[PowerShell] Get-SamAccountName

Function Get-SamAccountName {

    [cmdletbinding()]

    param(
        [String]
        $FirstName,

        [String]
        $LastName
    )

    If($FirstName -eq $null -and $LastName -eq $null){
        Write-Host "FirstName and LastName cannot both be empty." -ForegroundColor Red
        Break
    }

    $FirstNameWild = "*$FirstName*"
    $LastNameWild = "*$LastName*"

    If($FirstName -and $LastName){
        $users = Get-ADUser -Filter {Givenname -like $FirstName -and Surname -like $LastName -and Enabled -eq $true}
        If($users -eq $null){
            $users = Get-ADUser -Filter {Givenname -like $FirstNameWild -and Surname -like $LastNameWild -and Enabled -eq $true}
            If($users -eq $null){
                Write-Host "No active users found with name $FirstName $LastName."
                Break
            }
        }
        $users | Sort-Object Surname | Select-Object SamAccountName, @{Name="FirstName";Expression={$_.Givenname}}, @{Name="LastName";Expression={$_.Surname}}
        Return
    }

    If($FirstName){
        $users = Get-ADUser -Filter {Givenname -like $FirstName -and Enabled -eq $true}
        If($users -eq $null){
            $users = Get-ADUser -Filter {Givenname -like $FirstNameWild -and Enabled -eq $true}
            If($users -eq $null){
                Write-Host "No active users found with name $FirstName."
                Break
            }
        }
        $users | Sort-Object Surname | Select-Object SamAccountName, @{Name="FirstName";Expression={$_.Givenname}}, @{Name="LastName";Expression={$_.Surname}}
        Return
    }

    If($LastName){
        $users = Get-ADUser -Filter {Surname -like $LastName -and Enabled -eq $true}
        If($users -eq $null){
            $users = Get-ADUser -Filter {Surname -like $LastNameWild -and Enabled -eq $true}
            If($users -eq $null){
                Write-Host "No active users found with name $LastName."
                Break
            }
        }
        $users | Sort-Object Surname | Select-Object SamAccountName, @{Name="FirstName";Expression={$_.Givenname}}, @{Name="LastName";Expression={$_.Surname}}
        Return
    }
}