Time to refactor legacy with OOP

The article starts from a legacy statistics method that is hard to inspect and easy to get wrong. A tuple-based UTM counter swaps Answered and Activated, which produces wrong final data without a compilation error. The author then argues for removing tuples, splitting the monolithic logic, and restructuring the code with OOP.

Reading notes

#

• A 500-line static method returns many dictionaries and nested tuple structures, which makes the code hard to follow and debug.
• The reported bug comes from mixing up Answered and Activated inside a tuple, and the mistake only appears in the data output.
• The first refactoring goal is to replace tuples with classes to avoid that kind of field mix-up.
• A naïve split into several smaller methods still leaves large loops and can hurt performance by repeating passes over the same dataset.
• The proposed direction is to combine the builder pattern with iterators so the data is traversed by date in a controlled way.
• A chart builder example is used to explain the pattern before applying the same idea to mail statistics.
• In the final design, date iterators group data by month or year, and a statistics builder collects counts through actions attached to the processing flow.
• The builder uses out parameters to return the series that will later be passed into charts.
• Separate methods are used for request counts and trial activations, and the builder is chained before Process runs the accumulated logic.
• The refactoring aims to improve modularity, readability, compile-time safety, and performance while keeping the counting logic flexible.