// Part of BNC, a utility for retrieving decoding and
// converting GNSS data streams from NTRIP broadcasters.
//
// Copyright (C) 2007
// German Federal Agency for Cartography and Geodesy (BKG)
// http://www.bkg.bund.de
// Czech Technical University Prague, Department of Geodesy
// http://www.fsv.cvut.cz
//
// Email: euref-ip@bkg.bund.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, version 2.
//
// 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.

/* -------------------------------------------------------------------------
 * BKG NTRIP Client
 * -------------------------------------------------------------------------
 *
 * Class:      RTCM3coDecoder
 *
 * Purpose:    RTCM3 Clock Orbit Decoder
 *
 * Author:     L. Mervart
 *
 * Created:    05-May-2008
 *
 * Changes:    
 *
 * -----------------------------------------------------------------------*/

#include <stdio.h>
#include <math.h>

#include "RTCM3coDecoder.h"
#include "bncutils.h"
#include "bncrinex.h"
#include "bncapp.h"
#include "bncsettings.h"
#include "rtcm3torinex.h"
#include "bnctime.h"

using namespace std;

// Constructor
////////////////////////////////////////////////////////////////////////////
RTCM3coDecoder::RTCM3coDecoder(const QString& staID) {

  _staID = staID;

  // File Output
  // -----------
  bncSettings settings;
  QString path = settings.value("corrPath").toString();
  if (!path.isEmpty()) {
    expandEnvVar(path);
    if ( path.length() > 0 && path[path.length()-1] != QDir::separator() ) {
      path += QDir::separator();
    }
    _fileNameSkl = path + staID;
  }
  _out      = 0;
  _GPSweeks = -1.0;

  connect(this, SIGNAL(newCorrLine(QString, QString, long)), 
          (bncApp*) qApp, SLOT(slotNewCorrLine(QString, QString, long)));

  connect(this, SIGNAL(newMessage(QByteArray,bool)), 
          (bncApp*) qApp, SLOT(slotMessage(const QByteArray,bool)));

  memset(&_co, 0, sizeof(_co));
  memset(&_bias, 0, sizeof(_bias));
}

// Destructor
////////////////////////////////////////////////////////////////////////////
RTCM3coDecoder::~RTCM3coDecoder() {
  delete _out;
}

// Reopen Output File
//////////////////////////////////////////////////////////////////////// 
void RTCM3coDecoder::reopen(const QString& fileNameSkl, QString& fileName,
                            ofstream*& out) {

  if (!fileNameSkl.isEmpty()) {

    bncSettings settings;

    QDateTime datTim = currentDateAndTimeGPS();

    QString hlpStr = bncRinex::nextEpochStr(datTim,
                                      settings.value("corrIntr").toString());

    QString fileNameHlp = fileNameSkl 
      + QString("%1").arg(datTim.date().dayOfYear(), 3, 10, QChar('0'))
      + hlpStr + datTim.toString(".yyC");

    if (fileName == fileNameHlp) {
      return;
    }
    else {
      fileName = fileNameHlp;
    }

    delete out;
    if ( Qt::CheckState(settings.value("rnxAppend").toInt()) == Qt::Checked) {
      out = new ofstream( fileName.toAscii().data(),
                           ios_base::out | ios_base::app );
    }
    else {
      out = new ofstream( fileName.toAscii().data() );
    }
  }
}

// 
////////////////////////////////////////////////////////////////////////////
t_irc RTCM3coDecoder::Decode(char* buffer, int bufLen, vector<string>& errmsg) {

  errmsg.clear();

  _buffer.append(QByteArray(buffer,bufLen));

  t_irc retCode = failure;

  while(_buffer.size()) {

    int bytesused = 0;
    struct ClockOrbit co_sav;
    memcpy(&co_sav, &_co, sizeof(co_sav)); // save state

    GCOB_RETURN irc = GetClockOrbitBias(&_co, &_bias, _buffer.data(),
                                        _buffer.size(), &bytesused);

    if      (irc <= -30) { // not enough data - restore state and exit loop
      memcpy(&_co, &co_sav, sizeof(co_sav));
      break;
    }

    else if (irc < 0) {    // error  - skip 1 byte and retry
      memset(&_co, 0, sizeof(_co));
      memset(&_bias, 0, sizeof(_bias));
      _buffer = _buffer.mid(bytesused ? bytesused : 1);
    }

    else {                 // OK or MESSAGEFOLLOWS
      _buffer = _buffer.mid(bytesused);

      if ( irc == GCOBR_OK && 
           (_co.NumberOfGPSSat   > 0 || _co.NumberOfGLONASSSat   > 0 ||
            _bias.NumberOfGPSSat > 0 || _bias.NumberOfGLONASSSat > 0) ) {

        reopen(_fileNameSkl, _fileName, _out);

