// ******************************************************************************
   //
   // 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.bonded;
  
  import ffx.numerics.math.DoubleMath;
  import ffx.potential.bonded.Residue.ResidueType;
  import ffx.potential.parameters.ForceField;
  import org.jogamp.java3d.BranchGroup;
  import org.jogamp.java3d.Material;
  import org.jogamp.vecmath.Color3f;
  
  import javax.swing.tree.TreeNode;
  import java.io.Serial;
  import java.util.ArrayList;
  import java.util.Enumeration;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Objects;
  
  /**
   * The Polymer class encapsulates a peptide or nucleotide chain.
   *
   * @author Michael J. Schnieders
   * @since 1.0
   */
  public class Polymer extends MSGroup {
  
    @Serial
    private static final long serialVersionUID = 1L;
  
    /** Constant <code>polymerColor</code> */
    private static final Map<Integer, Color3f> polymerColor = new HashMap<>();
    /** Polymer count. */
    private static int count = 0;
  
    static {
      polymerColor.put(0, RendererCache.RED);
      polymerColor.put(1, RendererCache.ORANGE);
      polymerColor.put(2, RendererCache.YELLOW);
      polymerColor.put(3, RendererCache.GREEN);
      polymerColor.put(4, RendererCache.BLUE);
      polymerColor.put(5, RendererCache.MAGENTA);
      polymerColor.put(6, RendererCache.CYAN);
      polymerColor.put(7, RendererCache.WHITE);
      polymerColor.put(8, RendererCache.GRAY);
      polymerColor.put(9, RendererCache.PINK);
    }
  
    public static final String CHAIN_IDS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz";
  
    /** Flag to indicate the residues in the polymer should be joined. */
    private boolean link = false;
    /** The number of this Polymer. */
    private final int polymerNumber;
    /** The ChainID of this Polymer. */
    private Character chainID;
  
    /**
     * Polymer constructor.
     *
     * @param chainID Possibly redundant PDB chainID.
     * @param segID Unique identifier from A-Z,0-9, then 1A-1Z,10-19, etc.
     */
   public Polymer(Character chainID, String segID) {
     super(segID);
     this.chainID = chainID;
     this.polymerNumber = ++count;
   }
 
   /**
    * Polymer constructor.
    *
    * @param chainID Possibly redundant PDB chainID.
    * @param segID Unique identifier from A-Z,0-9, then 1A-1Z,10-19, etc.
    * @param link a boolean.
    */
   public Polymer(Character chainID, String segID, boolean link) {
     this(chainID, segID);
     this.link = link;
   }
 
   /**
    * Polymer Constructor.
    *
    * @param segID A unique identifier from A-Z,0-9, then 1A-1Z,10-19, etc.
    * @param residues Represents a MSNode where the Polymer's residues have been attached.
    * @param chainID a {@link java.lang.Character} object.
    */
   public Polymer(Character chainID, String segID, MSNode residues) {
     super(segID, residues);
     this.chainID = chainID;
     polymerNumber = ++count;
   }
 
   /**
    * {@inheritDoc}
    *
    * <p>A generic method for adding a MSNode to the Polymer.
    */
   @Override
   public MSNode addMSNode(MSNode msNode) {
     assert (msNode instanceof Residue);
 
     Residue residue = (Residue) msNode;
     int resNumber = residue.getResidueNumber();
 
     MSNode residueNode = getAtomNode();
     int n = residueNode.getChildCount();
     int childIndex = n;
 
     for (int i = 0; i < n; i++) {
       Residue current = (Residue) residueNode.getChildAt(i);
       if (current.getResidueNumber() > resNumber) {
         childIndex = i;
         break;
       }
     }
 
     residueNode.insert(residue, childIndex);
 
     residue.setChainID(chainID);
 
     return msNode;
   }
 
   /**
    * Set the Polymer chainID. The residues that form the polymer are also updated.
    *
    * @param chainID The chainID to use.
    */
   public void setChainID(Character chainID) {
     this.chainID = chainID;
     for (Residue residue : getResidues()) {
       residue.setChainID(chainID);
     }
   }
 
