How to get Brightness/Contrast levels of a layer, using .jsx Adobe Photoshop scripting?

I have a .jsx Photoshop script workflow that begins by first applying a Brightness/Contrast adjustment to the current image, then uses the "Auto" setting.

For the next step, I'd like to get the properties of that Brightness/Contrast layer, and then IF the brightness meets a certain criteria? Change the brightness to some other value. Same for the contrast.

What's the best way to automate this in my .jsx file?

Thanks!