Import-Module ActiveDirectory

$securePassword = ConvertTo-SecureString "TESTpassw0rd!" -AsPlainText -Force

$filePath = Read-Host -Prompt "Please enter the path to the CSV file that contains the new user accounts"

$users = Import-Csv $filePath

foreach ($user in $users) {
    $fname = $user.'First Name'
    $lname = $user.'Last Name'
    $jtitle = $user.'Job Title'
    $officePhone = $user.'Office Phone'
    $emailAddress = $user.'Email Address'
    $description = $user.Description
    $OUpath = $user.'Organizational Unit'

    $accountNumber = verifyUsername($user.'First Name'[0] + $user.'Last Name')
    $username = ($user.'First Name'[0] + $user.'Last Name' + $accountNumber)

    New-ADUser `
        -Name "$fname $lname $accountNumber" `
        -GivenName $fname `
        -Surname $lname `
        -UserPrincipalName $username `
        -SamAccountName $username `
        -Title $jtitle `
        -OfficePhone $officePhone `
        -EmailAddress $emailAddress `
        -Description $description `
        -Path $OUpath `
        -AccountPassword $securePassword `
        -ChangePasswordAtLogon 1 `
        -Enabled $True
}

function verifyUsername($username) {
    $i = 1

    if (userNameTaken($username) -eq $True) {
        while (userNameTaken($username + $i) -eq $True) {
            $i++
        }
        else {
            return ""
        }
        return $i
    }
}

function userNameTaken($username) {
    $test1 = Get-ADUser -Filter { userPrincipalName -eq $username }
    $test2 = Get-ADUser -Filter { samAccountName -eq $username }

    if($test1 -eq $Null -and $test2 -eq $Null) {
        return $False
    } else {
        return $True
    }
}