What should I say/not say?
When you get to the Court today, the prosecutor may have the disclosure for you. If so, he or she will give it to you. The prosecutor will probably also offer you a deal. You can ask for a little time to review the disclosure, in which case the prosecutor will probably deal with the next couple of people before getting back to you. You can always refuse the deal, but you run the risk that the prosecutor will not make you the same offer the day of the trial. That will depend on how many trials are scheduled that day, the prosecutor's mood, how good the offer was in the first place and any other factors that arise that day.
If the prosecutor doesn't have the disclosure, it will be easier for you to achieve your goal. The prosecutor may make you an offer anyway, but you can easily say that you're not in a position to decide whether to accept it until you've seen the disclosure. Remember that it's your obligation to follow up on disclosure. If it's been more than a couple of weeks since you were supposed to receive it, the prosecutor may say you should have followed up.