//
   //  ========================================================================
   //  Copyright (c) 1995-2015 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.websocket.common.io;
  
  import java.io.EOFException;
  import java.io.IOException;
  import java.net.InetSocketAddress;
  import java.net.SocketTimeoutException;
  import java.nio.ByteBuffer;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.concurrent.Executor;
  import java.util.concurrent.RejectedExecutionException;
  import java.util.concurrent.atomic.AtomicBoolean;
  import java.util.concurrent.atomic.AtomicLong;
  
  import org.eclipse.jetty.io.AbstractConnection;
  import org.eclipse.jetty.io.ByteBufferPool;
  import org.eclipse.jetty.io.EndPoint;
  import org.eclipse.jetty.util.BufferUtil;
  import org.eclipse.jetty.util.component.ContainerLifeCycle;
  import org.eclipse.jetty.util.component.Dumpable;
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  import org.eclipse.jetty.util.thread.Scheduler;
  import org.eclipse.jetty.websocket.api.BatchMode;
  import org.eclipse.jetty.websocket.api.CloseException;
  import org.eclipse.jetty.websocket.api.StatusCode;
  import org.eclipse.jetty.websocket.api.SuspendToken;
  import org.eclipse.jetty.websocket.api.WebSocketPolicy;
  import org.eclipse.jetty.websocket.api.WriteCallback;
  import org.eclipse.jetty.websocket.api.extensions.ExtensionConfig;
  import org.eclipse.jetty.websocket.api.extensions.Frame;
  import org.eclipse.jetty.websocket.common.CloseInfo;
  import org.eclipse.jetty.websocket.common.ConnectionState;
  import org.eclipse.jetty.websocket.common.Generator;
  import org.eclipse.jetty.websocket.common.LogicalConnection;
  import org.eclipse.jetty.websocket.common.Parser;
  import org.eclipse.jetty.websocket.common.WebSocketSession;
  import org.eclipse.jetty.websocket.common.io.IOState.ConnectionStateListener;
  
  /**
   * Provides the implementation of {@link LogicalConnection} within the framework of the new {@link Connection} framework of {@code jetty-io}.
   */
  public abstract class AbstractWebSocketConnection extends AbstractConnection implements LogicalConnection, ConnectionStateListener, Dumpable
  {
      private class Flusher extends FrameFlusher
      {
          private Flusher(ByteBufferPool bufferPool, Generator generator, EndPoint endpoint)
          {
              super(bufferPool,generator,endpoint,getPolicy().getMaxBinaryMessageBufferSize(),8);
          }
  
          @Override
          protected void onFailure(Throwable x)
          {
              session.notifyError(x);
  
              if (ioState.wasAbnormalClose())
              {
                  LOG.ignore(x);
                  return;
              }
  
              if (LOG.isDebugEnabled())
                  LOG.debug("Write flush failure",x);
              ioState.onWriteFailure(x);
          }
      }
  
      public class OnDisconnectCallback implements WriteCallback
      {
          private final boolean outputOnly;
  
          public OnDisconnectCallback(boolean outputOnly)
          {
              this.outputOnly = outputOnly;
          }
  
          @Override
          public void writeFailed(Throwable x)
          {
              disconnect(outputOnly);
         }
 
         @Override
         public void writeSuccess()
         {
             disconnect(outputOnly);
         }
     }
 
     public class OnCloseLocalCallback implements WriteCallback
     {
         private final WriteCallback callback;
         private final CloseInfo close;
 
         public OnCloseLocalCallback(WriteCallback callback, CloseInfo close)
         {
             this.callback = callback;
             this.close = close;
         }
 
         public OnCloseLocalCallback(CloseInfo close)
         {
             this(null,close);
         }
 
         @Override
         public void writeFailed(Throwable x)
         {
             try
             {
                 if (callback != null)
                 {
                     callback.writeFailed(x);
                 }
             }
             finally
             {
                 onLocalClose();
             }
         }
 
         @Override
         public void writeSuccess()
         {
             try
             {
                 if (callback != null)
                 {
                     callback.writeSuccess();
                 }
             }
             finally
             {
                 onLocalClose();
             }
         }
 
         private void onLocalClose()
         {
             if (LOG.isDebugEnabled())
                 LOG.debug("Local Close Confirmed {}",close);
             if (close.isAbnormal())
             {
                 ioState.onAbnormalClose(close);
             }
             else
             {
                 ioState.onCloseLocal(close);
             }
         }
     }
 
     public static class Stats
     {
         private AtomicLong countFillInterestedEvents = new AtomicLong(0);
         private AtomicLong countOnFillableEvents = new AtomicLong(0);
         private AtomicLong countFillableErrors = new AtomicLong(0);
 
         public long getFillableErrorCount()
         {
             return countFillableErrors.get();
         }
 
         public long getFillInterestedCount()
         {
             return countFillInterestedEvents.get();
         }
 
         public long getOnFillableCount()
         {
             return countOnFillableEvents.get();
         }
     }
     
     private static enum ReadMode
     {
         PARSE,
         DISCARD,
         EOF
     }
 
     private static final Logger LOG = Log.getLogger(AbstractWebSocketConnection.class);
 
