package jrummikub.ai.fdsolver.constraint;

import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;

import jrummikub.ai.fdsolver.Constraint;
import jrummikub.ai.fdsolver.Propagator;
import jrummikub.ai.fdsolver.Satisfiability;
import jrummikub.ai.fdsolver.Var;

public class SumConstraint implements Constraint {
	Var<Integer> x, y, z;

	public SumConstraint(Var<Integer> x, Var<Integer> y, Var<Integer> z) {
		this.x = x;
		this.y = y;
		this.z = z;
	}

	@Override
	public Collection<Var<?>> getWatchedVars() {
		return Arrays.<Var<?>> asList(x, y, z);
	}

	@Override
	public Collection<Propagator> getPropagators(boolean negate) {
		// TODO Auto-generated method stub
		return Collections.emptyList();
	}

	@Override
	public Satisfiability getSatisfiability() {
		// HashSet<Integer> intersection = new HashSet<Integer>();
		for (int xv : x.getRange()) {
			for (int yv : y.getRange()) {
				if (z.getRange().contains(xv + yv)) {
					if (z.getRange().size() == 1 && x.getRange().size() == 1
							&& y.getRange().size() == 1) {
						return Satisfiability.TAUT;
					} else {
						return Satisfiability.SAT;
					}

				}
			}
		}
		return Satisfiability.UNSAT;
	}
}