/* 
 * Copyright (C) 2005-2008 MaNGOS <http://www.mangosproject.org/>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/** \addtogroup u2w User to World Communication
 * @{
 * \file WorldSocket.h
 * \author Derex <derex101@gmail.com>
 */

#ifndef _WORLDSOCKET_H
#define	_WORLDSOCKET_H

#include <ace/Basic_Types.h>
#include <ace/Synch_Traits.h>
#include <ace/Svc_Handler.h>
#include <ace/SOCK_Stream.h>
#include <ace/SOCK_Acceptor.h>
#include <ace/Acceptor.h>
#include <ace/Thread_Mutex.h>
#include <ace/Guard_T.h>
#include <ace/Unbounded_Queue.h>
#include <ace/Message_Block.h>

#if !defined (ACE_LACKS_PRAGMA_ONCE)
#pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */

#include "Common.h"
#include "Auth/AuthCrypt.h" 

class ACE_Message_Block;
class WorldPacket;
class WorldSession;

/// Handler that can communicate over stream sockets.
typedef ACE_Svc_Handler<ACE_SOCK_STREAM, ACE_NULL_SYNCH> WorldHandler;

/**
 * WorldSocket.
 * 
 * This class is responsible for the comunication with 
 * remote clients.
 * Most methods return -1 on failure. 
 * The class uses refferece counting.
 *
 * For output the class uses one buffer (64K usually) and 
 * a queue where it stores packet if there is no place on 
 * the queue. The reason this is done, is because the server 
 * does realy a lot of small-size writes to it, and it doesn't 
 * scale well to allocate memory for every. When something is 
 * writen to the output buffer the socket is not immideately 
 * activated for output (again for the same reason), there 
 * is 10ms celling (thats why there is Update() method). 
 * This concept is simmilar to TCP_CORK, but TCP_CORK 
 * usses 200ms celling. As result overhead generated by 
 * sending packets from "producer" threads is minimal, 
 * and doing a lot of writes with small size is tollerated.
 * 
 * The calls to Upate () method are managed by WorldSocketMgr
 * and ReactorRunnable.
 * 
 * For input ,the class uses one 1024 bytes buffer on stack 
 * to which it does recv() calls. And then recieved data is 
 * distributed where its needed. 1024 matches pritey well the 
 * traffic generated by client for now.
 *  
 * The input/output do speculative reads/writes (AKA it tryes 
 * to read all data avaible in the kernel buffer or tryes to 
 * write everything avaible in userspace buffer), 
 * which is ok for using with Level and Edge Trigered IO 
 * notification.
 * 
 */
class WorldSocket : protected WorldHandler
{
public:
  /// Declare some friends
  friend class ACE_Acceptor< WorldSocket, ACE_SOCK_ACCEPTOR >;
  friend class WorldSocketMgr;
  friend class ReactorRunnable;

  /// Declare the acceptor for this class
  typedef ACE_Acceptor< WorldSocket, ACE_SOCK_ACCEPTOR > Acceptor;

  /// Mutex type used for various syncronizations.
  typedef ACE_Thread_Mutex LockType;
  typedef ACE_Guard<LockType> GuardType;

  /// Queue for storing packets for which there is no space.
  typedef ACE_Unbounded_Queue< WorldPacket* > PacketQueueT;

  /// Check if socket is closed.
  bool IsClosed (void) const;

  /// Close the socket.
  void CloseSocket (void);

  /// Get address of connected peer.
  const std::string& GetRemoteAddress (void) const;

  /// Send A packet on the socket, this function is reentrant.
  /// @param pct packet to send
  /// @return -1 of failure
  int SendPacket (const WorldPacket& pct);

  /// Add refference to this object.
  long AddReference (void);

  /// Remove refference to this object.
  long RemoveReference (void);

protected:
  /// things called by ACE framework.
  WorldSocket (void);
  virtual ~WorldSocket (void);

  /// Called on open ,the void* is the acceptor.
  virtual int open (void *);

  /// Called on failures inside of the acceptor, don't call from your code.
  virtual int close (int);

  /// Called when we can read from the socket.
  virtual int handle_input (ACE_HANDLE = ACE_INVALID_HANDLE);

  /// Called when the socket can write.
  virtual int handle_output (ACE_HANDLE = ACE_INVALID_HANDLE);

  /// Called when connection is closed or error happens.
  virtual int handle_close (ACE_HANDLE = ACE_INVALID_HANDLE,
                            ACE_Reactor_Mask = ACE_Event_Handler::ALL_EVENTS_MASK);

  /// Called by WorldSocketMgr/ReactorRunnable.
  int Update (void);

private:
  /// Helper functions for processing incoming data.
  int handle_input_header (void);
  int handle_input_payload (void);
  int handle_input_missing_data (void);

  /// Help functions to mark/unmark the socket for output.
  /// @param g the guard is for m_OutBufferLock, the function will release it
  int cancel_wakeup_output (GuardType& g);
  int schedule_wakeup_output (GuardType& g);

  /// process one incoming packet.
  /// @param new_pct received packet ,note that you need to delete it. 
  int ProcessIncoming (WorldPacket* new_pct);

  /// Called by ProcessIncoming() on CMSG_AUTH_SESSION.
  int HandleAuthSession (WorldPacket& recvPacket);

  /// Called by ProcessIncoming() on CMSG_PING.
  int HandlePing (WorldPacket& recvPacket);

  /// Try to write WorldPacket to m_OutBuffer ,return -1 if no space
  /// Need to be called with m_OutBufferLock lock held
  int iSendPacket (const WorldPacket& pct);

  /// Flush m_PacketQueue if there are packets in it
  /// Need to be called with m_OutBufferLock lock held
  /// @return true if it wrote to the buffer ( AKA you need 
  /// to mark the socket for output ).
  bool iFlushPacketQueue ();

private:
  /// Time in which the last ping was received
  ACE_Time_Value m_LastPingTime;
  
  /// Keep track of overspeed pings ,to prevent ping flood.
  uint32 m_OverSpeedPings;

  /// Address of the remote peer
  std::string m_Address;

  /// Class used for managing encryption of the headers
  AuthCrypt m_Crypt;

  /// Mutex lock to protect m_Session
  LockType m_SessionLock;

  /// Session to which recieved packets are routed
  WorldSession* m_Session;

  /// here are stored the fragmens of the recieved data
  WorldPacket* m_RecvWPct;

  /// This block actually refers to m_RecvWPct contents,
  /// which alows easy and safe writing to it. 
  /// It wont free memory when its deleted. m_RecvWPct takes care of freeing.
  ACE_Message_Block m_RecvPct;

  /// Fragment of the recieved header.
  ACE_Message_Block m_Header;

  /// Mutex for protecting otuput related data.
  LockType m_OutBufferLock;

  /// Buffer used for writing output.
  ACE_Message_Block *m_OutBuffer;

  /// Size of the m_OutBuffer.
  size_t m_OutBufferSize;

  /// Here are stored packets for which there was no space on m_OutBuffer,
  /// this alows not-to kick player if its buffer is overflowed.
  PacketQueueT m_PacketQueue;

  /// True if the socket is registered with the reactor for output
  bool m_OutActive;

  uint32 m_Seed;
};

#endif	/* _WORLDSOCKET_H */

/// @}
