/*
 *   ORXONOX - the hottest 3D action shooter ever to exist
 *                    > www.orxonox.net <
 *
 *
 *   License notice:
 *
 *   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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 *   Author:
 *      Oliver Scheuss
 *   Co-authors:
 *      ...
 *
 */

//
// C++ Implementation: Server
//
// Description:
//
//
// Author:  Oliver Scheuss, (C) 2007
//
// Copyright: See COPYING file that comes with this distribution
//
//

#include "Server.h"

#define WIN32_LEAN_AND_MEAN
#include <enet/enet.h>
#include <cassert>
#include <string>

#include "util/Clock.h"
#include "util/Output.h"
#include "core/command/Executor.h"
#include "packet/Chat.h"
#include "packet/ClassID.h"
#include "packet/DeleteObjects.h"
#include "packet/FunctionIDs.h"
#include "packet/Gamestate.h"
#include "packet/Welcome.h"
#include "FunctionCallManager.h"
#include "GamestateManager.h"

namespace orxonox
{
  const unsigned int MAX_FAILURES = 20;

  /**
  * Constructor for default values (bindaddress is set to ENET_HOST_ANY
  *
  */
  Server::Server()
  {
    this->timeSinceLastUpdate_ = 0;
  }

  /**
  * Constructor
  * @param port Port to listen on
  */
  Server::Server(int port)
  {
    this->setPort(port);
    this->timeSinceLastUpdate_ = 0;
  }

  /**
  * Constructor
  * @param port Port to listen on
  * @param bindAddress Address to listen on
  */
  Server::Server(int port, const std::string& bindAddress)
  {
    this->setPort(port);
    this->setBindAddress(bindAddress);
    this->timeSinceLastUpdate_ = 0;
  }

  /**
  * @brief Destructor
  */
  Server::~Server()
  {
  }

  /**
  * This function opens the server by creating the listener thread
  */
  void Server::open()
  {
    Host::setActive(true);
    orxout(verbose, context::network) << "opening server" << endl;
    this->openListener();

    /* make discoverable on LAN */
    LANDiscoverable::setActivity(true);
    LANDiscoverable::updateClientNumber(0);

    /* make discoverable on WAN */
    WANDiscoverable::setActivity(true);
    WANDiscoverable::updateClientNumber(0);

    /* done */
    return;
  }

  /**
  * This function closes the server
  */
  void Server::close()
  {
    Host::setActive(false);
    orxout(verbose, context::network) << "closing server" << endl;
    this->disconnectClients();
    this->closeListener();

    /* tell master server we're closing */
    orxout(internal_info, context::network) << "disconnecting." << endl;
    WANDiscoverable::setActivity(false);
    orxout(internal_info, context::network) << "disconnecting done" << endl;

    LANDiscoverable::setActivity(false);
    return;
  }

  /**
  * Run this function once every tick
  * calls processQueue and updateGamestate
  * @param time time since last tick
  */
  void Server::update(const Clock& time)
  {
    // receive incoming packets
    Connection::processQueue();

    // receive and process incoming discovery packets
    LANDiscoverable::update();

    if (GamestateManager::hasPeers())
    {
      // process incoming gamestates
      GamestateManager::processGamestates();
      FunctionCallManager::processBufferedFunctionCalls();

      // send function calls to clients
      FunctionCallManager::sendCalls(static_cast<Host*>(this));

      // this steers our network frequency
      timeSinceLastUpdate_ += time.getDeltaTime();
      if(timeSinceLastUpdate_ >= NETWORK_PERIOD)
      {
        timeSinceLastUpdate_ -= static_cast<unsigned int>(timeSinceLastUpdate_ / NETWORK_PERIOD) * NETWORK_PERIOD;
        this->updateGamestate();
      }
    }
  }

  void Server::queuePacket(ENetPacket *packet, int clientID, uint8_t channelID)
  {
    ServerConnection::addPacket(packet, clientID, channelID);
  }

  /**
   * Print ping time to client in milliseconds.
   */
  void Server::printRTT()
  {
    // TODO: Implement
  }

  /**
   * Take a new snapshot of the gamestate and send it to the clients.
   */
  void Server::updateGamestate()
  {
    if(this->clientIDs_.size() == 0)
    {
      // no client connected
      return;
    }
    GamestateManager::update();
    this->sendGameStates();
    this->sendObjectDeletes();
  }

  /**
   * Send the current gamestate to all peers.
   */
  bool Server::sendGameStates()
  {
    std::vector<packet::Gamestate*> gamestates = GamestateManager::getGamestates();
    for(packet::Gamestate* gamestate : gamestates)
    {
      gamestate->send(static_cast<Host*>(this));
    }
    return true;
  }


