Programmatically change menu options in IntelliJ

Is it possible to programmatically change IntelliJ menu options? 

I'm looking to write a program that (initially...) uses my system clock to assess what time it is, and if it's a time that is likely to be dark (ie 9:30PM), I want to programmatically change the style/theme of Intellij to Darcula (or change to Default if not).  I have coding experience, but I'm not quite sure where to start for something like this.