Adding line counter to a text field

Question

I want to add a line counter to a textfield for a sort of text editor. Looking around, I've seen that a lot of questions on this topic are either unanswered, or do not answer in a satisfactory manner. Something like this How to add prefix widget on every new line in textfield in flutter? asks fundamentally the same question I am, however the only answer there is to create a new widget for each line.

This is one method that could be used, where I add new textfields in a list and build them in a row with their respective line number. However, this means I cannot have those textfields function on more than one line, and I will need to add more textfields each time a user wants to add enough text to make it overflow. The biggest flaw I see with this, though, is that it makes it harder (if not impossible?) to easily select and edit text as you would expect from a text editor, such as using the built in systems for a textfield.

Now, for my solution I am using https://pub.dev/packages/extended_text_field as a way to gain some functionality that I don't really want to take the time to figure out how to do on my own (embedded onClick callbacks for text), so it would be ideal if I could continue to use that without having to fork or even have to figure out how to write my own version.

The primary issue I'm running into is not necessarily getting the number of lines, which can be found using some solutions from How can I add line numbers to TextField on Flutter?, but rather how and where to show those line numbers.

As above, it's not really ideal to pair some number alongside a textfield and create a new textfield for each expected line. What would be ideal, however, is something like , where each line number is prefixed to the line built by the text field. For example, like this: . Something like the solution proposed in Add a prefix to every line in a multiline Text Input in Flutter? would not work especially well, because the solution there is to literally add string values to the textfield, which would require systems to clean the text, in addition to causing an unexpected ability to actually change the numbers (or other line prefix) by the user.

So -- is there any way to implement a line prefix for each line in a textfield? Would it be possible to override an InputDecoration (which allows creating the individual line prefix, but nothing more) to create a line prefix for each line drawn by the textfield? If not, exactly what would be needed to create this? I am familiar with flutter, but I am not quite as familiar with the lower level API's.