This is not an extremely complicated project .... I suggest starting a new forum thread .... maybe something about op-amp integrator .... Then set up an op-amp comparator to switch off the current at a desired set point, using the op-amp magnitude as one input, and the set point as the other.
This approach might get you some suggestions for specific parts .... Also, it might be a good idea to have a breadboard, so that you can build the actual circuit and check it out ... find any problems.