/*
 * CSP Project
 * Authors:
 * 		Jay Bernardo
 * 		Matt Rancourt
 * 
 * File: TransitionAssignment.java
 * 
 * Contains the TransitionAssignment class. This class functions for the purpose
 * of representing what we call "M". It contains a list of TransitionAssignmentVariables
 * and is able to determine whether it contains a decided variable or not 
 * 
 */
import java.util.*;
class TransitionAssignment{
	ArrayList<TransitionAssignmentVariable> M;
	boolean containsADecidedVariable;
	
	/**
	 * Basic constructor
	 */
	public TransitionAssignment(){
		M = new ArrayList<TransitionAssignmentVariable>();
		containsADecidedVariable = false;
	}

	/**
	 * Returns how many variables are contained within the assignment
	 * @return number of variables in the assignment as int
	 */
	public int numberOfVariables(){
		return M.size();
	}
	
	/**
	 * Returns a list of the decision variables in M, but negated (as Variable type)
	 * @return negated list of decision variables in M as Variable type
	 * @throws InvalidVariableValueException
	 */
	public ArrayList<Variable> getNegatedDecidedVariables()
	throws
		InvalidVariableValueException{
		
		ArrayList<Variable> list = new ArrayList<Variable>();
		
		Iterator<TransitionAssignmentVariable> it = M.iterator();
		while(it.hasNext()){
			TransitionAssignmentVariable v = it.next();
			
			if(v.decided == true){
				boolean pos;
				if(v.getValue() == 0){
					pos = true;
				}
				else{
					pos = false;
				}
				
				list.add(new Variable(v.getName(), -1, pos));
				
			}
			
		}
		
		return list;
	}
	
	/**
	 * Returns the TransitionVariableAssignment at a given position (indexing starts at 0)
	 * @param index - variable position
	 * @return TransitionAssignmentVariable at the given position
	 */
	public TransitionAssignmentVariable getVariableAt(int index){
		return M.get(index);
	}
	
	/**
	 * Adds the given TransitionAssignmentVariable to the list of variables in 
	 * the assignment
	 * @param a - TransitionVariableAssignment to add to the overall assignment
	 */
	public void add(TransitionAssignmentVariable a){
		M.add(a);
		
		if(a.decided == true){
			containsADecidedVariable = true;
		}
	}

	/**
	 * Resets the assignment, removing all variables and setting the 
	 * state of containing a decided variable to false
	 */
	public void reset(){
		M = new ArrayList<TransitionAssignmentVariable>();
		
		containsADecidedVariable = false;
	}
}