from letside, furthest and closest line in multiline string

[r0n]

Sorry for this simple question.

I want to get the line number of the line that is placed the most furthest away from the leftside
I want to get the line number of the line that is placed closest to the leftside
 

Code:

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         a
              b1
              b2
    c1
    c2

c1 = closest (first occurrence)
b1 = furthest (first occurrence)

The script I am using this in, will fetch selected text from anywhere where text can be selected.
This script then needs to know which line closest and which line is furthest.

Application examples: notepad, notepad++, QM,.... anywhere text can be selected.

The problem is (if tabs used) tab-values can differ from each application.
The empty leftside part of a line can contain spaces and/or tabs.

Again, sorry it seems stupid simple....I'm probably missing something.