/*
 * CSP Project
 * Authors:
 * 		Jay Bernardo
 * 		Matt Rancourt
 * 
 * File: FailState.java
 * 
 * Contains the FailState class. This transition determines if, given the variables in
 * M, the formula F is unsatisfiable.
 *  
 */
class FailState extends Transition{
	public FailState(TransitionAssignment M, CSP F){
		super(M, F);
	}
	
	/**
	 * Determines if the assignment given in M cannot satisfy F
	 * 
	 * @return 1 on failstate is true
	 *         undefined otherwise
	 * 
	 */
	public int doTransition()
	throws
		InvalidVariableValueException,
		RelationNumberOutOfBoundsException,
		RankOutOfBoundsException,
		InvalidVariableNamesLengthException,
		VariablePositionOutOfBoundsException{

		// Iterate over all variables in M -- but only if it
		// has a decided variable (this is the only case we can fail)
		if(M.containsADecidedVariable == false){
			int i = 0;
			for(; i < F.numberOfRelations(); i ++){
				Relation thisRelation = F.getRelationAt(i);
				
				// If there are no unassigned variables, and the relation is not
				// satisfied, then we have a failure
				if(thisRelation.findUnassignedVariableName() == null){
					if(thisRelation.isSatisfied() == false){
						return 1;
					}
				}
			}
		}
		
		return -1;
	}
}