package daikon.tools.jtb;

import java.util.Enumeration;
import jtb.syntaxtree.*;
import jtb.visitor.*;

/**
 * OrigModifier is a visitor that places "orig()" around varible names and correspondingly corrects
 * positioning fields of all the tokens in tree to accomodate the change. For example, the
 * expression get(this.x) would be changed to get(orig(this.x)).
 */
public class OrigModifier extends DepthFirstVisitor {

  private int columnshift = 0;
  private int columnshiftline = -1;

  // columnshifting only applies to a single line, then is turned off agian.
  // States for the variables:
  // columnshift == 0, columnshiftline == -1:
  //    no column shifting needed
  // columnshift != 0, columnshiftline != -1:
  //    column shifting being needed, applies only to specified line

  /**
   * Corrects column fields of n.
   *
   * <p>Modifies: n, this.
   */
  @Override
  public void visit(NodeToken n) {
    if (n.beginLine == columnshiftline) {
      n.beginColumn = n.beginColumn + columnshift;
      n.endColumn = n.endColumn + columnshift;
    } else {
      columnshift = 0;
      columnshiftline = -1;
    }
  }

  /**
   * Checks if n is a variable name. If so adds "orig(" to the front of the name and ")" to the end.
   *
   * <p>Modifies: n, this.
   */
  // f0 -> PrimaryPrefix()
  // f1 -> ( PrimarySuffix() )*
  @Override
  @SuppressWarnings("JdkObsolete") // JTB Enumeration
  public void visit(PrimaryExpression n) {
    // let simple variables be variables with out "."'s in their names
    // such as x or myList
    // let compound variables be variables with "."'s in their names
    // such as this.x or myPackage.MyObject.myList

    // First checks for and handles simple variables.

    // test if optional list length is zero, if not, then it is not
    // the name of a simple variable
    if (n.f1.size() == 0) {
      // checks if the nodeChoice's choice is Name
      if (n.f0.f0.choice instanceof Name) {
        // checks if the Name is simple
        if (((Name) n.f0.f0.choice).f1.size() == 0) {
          NodeToken variableToken = ((Name) n.f0.f0.choice).f0;
          variableToken.tokenImage = "orig(" + variableToken.tokenImage + ")";
          columnshift = columnshift + 6;
          columnshiftline = variableToken.endLine;
          super.visit(n);

          // Corrects for the fact that super.visit(n) incremented
          // variableToken.beginColumn by 6 too much since the addition of
          // "orig()" does not effect firstToken.beginColumn.
          variableToken.beginColumn = variableToken.beginColumn - 6;
          return;
        }
      }
    }

    if (n.f1.size() == 1) {
      // System.out.println("if1");
      if (n.f1.elementAt(0) instanceof PrimarySuffix) {
        // System.out.println("if2");
        if (((PrimarySuffix) n.f1.elementAt(0)).f0.choice instanceof NodeSequence) {
          if (n.f0.f0.choice instanceof NodeToken) {
            NodeToken firstToken = (NodeToken) n.f0.f0.choice;
            firstToken.tokenImage = "orig(" + firstToken.tokenImage;
            Enumeration<Node> nodeSequence =
                ((NodeSequence) ((PrimarySuffix) n.f1.elementAt(0)).f0.choice).elements();
            NodeToken lastToken = firstToken;
            while (nodeSequence.hasMoreElements()) {
              lastToken = (NodeToken) nodeSequence.nextElement();
            }
            lastToken.tokenImage = lastToken.tokenImage + ")";

            // Updates columnshift for the addition of "orig(", the
            // columnshift is updated for the addition of ")" after
            // super.visit(n)
            columnshift = columnshift + 5;
            columnshiftline = firstToken.beginLine;
            super.visit(n);

            // Corrects for the fact that super.visit(n) incremented
            // firstToken.beginColumn by 5 too much since the addition
            // of "orig(" does not effect firstToken.beginColumn.
            firstToken.beginColumn = firstToken.beginColumn - 5;

            // since lastToken is the last node in the visiting order
            // of n, all NodeToken effected by the addition of the
            // ")" at the end of lastToken are visited after all the children
            // of are visited.  Thus,super.visit(n) may be called before
            // all code that corrects the column fields for the addition of
            // ")".
            columnshiftline = lastToken.endLine;
            columnshift = columnshift + 1;
            lastToken.endColumn = lastToken.endColumn + 1;
            return;
          }
        }
      }
    }
    super.visit(n);
  }
}
