package net.sourceforge.phpdt.internal.compiler.ast;

import java.util.List;

/**
 * A Variable assignation.
 * $varname = initializer
 * @author Matthieu Casanova
 */
public class VarAssignation extends Expression {

  public static final int EQUAL = 0;
  public static final int PLUS_EQUAL = 1;
  public static final int MINUS_EQUAL = 2;
  public static final int STAR_EQUAL = 3;
  public static final int SLASH_EQUAL = 4;
  public static final int AND_EQUAL = 5;
  public static final int OR_EQUAL = 6;
  public static final int XOR_EQUAL = 7;
  public static final int DOT_EQUAL = 8;
  public static final int REM_EQUAL = 9;
  public static final int TILDE_EQUAL = 10;
  public static final int LSHIFT_EQUAL = 11;
  public static final int RSIGNEDSHIFT_EQUAL = 12;

  public Expression variableName;
  public Expression initializer;
  public int operator;

  /**
   * Create a new variable assignation.
   * @param variableName the name of the variable
   * @param initializer the expression in initializer
   * @param operator the operator of assignation
   * @param sourceStart the sourceStart
   * @param sourceEnd the sourceEnd
   */
  public VarAssignation(final Expression variableName,
                        final Expression initializer,
                        final int operator,
                        final int sourceStart,
                        final int sourceEnd) {
    super(sourceStart, sourceEnd);
    this.variableName = variableName;
    this.initializer = initializer;
    this.operator = operator;
  }

  /**
   * Return the operator as String.
   * @return the operator
   */
  public final String operatorToString() {
    switch (operator) {
      case EQUAL:
        return "="; //$NON-NLS-1$
      case PLUS_EQUAL:
        return "+=";   //$NON-NLS-1$
      case MINUS_EQUAL:
        return "-=";   //$NON-NLS-1$
      case STAR_EQUAL:
        return "*="; //$NON-NLS-1$
      case SLASH_EQUAL:
        return "/="; //$NON-NLS-1$
      case AND_EQUAL:
        return "<="; //$NON-NLS-1$
      case OR_EQUAL:
        return "|=";//$NON-NLS-1$
      case XOR_EQUAL:
        return "^=";//$NON-NLS-1$
      case DOT_EQUAL:
        return ".="; //$NON-NLS-1$
      case REM_EQUAL:
        return "%="; //$NON-NLS-1$
      case TILDE_EQUAL:
        return "~="; //$NON-NLS-1$
      case LSHIFT_EQUAL:
        return "<<="; //$NON-NLS-1$
      case RSIGNEDSHIFT_EQUAL:
        return ">>="; //$NON-NLS-1$
    }
    return " unknown operator ";//$NON-NLS-1$
  }

  /**
   * Return the expression as String.
   * @return the expression
   */
  public String toStringExpression() {
    final String varName = variableName.toStringExpression();
    final String init = initializer.toStringExpression();
    final String operatorString = operatorToString();
    final StringBuffer buff = new StringBuffer(varName.length() + operatorString.length() + init.length() + 2);
    buff.append(varName);
    buff.append(" ");//$NON-NLS-1$
    buff.append(operatorString);
    buff.append(" ");//$NON-NLS-1$
    buff.append(init);
    return buff.toString();
  }


  /**
   * Get the variables from outside (parameters, globals ...)
   */
  public void getOutsideVariable(final List list) {
  }

  /**
   * get the modified variables.
   */
  public void getModifiedVariable(final List list) {
    variableName.getUsedVariable(list);
    initializer.getModifiedVariable(list);
  }

  /**
   * Get the variables used.
   */
  public void getUsedVariable(final List list) {
    initializer.getUsedVariable(list);
  }
}