/*
 * ServerConnection.cpp
 *
 * 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/>.
 */

#include "ServerConnection.h"
#include "IPAddress.h"
#include <cstring>
#include <cerrno>
#include <sys/socket.h>
#include <sys/select.h>

namespace Mad {
namespace Net {

void ServerConnection::connectionHeaderReceiveHandler(const void *data, unsigned long length) {
  if(length != sizeof(ConnectionHeader))
    // Error... disconnect
    return;
  
  const ConnectionHeader *header = reinterpret_cast<const ConnectionHeader*>(data);
  
  if(header->m != 'M' || header->a != 'A' || header->d != 'D')
    // Error... disconnect
    return;
  
  if(header->protVerMin > 1 || header->protVerMax < 1)
    // Unsupported protocol... disconnect
    return;
  
  if(header->type == 'C')
    daemon = false;
  else if(header->type == 'D')
    daemon = true;
  else
    // Error... disconnect
    return;
  
  ConnectionHeader header2 = {'M', 'A', 'D', 0, 0, 1, 1, 0};
  
  rawSend(reinterpret_cast<unsigned char*>(&header2), sizeof(header2));
  
  connecting = false;
  enterReceiveLoop();
}

void ServerConnection::listen(const IPAddress &address) throw(ConnectionException) {
  const int kx_list[] = {GNUTLS_KX_ANON_DH, 0};
  
  if(connected)
    disconnect();
  
  int listen_sock = socket(PF_INET, SOCK_STREAM, 0);
  if(listen_sock < 0)
    throw ConnectionException("socket()", std::strerror(errno));
  
  peer = new IPAddress(address);
  
  if(bind(listen_sock, peer->getSockAddr(), peer->getSockAddrLength()) < 0) {
    close(listen_sock);
    delete peer;
    
    throw ConnectionException("bind()", std::strerror(errno));
  }
  
  if(::listen(listen_sock, 1024) < 0) {
    close(listen_sock);
    delete peer;
    
    throw ConnectionException("listen()", std::strerror(errno));
  }
  
  struct sockaddr_in sa;
  socklen_t addrlen = sizeof(sa);
  
  sock = accept(listen_sock, reinterpret_cast<struct sockaddr*>(&sa), &addrlen);
  if(sock < 0) {
    close(listen_sock);
    delete peer;
    
    throw ConnectionException("accept()", std::strerror(errno));
  }
  
  close(listen_sock);
  
  *peer = IPAddress(address);
  
  connected = true;
  connecting = true;
  
  gnutls_init(&session, GNUTLS_SERVER);
  
  gnutls_set_default_priority(session);
  gnutls_kx_set_priority(session, kx_list);
  
  gnutls_credentials_set(session, GNUTLS_CRD_ANON, anoncred);
  
  gnutls_transport_set_ptr(session, reinterpret_cast<gnutls_transport_ptr_t>(sock));
    
  int ret = gnutls_handshake(session);
  if(ret < 0) {
    disconnect();
    
    throw ConnectionException("gnutls_handshake()", gnutls_strerror(ret));
  }
  
  rawReceive(sizeof(ConnectionHeader), sigc::mem_fun(this, &ServerConnection::connectionHeaderReceiveHandler));
}

void ServerConnection::disconnect() {
  if(!connected)
    return;
  
  gnutls_bye(session, GNUTLS_SHUT_RDWR);
  
  shutdown(sock, SHUT_RDWR);
  close(sock);
  
  gnutls_deinit(session);
  
  delete peer;
  
  connected = false;
  connecting = false;
}

bool ServerConnection::dataPending() const {
  if(!connected)
    return false;
  
  fd_set fds;
  FD_ZERO(&fds);
  FD_SET(sock, &fds);
  
  struct timeval timeout = {0, 0};
  
  return (select(sock + 1, &fds, NULL, NULL, &timeout) == 1);
}

}
}