Powershell script to search, split and join in one line - regex

Question

Been racking my Friday brain on a regex problem with dealing with Sql Server object names.
An input to my Powershell script is a procedure name. The name can take many forms, such as
dbo.Procedure
[dbo].Procedure
dbo.[Procedure.Name]
etc
So far I'd come up with the following to split the value into it's constituent parts:
[string[]] $procNameA = $procedure.Split("(?:\.)(?=(?:[^\]]|\[[^\]]*\])*$)")
In addition I have a regex that I could use to handle the square brackets
(?:\[)*([A-Za-z0-9. !]+)(?:\])*
And this is about as far as my limited regex experience will take me.
Now granted I could deal with a lot of this by treating each element in a ForEach and doing a RegEx replace there, but y'know that just seems so, I dunno, ungainly. So, question I have for any passing Powershell & RegEx guru: "How can I do all this in one line?"
What'd I'm looking for is where I can get the following results
Original Corrected
===================== =====================
dbo.ProcName [dbo].[ProcName]
dbo.[ProcName] [dbo].[ProcName]
[dbo].ProcName [dbo].[ProcName]
[dbo].[ProcName] [dbo].[ProcName]
[My.Schema].[My.Proc] [My.Schema].[My.Proc]
[My.Schema].ProcName [MySchema].[ProcName]
dbo.[ABadBADName! [dbo].[[ABadBADName!]
(Notice the last instance where an object name starts but does not end with a square bracket (not that I'm expecting that [and if I saw anyone on my team naming an object like that I'd be asking HR if I can fire them for it], but I do like to be so thorough).
Think that covers everything...
So, over to you Powershell & RegEx gurus - how do I do this?
Please limit any answers to FULLY answering the question with code I can actually use and not just syntax suggestions.
Clarification: I am acutely aware that sometimes 'slow and steady wins the race' may apply here and that support wise it would be potentially safer to handle the rest in a ForEach, but that's not the point. Part of this is to help me understand just how flexible RegEx can be, so this is more of an educational exercise rather than a philosophical one.

Answer 1

Okay how about this:
#'
dbo.ProcName
dbo.[ProcName]
[dbo].ProcName
[dbo].[ProcName]
[My.Schema].[My.Proc]
[My.Schema].ProcName
dbo.[ABadBADName!
'# -split '\s*\r?\n\s*' | % {
$_ -replace '^(?:\[(?<schema>[^\]]+)\]|(?<schema>[^\.]+))\.(?:\[(?<proc>[^\]]+)\]|(?<proc>[^\.]+))$', '[${schema}].[${proc}]'
}
Note that I'm only using ForEach-Object (%) here to iterate through your test cases; the actual replace is done with a single regex / replace.
Explanation
So the important part here is the regex:
^(?:\[(?<schema>[^\]]+)\]|(?<schema>[^\.]+))\.(?:\[(?<proc>[^\]]+)\]|(?<proc>[^\.]+))$
Breaking it down:
^ -- match the beginning of the string
(?: -- open a non-capturing group (for alternation purposes)
\[ -- match a literal left bracket [
(?<schema> -- start a named capture group, with the name schema
[^\]]+ -- match 1 or more of any character that is not a literal right square bracket ]
) -- end the schema capture group
| -- alternation; if the previous expression didn't match, try what comes after this
(?<schema> -- again start a named capture group called schema; this is only tried if the other one didn't match.
[^\.]+ -- match 1 or more of any character that is not a literal dot .
) -- end the alternate schema capture group
) -- end the non-capturing group
\. -- match a literal dot . (this is the one separating schema and proc)
(the next part for proc is exactly the same steps as above, with a different name for the capturing group)
$ -- match the end of the string
In the replace, we just qualify the names of the groups with ${name} syntax instead of the numbers $1 (which would work too actually).