   /**
    * Set the Polymer segID. The residues that form the polymer are also updated.
    *
    * @param segID The segID to use.
    */
   public void setSegID(String segID) {
     setName(segID);
     for (Residue residue : getResidues()) {
       residue.setSegID(segID);
     }
   }
 
   /**
    * addMultiResidue.
    *
    * @param multiResidue a {@link ffx.potential.bonded.MultiResidue} object.
    */
   public void addMultiResidue(MultiResidue multiResidue) {
     Residue residue = multiResidue.getActive();
     MSNode residueNode = getAtomNode();
     int index = residueNode.getIndex(residue);
 
     if (index < 0) {
       System.err.println(
           "WARNING!  Polymer::addMultiResidue did not find a corresponding Residue on Polymer.");
       residueNode.add(multiResidue);
     } else {
       residue.removeFromParent();
       residueNode.insert(multiResidue, index);
       multiResidue.add(residue);
     }
   }
 
   /**
    * Form a Joint between two residues.
    *
    * @param residue1 The first Residue.
    * @param residue2 The second Residue.
    * @param forceField The ForceField to use for the Joint.
    * @return a {@link ffx.potential.bonded.Joint} object.
    */
   public Joint createJoint(Residue residue1, Residue residue2, ForceField forceField) {
     Joint joint = null;
     double[] da = new double[3];
     double[] db = new double[3];
     for (Enumeration<TreeNode> e = residue1.getAtomNode().children(); e.hasMoreElements(); ) {
       Atom a1 = (Atom) e.nextElement();
       a1.getXYZ(da);
       for (Enumeration<TreeNode> e2 = residue2.getAtomNode().children(); e2.hasMoreElements(); ) {
         Atom a2 = (Atom) e2.nextElement();
         a2.getXYZ(db);
         double d1 = DoubleMath.dist(da, db);
         double d2 = Bond.BUFF + a1.getVDWR() / 2 + a2.getVDWR() / 2;
         if (d1 < d2) {
           Bond b = new Bond(a1, a2);
           Joint newJoint = createJoint(b, residue1, residue2, forceField);
           if (joint != null) {
             joint.merge(newJoint);
           } else {
             joint = newJoint;
           }
         }
       }
     }
     return joint;
   }
 
   /**
    * {@inheritDoc}
    *
    * <p>Overridden equals method.
    */
   @Override
   public boolean equals(Object o) {
     if (this == o) {
       return true;
     }
     if (o == null || getClass() != o.getClass()) {
       return false;
     }
     Polymer polymer = (Polymer) o;
     return polymerNumber == polymer.polymerNumber && Objects.equals(getName(), polymer.getName());
   }
 
   /**
    * {@inheritDoc}
    *
    * <p>Finalize should be called after all the Residues have been added to the Polymer. This method
    * in turn calls the Finalize method of each Residue, then forms Joints between adjacent Residues
    * in the Polymer
    */
   @Override
   public void finalize(boolean finalizeGroups, ForceField forceField) {
     List<MSNode> residues = getAtomNodeList();
     setFinalized(false);
 
     // Finalize the residues in the Polymer
     if (finalizeGroups) {
       for (MSNode node : residues) {
         Residue residue = (Residue) node;
         residue.finalize(true, forceField);
       }
     }
     // Join the residues in the Polymer
     if (link) {
       Residue residue = getFirstResidue();
       if (residue.residueType == Residue.ResidueType.AA) {
         getAtomNode().setName("Amino Acids " + "(" + residues.size() + ")");
       } else if (residue.residueType == Residue.ResidueType.NA) {
         getAtomNode().setName("Nucleic Acids " + "(" + residues.size() + ")");
       } else {
         getAtomNode().setName("Residues " + "(" + residues.size() + ")");
       }
 
