// ******************************************************************************
   //
   // Title:       Force Field X.
   // Description: Force Field X - Software for Molecular Biophysics.
   // Copyright:   Copyright (c) Michael J. Schnieders 2001-2025.
   //
   // 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.potential.parsers;
  
  import static java.lang.Double.parseDouble;
  import static java.lang.Integer.parseInt;
  
  import java.io.BufferedReader;
  import java.io.File;
  import java.io.FileReader;
  import java.io.IOException;
  import javax.swing.filechooser.FileFilter;
  import org.apache.commons.io.FilenameUtils;
  
  /**
   * The XYZFileFilter class is used to choose a TINKER Cartesian Coordinate (*.XYZ) file.
   *
   * @author Michael J. Schnieders
   * @since 1.0
   */
  public final class XYZFileFilter extends FileFilter {
  
    /** Public Constructor. */
    public XYZFileFilter() {
    }
  
    /**
     * This is a static version of the accept method.
     *
     * <p>This method return <code>true</code> if the file is a directory or TINKER Cartesian
     * coordinate (*.XYZ) file.
     *
     * @param file The File to examine.
     * @return Returns true if this an XYZ file.
     */
    public static boolean isXYZ(File file) {
      return new XYZFileFilter().accept(file);
    }
  
    /**
     * {@inheritDoc}
     *
     * <p>This method return <code>true</code> if the file is a directory or TINKER Cartesian
     * coordinate (*.XYZ) file.
     */
    @Override
    public boolean accept(File file) {
      if (file.isDirectory()) {
        return true;
      }
      String ext = FilenameUtils.getExtension(file.getName());
      return ext.toUpperCase().startsWith("XYZ");
    }
  
    /**
     * acceptDeep
     *
     * @param file a {@link java.io.File} object.
     * @return a boolean.
     */
    public boolean acceptDeep(File file) {
      if (file == null || file.isDirectory() || !file.canRead()) {
        return false;
      }
 
     try (BufferedReader br = new BufferedReader(new FileReader(file))) {
       if (!br.ready()) {
         return false;
       }
 
       /*
        If the first token is not an integer this file is not a TINKER
        Cartesian Coordinate File.
       */
       String rawdata = br.readLine();
       String[] header = rawdata.trim().split(" +");
       if (header.length == 0) {
         return false;
       }
       try {
         parseInt(header[0]);
       } catch (Exception e) {
         return false;
       }
       /*
        If the the first line does not begin with an integer (an Atom Line)
        or a double (a unit cell parameter line) and contain at least
        six tokens, this is not a TINKER cartesian coordinate file.
       */
       String firstAtom = br.readLine();
       if (firstAtom == null) {
         return false;
       }
       String[] data = firstAtom.trim().split(" +");
       if (data.length < 6) {
         return false;
       }
       try {
         parseInt(data[0]);
       } catch (NumberFormatException e) {
         try {
           parseDouble(data[0]);
         } catch (NumberFormatException e2) {
           return false;
         }
       }
       return true;
     } catch (IOException e) {
       return true;
     }
   }
 
   /**
    * {@inheritDoc}
    *
    * <p>Provides a description of the XYZFileFilter.
    */
   @Override
   public String getDescription() {
     return "TINKER Cartesian Coordinates (*.XYZ)";
   }
 }