Parent page or spread?

Question

I'm fiddeling around with this one and i beg for some help:
set currSelection to object reference of item 1 of selection --Script will only be used when text is marked
set parentTextFrame to item 1 of (parent text frames of currSelection)
set parentPage to parent page of parentTextFrame --Get the page
set theLine to make graphic line at parentPage with properties {geometric bounds:{A, B, C, D}, stroke color:"Linecolor", stroke weight:1}
This works fine. But only if the textbox is on a page. But often I prepare those textboxes left/right offpage on the spread for late usage – then the script doesn' work, because parent page returns nothing, and i cant just exchange that with parent spread. I dont't know how to draw the line there. Further I don't know, if a spread belongs to/has a page number: My document has more than one pages, and the line should be drawed over that marked text on the spread.
Can someone help me out?

Answer 1

I made some more adjustments, and this seems to work. I dont know exactly why, but: mates, i think we got this.
I googled some code which helped someone to create cropmarks on documents with different zero points and came to this:
set rulerOrigin to ruler origin of view preferences
  if rulerOrigin is not spread origin then set ruler origin of view preferences to spread origin --(spread origin/page origin/spine origin)
set rulerZeroPoint to zero point
  if rulerZeroPoint is not {0, 0} then set zero point to {0, 0}
--> Here I nested my code, the fetching of the coordinates (like set Y1 to baseline of first character in selection) and the drawing of the line.
--> And set it back:
set zero point to rulerZeroPoint
set ruler origin of view preferences to rulerOrigin