not very smart to make a promotional video and share details for a book you haven't written yet....

And advertising your works isn't really permitted on the forums without permission. However, since you haven't written it yet, I would assume this is fine. Just giving you a heads up for future reference.

Here's a tip - write it before you tell people what it's about. Otherwise, you stand to lose the concept to someone else who's better prepared to get it written in double-quick time, then publish it using a pre-established network of professional connections.

I should know - I wrote a screenplay once, sent it off to publishers (without establishing legal rights to the formula) - next thing I know, six months later, someone ripped off the concept and started making a big-budget adaptation of my idea. B'stards. It put me off the industry for quite some time.

Get it written, get it legally defined as yours by a solicitor/ attorney, and then make sure that your network of production companies/ publishers is respected by other writers, before showing it to ANYONE.