/**
 * A position on the on the sudoku board.
 * This captures the value at that position as well as the 
 * possible values that the position could have
 * @author gtowell
 * Created: Oct 2020
 * Modified: Oct 2021
 */
public class Spot {
    int value; // the number in the location. 
    // 0 is empty
    boolean[] legalMoves; // an array of legal moves.  Only meaningful
    // when value is 0

    public Spot() {
        value=0;
        legalMoves = new boolean[9];
    }

    // make a spot with this value. 
    public Spot(int ival) {
        this();
        value = ival;
    }
    
    // copy constructor
    // but only copy the value, not the legal moves
    public Spot(Spot oldSpot) {
        this();
        value=oldSpot.value;
    }
    
    // what is says.
    public void clearLegal() {
        for (int i=0; i<9; i++)
            legalMoves[i]=true;
    }

    public String toString() {
        if (value>0)
            return ""+value;
        StringBuffer sb = new StringBuffer();
        sb.append("-[");
        for (int i=0; i<9; i++) {
            if (legalMoves[i]) {
                sb.append(" ");
                sb.append(i+1);
            }
        }
        sb.append("]");
        return sb.toString();
    }
}