        // Guess GPS week and sec using system time
        // ----------------------------------------
        int    GPSweek;
        double GPSweeksHlp;
        currentGPSWeeks(GPSweek, GPSweeksHlp);

        // Correction Epoch from GPSEpochTime
        // ----------------------------------
        if (_co.NumberOfGPSSat > 0 || _bias.NumberOfGPSSat > 0) {
          int GPSEpochTime = (_co.NumberOfGPSSat > 0) ? 
                             _co.GPSEpochTime : _bias.GPSEpochTime;
          if      (GPSweeksHlp > GPSEpochTime + 86400.0) {
            GPSweek += 1;
          }
          else if (GPSweeksHlp < GPSEpochTime - 86400.0) {
            GPSweek -= 1;
          }
          _GPSweeks = GPSEpochTime;
        }

        // Correction Epoch from Glonass Epoch
        // -----------------------------------
        else if (_co.NumberOfGLONASSSat > 0 || _bias.NumberOfGLONASSSat > 0){
          int GLONASSEpochTime = (_co.NumberOfGLONASSSat > 0) ? 
                              _co.GLONASSEpochTime : _bias.GLONASSEpochTime;

          // Second of day (GPS time) from Glonass Epoch
          // -------------------------------------------
          QDate date = dateAndTimeFromGPSweek(GPSweek, GPSweeksHlp).date();
          int leapSecond = gnumleap(date.year(), date.month(), date.day());
          int GPSDaySec  = GLONASSEpochTime - 3 * 3600 + leapSecond;

          int weekDay      = int(GPSweeksHlp/86400.0); 
          int GPSDaySecHlp = int(GPSweeksHlp) - weekDay * 86400;

          // Handle the difference between system clock and correction epoch
          // ---------------------------------------------------------------
          if      (GPSDaySec < GPSDaySecHlp - 3600) {
            weekDay += 1;
            if (weekDay > 6) {
              weekDay = 0;
              GPSweek += 1;
            }
          }
          else if (GPSDaySec > GPSDaySecHlp + 3600) {
            weekDay -= 1;
            if (weekDay < 0) {
              weekDay = 6;
              GPSweek -= 1;
            }
          } 

          _GPSweeks = weekDay * 86400.0 + GPSDaySec;
        }

        QStringList asciiLines = corrsToASCIIlines(GPSweek, _GPSweeks, 
                                                   _co, &_bias);

        QStringListIterator it(asciiLines);
        while (it.hasNext()) {
          QString line = it.next();
          printLine(line, GPSweek, _GPSweeks);
        }

        retCode = success;
        memset(&_co, 0, sizeof(_co));
        memset(&_bias, 0, sizeof(_bias));
      }
    }
  }

  if (retCode != success) {
    _GPSweeks = -1.0;
  }
  return retCode;
}

// 
////////////////////////////////////////////////////////////////////////////
void RTCM3coDecoder::printLine(const QString& line, int GPSweek, 
                               double GPSweeks) {
  if (_out) {
    *_out << line.toAscii().data() << endl;
    _out->flush();
  }

  int    currWeek;
  double currSec;
  currentGPSWeeks(currWeek, currSec);
  bncTime currTime(currWeek, currSec);

  bncTime corrTime(GPSweek, GPSweeks);

  double dt = currTime - corrTime;
  const double MAXDT = 10 * 60.0;
  if (fabs(dt) > MAXDT) {
    emit newMessage("suspicious correction: " + _staID.toAscii() + " " 
                    + line.toAscii(), false);
  }
  else {
    long coTime = GPSweek * 7*24*3600 + long(floor(_GPSweeks+0.5));
    emit newCorrLine(line, _staID, coTime);
  }
}

// 
////////////////////////////////////////////////////////////////////////////
QStringList RTCM3coDecoder::corrsToASCIIlines(int GPSweek, double GPSweeks,
                                              const ClockOrbit& co,
                                              const Bias* bias) {

  QStringList retLines;

  // Loop over all satellites (GPS and Glonass)
  // ------------------------------------------
  if (co.NumberOfGPSSat > 0 || co.NumberOfGLONASSSat > 0) {
    QString line1;
    line1.sprintf("! Orbits/Clocks: %d GPS %d Glonass",
                  co.NumberOfGPSSat, co.NumberOfGLONASSSat);
    retLines << line1;
  }
  for (int ii = 0; ii < CLOCKORBIT_NUMGPS+co.NumberOfGLONASSSat; ii++) {
    char sysCh = ' ';
    if      (ii < co.NumberOfGPSSat) {
      sysCh = 'G';
    }
    else if (ii >= CLOCKORBIT_NUMGPS) {
      sysCh = 'R';
    }

    if (sysCh != ' ') {

      QString linePart;
      linePart.sprintf("%d %d %d %.1f %c%2.2d",
                       co.messageType, co.UpdateInterval, GPSweek, GPSweeks,
                       sysCh, co.Sat[ii].ID);

