// ******************************************************************************
   //
   // 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
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  // 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
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  // exception statement from your version.
  //
  // ******************************************************************************
  package ffx.potential.bonded;
  
  import static java.lang.String.format;
  
  import java.util.Arrays;
  import java.util.HashMap;
  import java.util.List;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  /**
   * The ResidueState class encodes the current chemical and coordinate state of a Residue,
   * particularly a MultiResidue, for ease of reverting coordinates. Should not be too difficult to get
   * it to also store velocities, etc.
   *
   * @author Michael J. Schnieders
   * @author Jacob M. Litman
   * @since 1.0
   */
  public class ResidueState {
  
    private static final Logger logger = Logger.getLogger(ResidueState.class.getName());
  
    /**
     * For a MultiResidue, parent is the MultiResidue, while res is the chemical state to which this
     * ResidueState belongs. For a regular Residue, both are just the Residue. In general, use res to
     * store a chemical or other state, and parent to store the Residue to which this belongs.
     */
    private final Residue parent;
  
    private final Residue residue;
    private final HashMap<Atom, double[]> atomMap;
    private final Atom[] atoms;
  
    /**
     * Constructor for ResidueState.
     *
     * @param parent a {@link ffx.potential.bonded.Residue} object.
     * @param residue a {@link ffx.potential.bonded.Residue} object.
     */
    public ResidueState(Residue parent, Residue residue) {
      this.parent = parent;
      this.residue = residue;
  
      List<Atom> atomList = residue.getAtomList();
      int nAtoms = atomList.size();
      atomMap = new HashMap<>(nAtoms);
      atoms = new Atom[nAtoms];
  
      atomList.toArray(atoms);
      for (Atom atom : atoms) {
        double[] atXYZ = new double[3];
        atom.getXYZ(atXYZ);
        atomMap.put(atom, atXYZ);
      }
    }
  
    /**
     * Constructor for ResidueState.
     *
     * @param residue a {@link ffx.potential.bonded.Residue} object.
     */
   public ResidueState(Residue residue) {
     this(residue, residue);
     if (residue instanceof MultiResidue) {
       throw new IllegalArgumentException(format(
           " Residue %s is a MultiResidue: this ResidueState has been incorrectly constructed!",
           residue));
     }
   }
 
   /**
    * revertAllCoordinates.
    *
    * @param residueList a {@link java.util.List} object.
    * @param states an array of {@link ffx.potential.bonded.ResidueState} objects.
    */
   public static void revertAllCoordinates(List<Residue> residueList, ResidueState[] states) {
     revertAllCoordinates(residueList.toArray(new Residue[0]), states);
   }
 
   /**
    * Uses a double[nAtoms][3] to revert the coordinates of an array of atoms. Does not check to see
    * if the arrays are properly ordered; make sure you are using the correct arrays.
    *
    * @param atoms To revert coordinates of
    * @param coords Coordinates
    */
   public static void revertAtomicCoordinates(Atom[] atoms, double[][] coords) {
     int nAtoms = atoms.length;
     if (coords.length != nAtoms) {
       throw new IllegalArgumentException(
           format(" Length %d of atoms " + "array does not match length %d of coordinates array",
               nAtoms, coords.length));
     }
     for (int i = 0; i < nAtoms; i++) {
       atoms[i].setXYZ(coords[i]);
     }
   }
 
   /**
    * storeAllCoordinates.
    *
    * @param residueList a {@link java.util.List} object.
    * @return an array of {@link ffx.potential.bonded.ResidueState} objects.
    */
   public static ResidueState[] storeAllCoordinates(List<Residue> residueList) {
     return storeAllCoordinates(residueList.toArray(new Residue[0]));
   }
 
   /**
    * storeAllCoordinates.
    *
    * @param residues an array of {@link ffx.potential.bonded.Residue} objects.
    * @return an array of {@link ffx.potential.bonded.ResidueState} objects.
    */
   public static ResidueState[] storeAllCoordinates(Residue[] residues) {
     int nResidues = residues.length;
     ResidueState[] states = new ResidueState[nResidues];
     for (int i = 0; i < nResidues; i++) {
       states[i] = residues[i].storeState();
     }
     return states;
   }
 
   /**
    * Returns a new double[nAtoms][3] with the coordinates of an array of atoms.
    *
    * @param atoms To store coordinates of
    * @return Coordinates
    */
   public static double[][] storeAtomicCoordinates(Atom[] atoms) {
     int nAtoms = atoms.length;
     double[][] coords = new double[nAtoms][3];
     for (int i = 0; i < nAtoms; i++) {
       atoms[i].getXYZ(coords[i]);
     }
     return coords;
   }
 
