You can use any number of methods. There isn't a preferrable one persay.
Depends on what you are familiar with and how smart you want your manager AI to be.
For instance, you could make it a rule based machine, where if something happens, it directly triggers a response. You could use a finite state machine. If you wanted to be clever and make it hard for the player, use a genetic algorithm or neural networks that can learn. or a combination of any of the above. Its really just what you are comfortable with and what you know how to use.