/******************************************************************************
 * TrafficMGr.cxx
 * Written by Durk Talsma, started May 5, 2004.
 *
 * 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.
 *
 *
 **************************************************************************/
 
/* This a prototype version of a top-level flight plan manager for Flightgear.
 * It parses the fgtraffic.txt file and determine for a specific time/date, 
 * where each aircraft listed in this file is at the current time. 
 * 
 * I'm currently assuming the following simplifications:
 * 1) The earth is a perfect sphere
 * 2) Each aircraft flies a perfect great circle route.
 * 3) Each aircraft flies at a constant speed (with infinite accelerations and
 *    decelerations) 
 * 4) Each aircraft leaves at exactly the departure time. 
 * 5) Each aircraft arrives at exactly the specified arrival time. 
 *
 *
 *****************************************************************************/

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#include <stdlib.h>
#include <time.h>
#include <iostream>
#include <fstream>


#include <string>
#include <vector>
#include <algorithm>

#include <plib/sg.h>
#include <plib/ul.h>

#include <simgear/compiler.h>
#include <simgear/math/polar3d.hxx>
#include <simgear/math/sg_geodesy.hxx>
#include <simgear/misc/sg_path.hxx>
#include <simgear/props/props.hxx>
#include <simgear/route/waypoint.hxx>
#include <simgear/structure/subsystem_mgr.hxx>
#include <simgear/xml/easyxml.hxx>

#include <AIModel/AIAircraft.hxx>
#include <AIModel/AIFlightPlan.hxx>
#include <AIModel/AIBase.hxx>
#include <Airports/simple.hxx>
#include <Main/fg_init.hxx>



#include "TrafficMgr.hxx"

SG_USING_STD(sort);
 
/******************************************************************************
 * TrafficManager
 *****************************************************************************/
FGTrafficManager::FGTrafficManager()
{
  score = 0;
  runCount = 0;
}

FGTrafficManager:: ~FGTrafficManager()
{
  for (ScheduleVectorIterator sched = scheduledAircraft.begin(); sched != scheduledAircraft.end(); sched++)
    {
      delete (*sched);
    }
  scheduledAircraft.clear();
  // for (FGScheduledFlightVecIterator flt = flights.begin(); flt != flights.end(); flt++)
//     {
//       delete (*flt);
//     }
//   flights.clear();
}


void FGTrafficManager::init()
{ 
  //cerr << "Initializing Schedules" << endl;
  //time_t now = time(NULL) + fgGetLong("/sim/time/warp");
  //currAircraft = scheduledAircraft.begin();
  //while (currAircraft != scheduledAircraft.end())
  //  {
  //    if (!(currAircraft->init()))
  //	{
  //	  currAircraft=scheduledAircraft.erase(currAircraft);
  //	  //cerr << "Erasing " << currAircraft->getRegistration() << endl;
  //	}
  //   else 
  //	{
  //	  currAircraft++;
  //	}
  //   }
  // Sort by points: Aircraft with frequent visits to the
  // startup airport will be processed first
  ulDir* d, *d2;
  ulDirEnt* dent, *dent2;
  SGPath aircraftDir = globals->get_fg_root();

  /* keep the following three lines (which mimicks the old "fixed path" behavior)
   * until we have some AI models with traffic in the base package
   */ 
  SGPath path = aircraftDir;
  path.append("Traffic/fgtraffic.xml");
  if (path.exists())
    readXML(path.str(),*this);

  aircraftDir.append("AI/Aircraft");
  if ((d = ulOpenDir(aircraftDir.c_str())) != NULL)
    {
      while((dent = ulReadDir(d)) != NULL) {
	//cerr << "Scanning : " << dent->d_name << endl;
	if (string(dent->d_name) != string(".")  && 
	    string(dent->d_name) != string("..") &&
	    dent->d_isdir)
	  {
	    SGPath currACDir = aircraftDir;
	    currACDir.append(dent->d_name);
	    if ((d2 = ulOpenDir(currACDir.c_str())) == NULL)
	      return;
	    while ((dent2 = ulReadDir(d2)) != NULL) {
	      SGPath currFile = currACDir;
	      currFile.append(dent2->d_name);
	      if (currFile.extension() == string("xml"))
		{
		  //cerr << "found " << dent2->d_name << " for parsing" << endl;
		  SGPath currFile = currACDir;
		  currFile.append(dent2->d_name);
		  SG_LOG(SG_GENERAL, SG_INFO, "Scanning " << currFile.str() << " for traffic");
		  readXML(currFile.str(),*this);
		}
	    }
	    ulCloseDir(d2);
	  }
      }
      ulCloseDir(d);
    }
  // Sort by points: Aircraft with frequent visits to the
  // startup airport will be processed first
  sort(scheduledAircraft.begin(), scheduledAircraft.end(), compareSchedules);
  currAircraft = scheduledAircraft.begin();
  currAircraftClosest = scheduledAircraft.begin();
  //cerr << "Done initializing schedules" << endl;
}

