class MineSquare {
    boolean isMine = false;

    /** 
     * possible statuses:
     * 0 = unopened
     * 1 = marked
     * 2 = opened
     */ 
    int status = 0;
    int neighbourMines = 0;

    public boolean setMine() {
        if (isMine) {
            return false;
        } else {
            isMine = true;
            return true;
        }
    }

    public void toggleMark() {
        if (status == 0) {
            status = 1;
        } else if (status == 1) {
            status = 0;
        }
    }

    public boolean open() {
        status = 2;
        return isMine;
    }

    @Override
    public String toString() {
        switch (status) {
            case 0:
                return "[ ]";
        
            case 1:
                return "[M]";

            case 2:
                return (isMine) ? "[X]" : String.format("[%d]", neighbourMines);
            
            default:
                return "[ ]";
        }

        // return (isMine) ? "[X]" : String.format("[%d]", neighbourMines);
    }
}