Refactor: Command: Purge - Reduce Cognitive Complexity

[ctsstc]

Currently the purge command is contained all in a single method with a lot of if blocks and nested logic.

Code Climate reports this file to have a cognitive complexity of 9 out of threshold of 5.

After getting tests in place for it from issue #31 & PR #107 this should be refactored to reduce the complexity. We should be able to accomplish this by splitting logic out into additional methods and trying to reduce nested if statements if possible.

The pain is not knowing how to test the cognitive complexity locally, so we'll have to push it up to see what code climate things about it unfortunately.