// CSE 142, Autumn 2009, Marty Stepp
// A Snake moves in a "slithering" pattern, where he goes
// E, S, WW, S, EEE, S, WWWW, S, EEEEE, S, WWWWWW, S, ...

public class Snake extends Critter {
    private int moves;           // total moves he has made
    private int eastWestLength;  // number of total squares to walk W or E
    private int eastWestMoves;   // # moves he has currently walked W or E

    public Snake() {
        moves = 0;
        eastWestLength = 1;
        eastWestMoves = 0;
    }
    
    public Direction getMove() {
        moves++;
        if (eastWestLength % 2 == 1 && eastWestMoves < eastWestLength) {
            // he has changed W/E an even number of times (so EAST),
            // and he has not walked that way enough times yet;
            // so keep going east
            eastWestMoves++;
            return Direction.EAST;
        } else if (eastWestLength % 2 == 0 && eastWestMoves < eastWestLength) {
            // he has changed W/E an odd number of times (so WEST),
            // and he has not walked that way enough times yet;
            // so keep going west
            eastWestMoves++;
            return Direction.WEST;
        } else {
            // he has reached the end; go south, and change field values
            // so that he will start over a new east/west walk next time
            // that is 1 move longer in total length
            eastWestLength++;
            eastWestMoves = 0;
            return Direction.SOUTH;
        }
    }

    public String toString() {
        return "S";
    }
}