// Excerpt: RDisagg.Delegate.cpp, 4-20-2012

// private slot
bool RDisagg::Delegate::executeRScript (const QString& scriptStr,
                                        QString& resultMsg,
                                        int& msecsRet) const
{
   static const char* mname ("RDisagg::Delegate::executeRScript");
   // DIAG() << mname;

   Delegate* mutableThis = const_cast<Delegate*> (this);

   resultMsg = "";
   msecsRet = 0;

   // clear execution time display.
   _ui._execProgressDispLineEdit->setText ("");

   // *********************************************
   // *** (1) Open "R" Script File for Writing  ***
   // *********************************************

   const QString plugDir = UtilsNS::pluginDir();
   const QFileInfo scriptFileInfo (plugDir, "RDisagg.R");
   const QString scriptPath = scriptFileInfo.absoluteFilePath();

   QFile scriptFile (scriptPath);
   const bool openScriptOk = scriptFile.open (QIODevice::WriteOnly);
   if (!openScriptOk)
   {
      DIAG() << mname << " ERROR Opening '" 
             << qPrintable (scriptPath) << "'";

      QApplication::beep();
      return (false); // failure
      //----------->>
   }

   // DIAG() << mname << " Opened '" << qPrintable (scriptPath) << "'";

   // *****************************************
   // *** (2) Prepare Script Response File  ***
   // *****************************************

   const QFileInfo scriptRespFileInfo (plugDir, ResultFileName);
   _scriptOutPath = scriptRespFileInfo.absoluteFilePath();

   QFile scriptOutFile (_scriptOutPath);
   if (scriptOutFile.exists())
   {
      const bool removeOk = scriptOutFile.remove();
      if (!removeOk)
      {
         DIAG() << mname << " ERROR Removing '"
                << qPrintable (_scriptOutPath) << "'";

         QApplication::beep();
         return (false); // failure
         //----------->>
      }
   }

   // **********************************
   // *** (3) Write "R" Script File  ***
   // **********************************

   // Script Header Comment String
   QString headerCmtStr = "# RDisagg.R script. Generated: ";
   headerCmtStr += QDateTime::currentDateTime().toString();
   headerCmtStr += "\n";

   QString scriptStr2 = scriptStr;
   scriptStr2.replace (SYM_SCRIPT_OUT_PATH, _scriptOutPath);
   _recentScriptStr = scriptStr2;

   scriptFile.write (qPrintable (headerCmtStr));
   scriptFile.write (qPrintable (scriptStr2));
   scriptFile.close();

   // ****************************************
   // *** (4) Execute the "R" Script File  ***
   // ****************************************

   _stopRequested = false;
   _running = true;
   mutableThis->updateWidgets();

   static const QString cmdStrFmt ("Rscript --slave %1");
   const QString cmdStr = cmdStrFmt .arg (scriptPath);

   QProcess cmdProc (mutableThis);
   cmdProc.start (cmdStr);

   // Use an actual QTime for a more precise timing.
   QTime procTime;
   procTime.start();
   double secs (0.0);

   bool didFinish (false);
   int waitCount (0);
   while (!didFinish)
   {
      didFinish = cmdProc.waitForFinished (100); // milliseconds
      ++waitCount;

      const int tenthSecs = (int) (procTime.elapsed() / 100.0);
      secs = double (tenthSecs / 10.0);

      _ui._execProgressDispLineEdit->setText (QString::number (secs));

      QApplication::processEvents (QEventLoop::AllEvents,
                                   20); // maxtime, milliseconds

      if (_stopRequested || (!NO_TIMEOUT && (secs > TIMEOUT_SECS)))
      {
         cmdProc.kill();
         break; //------
      }
   }

   _running = false;
   mutableThis->updateWidgets();

   msecsRet = int (secs * 1000.0);
   const QProcess::ExitStatus exStat = cmdProc.exitStatus();

   const QString stdOutTxt = cmdProc.readAllStandardOutput();
   const QString stdErrTxt = cmdProc.readAllStandardError();

   // *******************************
   // *** (5) Read Script Result  ***
   // *******************************

   // SIDE EFFECT: Computes QString _scriptOutPath, if undefined.
   bool resultFileExists (false); // tentative
   const QString resultFileStr = resultFileText (&resultFileExists);

   if (!didFinish)
   {
      // ***********************************
      // *** Did Not Finish Successfully ***
      // ***********************************
   
      resultMsg = "DID NOT FINISH, ExitStatus: [";
      resultMsg += QString::number ((int) exStat) + "] ";
      resultMsg += ((exStat == QProcess::NormalExit) ? "NORMAL" : "CRASH");
   }

   if (!resultFileExists)
   {
      resultMsg += 
        QString ("\n\nERROR Result File Missing '%1'")
        .arg (_scriptOutPath);
   }
   else
   {
      resultMsg += "\n\nRESULT ...\n";
      resultMsg += resultFileStr;
   } 

   static const QString SuccessStr ("FUNCTION STATUS: SUCCESS");
   const bool successFound = resultMsg.contains (SuccessStr);

   if (!successFound || !didFinish || DEBUG_INCLUDE_STD_OUT)
   {
      resultMsg += "\n\nSTANDARD OUT ...\n";
      resultMsg += stdOutTxt;
   }   
      
   if (!successFound || !didFinish || DEBUG_INCLUDE_STD_ERR)
   {
      resultMsg += "\n\nSTANDARD ERROR ...\n";
      resultMsg += stdErrTxt;
   }

   resultMsg = resultMsg.trimmed();

   return (didFinish && successFound);
}