   /**
    * revertAllCoordinates.
    *
    * @param residueArray an array of {@link ffx.potential.bonded.Residue} objects.
    * @param states an array of {@link ffx.potential.bonded.ResidueState} objects.
    */
   private static void revertAllCoordinates(Residue[] residueArray, ResidueState[] states) {
     int nResidues = residueArray.length;
     if (nResidues != states.length) {
       throw new IllegalArgumentException(
           format("Length of residue " + "array %d and residue state array %d do not match.",
               nResidues, states.length));
     }
 
     for (int i = 0; i < nResidues; i++) {
       Residue resi = residueArray[i];
       // If indexing did not get thrown off:
       if (resi.equals(states[i].getParent())) {
         resi.revertState(states[i]);
       } else {
         // Else must search states[]
         boolean matchFound = false;
         for (int j = 0; j < nResidues; j++) {
           if (resi.equals(states[j].getParent())) {
             matchFound = true;
             resi.revertState(states[j]);
             break;
           }
         }
 
         if (!matchFound) {
           throw new IllegalArgumentException(
               format("Could not " + "find match for residue %s among residue states array.", resi));
         }
       }
     }
   }
 
   public double compareTo(ResidueState residueState) {
     logger.info("Comparing rotamers using the compareTo method in ResidueState");
     double[][] tempx1 = new double[this.atoms.length][3];
     double[][] tempx2 = new double[residueState.atoms.length][3];
     double[] x1 = new double[this.atoms.length * 3];
     double[] x2 = new double[residueState.atoms.length * 3];
     // Create arrays of atoms for keptRotamer[k] ResidueState and newResState
     // Here, each residue state is the same residue with a different rotamer applied.
     Atom[] x1atoms = this.atoms;
     Atom[] x2atoms = residueState.atoms;
     // logger.info("Total number of atoms for current residue state: " + x1atoms.length);
     // logger.info("Total number of atoms for previously kept residue state to be tested against: "+
     // x2atoms.length);
 
     // Get the coordinate arrays for each atom in the current residue state using the atomMap
     for (int atomCount = 0; atomCount < x1atoms.length; atomCount++) {
       Atom exampleAtom = x1atoms[atomCount];
       tempx1[atomCount] = this.atomMap.get(exampleAtom);
     }
 
     // Add coordinates from tempx1[][] to x1[] for RMSD calculations
     int x1count = 0;
     for (double[] coordSet : tempx1) {
       for (int coordCount = 0; coordCount < 3; coordCount++) {
         x1[x1count] = coordSet[coordCount];
         x1count++;
       }
     }
 
     // Get the coorinate arrays for each atom in the previously kept residue state to be
     // tested against using the atomMap for that residue state
     for (int atomCount = 0; atomCount < x2atoms.length; atomCount++) {
       Atom exampleAtom = x2atoms[atomCount];
       tempx2[atomCount] = residueState.atomMap.get(exampleAtom);
     }
 
     // Add coordinate from tempx2[][] to x2[] for RMSD calculations
     int x2count = 0;
     for (double[] coordSet : tempx2) {
       for (int coordCount = 0; coordCount < 3; coordCount++) {
         x2[x2count] = coordSet[coordCount];
         x2count++;
       }
     }
 
     // Create a mass array of ones so the RMSD isn't mass weighted
     double[] mass = new double[x1.length];
     Arrays.fill(mass, 1);
     return ffx.potential.utils.Superpose.rmsd(x1, x2, mass);
   }
 
   /**
    * Getter for the field <code>atoms</code>.
    *
    * @return an array of {@link ffx.potential.bonded.Atom} objects.
    */
   public Atom[] getAtoms() {
     return atoms;
   }
 
   /**
    * Getter for the field <code>parent</code>.
    *
    * @return a {@link ffx.potential.bonded.Residue} object.
    */
   public Residue getParent() {
     return parent;
   }
 
   /** {@inheritDoc} */
   @Override
   public String toString() {
     return format(" ResidueState with parent residue %s, state residue " + "%s, number of atoms %d",
         parent, residue, atoms.length);
   }
 
   /**
    * getStateResidue.
    *
    * @return a {@link ffx.potential.bonded.Residue} object.
    */
   Residue getStateResidue() {
     return residue;
   }
 
   /**
    * Returns the coordinates of the selected atom; or null if atom not contained.
    *
    * @param atom An Atom.
    * @return xyz coordinates.
    */
   double[] getAtomCoords(Atom atom) {
     double[] xyz = new double[3];
     if (!atomMap.containsKey(atom)) {
       logger.info(
           format(" Illegal call to ResidueState.getAtomCoords: atom %s not found: hashcode %d", atom,
               atom.hashCode()));
       for (Atom ratom : residue.getAtomList()) {
         logger.info(format(" Atoms in residue: %s hashcode: %d", ratom, ratom.hashCode()));
       }
       for (Atom matom : atomMap.keySet()) {
         logger.info(
             format(" Atoms in ResidueState atom cache: %s hashcode: %d", matom, matom.hashCode()));
       }
       logger.log(Level.SEVERE, " Error in ResidueState.getAtomCoords.", new IllegalStateException());
     }
     System.arraycopy(atomMap.get(atom), 0, xyz, 0, 3);
     return xyz;
   }
 }