       Joint j;
       MSNode joints = getTermNode();
       joints.removeAllChildren();
       List<Atom> atoms = getAtomList();
       for (Atom a : atoms) {
         if (a.getNumBonds() > 0) {
           for (Bond b : a.getBonds()) {
             if (!b.sameGroup() && b.getParent() == null) {
               Residue r1 = a.getMSNode(Residue.class);
               Residue r2 = b.get1_2(a).getMSNode(Residue.class);
               j = createJoint(b, r1, r2, forceField);
               joints.add(j);
             }
           }
         }
       }
 
       if (residue.residueType == Residue.ResidueType.AA) {
         getTermNode().setName("Peptide Bonds " + "(" + joints.getChildCount() + ")");
       } else {
         getTermNode().setName("Linkages " + "(" + joints.getChildCount() + ")");
       }
 
     } else {
       getAtomNode().setName("Sub-Groups " + "(" + residues.size() + ")");
       if (getTermNode().getParent() != null) {
         removeChild(getTermNode());
       }
     }
     removeLeaves();
     setFinalized(true);
   }
 
   /**
    * Getter for the field <code>chainID</code>.
    *
    * @return a {@link java.lang.Character} object.
    */
   public Character getChainID() {
     return chainID;
   }
 
   /**
    * getFirstResidue
    *
    * @return a {@link ffx.potential.bonded.Residue} object.
    */
   public Residue getFirstResidue() {
     MSNode atomNode = getAtomNode();
     if (atomNode == null) {
       return null;
     }
     return (Residue) atomNode.getChildAt(0);
   }
 
   /**
    * Getter for the field <code>link</code>.
    *
    * @return a boolean.
    */
   public boolean getLink() {
     return link;
   }
 
   /**
    * Setter for the field <code>link</code>.
    *
    * @param link a boolean.
    */
   public void setLink(boolean link) {
     this.link = link;
   }
 
   /**
    * Get lists of the phi and psi torsions.
    *
    * @return A List of Dihedral objects representing the Phi/Psi angles of the Polymer.
    */
   public List<List<Torsion>> getPhiPsiList() {
     List<List<Torsion>> phiPsi = new ArrayList<>();
     List<Torsion> phi = new ArrayList<>();
     List<Torsion> psi = new ArrayList<>();
     phiPsi.add(phi);
     phiPsi.add(psi);
     for (Residue residue : this.getResidues()) {
       for (Torsion torsion : residue.getTorsionList()) {
         Atom[] atoms = torsion.atoms;
         StringBuilder s = new StringBuilder(atoms[0].getName());
         for (int i = 1; i < 4; i++) {
           s.append("-").append(atoms[i].getName());
         }
         // Phi
         if (s.toString().equals("C-N-CA-C") || s.toString().equals("C-CA-N-C")) {
           phi.add(torsion);
         } // Psi
         else if (s.toString().equals("N-C-CA-N") || s.toString().equals("N-CA-C-N")) {
           psi.add(torsion);
         }
       }
     }
     return phiPsi;
   }
 
   /**
    * getResidue
    *
    * @param resNum The residue number.
    * @return a {@link ffx.potential.bonded.Residue} object.
    */
   public Residue getResidue(int resNum) {
     if (resNum > 0 && getAtomNode().getChildCount() >= resNum) {
       Residue r = (Residue) getAtomNode().getChildAt(resNum - 1);
       if (r.getResidueNumber() == resNum) {
         return r;
       }
     }
     // Fall back for non-ordered children
     for (Enumeration<TreeNode> e = getAtomNode().children(); e.hasMoreElements(); ) {
       Residue r = (Residue) e.nextElement();
       if (r.getResidueNumber() == resNum) {
         return r;
       }
     }
     return null;
   }
 
   /**
    * getResidue
    *
    * @param resName a {@link java.lang.String} object.
    * @param resNum The residue number.
    * @param create a boolean.
    * @return a {@link ffx.potential.bonded.Residue} object.
    */
   public Residue getResidue(String resName, int resNum, boolean create) {
     return getResidue(resName, resNum, create, Residue.ResidueType.UNK);
   }
 