     /**
      * Minimum size of a buffer is the determined to be what would be the maximum framing header size (not including payload)
      */
     private static final int MIN_BUFFER_SIZE = Generator.MAX_HEADER_LENGTH;
 
     private final ByteBufferPool bufferPool;
     private final Scheduler scheduler;
     private final Generator generator;
     private final Parser parser;
     private final WebSocketPolicy policy;
     private final AtomicBoolean suspendToken;
     private final FrameFlusher flusher;
     private WebSocketSession session;
     private List<ExtensionConfig> extensions;
     private boolean isFilling;
     private ByteBuffer buffer;
     private ReadMode readMode = ReadMode.PARSE;
     private IOState ioState;
     private Stats stats = new Stats();
 
     public AbstractWebSocketConnection(EndPoint endp, Executor executor, Scheduler scheduler, WebSocketPolicy policy, ByteBufferPool bufferPool)
     {
         super(endp,executor,EXECUTE_ONFILLABLE); // TODO review if this is best. Specifically with MUX
         this.policy = policy;
         this.bufferPool = bufferPool;
         this.generator = new Generator(policy,bufferPool);
         this.parser = new Parser(policy,bufferPool);
         this.scheduler = scheduler;
         this.extensions = new ArrayList<>();
         this.suspendToken = new AtomicBoolean(false);
         this.ioState = new IOState();
         this.ioState.addListener(this);
         this.flusher = new Flusher(bufferPool,generator,endp);
         this.setInputBufferSize(policy.getInputBufferSize());
         this.setMaxIdleTimeout(policy.getIdleTimeout());
     }
 
     @Override
     public Executor getExecutor()
     {
         return super.getExecutor();
     }
 
     @Override
     public void close()
     {
         close(StatusCode.NORMAL,null);
     }
 
     /**
      * Close the connection.
      * <p>                    fillInterested();
 
      * This can result in a close handshake over the network, or a simple local abnormal close
      * 
      * @param statusCode
      *            the WebSocket status code.
      * @param reason
      *            the (optional) reason string. (null is allowed)
      * @see StatusCode
      */
     @Override
     public void close(int statusCode, String reason)
     {
         if (LOG.isDebugEnabled())
             LOG.debug("close({},{})",statusCode,reason);
         CloseInfo close = new CloseInfo(statusCode,reason);
         this.outgoingFrame(close.asFrame(),new OnCloseLocalCallback(close),BatchMode.OFF);
     }
 
     @Override
     public void disconnect()
     {
         disconnect(false);
     }
 
     private void disconnect(boolean onlyOutput)
     {
         if (LOG.isDebugEnabled())
             LOG.debug("{} disconnect({})",policy.getBehavior(),onlyOutput?"outputOnly":"both");
         // close FrameFlusher, we cannot write anymore at this point.
         flusher.close();
         EndPoint endPoint = getEndPoint();
         // We need to gently close first, to allow
         // SSL close alerts to be sent by Jetty
         if (LOG.isDebugEnabled())
             LOG.debug("Shutting down output {}",endPoint);
         endPoint.shutdownOutput();
         if (!onlyOutput)
         {
             LOG.debug("Closing {}",endPoint);
             endPoint.close();
         }
     }
 
     protected void execute(Runnable task)
     {
         try
         {
             getExecutor().execute(task);
         }
         catch (RejectedExecutionException e)
         {
             if (LOG.isDebugEnabled())
                 LOG.debug("Job not dispatched: {}",task);
         }
     }
 
     @Override
     public void fillInterested()
     {
         stats.countFillInterestedEvents.incrementAndGet();
         super.fillInterested();
     }
 
     @Override
     public ByteBufferPool getBufferPool()
     {
         return bufferPool;
     }
 
     /**
      * Get the list of extensions in use.
      * <p>
      * This list is negotiated during the WebSocket Upgrade Request/Response handshake.
      * 
      * @return the list of negotiated extensions in use.
      */
     public List<ExtensionConfig> getExtensions()
     {
         return extensions;
     }
 
     public Generator getGenerator()
     {
         return generator;
     }
 
     @Override
     public long getIdleTimeout()
     {
         return getEndPoint().getIdleTimeout();
     }
 