  /**
   * Send 'DeleteObjects' packet
   */
  bool Server::sendObjectDeletes()
  {
    // no client connected
    if(this->clientIDs_.size() == 0)
    {
      return true;
    }

    packet::DeleteObjects *del = new packet::DeleteObjects();
    if(!del->fetchIDs())
    {
      delete del;
      return true;  //everything ok (no deletes this tick)
    }

    del->setPeerID(NETWORK_PEER_ID_BROADCAST);
    if (!del->send( static_cast<Host*>(this)))
    {
      orxout(internal_warning, context::network) << "Server: could not broadcast deleteObjects packet" << endl;
    }

    return true;
  }

  /**
   * Add a new peer to the server.
   */
  void Server::addPeer(uint32_t peerID)
  {
    // inform all the listeners
    this->clientIDs_.push_back(peerID);
    WANDiscoverable::updateClientNumber(this->clientIDs_.size());
    LANDiscoverable::updateClientNumber(this->clientIDs_.size());

    ClientConnectionListener::broadcastClientConnected(peerID);
    GamestateManager::addPeer(peerID);

    orxout(internal_info, context::network) << "Server: added client id: " << peerID << endl;

    this->createClient(peerID);
  }

  /**
   * Remove a peer from the server.
   */
  void Server::removePeer(uint32_t peerID)
  {
    orxout(verbose, context::network) << "removing client from list" << endl;

    // erase the peer from the list
    std::vector<uint32_t>::iterator it;
    for(it=this->clientIDs_.begin(); it!=this->clientIDs_.end(); ++it)
    {
      if(*it == peerID)
      {
        this->clientIDs_.erase(it);
        break;
      }
    }

    WANDiscoverable::updateClientNumber(this->clientIDs_.size());
    LANDiscoverable::updateClientNumber(this->clientIDs_.size());

    // Send 'clientDisconnected' message
    ClientConnectionListener::broadcastClientDisconnected(peerID);

    GamestateManager::removePeer(peerID);
  }

  /**
   * Process an incoming packet.
   */
  void Server::processPacket(packet::Packet* packet)
  {
    if(packet->isReliable())
    {
      if(this->getLastReceivedGamestateID(packet->getPeerID()) >= packet->getRequiredGamestateID())
      {
        packet->process(static_cast<Host*>(this));
      }
      else
      {
        this->packetQueue_.push_back(packet);
      }
    }
    else
    {
      packet->process(static_cast<Host*>(this));
    }
  }

  /**
   * Create a client.
   */
  bool Server::createClient(int clientID)
  {

    // synchronise class ids
    this->syncClassid(clientID);

    // now synchronise functionIDs
    packet::FunctionIDs *fIDs = new packet::FunctionIDs();
    fIDs->setPeerID(clientID);
    bool b = fIDs->send(static_cast<Host*>(this));
    assert(b);

    GamestateManager::setSynched(clientID);

    // Send 'Welcome' packet to client
    orxout(verbose, context::network) << "sending welcome" << endl;
    packet::Welcome *w = new packet::Welcome(clientID);
    w->setPeerID(clientID);
    b = w->send(static_cast<Host*>(this));
    assert(b);

    (void)b; // avoid compiler warning
    return true;
  }

  /**
   * Disconnect a client.
   */
  void Server::disconnectClient(uint32_t clientID)
  {
    ServerConnection::disconnectClient(clientID);
    GamestateManager::removePeer(clientID);
  }

  /**
   * @brief Sends a chat message to the given target ID.
   * @param message message to be sent
   * @param sourceID the ID of the sender
   * @param targetID the ID of the receiver
   */
  void Server::doSendChat(const std::string& message, unsigned int sourceID, unsigned int targetID)
  {
    // check if the target exists. just ignore the message otherwise
    if (!this->isValidTarget(targetID))
    {
      return;
    }

    // send the message to the target
    packet::Chat* packet = new packet::Chat(message, sourceID, targetID);
    packet->setPeerID(targetID);
    packet->send(static_cast<Host*>(this));

    // if the target is (or includes) this host as well, call the parent function which passes the message to the listeners
    if (targetID == NETWORK_PEER_ID_BROADCAST || targetID == Host::getPlayerID())
    {
      Host::doReceiveChat(message, sourceID, targetID);
    }
  }

  /**
   * @brief Gets called if a packet::Chat packet is received. Forwards the packet to the target
   * and calls the parent function if necessary.
   */
  void Server::doReceiveChat(const std::string& message, unsigned int sourceID, unsigned int targetID)
  {
      this->doSendChat(message, sourceID, targetID);
  }

  /**
   * @brief Returns true if the target ID is in the list of clients (or if it
   * corresponds to the broadcast or the server ID).
   */
  bool Server::isValidTarget(unsigned int targetID)
  {
    // Broadcast or server ID are okay
    if (targetID == NETWORK_PEER_ID_BROADCAST || targetID == NETWORK_PEER_ID_SERVER)
    {
      return true;
    }

    // IDs in the client list are okay also
    for(uint32_t id : this->clientIDs_)
    {
      if(id == targetID)
      {
        return true;
      }
    }

    return false;
  }

  void Server::syncClassid(unsigned int clientID)
  {
    packet::ClassID *classid = new packet::ClassID();
    classid->setPeerID(clientID);

    int failures = 0;
    while(!classid->send(static_cast<Host*>(this)) && failures < 10)\
    {
      failures++;
    }
    assert(failures<10);
    orxout(verbose, context::network) << "syncClassid:\tall synchClassID packets have been sent" << endl;
  }

}