Undue can be fairly trivial if your data structure and controls are implemented correctly, for example a common undo redo pattern is to have an immutable structure in a vector, new operations clone the last good object, add an entry on top of the vector, and undo is to just move your reference to the previous object, redo you move it forward.

There are other patterns but this one works fairly well for simple time-travel undue / redo operations.