Regular expression to match optional patterns

I know that Regex is a pretty hot topic and that there's a plethora of similar questions, however, I have not found one which matches my needs.

I need to check the formatting of my string to be as follows:

All line must start with 5 digits.
Characters 6 to 12 must be white space.
Character 13 must be either white space or asterisk.
if there is any period, colon or semicolon before the final period, the character must not be preceded by a white space, but it must be followed by a white space.
opening parentheses cannot be followed by a white space.
closing parentheses cannot be preceded by a white space.

I haven't tried to implement the colon, semicolon or parentheses, but so far I'm stuck at just the period. These characters are optional so I can't make a hard check, and I'm trying to catch them but I'm still getting a match in a case like

00000      *TEST .FINAL STATEMENT. //Matches, but it shouldn't match.
00001      *TEST2 . FINAL STATEMENT. //Matches, but it shouldn't match.
00002      *TEST3. FINAL STATEMENT. //Matches, **should** match.

This is the regex I have so far:

^\d{5}\s{6}[\s\*][^.]*([^.\s]+\.\s)?[^.]*\..*$

I really don't see how this is happening, especially because I'm using [^.] to indicate I'll accept anything except a period as a wildcard, and the optional pattern looks correct at a glance: If there's a period, it should not have white space behind it and it should have white space after it.

Solution

Try this:

^\d{5}\s{6}[\s\*]   # Your original pattern
(?:                 # Repeat 0 or more times:
  [^.:;()]*|        # Unconstrained characters
  (?<!\s)[.:;](?=\s)|    # Punctuation after non-space, followed by space
  \((?!\s)|         # Opening parentheses not followed by space
  (?<!\s)\)         # Closing parentheses not preceeded by space
)*
\.$                 # Period, then end of string

https://regex101.com/r/WwpssV/1

In the last part of the pattern, the characters with special requirements are .:;(), so use a negative character set to match anything but those characters: [^.:;()]* Then alternate with:

if there is any period, colon or semicolon before the final period, the character must not be preceded by a white space, but it must be followed by a white space.

Fulfilled by (?<!\s)[.:;](?=\s) - match one of those characters only if not preceded by a space, and if followed by a space.

opening parentheses cannot be followed by a white space.

Fulfilled by \((?!\s)

closing parentheses cannot be preceded by a white space.

Fulfilled by (?<!\s)\)

Then just alternate between those 4 possibilities at the end of the pattern.