/**

  * Copyright 2010 The Kuali Foundation Licensed under the

  * Educational Community License, Version 2.0 (the "License"); you may

  * not use this file except in compliance with the License. You may

  * obtain a copy of the License at

  *

  * http://www.osedu.org/licenses/ECL-2.0

  *

  * Unless required by applicable law or agreed to in writing,

  * software distributed under the License is distributed on an "AS IS"

  * BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

  * or implied. See the License for the specific language governing

  * permissions and limitations under the License.

  */

 /**

  * 

  */

 package org.kuali.student.common.messagebuilder.booleanmessage.ast;

 import java.util.ArrayList;

 import java.util.List;

 public class BooleanFunction {

     private String booleanExpression;

     private BinaryMessageTree ASTtree;

     private BooleanNode root;

     private ArrayList<String> funcVars = new ArrayList<String>();

     private ArrayList<String> symbols = new ArrayList<String>();

     public BooleanFunction(String booleanExpression) {

         // Since the AST calls the Boolean Function parser,

         // calling the AST here asserts the function is valid

         ASTtree = new BinaryMessageTree();

         root = ASTtree.buildTree(booleanExpression);

         this.booleanExpression = booleanExpression;

     }

     /**

      * Parse function string to get the variables 

      * 1. Need this function at rule creation time (i.e when in BRMS) to insert

      * the action part of the rules 

      * 2. Also need this at runtime to populate the HashMaps in the 

      * proposition which are used as tree leaf nodes in the AST.

      * 

      * @return List of variables

      */

     public List<String> getVariables() {

         ASTtree.traverseTreePostOrderDontSetNode(root, null);

         List<BooleanNode> treeNodes = ASTtree.getAllNodes();

         for (BooleanNode bnode : treeNodes) {

             String label = bnode.getLabel();

             if (label.equals("+") || label.equals("*")) {

                 continue;

             }

             funcVars.add(label);

         }

         return funcVars;

     }

     /**

      * Parse function string to get all the symbols. 

      * Need this only at rule creation time. Can't load the symbols in

      * getVariables() because the AST removes the parenthesis and 

      * we need those. Get them from the string which has been

      * validated in the constructor example A0*B4+(C*D)

      * 

      * @return List of symbols

      */

     public List<String> getSymbols() {

                 String workString = null;

                 // remove spaces

                 this.booleanExpression = (booleanExpression == null ? null : booleanExpression.replaceAll("\\s+", ""));

                 workString = this.booleanExpression;

                 while (workString != null && workString.length() > 0) {

                         String propositionKeyPattern = "^[A-Z][0-9]*";

                         String restOfFunctionString = null;

                         String theSymbol = null;

                         int restOfFunctionStringStartIndex = 0;

                         if (workString.matches(propositionKeyPattern + ".*")) {

                                 restOfFunctionString = workString.replaceFirst(propositionKeyPattern, "");

                                 restOfFunctionStringStartIndex = workString.indexOf(restOfFunctionString);

                                 if (restOfFunctionStringStartIndex <= 0) {

                                         theSymbol = workString;

                                         workString = "";

                                 } else {

                                         theSymbol = workString.substring(0, restOfFunctionStringStartIndex);

                                         workString = restOfFunctionString;

                                 }

                         } else {

                                 theSymbol = workString.substring(0, 1);

                                 workString = workString.substring(1, workString.length());

                         }

                         symbols.add(theSymbol);

                 }

                 return symbols;

         }

 }