      // Combined message (orbit and clock)
      // ----------------------------------
      if ( co.messageType == COTYPE_GPSCOMBINED     || 
           co.messageType == COTYPE_GLONASSCOMBINED ) {
        QString line;
        line.sprintf("   %3d"
                     "   %8.3f %8.3f %8.3f %8.3f"
                     "   %10.5f %10.5f %10.5f %10.5f"
                     "   %10.5f",
                     co.Sat[ii].IOD, 
                     co.Sat[ii].Clock.DeltaA0,
                     co.Sat[ii].Orbit.DeltaRadial, 
                     co.Sat[ii].Orbit.DeltaAlongTrack,
                     co.Sat[ii].Orbit.DeltaCrossTrack,
                     co.Sat[ii].Clock.DeltaA1,
                     co.Sat[ii].Orbit.DotDeltaRadial, 
                     co.Sat[ii].Orbit.DotDeltaAlongTrack,
                     co.Sat[ii].Orbit.DotDeltaCrossTrack,
                     co.Sat[ii].Clock.DeltaA2);
        retLines << linePart+line;
      }

      // Orbits only
      // -----------
      else if ( co.messageType == COTYPE_GPSORBIT     || 
                co.messageType == COTYPE_GLONASSORBIT ) {
        QString line;
        line.sprintf("   %3d"
                     "   %8.3f %8.3f %8.3f"
                     "   %10.5f %10.5f %10.5f",
                     co.Sat[ii].IOD, 
                     co.Sat[ii].Orbit.DeltaRadial, 
                     co.Sat[ii].Orbit.DeltaAlongTrack,
                     co.Sat[ii].Orbit.DeltaCrossTrack,
                     co.Sat[ii].Orbit.DotDeltaRadial, 
                     co.Sat[ii].Orbit.DotDeltaAlongTrack,
                     co.Sat[ii].Orbit.DotDeltaCrossTrack);
        retLines << linePart+line;
      }

      // Clocks only
      // -----------
      else if ( co.messageType == COTYPE_GPSCLOCK     || 
                co.messageType == COTYPE_GLONASSCLOCK ) {
        QString line;
        line.sprintf("   %3d   %8.3f   %10.5f   %10.5f",
                     co.Sat[ii].IOD, 
                     co.Sat[ii].Clock.DeltaA0,
                     co.Sat[ii].Clock.DeltaA1,
                     co.Sat[ii].Clock.DeltaA2);
        retLines << linePart+line;
      }

      // User Range Accuracy
      // -------------------
      else if ( co.messageType == COTYPE_GPSURA     || 
                co.messageType == COTYPE_GLONASSURA ) {
        QString line;
        line.sprintf("   %3d   %f",
                     co.Sat[ii].IOD, co.Sat[ii].UserRangeAccuracy);
        retLines << linePart+line;
      }

      // High-Resolution Clocks
      // ----------------------
      else if ( co.messageType == COTYPE_GPSHR     || 
                co.messageType == COTYPE_GLONASSHR ) {
        QString line;
        line.sprintf("   %3d   %8.3f",
                     co.Sat[ii].IOD, co.Sat[ii].hrclock);
        retLines << linePart+line;
      }
    }
  }

  // Loop over all satellites (GPS and Glonass)
  // ------------------------------------------
  if (bias) {
    if (bias->NumberOfGPSSat > 0 || bias->NumberOfGLONASSSat > 0) {
      QString line1;
      line1.sprintf("! Biases: %d GPS %d Glonass",
                    bias->NumberOfGPSSat, bias->NumberOfGLONASSSat);
      retLines << line1;
    }
    for (int ii = 0; ii < CLOCKORBIT_NUMGPS + bias->NumberOfGLONASSSat; ii++) {
      char sysCh = ' ';
      int messageType;
      if      (ii < bias->NumberOfGPSSat) {
        sysCh = 'G';
        messageType = BTYPE_GPS;
      }
      else if (ii >= CLOCKORBIT_NUMGPS) {
        sysCh = 'R';
        messageType = BTYPE_GLONASS;
      }
      if (sysCh != ' ') {
        QString line;
        line.sprintf("%d %d %d %.1f %c%2.2d %d", 
                     messageType, bias->UpdateInterval, GPSweek, GPSweeks, 
                     sysCh, bias->Sat[ii].ID,
                     bias->Sat[ii].NumberOfCodeBiases);
        for (int jj = 0; jj < bias->Sat[ii].NumberOfCodeBiases; jj++) {
          QString hlp;
          hlp.sprintf(" %d %8.3f",  bias->Sat[ii].Biases[jj].Type,
                      bias->Sat[ii].Biases[jj].Bias);
          line += hlp;
        }
        retLines << line;
      }
    }
  }

  return retLines;
}