perl – Regex to verify properly formatted person’s name ending with Sr or Jr

I am trying to create a Perl regular expression that will match a person’s name. When the name ends with Sr or Jr it is formatted properly with a leading comma and space, and ending with a period.

For example:

Should match:
John Smith
John Smith, Sr.
John Smith, Jr.

Should not match:
John Smith Sr
John Smith, Sr
John Smith, SR.
John Smith Sr.
John Smith, John Smith Sr.
John Smith-

Must also be properly capitalized, i.e. Sr or Jr not sr, SR, sR, jr, JR, or jR.
Name should not end with any punctuation, except for a period when Sr or Jr is used.

I tried

^(?!.(Jr|Sr)(?

But the above Regex allows for several names that are not acceptable, i.e.
John Smith,
John Smith Sr.

I then found:

^([A-Za-z]+['-]?[A-Za-z]\s)([A-Za-z]+['-]?[A-Za-z]*)(,\s(Jr|Sr).)?$ 

but it allowed name to end in a hyphen, John Smith-, which should not be acceptable.