package searchproblem;
import java.util.*;

public class SearchProblem {
	protected State initial;
	protected Set<State> goalStates;
	
	public SearchProblem(State initial) {
		this.initial = initial;
		this.goalStates = null;
	}

	public SearchProblem(State initial, Set<State> goals) {
		this.initial = initial;
		this.goalStates = goals;
	}
	
	public SearchProblem(State initial, State goal) {
		this.initial = initial;
		this.goalStates = new HashSet<State>(1);
		this.goalStates.add(goal);
	}
		
	public boolean goalTest(State n) {
		if( goalStates != null )
			return goalStates.contains(n);
		else
			return false;
	}
		
	public State getInitial() {
		return initial;
	}
	
	public double heuristic(State n) {
		double d, h=Double.MAX_VALUE;
		if( goalStates != null ) {
			for (State g:  goalStates) {
				d = n.location.straightLineDistance(g.location);
				if (d<h) h = d;
			}
			return h;
		}
		return 0;
	}

}