Re-number footnotes

Did a search here on “footnotes” with no hits.
Has anyone ever written a script that will “reflow” footnotes in a plain text document, renumbering those following a new added footnote?

For example, I may have existing text like this:

Lorem ipsum (1) lorem ipsum lorem ipsum
lorem ipsum lorem (2) ipsum lorem ipsum
lorem ipsum lorem ipsum lorem ipsum. (3)

(1) lorem ipsum lorem ipsum lorem ipsum.
(2) lorem ipsum lorem ipsum lorem ipsum.
(3) lorem ipsum lorem ipsum lorem ipsum.

…to which I wish to add in the first line another footnote as an afterthought:

Lorem ipsum (1) lorem ipsum lorem ipsum (2)
lorem ipsum lorem (2) ipsum lorem ipsum
lorem ipsum lorem ipsum lorem ipsum. (3)

(1) lorem ipsum lorem ipsum lorem ipsum.
(2) lorem ipsum lorem ipsum lorem ipsum.
(2) lorem ipsum lorem ipsum lorem ipsum.
(3) lorem ipsum lorem ipsum lorem ipsum.

I want to start at the second “(2)” and successively increment the numbers, both in the body text and in the footnote section.

I am not asking anyone to write one from scratch for me - I can figure it out.
I’m just in the middle of some writing that needs it, and my only request is if someone already happens to have one ready to go, to save me some time.
(Otherwise, be assured I’ll make mine available here whenever I get it done.)

Thanks!