Conditionally displaying post content

Hi, Im trying to conditionally display post content.
There is a button that is storing the preference of the user in a variable.
Once you have this variable (for example, day or night) I would like to show the content of the post depending on it.
I enclosed the post content into shortcodes.
[day] Good Morning [/day]
[night] Good Night! [/night]

So this is not about showing specific posts, but showing specific content inside a post.

Somewhat like this plugin is doing