Sure, it makes sense. You are right that this part of the code should be added in the ‘if (os.old_status.rain_sensed != os.status.rain_sensed)’ block because you want to make sure it only triggers the program once every time the rain sensor status changes.
I am not sure how you plan to implement run_program() and stop_program() functions. There is a ‘manual_start_program’ that’s already implemented and you can certainly make use of it. Note that since programs usually come with specified water times, so once starting they will eventually stop after the specified water times have elapsed. Therefore I am not sure what ‘stop_program’ is really doing. Perhaps you meant calling reset_all_stations there?