Sorry, seen this only now. Yep, I do consider these states, and yes, I am aware that trying to scale up to a "simple" rule engine is a huge effort. Personally

Sorry, seen this only now. Yep, I do consider these states, and yes, I am aware that trying to scale up to a "simple" rule engine is a huge effort. Personally I always worked with relatively simple state machines and always wrote actual code to handle new cases or edge conditions that were not in the original design. As a tool (and at the tactical level), these work fine. Making these an overarching paradigm for your whole system, and especially adding a rule engine is something I never did and I would be wary to try, personally.