Adding the next letter to user name if samaccountname is found - powershell

Question

I am automating the new user account process from Cherwell to AD, I am stuck with duplicate samaccountname. I have successfully gotten accounts to create if the samaccountname does not already exist. I have a check in place that for now just writes the output to say whether the name is found or not.
Tinker Bell is my test user as she is my daughters favourite character.
$FirstName = “tinker”
$SurName = “bell”
for ($i = 1; $i -le $SurName.Length; ++$i) {
$Account = $null;
$Identity = $FirstName + $SurName.Substring(0,$i)
$Account = Get-ADUser -Filter {sAMAccountName -eq $Identity}
if ($Account -eq $null) {"User does not exist in AD"}
Else {"User found in AD"}
write-Output $Identity
}
I have this in place which does what it should do, I am just not sure how to stop it when the next samaccountname is created.
This is what I get as output
User found in AD
tinkerb
User does not exist in AD
tinkerbe
User does not exist in AD
tinkerbel
User does not exist in AD
tinkerbell
So it does the first part correctly, finds the account and then moves on to the next one, but then it just loops and I am not sure how to drop it out to have a variable called $newSam created when in this example 'tinkerbe' is determined.
S.

Answer 1

Turn your code into a simple function that returns the first available user name:
function New-Username
{
param(
[string]$FirstName,
[string]$SurName
)
for ($i = 1; $i -le $SurName.Length; ++$i) {
$Account = $null;
$Identity = $FirstName + $SurName.Substring(0,$i)
$Account = Get-ADUser -Filter {sAMAccountName -eq $Identity}
if ($Account -eq $null) {
return $Identity
}
else {
Write-Warning "User found in AD: $Identity"
}
}
throw "Unable to generate distinct username"
}
and the use it like:
$NewUsername = New-Username -FirstName tinker -SurName bell
New-ADUser -SAMAccountName $NewUserName