// ******************************************************************************
   //
   // Title:       Force Field X.
   // Description: Force Field X - Software for Molecular Biophysics.
   // Copyright:   Copyright (c) Michael J. Schnieders 2001-2024.
   //
   // This file is part of Force Field X.
   //
   // Force Field X is free software; you can redistribute it and/or modify it
  // under the terms of the GNU General Public License version 3 as published by
  // the Free Software Foundation.
  //
  // Force Field X 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
  // Force Field X; if not, write to the Free Software Foundation, Inc., 59 Temple
  // Place, Suite 330, Boston, MA 02111-1307 USA
  //
  // Linking this library statically or dynamically with other modules is making a
  // combined work based on this library. Thus, the terms and conditions of the
  // GNU General Public License cover the whole combination.
  //
  // As a special exception, the copyright holders of this library give you
  // permission to link this library with independent modules to produce an
  // executable, regardless of the license terms of these independent modules, and
  // to copy and distribute the resulting executable under terms of your choice,
  // provided that you also meet, for each linked independent module, the terms
  // and conditions of the license of that module. An independent module is a
  // module which is not derived from or based on this library. If you modify this
  // library, you may extend this exception to your version of the library, but
  // you are not obligated to do so. If you do not wish to do so, delete this
  // exception statement from your version.
  //
  // ******************************************************************************
  package ffx.ui;
  
  import edu.rit.pj.Comm;
  import ffx.potential.Utilities;
  import ffx.ui.MainPanel.ExitStatus;
  import java.awt.GraphicsEnvironment;
  import java.io.File;
  import java.io.FileOutputStream;
  import java.io.PrintStream;
  import java.util.logging.ErrorManager;
  import java.util.logging.Handler;
  import java.util.logging.Level;
  import java.util.logging.LogRecord;
  
  /**
   * The default ConsoleHanlder publishes logging to System.err. This class publishes to System.out,
   * which is normally intercepted by the Force Field X Shell.
   *
   * <p>The formatter used reduces verbosity relative to the default SimpleFormatter.
   *
   * @author Michael J. Schnieders
   * @since 1.0
   */
  public class LogHandler extends Handler {
  
    /**
     * If true, FFX is running in a headless environment.
     */
    private static final boolean headless = GraphicsEnvironment.isHeadless();
  
    /**
     * If the MainPanel variable has been set, we can publish records to the ModelingShell.
     */
    private MainPanel mainPanel = null;
  
    /**
     * If true, we have received a Record at the Level.SEVERE and FFX will exit.
     */
    private boolean fatal = false;
  
    /**
     * Construct the Force Field X Log Handler.
     *
     * @since 1.0
     */
    public LogHandler() {
      setLevel(Level.ALL);
  
      // Log all messages to the file specified by "ffx.log.file" if in Headless mode.
      // For MPI jobs, a separate file is used for each process.
      boolean prependRank = false;
      if (headless) {
        String log = System.getProperty("ffx.log.file", "");
        if (log != null && !log.equalsIgnoreCase("")) {
          Comm comm = Comm.world();
          int np = comm.size();
          int rank = comm.rank();
  
          // Define the log file directory and filename.
          String logFile;
          if (np == 1) {
            logFile = new File(log).getAbsolutePath();
         } else {
           prependRank = true;
           File dir = new File(Integer.toString(rank));
           if (!dir.exists()) {
             dir.mkdir();
           }
           logFile = dir.getAbsolutePath() + File.separator + log;
         }
 
         try {
           PrintStream printStream = new PrintStream(new FileOutputStream(logFile, true));
           System.setOut(printStream);
           System.setErr(printStream);
         } catch (Exception e) {
           System.err.println(Utilities.stackTraceToString(e));
         }
       }
     }
 
     // If each process has a separate log file, then it's not necessary to prepend a rank.
     if (prependRank) {
       setFormatter(new LogFormatter(false));
     } else {
       setFormatter(new LogFormatter());
     }
 
   }
 
   /**
    * {@inheritDoc}
    *
    * <p>Flush, but do not close System.out or the Shell.
    *
    * @since 1.0
    */
   @Override
   public void close() {
     flush();
   }
 
   /** {@inheritDoc} */
   @Override
   public void flush() {
     System.out.flush();
     System.err.flush();
     if (mainPanel.getModelingShell() != null) {
       // Scroll to visible!
     }
   }
 
   /**
    * {@inheritDoc}
    *
    * <p>Publish a LogRecord.
    *
    * @since 1.0.
    */
   @Override
   public synchronized void publish(LogRecord record) {
 
     // Check if the record is loggable and that we have not already encountered a fatal error.
     if (!isLoggable(record) || fatal) {
       return;
     }
 
     String msg;
     try {
       msg = getFormatter().format(record);
     } catch (Exception e) {
       // Report the exception to any registered ErrorManager.
       reportError(null, e, ErrorManager.FORMAT_FAILURE);
       return;
     }
 
     try {
       // FFX logs severe messages to System.err and then exits.
       if (record.getLevel() == Level.SEVERE) {
         // Set the fatal flag to true; this is the final record that will be logged.
         fatal = true;
 
         // Log the message to System.err.
         System.err.println(msg);
         Throwable throwable = record.getThrown();
         if (throwable != null) {
           System.err.printf(" %s%n", throwable);
         }
 
         System.err.println(" Force Field X will not continue.");
         System.err.println(" Shutting down...");
         flush();
         mainPanel.setExitType(ExitStatus.SEVERE);
         mainPanel.exit();
       }
 
       ModelingShell shell = null;
       if (mainPanel != null) {
         shell = mainPanel.getModelingShell();
       }
 
       if (!headless && shell != null) {
         shell.appendOutputNl(msg, shell.getResultStyle());
       } else {
         System.out.println(msg);
       }
     } catch (Exception e) {
       // Report the exception to any registered ErrorManager.
       reportError(null, e, ErrorManager.WRITE_FAILURE);
     }
   }
 
   /**
    * A reference to the Force Field X MainPanel container to shut down if we encounter a fatal
    * (SEVERE) exception. If we are not in Headless mode, then LogRecords can be published to the
    * ModelingShell.
    *
    * @param mainPanel the Force Field X MainPanel.
    * @since 1.0
    */
   public void setMainPanel(MainPanel mainPanel) {
     this.mainPanel = mainPanel;
   }
 }