How to duplicate an entire Wordpress site?

At first glance I thought this would be really simple to do but I haven't found a simple solution after some time.

So here's what I'm trying to do.

We have an existing site on mysite.com

We're doing a revamp and this is an active site so we did the revamp on mysite.com/revamp

The revamp is complete and we would like to duplicate the entire mysite.com/revamp onto mysite.com

Obviously EVERYTHING has to be duplicated, including images, layouts, custom CSS, EVERYTHING.

I can't believe I can't find a simple way to do this, can someone enlighten me please?

Thank you!