     @Override
     public IOState getIOState()
     {
         return ioState;
     }
 
     @Override
     public long getMaxIdleTimeout()
     {
         return getEndPoint().getIdleTimeout();
     }
 
     public Parser getParser()
     {
         return parser;
     }
 
     @Override
     public WebSocketPolicy getPolicy()
     {
         return this.policy;
     }
 
     @Override
     public InetSocketAddress getRemoteAddress()
     {
         return getEndPoint().getRemoteAddress();
     }
 
     public Scheduler getScheduler()
     {
         return scheduler;
     }
 
     @Override
     public WebSocketSession getSession()
     {
         return session;
     }
 
     public Stats getStats()
     {
         return stats;
     }
 
     @Override
     public boolean isOpen()
     {
         return getIOState().isOpen() && getEndPoint().isOpen();
     }
 
     @Override
     public boolean isReading()
     {
         return isFilling;
     }
 
     /**
      * Physical connection disconnect.
      * <p>
      * Not related to WebSocket close handshake.
      */
     @Override
     public void onClose()
     {
         if (LOG.isDebugEnabled())
             LOG.debug("{} onClose()",policy.getBehavior());
         super.onClose();
         // ioState.onDisconnected();
         flusher.close();
     }
 
     @Override
     public void onConnectionStateChange(ConnectionState state)
     {
         if (LOG.isDebugEnabled())
             LOG.debug("{} Connection State Change: {}",policy.getBehavior(),state);
         switch (state)
         {
             case OPEN:
                 if (BufferUtil.isEmpty(buffer))
                 {
                     if (LOG.isDebugEnabled())
                         LOG.debug("fillInterested");
                     fillInterested();
                 }
                 else
                     onFillable();
                 break;
             case CLOSED:
                 if (ioState.wasAbnormalClose())
                 {
                     // Fire out a close frame, indicating abnormal shutdown, then disconnect
                     CloseInfo abnormal = new CloseInfo(StatusCode.SHUTDOWN,"Abnormal Close - " + ioState.getCloseInfo().getReason());
                     outgoingFrame(abnormal.asFrame(),new OnDisconnectCallback(false),BatchMode.OFF);
                 }
                 else
                 {
                     // Just disconnect
                     this.disconnect(false);
                 }
                 break;
             case CLOSING:
                 // First occurrence of .onCloseLocal or .onCloseRemote use
                 if (ioState.wasRemoteCloseInitiated())
                 {
                     CloseInfo close = ioState.getCloseInfo();
                     // reply to close handshake from remote
                     outgoingFrame(close.asFrame(),new OnCloseLocalCallback(new OnDisconnectCallback(true),close),BatchMode.OFF);
                 }
             default:
                 break;
         }
     }
 
     @Override
     public void onFillable()
     {
         if (LOG.isDebugEnabled())
             LOG.debug("{} onFillable()",policy.getBehavior());
         stats.countOnFillableEvents.incrementAndGet();
         if (buffer==null)
             buffer = bufferPool.acquire(getInputBufferSize(),true);
         try
         {
             isFilling = true;
 
             if(readMode == ReadMode.PARSE)
             {
                 readMode = readParse(buffer);
             } 
             else
             {
                 readMode = readDiscard(buffer);
             }
         }
         finally
         {
             bufferPool.release(buffer);
             buffer=null;
         }
 
         if ((readMode != ReadMode.EOF) && (suspendToken.get() == false))
         {
             fillInterested();
         }
         else
         {
             isFilling = false;
         }
     }
 
     
 
     @Override
     protected void onFillInterestedFailed(Throwable cause)
     {
         LOG.ignore(cause);
         stats.countFillInterestedEvents.incrementAndGet();
         super.onFillInterestedFailed(cause);
     }
 
     protected void prefill(ByteBuffer prefilled)
     {
         buffer=prefilled;
     }
     
     @Override
     public void onOpen()
     {
         super.onOpen();
         this.ioState.onOpened();
     }
 
