, the session will not be attempted to be de-idled again.
       */
      private transient boolean _deIdleFailed = false;
  
      /* ------------------------------------------------------------- */
      protected HashedSession(HashSessionManager hashSessionManager, HttpServletRequest request)
      {
          super(hashSessionManager,request);
          _hashSessionManager = hashSessionManager;
      }
  
      /* ------------------------------------------------------------- */
      protected HashedSession(HashSessionManager hashSessionManager, long created, long accessed, String clusterId)
      {
          super(hashSessionManager,created, accessed, clusterId);
          _hashSessionManager = hashSessionManager;
      }
  
      /* ------------------------------------------------------------- */
      protected void checkValid()
      {
          if (!_deIdleFailed && _hashSessionManager._idleSavePeriodMs!=0)
              deIdle();
          super.checkValid();
      }
  
      /* ------------------------------------------------------------- */
      @Override
      public void setMaxInactiveInterval(int secs)
      {
          super.setMaxInactiveInterval(secs);
          if (getMaxInactiveInterval()>0&&(getMaxInactiveInterval()*1000L/10)<_hashSessionManager._scavengePeriodMs)
              _hashSessionManager.setScavengePeriod((secs+9)/10);
      }
  
      /* ------------------------------------------------------------ */
      @Override
      protected void doInvalidate()
      throws IllegalStateException
      {
          super.doInvalidate();
          remove();
      }
      
     
     /* ------------------------------------------------------------ */
     /**
      * Remove from the disk
      */
     synchronized void remove ()
     {
         if (_hashSessionManager._storeDir!=null && getId()!=null)
         {
             String id=getId();
             File f = new File(_hashSessionManager._storeDir, id);
             f.delete();
         }
     }
 
     /* ------------------------------------------------------------ */
     synchronized void save(boolean reactivate)
     throws Exception
     {
         // Only idle the session if not already idled and no previous save/idle has failed
         if (!isIdled() && !_saveFailed)
         {
             if (LOG.isDebugEnabled())
                 LOG.debug("Saving {} {}",super.getId(),reactivate);
 
             try
             {
                 willPassivate();
                 save();
                 if (reactivate)
                     didActivate();
                 else
                     clearAttributes();
             }
             catch (Exception e)
             {       
                 LOG.warn("Problem saving session " + super.getId(), e);
                 _idled=false; // assume problem was before _values.clear();
             }
         }
     }
     
     
     
     synchronized void save ()
     throws Exception
     {   
         File file = null;
         if (!_saveFailed && _hashSessionManager._storeDir != null)
         {
             file = new File(_hashSessionManager._storeDir, super.getId());
             if (file.exists())
             {
                 file.delete();
             }
 
             try(FileOutputStream fos = new FileOutputStream(file,false))
             {
                 save(fos);
             }
             catch (Exception e)
             {
                 saveFailed(); // We won't try again for this session
                 if (file != null) 
                     file.delete(); // No point keeping the file if we didn't save the whole session
                 throw e;             
             }
         }
     }
     
     
     /* ------------------------------------------------------------ */
     public synchronized void save(OutputStream os)  throws IOException
     {
         DataOutputStream out = new DataOutputStream(os);
         out.writeUTF(getClusterId());
         out.writeUTF(getNodeId());
         out.writeLong(getCreationTime());
         out.writeLong(getAccessed());
 
         /* Don't write these out, as they don't make sense to store because they
          * either they cannot be true or their value will be restored in the
          * Session constructor.
          */
         //out.writeBoolean(_invalid);
         //out.writeBoolean(_doInvalidate);
         //out.writeBoolean( _newSession);
         out.writeInt(getRequests());
         out.writeInt(getAttributes());
         ObjectOutputStream oos = new ObjectOutputStream(out);
         Enumeration<String> e=getAttributeNames();
         while(e.hasMoreElements())
         {
             String key=e.nextElement();
             oos.writeUTF(key);
             oos.writeObject(doGet(key));
         }
         
         out.writeInt(getMaxInactiveInterval());
     }
 
     /* ------------------------------------------------------------ */
     public synchronized void deIdle()
     {
         if (isIdled() && !_deIdleFailed)
         {
             // Access now to prevent race with idling period
             access(System.currentTimeMillis());
 
             if (LOG.isDebugEnabled())
                 LOG.debug("De-idling " + super.getId());
 
             FileInputStream fis = null;
 
             try
             {
                 File file = new File(_hashSessionManager._storeDir, super.getId());
                 if (!file.exists() || !file.canRead())
                     throw new FileNotFoundException(file.getName());
 
                 fis = new FileInputStream(file);
                 _idled = false;
                 _hashSessionManager.restoreSession(fis, this);
                 IO.close(fis); 
                 
                 didActivate();
 
                 // If we are doing period saves, then there is no point deleting at this point 
                 if (_hashSessionManager._savePeriodMs == 0)
                     file.delete();
             }
             catch (Exception e)
             {
                 deIdleFailed();
                 LOG.warn("Problem de-idling session " + super.getId(), e);
                 if (fis != null) IO.close(fis);//Must ensure closed before invalidate
                 invalidate();
             }
         }
     }
 
 
     /* ------------------------------------------------------------ */
     /**
      * Idle the session to reduce session memory footprint.
      *
      * The session is idled by persisting it, then clearing the session values attribute map and finally setting
      * it to an idled state.
      * @throws Exception if unable to save session
      */
     public synchronized void idle()
     throws Exception
     {
         save(false);
         _idled = true;
     }
 
     /* ------------------------------------------------------------ */
     public synchronized boolean isIdled()
     {
       return _idled;
     }
 
     /* ------------------------------------------------------------ */
     public synchronized boolean isSaveFailed()
     {
         return _saveFailed;
     }
 
     /* ------------------------------------------------------------ */
     public synchronized void saveFailed()
     {
         _saveFailed = true;
     }
 
     /* ------------------------------------------------------------ */
     public synchronized void deIdleFailed()
     {
         _deIdleFailed = true;
     }
     
     /* ------------------------------------------------------------ */
     public synchronized boolean isDeIdleFailed()
     {
         return _deIdleFailed;
     }
 }