How to detect () and automatically change the citation style?

Many journals require such a citation style:

if the citation appears in a pair of brackets, the citation itself should drop brackets, like:

This is an example (e.g., Norman 1977 argues that .....)

Otherwise, include brackets around year in citation:

Norman (1977) argues that .....

I’m wondering if Endnote can detect whether the citation is within a pair of brackets and change the citation style automatically. If yes, how can I modify the syle file to fit that.

Thanks!

Not automatically. 

In the first case, there is no way to automatically drop the parentheses, but if you edit citation you can add the prefix text and suffix text in the citation itself.  so the prefix would be "e.g., "followed by a space and the suffix would be “argues that …”.  The only caveate is that the indroduced text can not have any formating such as italics.  If you have fancy text than you can edit the citation so that no author or year appear (exclude both in the edit citation options) and type exactly how you want it to appear.  Your citation in this case would be “invisible”, unless you unformat the citation. 

For the second example,  you can hide the author in the formated citation (right click and edit citation to exclude author) and then type in the author’s name in the form you wish.