   /**
    * getResidue
    *
    * @param resName The residue name.
    * @param resNum The residue number.
    * @param create If true, create the residue if it does not exist.
    * @param defaultRT Default ResidueType if it cannot be assigned.
    * @return a {@link ffx.potential.bonded.Residue} object.
    */
   public Residue getResidue(String resName, int resNum, boolean create, ResidueType defaultRT) {
     for (Enumeration<TreeNode> e = getAtomNode().children(); e.hasMoreElements(); ) {
       Residue r = (Residue) e.nextElement();
       if (r.getResidueNumber() == resNum && r.getName().equalsIgnoreCase(resName)) {
         return r;
       } else if (resName.equals(AminoAcidUtils.AminoAcid3.UNK.name())
           && resNum == r.getResidueNumber()) {
         return r;
       }
     }
     if (!create) {
       return null;
     }
     Residue residue = null;
     resName = resName.toUpperCase();
     if (resName.length() == 1) {
       try {
         NucleicAcidUtils.NucleicAcid1.valueOf(resName);
         residue = new Residue(resName, resNum, Residue.ResidueType.NA, chainID, getName());
       } catch (Exception e) {
         try {
           AminoAcidUtils.AminoAcid1.valueOf(resName);
           residue = new Residue(resName, resNum, Residue.ResidueType.AA, chainID, getName());
         } catch (Exception ex) {
           //
         }
       }
     } else if (resName.length() >= 2) {
       try {
         NucleicAcidUtils.NucleicAcid3.valueOf(resName);
         residue = new Residue(resName, resNum, Residue.ResidueType.NA, chainID, getName());
       } catch (Exception e) {
         try {
           AminoAcidUtils.AminoAcid3.valueOf(resName);
           residue = new Residue(resName, resNum, Residue.ResidueType.AA, chainID, getName());
         } catch (Exception ex) {
           //
         }
       }
     }
     if (residue == null) {
       residue = new Residue(resName, resNum, defaultRT, chainID, getName());
     }
     addMSNode(residue);
     return residue;
   }
 
   /**
    * getResidues
    *
    * @return a {@link java.util.List} object.
    */
   public List<Residue> getResidues() {
     List<Residue> residues = new ArrayList<>();
     for (Enumeration<TreeNode> e = getAtomNode().children(); e.hasMoreElements(); ) {
       Residue r = (Residue) e.nextElement();
       residues.add(r);
     }
     return residues;
   }
 
   /** {@inheritDoc} */
   @Override
   public int hashCode() {
     return Objects.hash(polymerNumber, getName());
   }
 
   /** {@inheritDoc} */
   @Override
   public void setColor(RendererCache.ColorModel newColorModel, Color3f color, Material mat) {
     // If coloring by Polymer, pass this Polymer's color
     if (newColorModel == RendererCache.ColorModel.POLYMER) {
       int index = polymerNumber % 10;
       color = polymerColor.get(index);
       mat = RendererCache.materialFactory(color);
     }
     for (MSNode node : getAtomNodeList()) {
       MSGroup atomGroup = (MSGroup) node;
       atomGroup.setColor(newColorModel, color, mat);
     }
     for (Enumeration<TreeNode> e = getTermNode().children(); e.hasMoreElements(); ) {
       Joint joint = (Joint) e.nextElement();
       joint.setColor(newColorModel);
     }
   }
 
   /** {@inheritDoc} */
   @Override
   public void setView(RendererCache.ViewModel newViewModel, List<BranchGroup> newShapes) {
     for (MSNode node : getAtomNodeList()) {
       MSGroup atomGroup = (MSGroup) node;
       atomGroup.setView(newViewModel, newShapes);
     }
     for (Enumeration<TreeNode> e = getTermNode().children(); e.hasMoreElements(); ) {
       Joint joint = (Joint) e.nextElement();
       joint.setView(newViewModel, newShapes);
     }
   }
 }