     /**
      * Event for no activity on connection (read or write)
      */
     @Override
     protected boolean onReadTimeout()
     {
         IOState state = getIOState();
         ConnectionState cstate = state.getConnectionState();
         if (LOG.isDebugEnabled())
             LOG.debug("{} Read Timeout - {}",policy.getBehavior(),cstate);
 
         if (cstate == ConnectionState.CLOSED)
         {
             // close already completed, extra timeouts not relevant
             // allow underlying connection and endpoint to disconnect on its own
             return true;
         }
 
         try
         {
             session.notifyError(new SocketTimeoutException("Timeout on Read"));
         }
         finally
         {
             // This is an Abnormal Close condition
             close(StatusCode.SHUTDOWN,"Idle Timeout");
         }
 
         return false;
     }
 
     /**
      * Frame from API, User, or Internal implementation destined for network.
      */
     @Override
     public void outgoingFrame(Frame frame, WriteCallback callback, BatchMode batchMode)
     {
         if (LOG.isDebugEnabled())
         {
             LOG.debug("outgoingFrame({}, {})",frame,callback);
         }
 
         flusher.enqueue(frame,callback,batchMode);
     }
 
     private ReadMode readDiscard(ByteBuffer buffer)
     {
         EndPoint endPoint = getEndPoint();
         try
         {
             while (true)
             {
                 int filled = endPoint.fill(buffer);
                 if (filled == 0)
                 {
                     return ReadMode.DISCARD;
                 }
                 else if (filled < 0)
                 {
                     LOG.debug("read - EOF Reached (remote: {})",getRemoteAddress());
                     return ReadMode.EOF;
                 }
                 else
                 {
                     if (LOG.isDebugEnabled())
                     {
                         LOG.debug("Discarded {} bytes - {}",filled,BufferUtil.toDetailString(buffer));
                     }
                 }
             }
         }
         catch (IOException e)
         {
             LOG.ignore(e);
             return ReadMode.EOF;
         }
         catch (Throwable t)
         {
             LOG.ignore(t);
             return ReadMode.DISCARD;
         }
     }
     
     private ReadMode readParse(ByteBuffer buffer)
     {
         EndPoint endPoint = getEndPoint();
         try
         {
             while (true) // TODO: should this honor the LogicalConnection.suspend() ?
             {
                 int filled = endPoint.fill(buffer);
                 if (filled == 0)
                 {
                     return ReadMode.PARSE;
                 }
                 else if (filled < 0)
                 {
                     LOG.debug("read - EOF Reached (remote: {})",getRemoteAddress());
                     ioState.onReadFailure(new EOFException("Remote Read EOF"));
                     return ReadMode.EOF;
                 }
                 else
                 {
                     if (LOG.isDebugEnabled())
                     {
                         LOG.debug("Filled {} bytes - {}",filled,BufferUtil.toDetailString(buffer));
                     }
                     parser.parse(buffer);
                 }
             }
         }
         catch (IOException e)
         {
             LOG.warn(e);
             close(StatusCode.PROTOCOL,e.getMessage());
             return ReadMode.DISCARD;
         }
         catch (CloseException e)
         {
             LOG.debug(e);
             close(e.getStatusCode(),e.getMessage());
             return ReadMode.DISCARD;
         }
         catch (Throwable t)
         {
             LOG.warn(t);
             close(StatusCode.ABNORMAL,t.getMessage());
             // TODO: should probably only switch to discard if a non-ws-endpoint error
             return ReadMode.DISCARD;
         }
     }
 
     @Override
     public void resume()
     {
         if (suspendToken.getAndSet(false))
         {
             fillInterested();
         }
     }
 
     /**
      * Get the list of extensions in use.
      * <p>
      * This list is negotiated during the WebSocket Upgrade Request/Response handshake.
      * 
      * @param extensions
      *            the list of negotiated extensions in use.
      */
     public void setExtensions(List<ExtensionConfig> extensions)
     {
         this.extensions = extensions;
     }
 
     @Override
     public void setInputBufferSize(int inputBufferSize)
     {
         if (inputBufferSize < MIN_BUFFER_SIZE)
         {
             throw new IllegalArgumentException("Cannot have buffer size less than " + MIN_BUFFER_SIZE);
         }
         super.setInputBufferSize(inputBufferSize);
     }
 
     @Override
     public void setMaxIdleTimeout(long ms)
     {
         getEndPoint().setIdleTimeout(ms);
     }
 
     @Override
     public void setSession(WebSocketSession session)
     {
         this.session = session;
     }
 
     @Override
     public SuspendToken suspend()
     {
         suspendToken.set(true);
         return this;
     }
 
     @Override
     public String dump()
     {
         return ContainerLifeCycle.dump(this);
     }
 
     @Override
     public void dump(Appendable out, String indent) throws IOException
     {
         out.append(toString()).append(System.lineSeparator());
     }
 
     @Override
     public String toString()
     {
         return String.format("%s{f=%s,g=%s,p=%s}",super.toString(),flusher,generator,parser);
     }
 
 }