Parse Thai Name into First Last - sql-server

Question

I need to parse a list of FullNames into First and Last Name. If a middle name is included, it should be included in the fist name field.
John Smith would be:
FirstName = John
LastName = Smith
John J. Smith would be:
FirstName = John J.
LastName = Smith
The issue is the names might be either Thai or English character set. I need to properly parse either set. I have tried just about everything...
DECLARE #FullName NVARCHAR(MAX) = N'กล้วยไม้ สวามิวัศดุ์'
--DECLARE #FullName NVARCHAR(MAX) = N'Mark C. Wilson'
SELECT
LEN(#FullName) AS StringLength,
LEN(#FullName) - LEN(REPLACE(#FullName,N' ', N'')),
LEN(REPLACE(#FullName,N' ', N'')),
#FullName AS FullName,
REVERSE(#FullName) AS ReverseName, -- This is obviously no Reverse of the string
CHARINDEX(N' ', REVERSE(#FullName)) AS LastSpaceLocation,
CHARINDEX(N' ', #FullName) AS FirstSpaceLocation,
LEN(#FullName) AS LenString,
STUFF(#FullName, 1, CHARINDEX(N' ', #FullName), N'') as FirstName,
RIGHT(#FullName, LEN(#FullName) - CHARINDEX(N' ', #FullName) + 1) as LastName,
LEFT(#FullName, LEN(#FullName) - CHARINDEX(N' ', REVERSE(#FullName))) AS FirstName,
STUFF(RIGHT(#FullName, CHARINDEX(N' ', REVERSE(#FullName))),1,1,N'') AS LastName,
LEN(#FullName),
REVERSE(#FullName),
REVERSE(' '),
LEN(#FullName) - CHARINDEX(reverse(' '), REVERSE(#FullName)) - LEN(' ') + 1
The REVERSE simply does not work when the Thai character set is used.

Answer 1

I can't read Thai (I'm not that bright), but perhaps this may help.
Here we are using a CROSS APPLY to "fix" the string, and then it is a small matter of PasrName() and Concat()
I should add, parsing names is a slippery slope. One needs to consider
Multi Word Last Names ie De la Cruz
Suffix ie. Richard R Cappelletti MD
Example
Declare #YourTable table (FullName nvarchar(100))
Insert Into #YourTable values
('John Smith')
,('John J. Smith')
,(N'กล้วยไม้ สวามิวัศดุ์')
Select A.*
,LastName = replace(parsename(S,1),'|','.')
,FirstName = replace(concat(parsename(S,4),' '+parsename(S,3),' '+parsename(S,2)),'|','.')
From #YourTable A
Cross Apply ( values (replace(replace(FullName,'.','|'),' ','.'))) B(S)
Returns
FullName LastName FirstName
John Smith Smith John
John J. Smith Smith John J.
กล้วยไม้ สวามิวัศดุ์ สวามิวัศดุ์ กล้วยไม้
EDIT 2008 Version
Select A.*
,LastName = replace(parsename(S,1),'|','.')
,FirstName = replace( IsNull(parsename(S,4),'') + IsNull(' '+parsename(S,3),'') + IsNull(' '+parsename(S,2),''),'|','.')
From #YourTable A
Cross Apply ( values (replace(replace(FullName,'.','|'),' ','.'))) B(S)

Answer 2

I'm Thai and one thing I know is that Thai people don't do middle name.