Applescript wrap lines with HTML tags and MarsEdit.app script problem

Question

Im currently using a script in MarsEdit.app which has a flaw. It checks the HTML document for cases where paragraphs are wrapped with <p> tags as follows:

-- If already starts with <p>, don't prepend another one

if not {oneParagraph starts with "<p>"} then
           set newBodyText to newBodyText & "<p>"
end if
set newBodyText to newBodyText & oneParagraph

The problem here is that if the paragraph (or single line) is wrapped with any other HTML tag other than a <p> tag the script wraps <p> tags across the board.

Another portion of the script, which checks for ending tags at the end of the paragraph does pretty much the same thing.

-- If already ends with </p>, don't append another one

if not (oneParagraph ends with "</p>") then
    set newBodyText to newBodyText & "</p>"
end if

set newBodyText to newBodyText & return

Example:

<h5>Foobar </h5>

becomes

<p><h5>Foobar </h5></p>

In another question Applescript and "starts with" operator, @lri was kind enough to provide me a solution related to it.

on startswith(txt, l)
repeat with v in l
    if txt starts with v then return true
end repeat
false
end startswith

startswith("abc", {"a", "d", "e"}) -- true

and another of his recommendations can be found on this website as well Wrap lines with tags on applescript

Implementing these recommendations with MarsEdit.app is another issue for me.

I uploaded the entire script on pastebin. Pastebin: MarsEdit.app, wrap line with

tags script If anyone can help me edit the script to @lri's recommendations that would be great. Thanks in advance.