void FGTrafficManager::update(double /*dt*/)
{
  //SG_LOG( SG_GENERAL, SG_INFO, "Running TrafficManager::Update() ");
  // Hack alert: Skip running for the first frames 1000 after 
  // initialization to allow proper initialization of wheather stuff 
  // and runway assignments
  if (runCount < 1000)
    {
      runCount++;
      return;
    }
  //runCount = 0;
  time_t now = time(NULL) + fgGetLong("/sim/time/warp");
  if (scheduledAircraft.size() == 0) {
    //SG_LOG( SG_GENERAL, SG_INFO, "Returned Running TrafficManager::Update() ");
    return;
  }
  if(currAircraft == scheduledAircraft.end())
    {
      //cerr << "resetting schedule " << endl;
      currAircraft = scheduledAircraft.begin();
    }
  if (!((*currAircraft)->update(now)))
    {
      // after proper initialization, we shouldnt get here.
      // But let's make sure
      SG_LOG( SG_GENERAL, SG_ALERT, "Failed to update aircraft schedule in traffic manager");
    }
  currAircraft++;
  //SG_LOG( SG_GENERAL, SG_INFO, "Done Running TrafficManager::Update() ");
}

void FGTrafficManager::release(int id)
{
  releaseList.push_back(id);
}

bool FGTrafficManager::isReleased(int id)
{
  IdListIterator i = releaseList.begin();
  while (i != releaseList.end())
    {
      if ((*i) == id)
	{
	  releaseList.erase(i);
	  return true;
	}
      i++;
    }
  return false;
}

void  FGTrafficManager::startXML () {
  //cout << "Start XML" << endl;
}

void  FGTrafficManager::endXML () {
  //cout << "End XML" << endl;
}

void  FGTrafficManager::startElement (const char * name, const XMLAttributes &atts) {
  const char * attval;
  //cout << "Start element " << name << endl;
  //FGTrafficManager temp;
  //for (int i = 0; i < atts.size(); i++)
  //  if (string(atts.getName(i)) == string("include"))
  attval = atts.getValue("include");
  if (attval != 0)
      {
	//cout << "including " << attval << endl;
	SGPath path = 
	  globals->get_fg_root();
	path.append("/Traffic/");
	path.append(attval);
	readXML(path.str(), *this);
      }
  //  cout << "  " << atts.getName(i) << '=' << atts.getValue(i) << endl; 
}

void  FGTrafficManager::endElement (const char * name) {
  //cout << "End element " << name << endl;
  string element(name);
  if (element == string("model"))
    mdl = value;
  else if (element == string("livery"))
    livery = value;
  else if (element == string("registration"))
    registration = value;
  else if (element == string("airline"))
    airline = value;
  else if (element == string("actype"))
    acType = value;
  else if (element == string("flighttype"))
    flighttype = value;
  else if (element == string("radius"))
    radius = atoi(value.c_str());
  else if (element == string("offset"))
    offset = atoi(value.c_str());
  else if (element == string("performance-class"))
    m_class = value;
  else if (element == string("heavy"))
    {
      if(value == string("true"))
	heavy = true;
      else
	heavy = false;
    }
  else if (element == string("callsign"))
    callsign = value;
  else if (element == string("fltrules"))
    fltrules = value;
  else if (element == string("port"))
    port = value;
  else if (element == string("time"))
    timeString = value;
  else if (element == string("departure"))
    {
      departurePort = port;
      departureTime = timeString;
    }
  else if (element == string("cruise-alt"))
    cruiseAlt = atoi(value.c_str());
  else if (element == string("arrival"))
    {
      arrivalPort = port;
      arrivalTime = timeString;
    }
  else if (element == string("repeat"))
    repeat = value;
  else if (element == string("flight"))
    {
      // We have loaded and parsed all the information belonging to this flight
      // so we temporarily store it. 
      //cerr << "Pusing back flight " << callsign << endl;
      //cerr << callsign  <<  " " << fltrules     << " "<< departurePort << " " <<  arrivalPort << " "
      //   << cruiseAlt <<  " " << departureTime<< " "<< arrivalTime   << " " << repeat << endl;

      //Prioritize aircraft 
      string apt = fgGetString("/sim/presets/airport-id");
      //cerr << "Airport information: " << apt << " " << departurePort << " " << arrivalPort << endl;
      if (departurePort == apt) score++;
      flights.push_back(new FGScheduledFlight(callsign,
					  fltrules,
					  departurePort,
					  arrivalPort,
					  cruiseAlt,
					  departureTime,
					  arrivalTime,
					  repeat));
    }
  else if (element == string("aircraft"))
    {
      //cerr << "Pushing back aircraft " << registration << endl;
      scheduledAircraft.push_back(new FGAISchedule(mdl, 
					       livery, 
					       registration, 
					       heavy,
					       acType, 
					       airline, 
					       m_class, 
					       flighttype,
					       radius,
					       offset,
					       score,
					       flights));
     //  while(flights.begin() != flights.end()) {
// 	flights.pop_back();
//       }
      for (FGScheduledFlightVecIterator flt = flights.begin(); flt != flights.end(); flt++)
    {
      delete (*flt);
    }
  flights.clear();
      SG_LOG( SG_GENERAL, SG_BULK, "Reading aircraft : " 
	      << registration 
	      << " with prioritization score " 
	      << score);
      score = 0;
    }
}

void  FGTrafficManager::data (const char * s, int len) {
  string token = string(s,len);
  //cout << "Character data " << string(s,len) << endl;
  if ((token.find(" ") == string::npos && (token.find('\n')) == string::npos))
      value += token;
  else
    value = string("");
}

void  FGTrafficManager::pi (const char * target, const char * data) {
  //cout << "Processing instruction " << target << ' ' << data << endl;
}

void  FGTrafficManager::warning (const char * message, int line, int column) {
  SG_LOG(SG_IO, SG_WARN, "Warning: " << message << " (" << line << ',' << column << ')');
}

void  FGTrafficManager::error (const char * message, int line, int column) {
  SG_LOG(SG_IO, SG_ALERT, "Error: " << message << " (" << line << ',' << column << ')');
}