/*
 * Connection.h
 *
 * Copyright (C) 2008 Matthias Schiffer <matthias@gamezock.de>
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */

#ifndef MAD_NET_CONNECTION_H_
#define MAD_NET_CONNECTION_H_

#include <queue>
#include <gnutls/gnutls.h>
#include <sigc++/signal.h>
#include <poll.h>
#include "Packet.h"

namespace Mad {
namespace Net {

class IPAddress;
class Packet;

class Connection {
  private:
    struct Transmission {
      unsigned long length;
      unsigned long transmitted;

      unsigned char *data;

      sigc::slot<void,const void*,unsigned long> notify;
    };

    enum State {
      DISCONNECTED, HANDSHAKE, CONNECTION_HEADER, PACKET_HEADER, PACKET_DATA, DISCONNECT, BYE
    } state;

    Transmission transR;
    std::queue<Transmission> transS;

    Packet::Data header;

    sigc::signal<void,Connection*,const Packet&> signal;

    void doHandshake();

    void packetHeaderReceiveHandler(const void *data, unsigned long length);
    void packetDataReceiveHandler(const void *data, unsigned long length);

    void doReceive();
    void doSend();

    void doBye();

    void doDisconnect();

    bool receiveComplete() const {
      return (transR.length == transR.transmitted);
    }

    void bye() {
      if(state != DISCONNECT)
        return;

      state = BYE;

      doBye();
    }

    // Prevent shallow copy
    Connection(const Connection &o);
    Connection& operator=(const Connection &o);

  protected:
    struct ConnectionHeader {
      unsigned char m;
      unsigned char a;
      unsigned char d;
      unsigned char type;

      unsigned char versionMajor;
      unsigned char versionMinor;
      unsigned char protVerMin;
      unsigned char protVerMax;
    };

    int sock;
    gnutls_session_t session;

    IPAddress *peer;

    void handshake() {
      if(isConnected())
        return;

      state = HANDSHAKE;

      doHandshake();
    }

    virtual void connectionHeader() = 0;

    bool rawReceive(unsigned long length, const sigc::slot<void,const void*,unsigned long> &notify);
    bool rawSend(const unsigned char *data, unsigned long length);

    bool enterReceiveLoop() {
      if(!isConnected() || isDisconnecting())
        return false;

      state = PACKET_HEADER;

      return rawReceive(sizeof(Packet::Data), sigc::mem_fun(this, &Connection::packetHeaderReceiveHandler));
    }

  public:
    Connection() : state(DISCONNECTED), peer(0) {
      transR.length = transR.transmitted = 0;
      transR.data = 0;
    }

    virtual ~Connection() {
      if(isConnected())
        doDisconnect();

      if(transR.data)
        delete [] transR.data;

      while(!sendQueueEmpty()) {
        delete [] transS.front().data;
        transS.pop();
      }
    }

    bool isConnected() const {return (state != DISCONNECTED);}
    bool isConnecting() const {
      return (state == HANDSHAKE || state == CONNECTION_HEADER);
    }

    bool isDisconnecting() const {
      return (state == DISCONNECT || state == BYE);
    }

    const IPAddress* getPeer() {return peer;}
    int getSocket() const {return sock;}

    void disconnect() {
      if(isConnected() && !isDisconnecting()) {
        state = DISCONNECT;

        if(sendQueueEmpty())
          bye();
      }
    }

    struct pollfd getPollfd() const;

    bool send(const Packet &packet) {
      if(!isConnected() || isConnecting() || isDisconnecting())
        return false;

      return rawSend(reinterpret_cast<const unsigned char*>(packet.getRawData()), packet.getRawDataLength());
    }

    void sendReceive(short events = POLLIN|POLLOUT);

    bool sendQueueEmpty() const {return transS.empty();}

    sigc::signal<void,Connection*,const Packet&> signalReceive() const {return signal;}

    static void init() {
      gnutls_global_init();
    }

    static void deinit() {
      gnutls_global_deinit();
    }
};

}
}

#endif /*MAD_NET_CONNECTION_H_*/