/**
    * 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;
 	}
 }