Variables in an action to use in script

Question

I want to duplicate an image, then change the duplicated image name to the original image name with some extra text at the end to make it slightly different.
Example.
Original..    Image123
Duplicate...  Image123BW. Or Image123BG. etc.
So as not to have to have a separate script for each different text addition I wondered if I can have a variable in the action that can be passed to the script to add to the new document name?

Answer 1

Code to duplicate document:
var doc = app.activeDocument
var fname = doc.name.split(".")
var fname = fname[0]
var ToneType = 'BW'
var newDoc = doc.duplicate(fname+ToneType,true)
//var newDoc = doc.duplicate(fname,true)
newDoc.flatten();
I have 3 actions that I want to use the script for. One action to make a B&W (BW), one for Sepia (SP), one for Warm B&W (WBW). If I use the above code it will just duplicate the document with the same name, adding the hardcoded ToneType to the end of the document name. I could make three scripts, one for each, but I thought if I could have a variable (ToneType = 'BW') for example, that would pass to the script then I could only use one script that would change depending on the variable name that was in the action.
This code will just duplicate the document without the text  COPY  at the end but I need to make one for each ToneType I have. Maybe that's the easiest way but I like to make a script with multiple uses.
When you suggested that rename the active layer with a specific name, I can rename the background layer to  BW  for example, but at the end I still need to rename the file with the   BW . I can script the part to add the active layer to the document name but can't figure out how to replace the name when the script goes back to Photoshop.  I know something is missing in this code that will replace the active documents name. Just not sure what.
this is the code for that try:
//replace name of current document with document name + active layer name
layerN = activeDocument.activeLayer.name
var doc = app.activeDocument
var fname = doc.name.split(".")
var fname = fname[0]
app.activeDocument.name = (fname+layerN,true)
Thanks for any help!